The authors are grateful to the Andrology Laboratory of the Center for Reproductive Medicine, the Third Affiliated Hospital of Sun Yat-sen University, for providing the facilities for this study. No funding was involved in the preparation of this article.

This study has been reviewed and approved by the Medical Ethics Committee of The Third Affiliated Hospital of Sun Yat-sen University.
1. Preparation of the working solution
<ol>
	<li>Gather the following reagents essential for preparing the working solution- ortho-toluidine substrate solution, saturated ammonium chloride (NH4Cl) solution, 148 mmol/L ethylenediaminetetraacetic acid disodium salt (Na2EDTA) solution, and 6% (v/v) hydrogen peroxide solution. Place them on a room temperature (RT) lab bench along with the necessary tools, such as transfer pipettes (1000 &#181;L, 200 &#181;L, 10 &#181;L) and test tube racks. 
	CAUTION: Read the safety data sheet (SDS) before handling the above-mentioned reagents.</li>
	<li>Prepare an opaque brown reagent bottle to store and protect the prepared working solution from exposure to light.</li>
	<li>Transfer the reagents into the opaque brown reagent bottle as per the proportions specified below:
	<ol>
		<li>Utilize the 200 &#181;L transfer pipette and adjust the scale to 100 &#181;L by turning the knob. Then, transfer 100 &#181;L of the NH4Cl solution into the opaque brown reagent bottle.</li>
		<li>Replace the pipette tip and transfer 100 &#181;L of the 148 mmol/L Na2EDTA solution into the opaque brown reagent bottle using the 200 &#181;L transfer pipette mentioned above. Then, gently blow by pipetting and thoroughly homogenize the solution.</li>
		<li>Utilize the 1000 &#181;L transfer pipette and adjust the scale to 900 &#181;L by turning the knob. Then, transfer 900 &#181;L of the ortho-toluidine substrate solution into the opaque brown reagent bottle, gently blow by pipetting, and thoroughly homogenize the solution.</li>
		<li>Utilize the 10 &#181;L transfer pipette and adjust the scale to 5 &#181;L by turning the knob. Then, transfer 5 &#181;L of the 6% (v/v) hydrogen peroxide solution into the opaque brown reagent bottle.</li>
	</ol>
	</li>
	<li>Utilize the 1000 &#181;L transfer pipette and adjust the scale to 1000 &#181;L by turning the knob. Replace the pipette tip, gently blow by pipetting, and thoroughly homogenize the solution in the opaque brown reagent bottle.</li>
	<li>Store the ready-to-utilize working solution in the opaque brown reagent bottle at RT, away from light. The working solution is reactive for 24 h.</li>
	<li>Each semen sample requires 900 &#181;L of the working solution. Ensure that the quantity of the working solution prepared each day corresponds to the number of samples examined daily.</li>
</ol>
2. Preparation of semen sample
<ol>
	<li>Before collecting the semen sample, ensure the patient has abstained from ejaculation for 2 to 7 days as required by the World Health Organization (WHO) laboratory manual for examining and processing human semen (5th ed.)8. Masturbation is the preferred method for obtaining semen samples. To improve the accuracy of the examination, instruct the patient to collect all ejaculated semen.</li>
	<li>Turn on the constant temperature stand and heat up to 37 &#176;C in advance so that the subsequent liquefaction of the semen sample can proceed smoothly.</li>
	<li>Upon receipt of the patient&#39;s semen sample, meticulously record detailed information, including identification code, collection time, abstinence duration, and other pertinent information, on the outer wall of the polymer-based receptacle.</li>
	<li>Place the polymer-based receptacle housing the semen sample on the constant temperature stand preheated to 37 &#176;C, which is beneficial for the semen liquefaction.</li>
	<li>Draw the semen sample into a polymer-based pipette and observe the state of liquefaction every 5 min until the semen sample is fully liquefied.</li>
	<li>If the semen sample has not been fully liquefied within 30 min, do not perform the examination yet; continue to wait for another 30 min. If the semen is still not fully liquefied after 60 min, add an equal volume of phosphate buffer solution for a 1:1 dilution and gently agitate to promote liquefaction.</li>
	<li>After thorough agitation and consistent homogenizing, retain the fully liquefied semen sample for the subsequent examination procedures.</li>
</ol>
3. Staining of the peroxidase-positive leukocytes and analyzing the original semen sample
<ol>
	<li>Prior to sampling, utilize a polymer-based pipette to repeatedly blow by pipetting and thoroughly homogenize the semen sample under examination.</li>
	<li>Utilize the 200 &#181;L transfer pipette and adjust the scale to 100 &#181;L by turning the knob. Replace the pipette tip, and then transfer 100 &#181;L of the semen sample into a centrifuge tube.</li>
	<li>Utilize the 1000 &#181;L transfer pipette and adjust the scale to 900 &#181;L by turning the knob. Replace the pipette tip, then transfer 900 &#181;L of the above-mentioned working solution into the centrifuge tube.</li>
	<li>Repeatedly blow by pipetting and thoroughly homogenize the reactant, which consists of the semen sample and working solution, using the 1000 &#181;L transfer pipette.</li>
	<li>Position the centrifuge tube into a test-tube rack upon a two-dimensional shaker and subject it to continuous agitation at 200 rpm for 30 min at RT.</li>
	<li>While waiting for the staining reaction, analyze the semen sample utilizing the CASA system to determine the concentration of spermatozoa in the original semen sample in the polymer-based receptacle.
	<ol>
		<li>Turn on the power switch of the CASA system and double-click the SCA SCOPE icon to open the application software.</li>
		<li>Before sampling, repeatedly blow by pipetting and thoroughly homogenize the original semen sample again with a polymer-based pipette.</li>
		<li>Utilize the 10 &#181;L transfer pipette and adjust the scale to 10 &#181;L by turning the knob. Replace the pipette tip, pipette up 10 &#181;L of the original semen sample, and place it into the SCA counting chamber. Wait for 60 s for the semen sample to stop drifting.</li>
		<li>Position the SCA counting chamber onto the sample holder of the CASA system and set the patient&#39;s information in the dialog box of the application software to prepare for the formal examination.</li>
		<li>Examine the original semen sample in the SCA counting chamber with the CASA system by clicking the Start button and record the necessary data, such as the concentration of spermatozoa.</li>
	</ol>
	</li>
</ol>
4. Observation of the peroxidase-positive leukocytes and spermatozoa
<ol>
	<li>Utilize the 1000 &#181;L transfer pipette and adjust the scale to 1000 &#181;L by turning the knob. Replace the pipette tip, then repeatedly blow by pipetting and thoroughly homogenize the reactant, which consists of semen sample and working solution in the centrifuge tube again at the end of the 30 min reaction process.</li>
	<li>Utilize the 10 &#181;L transfer pipette and adjust the scale to 10 &#181;L by turning the knob. Replace the pipette tip, pipette up 10 &#181;L of the reactant mentioned above, and place it into the sperm counting chamber. Finally, cover the sperm counting chamber with a dedicated glass coverslip.</li>
	<li>Place the sperm counting chamber onto the microscopic stage and turn on the power switch of the optical microscope with two 10x eyepieces. Then, wait for 60 s for the reactant sample to stop drifting.</li>
	<li>Switch the microscopic converter to the 10x objective lens during the waiting time. Then adjust the coarse adjustment knob and the fine adjustment knob in sequence. Finally, observe the spermatozoa and round cells under a magnification of 10&#215;10.</li>
	<li>Switch the microscopic converter to the 40x objective lens after determining the field of view to be analyzed, and observe the spermatozoa and brown peroxidase-positive leukocytes under a magnification of 10 &#215; 40.</li>
	<li>Utilize the electronic counter system to count at least 200 spermatozoa and the number of brown peroxidase-positive leukocytes within the corresponding fields.</li>
</ol>
5. Calculation of the concentration of peroxidase-positive leukocytes
<ol>
	<li>Calculate the concentration of peroxidase-positive leukocytes through the using the following formula: 
	<img alt="Equation 1" src="/files/ftp_upload/66211/66211eq01v2.jpg" style="margin: auto;" /></li>
</ol>

