VP is a participant in the Charit&#233; Clinical Scientist Program, funded by the Charit&#233; - Universit&#228;tsmedizin Berlin and the Berlin Institute of Health. TB is an SNSF PostDoc Mobility fellow. The authors receive grant support from EinsteinStiftung/A-2012-153 to PV.

ETHICS STATEMENT: Experiments involving animal subjects were performed in accordance with the guidelines and regulations set forth by Landesamt fuer Gesundheit und Soziales, Berlin, Germany (G0298/13) and the ARRIVE criteria, as applicable. For this study, 10- to 12-week-old male C57Bl/6J mice were used.
1. Lateral Chronic Cranial Window Preparation
<ol>
	<li>Perform anesthesia with a subcutaneous injection of ketamine (90 mg/kg) and xylazine (10 mg/kg). Test for adequate sedation with a pain stimulus.</li>
	<li>Sterilize the surgical instruments and surgical field with 70% ethanol.</li>
	<li>Remove the scalp hair from the neck to the eyes using a rodent shaver.</li>
	<li>Fix the head in a stereotactic frame.</li>
	<li>Use dexpanthenol eye ointment on both eyes to avoid dehydration.</li>
	<li>Clean the surgical area to remove all hairs and sterilize it with 3 layers of 74.1% ethanol and 10% 2-propanolol.</li>
	<li>Perform a midline incision from the neck to the eyes using a scalpel.</li>
	<li>Span the skin flap with 4 tenting sutures.</li>
	<li>Remove the periosteum carefully on the left hemisphere by scraping it off with a scalpel to the point where the temporal muscle begins. 
	NOTE: This preparation also serves to create a good adhesion area for the dental glue, which fixes the cover glass.</li>
	<li>Perform a fronto-parietal craniotomy with a diameter of 4 mm by thinning the skull at the rim of the bone flap using a microdrill. Apply saline solution while drilling to avoid heat injury.</li>
	<li>Elevate the bone flap with cannulas and remove it using microforceps.</li>
	<li>Irrigate carefully and extensively with saline solution.</li>
	<li>Mix the dental glue until it has the proper consistency and is not fluid (i.e., the glue should not produce threads anymore). Place it on the bone around the craniotomy.</li>
	<li>Place a cover glass with a 6-mm diameter on the prepared glue and fix it with the rest of the dental glue. Be sure that it is watertight. Wait until the glue is dried and hard by testing it with forceps. 
	NOTE: An additional irrigation accelerates the curing process.</li>
	<li>Remove the tenting sutures and close the wound with skin sutures.</li>
	<li>Pull up the skin of the flank of the mouse. Insert a needle subcutaneously and gently substitute 0.5 ml of sterile saline subcutaneously for fluid balance.</li>
	<li>After surgery, keep the animals in the heated recovery cage for 90 min. Wait until the animals are fully awake before leaving them unattended. Wait until the animals are completely recovered before returning them to a cage with other animals.</li>
	<li>Repeat the subcutaneous saline volume substitution after about 12 hr, as described in step 1.16.</li>
	<li>Always apply analgesia via gavage or directly into the oral cavity&#160;after surgery (e.g., paracetamol (10 mg/ml) or other non-steroidal anti-inflammatory drugs).</li>
	<li>Check the condition of the animals every day after surgery, and always provide mashed animal food on the floor in a petri-dish to make eating simple and to avoid critical weight loss after surgery. 
	NOTE: Intravital microscopy can be performed on the first day after cranial window preparation.</li>
	<li>&#160;Apply isoflurane anesthesia and fix the animal in a head holder. Open the skin suture and clean the window with cotton buds and sterile saline.&#160;After 24 hr, the cranial window should be filled with cerebrospinal fluid by that time point, which enables imaging. Perform imaging by using established microscopy protocols18.</li>
</ol>
2. Distal MCAo
NOTE: The MCAo procedure should be performed about 5 d after CW preparation. This minimizes interference from the immune reaction caused by the CW preparation with the stroke-induced immune reaction.
<img alt="Figure 1" src="/files/ftp_upload/54701/54701fig1.jpg" /> 
Figure 1. Overview of Distal MCAo. A. This is a nice overview about the vessels before the op. B. The vessels after first bipolar contact. C. The vessels after second bipolar contact. D. The overview about the vessels, which are completely closed now. E. Final overview with lower magnification. <a href="https://cloudfront-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/54701/54701fig1large.jpg" target="_blank">Please click here to view a larger version of this figure.</a>