Analysis of Semen for Peroxidase-Positive Leukocyte Cells

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	<li>Agarwal, A., Mulgund, A., Hamada, A., Chyatte, M. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+unique+view+on+male+infertility+around+the+globe.">A unique view on male infertility around the globe.</a> Reprod Biol Endocrinol. 13, 37 (2015).</li><li>Sharlip, I. D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Best+practice+policies+for+male+infertility.">Best practice policies for male infertility.</a> Fertil Steril. 77 (5), 873-882 (2002).</li><li>Choy, J. T., Eisenberg, M. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Male+infertility+as+a+window+to+health.">Male infertility as a window to health.</a> Fertil Steril. 110 (5), 810-814 (2018).</li><li>Pellati, D., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Genital+tract+infections+and+infertility.">Genital tract infections and infertility.</a> Eur J Obstet Gynecol Reprod Biol. 140 (1), 3-11 (2008).</li><li>Rivero, M. J., Kulkarni, N., Thirumavalavan, N., Ramasamy, R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+and+management+of+male+genital+tract+infections+in+the+setting+of+male+infertility:+an+updated+review.">Evaluation and management of male genital tract infections in the setting of male infertility: an updated review.</a> Curr Opin Urol. 33 (3), 180-186 (2023).</li><li>Long, S., Kenworthy, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Round+cells+in+diagnostic+semen+analysis:+A+guide+for+laboratories+and+clinicians.">Round cells in diagnostic semen analysis: A guide for laboratories and clinicians.</a> Br J Biomed Sci. 79, 10129 (2022).</li><li>Johanisson, E., Campana, A., Luthi, R., de Agostini, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Evaluation+of+'round+cells'+in+semen+analysis:+a+comparative+study.">Evaluation of 'round cells' in semen analysis: a comparative study.</a> Hum Reprod Update. 6 (4), 404-412 (2000).</li><li>World Health Organization. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=WHO+Laboratory+Manual+for+the+Examination+and+Processing+of+Human+Semen.+5th+edn.">WHO Laboratory Manual for the Examination and Processing of Human Semen. 5th edn.</a> World Health Organization. , (2010).</li><li>Domes, T., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+incidence+and+effect+of+bacteriospermia+and+elevated+seminal+leukocytes+on+semen+parameters.">The incidence and effect of bacteriospermia and elevated seminal leukocytes on semen parameters.</a> Fertil Steril. 97 (5), 1050-1055 (2012).</li><li>Aziz, N., Agarwal, A., Lewis-Jones, I., Sharma, R. K., Thomas, A. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+associations+between+specific+sperm+morphological+defects+and+leukocytospermia.">Novel associations between specific sperm morphological defects and leukocytospermia.</a> Fertil Steril. 82 (3), 621-627 (2004).</li><li>Alahmar, A. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Role+of+oxidative+stress+in+male+infertility:+An+updated+review.">Role of oxidative stress in male infertility: An updated review.</a> J Hum Reprod Sci. 12 (1), 4-18 (2019).</li><li>Schlegel, P. N., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Diagnosis+and+treatment+of+infertility+in+men:+AUA/ASRM+guideline+Part+I.">Diagnosis and treatment of infertility in men: AUA/ASRM guideline Part I.</a> J Urol. 205 (1), 36-43 (2021).</li><li>Ricci, G., Presani, G., Guaschino, S., Simeone, R., Perticarari, S. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Leukocyte+detection+in+human+semen+using+flow+cytometry.">Leukocyte detection in human semen using flow cytometry.</a> Hum Reprod. 15 (6), 1329-1337 (2000).</li><li>Brunner, R. J., Demeter, J. H., Sindhwani, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Review+of+guidelines+for+the+evaluation+and+treatment+of+leukocytospermia+in+male+infertility.">Review of guidelines for the evaluation and treatment of leukocytospermia in male infertility.</a> World J Mens Health. 37 (2), 128-137 (2019).</li><li>Amulic, B., Cazalet, C., Hayes, G. L., Metzler, K. D., Zychlinsky, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neutrophil+function:+from+mechanisms+to+disease.">Neutrophil function: from mechanisms to disease.</a> Annu Rev Immunol. 30, 459-489 (2012).</li><li>Khan, A. A., Alsahli, M. A., Rahmani, A. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myeloperoxidase+as+an+active+disease+biomarker:+recent+biochemical+and+pathological+perspectives.">Myeloperoxidase as an active disease biomarker: recent biochemical and pathological perspectives.</a> Med Sci (Basel). 6 (2), 33 (2018).</li><li>Khan, A. A., Rahmani, A. H., Aldebasi, Y. H., Aly, S. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Biochemical+and+pathological+studies+on+peroxidases+-an+updated+review).">Biochemical and pathological studies on peroxidases -an updated review).</a> Glob J Health Sci. 6 (5), 87-98 (2014).</li><li>Liu, W. Q., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myeloperoxidase-derived+hypochlorous+acid+promotes+ox-LDL-induced+senescence+of+endothelial+cells+through+a+mechanism+involving+beta-catenin+signaling+in+hyperlipidemia.">Myeloperoxidase-derived hypochlorous acid promotes ox-LDL-induced senescence of endothelial cells through a mechanism involving beta-catenin signaling in hyperlipidemia.</a> Biochem Biophys Res Commun. 467 (4), 859-865 (2015).</li><li>Nicholls, S. J., Hazen, S. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Myeloperoxidase+and+cardiovascular+disease.">Myeloperoxidase and cardiovascular disease.</a> Arterioscler Thromb Vasc Biol. 25 (6), 1102-1111 (2005).</li><li>Wolff, H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+biologic+significance+of+white+blood+cells+in+semen.">The biologic significance of white blood cells in semen.</a> Fertil Steril. 63 (6), 1143-1157 (1995).</li><li>Chen, Y., Hashiguchi, N., Yip, L., Junger, W. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Hypertonic+saline+enhances+neutrophil+elastase+release+through+activation+of+P2+and+A3+receptors.">Hypertonic saline enhances neutrophil elastase release through activation of P2 and A3 receptors.</a> Am J Physiol Cell Physiol. 290 (4), C1051-C1059 (2006).</li><li>Weiss, S. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Tissue+destruction+by+neutrophils.">Tissue destruction by neutrophils.</a> N Engl J Med. 320 (6), 365-376 (1989).</li></ol>

The authors have nothing to disclose.

Ortho-toluidine and hydrogen peroxide have photosensitive properties and can decompose when exposed to light. To ensure the effectiveness of the test reagents, it is recommended that the prepared working fluid be stored in a dark place. 
Semen samples naturally exhibit heterogeneous characteristics. In the preparation process of semen samples, correctly judging the liquefaction state of semen and thoroughly homogenizing the semen samples before each sampling are crucial for improving the reliability of the test results. Semen samples liquefy completely within 15 min. Mechanical homogenizing or enzymatic digestion should be considered if they have not completely liquefied after 60 min. More homogeneous semen samples can be obtained by gently shaking the sample container continuously during the liquefaction process using a two-dimensional shaker8.
The examination method presented in this paper possesses the advantages of simplicity, speed, and cost-effectiveness. However, it may not be advantageous under certain circumstances: peroxidase is stored in azurophilic granules that will be secreted into the intercellular space through degranulation or cytopempsis upon activation21,22. Consequently, neutrophils may fail to stain and cannot be identified. In such cases, repeating the staining process or even requiring the patient to provide a new semen sample for re-examination becomes necessary. To minimize this situation, it is recommended to utilize fresh semen samples whenever possible with minimal placement time and a gentle homogenizing process. This method can only identify active diseases or infections and cannot identify diseases in later stages, such as chronic infections16. Additionally, other types of leukocytes with lower peroxidase content, such as lymphocytes, macrophages, and monocytes, pose difficulties in staining using this method; hence, obtaining reliable results can be achieved by employing leukocyte antigen (e.g., CD45) immunohistochemical staining.
As required by the 5th edition of the WHO manual, traditional positive myeloperoxidase staining (Endtz test) requires microscopic counting of at least 200 peroxidase-positive leukocytes in a blood cell count plate to calculate their concentration8. Compared to the traditional manual Endtz test, this protocol introduces the spermatozoa concentration data obtained by CASA detection, combining manual and automatic methods. To calculate the concentration of peroxidase-positive leukocytes, at least 200 spermatozoa and leukocytes in the corresponding field of view were counted under a microscope. Since the concentration of spermatozoa in semen is much greater than that of leukocytes, less time was required to count 200 spermatozoa compared to counting 200 peroxidase-positive leukocytes.
Patients with severe oligospermia, cryptozoospermia, and azoospermia often face challenges in counting a sufficient number of spermatozoa. In such cases, the concentration of peroxidase-positive leukocytes can be directly calculated using a blood cell counting plate as described in the manual for the plate. Additionally, for patients who do not require CASA or laboratories without CASA equipment, a blood cell counting plate can also be utilized to determine the concentration of peroxidase-positive leukocytes.

Infertility has emerged as a global public health issue affecting approximately 15% of couples in their reproductive age. Male factors are contributed by around 50% of total subfertility cases, and nearly 20% to 30% can be attributed solely to male factors1,2,3. Male genital tract infections (MGTIs) constitute one of the significant causes of male infertility, accounting for about 15% of cases4,5.
Most individuals have leukocytes in their semen, constituting 13% of non-spermatozoan cells, with differential proportions being neutrophils 12%, macrophages 0.9%, and lymphocytes 0.1%6,7. According to the World Health Organization (WHO) laboratory manual for the examination and processing of human semen (5th ed.), leukocytospermia is usually defined as the presence of &#62;1 &#215; 106 cells/mL leucocytes in semen8. This condition can be caused by numerous factors such as environmental toxins, substance abuse, varicoceles, MGTIs, etc., all potentially leading to an abnormal increase in leukocyte concentration in semen9. Leukocytes can elevate reactive oxygen species (ROS) levels in semen, causing lipid peroxidation and oxidative damage to protein and DNA, which results in decreased spermatozoa motility, increased spermatozoa morphological abnormalities, elevated spermatozoa DNA fragmentation index, impairment of the spermatozoa acrosome function, and even negative impacts on embryo development10,11.
Currently, andrologists commonly choose to examine round cells in semen or elastase in seminal plasma when identifying genital tract inflammation. However, it&#39;s often challenging to distinguish sloughed spermatogenic cells and reproductive tract epithelial cells, which do not contribute to reducing the indiscriminate and unnecessary use of antibiotics6. The latter examination method is relatively complicated and time-consuming, with slow result reporting, which is not beneficial for early diagnosis and treatment of diseases such as MGTIs. The American Urological Association (AUA) suggests further differentiation between leukocytes and sloughed cells from the genital tract should be made when the round cell concentration in semen analysis is greater than 1 &#215; 106 cells/mL12. Some andrology labs utilize flow cytometry13 or leukocyte antigen (e.g., CD45) immunocytochemistry14 to examine leukocytes. While these methods are precise, they are expensive and time-consuming, making large-scale clinical implementation difficult, especially in developing countries.
Peroxidase is widely distributed in various types of cells and plays a crucial role in the resistance to oxidative stress damage. Myeloperoxidase (MPO) is a member of the peroxidase subfamily that is generally expressed in immune cells. It is most highly expressed in neutrophils&#39; azurophilic granules15,16 and is also expressed in lymphocytes17,18, monocytes, and macrophages19. The concentration of leukocytes, especially neutrophils, in semen can be obtained by examining round cells that are peroxidase-positive7,20. To make the examination process of leukocytes in semen economical, convenient, and efficient, we reengineered the examination method. Assisted by the computer-assisted semen analysis (CASA) system, the concentration of leukocytes can be obtained within 60 min. This new method reduces the patients&#39; examination costs and waiting time for obtaining results, alleviates the workload of lab technicians, and shortens the doctor&#39;s diagnosis and treatment waiting period.

<table><tbody><tr><td>148 mmol/L ethylenediamine tetraacetic acid disodium (Na&lt;sub&gt;2&lt;/sub&gt;EDTA) solution</td><td>ShenZhen HuaKang Biomedical Engineering Co.,LTD</td><td>20230301</td><td>Agentia B</td></tr><tr><td>6% (v/v) hydrogen peroxide solution</td><td>ShenZhen HuaKang Biomedical Engineering Co.,LTD</td><td>20230301</td><td>Agentia D</td></tr><tr><td>Automatic Sperm Class Analyzer &amp;ndash; SCA SCOPE&amp;nbsp;</td><td>Microptic S.L.</td><td>1222996; Model type: SCA-SCOPE-H</td><td>Computer-Assisted Semen Analysis (CASA) equipment</td></tr><tr><td>Disposable centrifugal tube (1.5 mL)</td><td>Zhejiang Gongdong Medical Equipment Co., LTD</td><td>2210009</td><td>Centrifugal tube for Staining process</td></tr><tr><td>Disposable transfer pipette (3 mL)</td><td>Jiangsu Kangjian Medical Supplies Co., LTD</td><td>20221101</td><td>Polymer-based pipette</td></tr><tr><td>Electronic counter</td><td>None</td><td>None</td><td>A multichannel counter</td></tr><tr><td>Electronic scales</td><td>Shanghai Liangping Instrument Co., LTD</td><td>D9008084</td><td>MAX = 100 g, e = 10 d, d = 0.01 g</td></tr><tr><td>Makler counting chamber</td><td>Makler</td><td>MQ30004</td><td>0.01 sq.mm, 10 &amp;mu;m deep</td></tr><tr><td>Optical microscope</td><td>Olympus</td><td>3G41067201307</td><td>CX31, 10&amp;times;40</td></tr><tr><td>Ortho-toluidine substrate solution</td><td>ShenZhen HuaKang Biomedical Engineering Co.,LTD</td><td>20230301</td><td>Agentia C</td></tr><tr><td>Pipet tips(1 mL)</td><td>Coming Life Sciences (Wujiang) Co.,Ltd</td><td>02923205</td><td>1000 tips/unit, 5 units/case</td></tr><tr><td>Pipet tips(10 &amp;micro;L)</td><td>Coming Life Sciences (Wujiang) Co.,Ltd</td><td>00323961</td><td>1000 tips/unit, 20 units/case</td></tr><tr><td>Pipet tips(200 &amp;micro;L)</td><td>Coming Life Sciences (Wujiang) Co.,Ltd</td><td>32822810</td><td>1000 tips/unit, 20 units/case</td></tr><tr><td>Saturated ammonium chloride (NH&lt;sub&gt;4&lt;/sub&gt;Cl) solution</td><td>ShenZhen HuaKang Biomedical Engineering Co.,LTD</td><td>20230301</td><td>Agentia A</td></tr><tr><td>SCA counting chamber</td><td>Microptic S.L.</td><td>102230608</td><td>10 &amp;micro;m, 2 Chambers</td></tr><tr><td>The container for semen sample</td><td>Jiangsu Kangjian Medical Supplies Co., LTD</td><td>20230701</td><td>Polymer-based receptacle for semen sample</td></tr><tr><td>Thermostatic table</td><td>Shenzhen MIAOQUAN Instrument Co., LTD</td><td>MQ30004</td><td>MQ-300</td></tr><tr><td>Transfer pipette (10 &amp;micro;L)</td><td>Eppendoff</td><td>3121000.015</td><td></td></tr><tr><td>Transfer pipette (1000 &amp;micro;L)</td><td>Eppendoff</td><td>3121000.12</td><td></td></tr><tr><td>Transfer pipette (200 &amp;micro;L)</td><td>Eppendoff</td><td>3121000.082</td><td></td></tr><tr><td>Two-dimensional shaker</td><td>DragonLab</td><td>822000010000</td><td>VC5A002205</td></tr></tbody></table>

the examination of peroxidase-positive leukocytes in semen

Leukocytospermia can lead to decreased spermatozoa motility, increased spermatozoa morphological abnormalities, elevated spermatozoa DNA fragmentation index, impairment of the spermatozoa acrosome function, and even affected embryonic development. It is a common andrological disease in clinical practice and one of the important causes of male infertility. When determining whether male reproductive tract inflammation exists, andrologists often choose to examine round cells or seminal plasma elastase in the semen as a clinical diagnostic basis. However, the examination of round cells is easily influenced by sloughed spermatogenic cells and reproductive tract epithelial cells, which do not contribute to reducing the indiscriminate and unnecessary use of antibiotics. At the same time, the detection process of elastase is relatively complicated, time-consuming, and slow in reporting results, which is not beneficial for early diagnosis and treatment of diseases such as male genital tract infections (MGTIs). We have innovatively applied the examination of peroxidase-positive leukocytes in semen assisted by a computer-assisted semen analysis (CASA) system as a diagnostic criterion for leukocytospermia, successfully solving these problems. This examination only requires the addition of the operating fluid consisting of four reagents into the specimen, and the total reaction time at room temperature can be controlled within 20-30 min. With the subsequent smear and microscopic examination, the concentration of peroxidase-positive leukocytes in semen can be obtained within a total of 60 min, which can be used to diagnose whether the inflammation of the male reproductive tract existed.

Upon implementing the aforementioned procedure, the reactant in the centrifuge tube frequently manifests a subtranslucent, opalescent appearance (Figure 1). Detecting an obviously brown color discloses potential degranulation of leukocytes, which may result in liquid staining. Consequently, the staining process could fail, rendering it necessary to either re-stain or collect a new semen sample for retesting21.
Peroxidase-positive leukocytes displayed a brown hue, contrasting with the unstained ordinary round cells (Figure 2, ordinary slide). Subsequently, every spermatozoon and brown leukocyte under the current microscope field was counted before shifting to an entirely new field for continuous observation and tallying. To ensure optimal accuracy, it is necessary to count a minimum of 200 spermatozoa and the leukocytes present in the corresponding field of view.
<img alt="Figure 1" class="xfigimg" src="/files/ftp_upload/66211/66211fig01.jpg" /> 
Figure 1: Reactant solution. The reactant that completes the reaction process is a subtranslucent opalescent liquid. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66211/66211fig01large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<img alt="Figure 2" class="xfigimg" src="/files/ftp_upload/66211/66211fig02.jpg" /> 
Figure 2: Observation under optical microscope (ordinary slide). (A) Peroxidase-positive leukocyte and (B) ordinary round cell observed at 10 x 40 magnification optical microscope. <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/66211/66211fig02large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>

Watch this Scientific Journal Video about A Simple and Cost-Effective Method for Leukocyte Analysis in Semen at JoVE.com

Author Spotlight: A Simple and Cost-Effective Method for Leukocyte Analysis in Semen 

This paper presents an economical and efficient protocol for examining peroxidase-positive leukocytes in semen. With the assistance of a computer-assisted semen analysis (CASA) system, the concentration of peroxidase-positive leukocytes in semen can be obtained within a total of 60 min, effectively improving the efficiency of andrology laboratory and andrologists.

The Examination of Peroxidase-Positive Leukocytes in Semen

Leukocytospermia can lead to decreased spermatozoa motility, increased spermatozoa morphological abnormalities, elevated spermatozoa DNA fragmentation ...

the-examination-of-peroxidase-positive-leukocytes-in-semen

Nanyang Technological University

Research

JoVE Journal

Medicine

3.6K Views.  The Third Affiliated Hospital of Sun Yat-sen University. This paper presents an economical and efficient protocol for examining peroxidase-positive leukocytes in semen. With the assistance of a computer-assisted semen analysis (CASA) system, the concentration of peroxidase-positive leukocytes in semen can be obtained within a total of 60 min, effectively improving the efficiency of andrology laboratory and andrologists.

Video: Author Spotlight: A Simple and Cost-Effective Method for Leukocyte Analysis in Semen 

Making Sense of Listening: The IMAP Test Battery

The ability to hear is only the first step towards making sense of the range of information contained in an auditory signal. Of equal importance are the abilities to extract and use the information encoded in the auditory signal. We refer to these as listening skills (or auditory processing AP). Deficits in these skills are associated with delayed language and literacy development, though the nature of the relevant deficits and their causal connection with these delays is hotly debated.
When a child is referred to a health professional with normal hearing and unexplained difficulties in listening, or associated delays in language or literacy development, they should ideally be assessed with a combination of psychoacoustic (AP) tests, suitable for children and for use in a clinic, together with cognitive tests to measure attention, working memory, IQ, and language skills. Such a detailed examination needs to be relatively short and within the technical capability of any suitably qualified professional. Current tests for the presence of AP deficits tend to be poorly constructed and inadequately validated within the normal population. They have little or no reference to the presenting symptoms of the child, and typically include a linguistic component. Poor performance may thus reflect problems with language rather than with AP. To assist in the assessment of children with listening difficulties, pediatric audiologists need a single, standardized child-appropriate test battery based on the use of language-free stimuli.
We present the IMAP test battery which was developed at the MRC Institute of Hearing Research to supplement tests currently used to investigate cases of suspected AP deficits. IMAP assesses a range of relevant auditory and cognitive skills and takes about one hour to complete. It has been standardized in 1500 normally-hearing children from across the UK, aged 6-11 years. Since its development, it has been successfully used in a number of large scale studies both in the UK and the USA. IMAP provides measures for separating out sensory from cognitive contributions to hearing. It further limits confounds due to procedural effects by presenting tests in a child-friendly game-format. Stimulus-generation, management of test protocols and control of test presentation is mediated by the IHR-STAR software platform. This provides a standardized methodology for a range of applications and ensures replicable procedures across testers. IHR-STAR provides a flexible, user-programmable environment that currently has additional applications for hearing screening, mapping cochlear implant electrodes, and academic research or teaching.

A test battery (IMAP) for performing an in-depth assessment of auditory and cognitive abilities contributing to listening skills is described. It is quick to administer, child-friendly and free from linguistic confounds. Stimulus generation and protocol management are controlled via a software platform (IHR-STAR) to ensure replicable procedures.

The ability to hear is only the first step towards making sense of the range of information contained in an auditory signal. Of equal importance are the ...

Evaluation of Intracellular Location of Reactive Oxygen Species in Solea Senegalensis Spermatozoa

Oxidative stress is one of the important factors in decreasing sperm quality. Developing efficient protocols for detecting reactive oxygen species (ROS) in spermatozoa is of high importance in any species, but these methods are rarely used and even less in teleost. Cryopreservation is a useful technique in aquaculture for different purposes, including gene banking and guaranteed sperm availability throughout the year. Freezing/thawing procedures could cause ROS production and damage the sperm cells. Considering the prospective damage that an excess of ROS production could cause in spermatozoa depending on their localization, here a detailed methodology to detect H2O2 and to evaluate its intracellular localization by confocal microscopy is provided. For this purpose, a combination of 3 fluorochromes (2&#8242;,7&#8242;-Dichlorodihydrofluorescein diacetate (DCFH-DA), a live mitochondria stain and 4&#8242;,6-Diamidino-2-phenylindole dihydrochloride (DAPI)) are used to evaluate the co-localization of H2O2 with spermatozoa nuclei or mitochondria in Solea senegalesis sperm samples.

Evaluation of Intracellular Location of Reactive Oxygen Species in Solea Senegalensis Spermatozoa

This protocol describes a detailed methodology for detecting H2O2 localization within Solea senegalensis spermatozoa using a sensitive fluorochrome DCFH-DA for ROS, a live mitochondria stain for mitochondria, and DAPI for nuclei visualization, respectively. The protocol is designed to be performed within 2 h with either fresh or thawed spermatozoa.

Oxidative stress is one of the important factors in decreasing sperm quality. Developing efficient protocols for detecting reactive oxygen species (ROS) ...

Developmental Biology

Collection of Post-mating Semen from the Female Reproductive Tract and Measurement of Semen Liquefaction in Mice

In mice, ejaculated semen is deposited in the uterus. After ejaculation, the semen changes consistency from gel-like to watery, a process called liquefaction. In this study, we show how to collect the post-ejaculated semen from the female reproductive tract in a mouse model. First, adult female mice in the estrus stage were housed in a male&#39;s cage overnight. The next morning, copulation was confirmed by the presence of copulatory plug at the vaginal opening. Female mice with copulatory plugs were euthanized, and each reproductive tract was collected as a whole (vagina, uterus, oviducts, ovaries), ensuring a closed system to contain the semen. The reproductive tract was placed in a 1.5 mL microcentrifuge tube, and the vagina was cut off to release the semen into the tube. To ensure maximum semen volume for analysis, toothless forceps were used to squeeze the uterine horns from ovarian end to vaginal end expelling remaining semen. The whole reproductive tract was then discarded. The semen-containing tube was briefly spun down. A 25 &#956;L capillary pipette was placed into the tube at a 180&#176; angle (parallel to the tube wall). The amount of time used to fill the capillary tube to the 25 &#956;L line was recorded. Semen from a proven male breeder usually takes approximately 60-180 s to fill a 25 &#956;L capillary tube. This semen collection technique can also be used in other downstream applications such as sperm imaging and motility analysis.

Semen liquefaction is required for sperm to be liberated from the seminal gel. This study provides the procedures for collecting semen from the female reproductive tract post-coitus, and measuring semen liquefaction time.

In mice, ejaculated semen is deposited in the uterus. After ejaculation, the semen changes consistency from gel-like to watery, a process called ...

Fluorimetric Techniques for the Assessment of Sperm Membranes

Standard spermiograms describing sperm quality are mostly based on the physiological and visual parameters, such as ejaculate volume and concentration, motility and progressive motility, and sperm morphology and viability. However, none of these assessments is good enough to predict the semen quality. Given that maintenance of sperm viability and fertilization potential depends on membrane integrity and intracellular functionality, evaluation of these parameters might enable a better prediction of sperm fertilization competence. Here, we describe three feasible methods to evaluate sperm quality using specific fluorescent probes combined with fluorescence microscopy or flow cytometry analyses. Analyses assessed plasma membrane integrity using 4&#39;,6-diamidino-2-phenylindole (DAPI) and propidium iodide (PI), acrosomal membrane integrity using fluorescein isothiocyanate-conjugated Pisum sativum agglutinin (FITC-PSA) and mitochondrial membrane integrity using 5,5&#39;,6,6&#39;-tetra-chloro-1,1&#39;,3,3&#39;-tetraethylbenzimidazolyl carbocyanine iodide (JC-1). Combinations of these methods are also presented. For instance, use of annexin V combined with PI fluorochromes enables assessing apoptosis and calculating the proportion of apoptotic sperm (apoptotic index). We believe that these methodologies, which are based on examining spermatozoon membranes, are very useful for the evaluation of sperm quality.

Here, we present methodologies to evaluate spermatozoan membrane integrity, a cellular feature associated with sperm fertilization competence. We describe three techniques for the fluorimetric assessment of sperm membranes: simultaneous staining with specific fluorescent probes, fluorescence microscopy, and advanced sperm-dedicated flow cytometry. Examples of combining the methodologies are also presented.

Standard spermiograms describing sperm quality are mostly based on the physiological and visual parameters, such as ejaculate volume and concentration, ...

Isolation of Murine Spermatogenic Cells using a Violet-Excited Cell-Permeable DNA Binding Dye

Isolation of meiotic spermatocytes is essential to investigate molecular mechanisms underlying meiosis and spermatogenesis. Although there are established cell isolation protocols using Hoechst 33342 staining in combination with fluorescence-activated cell sorting, it requires cell sorters equipped with an ultraviolet laser. Here we describe a cell isolation protocol using the DyeCycle Violet (DCV) stain, a low cytotoxicity DNA binding dye structurally similar to Hoechst 33342. DCV can be excited by both ultraviolet and violet lasers, which improves the flexibility of equipment choice, including a cell sorter not equipped with an ultraviolet laser. Using this protocol, one can isolate three live-cell subpopulations in meiotic prophase I, including leptotene/zygotene, pachytene, and diplotene spermatocytes, as well as post-meiotic round spermatids. We also describe a protocol to prepare single-cell suspension from mouse testes. Overall, the procedure requires a short time to complete (4-5 hours depending on the number of needed cells), which facilitates many downstream applications.

Here we present a simple and efficient method to isolate live meiotic and post-meiotic germ cells from adult mouse testes. Using a low-cytotoxicity, violet-excited DNA binding dye and fluorescence-activated cell sorting, one can isolate highly enriched spermatogenic cell populations for many downstream applications.

Isolation of meiotic spermatocytes is essential to investigate molecular mechanisms underlying meiosis and spermatogenesis. Although there are established ...

Fast and Specific Assessment of the Halogenating Peroxidase Activity in Leukocyte-enriched Blood Samples

In this paper a protocol for the quick and standardized enrichment of leukocytes from small whole blood samples is described. This procedure is based on the hypotonic lysis of erythrocytes and can be applied to human samples as well as to blood of non-human origin. The small initial sample volume of about 50 to 100 &#181;l makes this method applicable to recurrent blood sampling from small laboratory animals. Moreover, leukocyte enrichment is achieved within minutes and with low material efforts regarding chemicals and instrumentation, making this method applicable in multiple laboratory environments.
Standardized purification of leukocytes is combined with a highly selective staining method to evaluate halogenating peroxidase activity of the heme peroxidases, myeloperoxidase (MPO) and eosinophil peroxidase (EPO), i.e., the formation of hypochlorous and hypobromous acid (HOCl and HOBr). While MPO is strongly expressed in neutrophils, the most abundant immune cell type in human blood as well as in monocytes, the related enzyme EPO is exclusively expressed in eosinophils. The halogenating activity of these enzymes is addressed by using the almost HOCl- and HOBr-specific dye aminophenyl fluorescein (APF) and the primary peroxidase substrate hydrogen peroxide. Upon subsequent flow cytometry analysis all peroxidase-positive cells (neutrophils, monocytes, eosinophils) are distinguishable and their halogenating peroxidase activity can be quantified. Since APF staining may be combined with the application of cell surface markers, this protocol can be extended to specifically address leukocyte sub-fractions. The method is applicable to detect HOCl and HOBr production both in human and in rodent leukocytes.
Given the widely and diversely discussed immunological role of these enzymatic products in chronic inflammatory diseases, this protocol may contribute to a better understanding of the immunological relevance of leukocyte-derived heme peroxidases.

This protocol describes the quick enrichment of leukocytes from small blood samples for a subsequent specific determination of the halogenating peroxidase activity within the cells. The method can be applied to human and non-human material and may contribute to the evaluation of new inflammatory markers.

In this paper a protocol for the quick and standardized enrichment of leukocytes from small whole blood samples is described. This procedure is based on ...

Immunology and Infection

Phosphopeptide Analysis of Rodent Epididymal Spermatozoa

Spermatozoa are quite unique amongst cell types. Although produced in the testis, both nuclear gene transcription and translation are switched off once the pre-cursor round cell begins to elongate and differentiate into what is morphologically recognized as a spermatozoon. However, the spermatozoon is very immature, having no ability for motility or egg recognition. Both of these events occur once the spermatozoa transit a secondary organ known as the epididymis. During the ~12 day passage that it takes for a sperm cell to pass through the epididymis, post-translational modifications of existing proteins play a pivotal role in the maturation of the cell. One major facet of such is protein phosphorylation. In order to characterize phosphorylation events taking place during sperm maturation, both pure sperm cell populations and pre-fractionation of phosphopeptides must be established. Using back flushing techniques, a method for the isolation of pure spermatozoa of high quality and yield from the distal or caudal epididymides is outlined. The steps for solubilization, digestion, and pre-fractionation of sperm phosphopeptides through TiO2 affinity chromatography are explained. Once isolated, phosphopeptides can be injected into MS to identify both protein phosphorylation events on specific amino acid residues and quantify the levels of phosphorylation taking place during the sperm maturation processes.

Proteomic analysis of any cell type is highly dependent on both purity and pre-fractionation of the starting material in order to de-complexify the sample prior to liquid chromatography mass spectrometry (MS). By using back-flushing techniques, pure spermatozoa can be obtained from rodents. Following digestion, phosphopeptides can be enriched using TiO2.

Spermatozoa are quite unique amongst cell types. Although produced in the testis, both nuclear gene transcription and translation are switched off once ...

Biology

Flow Cytometric Analysis of Biomarkers for Detecting Human Sperm Functional Defects

The conventional semen parameter analysis is widely used to assess male fertility. However, studies have found that ~15% of infertile patients show no abnormalities in conventional semen parameters. Additional technologies are needed to explain the idiopathic infertility and detect subtle sperm defects. Currently, biomarkers of sperm function, including sperm apoptosis, mitochondrial membrane potential (MMP), and DNA damage, reveal sperm physiology at the molecular level and are capable of predicting male fertility.
With flow cytometry (FCM) techniques, each of these markers can be rapidly, accurately, and precisely measured in human semen samples, but time costs substantially increase and results could be obstructed if all the biomarkers need to be tested with a single cytometer. In this protocol, after collection and immediate incubation at 37 &#176;C for liquefication, semen samples were further analyzed for sperm apoptosis using Annexin V-fluorescein isothiocyanate (FITC)/propidium iodide (PI) staining. The MMP was labeled with 5,5&#8242;,6,6&#8242;-tetrachloro-1,1&#8242;,3,3&#8242;-tetraethyl-benzimidazolylcarbocyanine iodide (JC-1) probe, and DNA damage was assessed using the sperm chromatin structure assay (SCSA) with acridine orange (AO) staining. Thus, flow cytometric analysis of sperm function markers can be a practical and reliable toolkit for the diagnosis of infertility and evaluation of sperm function at both bench and bed.

The present protocol provides a practical solution that allows for the measurement of apoptosis, mitochondrial membrane potential, and DNA damage in human sperm with a single cytometer.

The conventional semen parameter analysis is widely used to assess male fertility. However, studies have found that ~15% of infertile patients show no ...

Sperm Collection of Differential Quality Using Density Gradient Centrifugation

In sexual reproduction, a male gamete or sperm cell fuses with a female gamete to bring about fertilization. However, a large number of sperm cells with fertilizing ability are required to interact with a female gamete to ensure fertilization. As such, the fertilizing ability of individual sperm cells is critical for successful reproduction. Density gradient centrifugation has been utilized for several decades as a reproducible, fast, efficient, effective and extremely adaptable method to collect only high-quality sperm to be used in assisted reproductive technology. The protocols we described herein focus on the utilization of the discontinuous Percoll density gradient centrifugation (PDGC) technique to isolate three distinct populations of rooster sperm by their quality. We were able to collect low-, medium- and high-quality sperm. We also describe reproducible protocols that entail determining fertility potential of sperm by assessing their viability, mobility and penetrability. Collection of sperm by their quality using PDGC technique would be useful to accurately and thoroughly characterize sperm with differential fertility potential.

In this paper, we aim to describe the performance of the density gradient centrifugation technique and its application in sperm physiology research.

In sexual reproduction, a male gamete or sperm cell fuses with a female gamete to bring about fertilization. However, a large number of sperm cells with ...

U-Shaped Horizontal Swimming Technique for Preparing High-Quality Sperm with Low DNA Fragmentation Index

Human semen is a complex mixture comprising progressively motile spermatozoa, non-progressively motile spermatozoa, immotile spermatozoa, cell debris, and viscous seminal plasma. High-quality sperm refers to progressively motile spermatozoa with normal morphology, which often exhibit a lower DNA fragmentation index (DFI) and higher fertilization potential. Preparing high-quality sperm is a critical step in human-assisted reproductive technology. The traditional sperm preparation method, discontinuous density gradient centrifugation (DGC), is time-consuming and labor-intensive. Repeated centrifugation can damage sperm DNA, thereby affecting subsequent fertilization and embryo development. This study introduces a U-shaped horizontal swimming (UHS) method for preparing intracytoplasmic sperm injection (ICSI) sperm, which significantly eliminates the detrimental effects of&#160;centrifugation on sperm DNA.&#160;The UHS method involves creating a UHS lane using a fertilization medium within an ICSI operating dish. A 10 &#181;L fertilization medium microdroplet is placed at the starting point on the left side of the UHS lane to hold the semen. Two additional 10 &#181;L fertilization medium buffer droplets are positioned at intervals along the left middle section of the lane, with all droplets connected by fertilization medium. The dish is then covered with culture oil and incubated overnight at 37 &#176;C with 6% CO2 to equilibrate. Subsequently, 3 &#181;L of semen is added to the microdroplet at the starting point. High-quality spermatozoa swim to the right side of the UHS lane, facilitating their suction into the ICSI injection needle. Dead sperm, cell debris, and other viscous impurities largely remain at the initial point or in the buffer droplets. We simultaneously processed 21 semen samples using both UHS and DGC techniques and compared their DFI. The results demonstrated that the DFI in the DGC group was 5.5% &#177; 3.2%, whereas the DFI in the UHS group was 1.7% &#177; 1.1%. The difference between the two groups was statistically significant (P &#60; 0.05).

This protocol describes a method for screening high-quality sperm with a low DNA fragmentation index by utilizing sperm motility characteristics and thigmotaxis. The method employs a U-shaped horizontal swimming lane, enabling high-quality sperm to reach the opposite side through buffer droplets, while dead sperm, cell debris, and impurities are excluded.

Human semen is a complex mixture comprising progressively motile spermatozoa, non-progressively motile spermatozoa, immotile spermatozoa, cell debris, and ...

The Examination of Peroxidase-Positive Leukocytes in Semen

Summary

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Chapters in this video

Making Sense of Listening: The IMAP Test Battery

Evaluation of Intracellular Location of Reactive Oxygen Species in Solea Senegalensis Spermatozoa

Collection of Post-mating Semen from the Female Reproductive Tract and Measurement of Semen Liquefaction in Mice

Fluorimetric Techniques for the Assessment of Sperm Membranes

Isolation of Murine Spermatogenic Cells using a Violet-Excited Cell-Permeable DNA Binding Dye

Fast and Specific Assessment of the Halogenating Peroxidase Activity in Leukocyte-enriched Blood Samples

Phosphopeptide Analysis of Rodent Epididymal Spermatozoa

Flow Cytometric Analysis of Biomarkers for Detecting Human Sperm Functional Defects

Sperm Collection of Differential Quality Using Density Gradient Centrifugation

U-Shaped Horizontal Swimming Technique for Preparing High-Quality Sperm with Low DNA Fragmentation Index