<ol>
	<li>Anaesthetize the mice using an anesthesia mask and an appropriate anesthetic regime, in consultation with veterinary staff (e.g., induction with 1.5 - 2% isoflurane and maintenance with 1.0 - 1.5% isoflurane in 2/3 N2O and 1/3 O2 via a vaporizer).</li>
	<li>Shave and remove the hair and disinfect the skin and surrounding fur with an appropriate agent (e.g., 70% ethyl alcohol), and dry it afterwards.</li>
	<li>Maintain the body temperature of the mice at 36.5 &#176;C &#177; 0.5 &#176;C during surgery. A feedback controlled heating pad, heated according to the rectal temperature of the mouse, is highly recommended.</li>
	<li>Place the animal in the lateral position. Fix the nose in the anesthesia mask and adjust the isoflurane concentration to 1.0 - 1.5%.</li>
	<li>Apply wet ointment (dexpanthenol) to both eyes.</li>
	<li>Use the skin incision made for the CW preparation.</li>
	<li>Gently separate the skin and identify the temporal muscle underneath.</li>
	<li>Adjust the energy of the high-frequency generator (5 - 7 W) and use the bipolar mode.</li>
	<li>Use the electrocoagulation forceps and carefully remove the temporal muscle from the skull, creating a muscle flap, without totally removing the muscle.</li>
	<li>Identify the MCA below the transparent skull in the rostral part of the temporal area, dorsal to the retro-orbital sinus. If the MCA bifurcation cannot be identified, try to identify the vessel most rostral.</li>
	<li>Thin the skull above the MCA branch with a microdrill while continuously irrigating to avoid heat damage.</li>
	<li>Lift the bone with cannulas and remove it with microforceps.</li>
	<li>Decrease the energy of the high-frequency generator to 3 - 5 W.</li>
	<li>Approach the artery from above and gently touch it with the bipolar forceps on both sides without lifting the vessel.</li>
	<li>Coagulate the artery proximally and distally to the vessel bifurcation.</li>
	<li>Wait for 30 sec, and then touch the artery gently to ensure that the blood flow is permanently interrupted. Repeat the electrocoagulation if a recanalization is observed.</li>
	<li>Fix the temporal muscle with 1 or 2 stitches at the muscle insertion to cover the bone defect, if possible.</li>
	<li>Suture the wound and place the animal into the heated recovery box. In general, animals recovery quickly after volatile anesthesia.</li>
	<li>For volume substitution, apply 0.5 ml of sterile saline subcutaneously, as described in step 1.16.</li>
	<li>After surgery, allow the animals to stay in the heated recovery cage for 90 min. Wait until the animals are conscious before leaving them unattended. Only return them to a cage with other animals when they are fully recovered.</li>
	<li>Repeat the volume substitution, as explained in step 1.16, after 12 hr.</li>
	<li>Apply postoperative analgesia via drinking water (e.g., paracetamol (10 mg/ml) or other non-steroidal anti-inflammatory drugs).</li>
	<li>Check the medical condition of the animals every day after surgery. Provide mashed animal food in a petri-dish on the floor to simplify eating and to minimize postoperative weight loss.</li>
</ol>
3. Sham Treatment
<ol>
	<li>Perform all procedures identically to steps 1 and 2, described above-including CW preparation-except do not coagulate the exposed middle cerebral artery.</li>
</ol>

<ol>
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The authors have nothing to disclose.

Stroke is among the principal causes of long-term disability and death worldwide1. Beyond acute treatment, investigating new approaches and mechanisms to accelerate and enhance recovery after stroke remains a prime medical goal7. Experimental stroke researchers frequently employ rodent models of focal cerebral ischemia. In fact, models inducing transient or permanent MCAo mimic one of the most common types of focal cerebral ischemia in patients4. Besides proximal occlusion of the MCA, the...

Stroke is among the principal causes of long-term disability and death worldwide1, coming second after coronary heart disease. In addition, stroke is the primary cause of long-term disability, underscoring its tremendous socioeconomic impact6-8. Beyond acute treatment, investigating new approaches and mechanisms to accelerate and enhance recovery after stroke remains a prime medical goal7. 
In the last few decades, data from experimental stroke research has contributed substantially to understanding the complex pathophysiological cascades triggered by ischemia9,10. Excitotoxicity, apoptosis, peri-infarct depolarization, and inflammation have been identified as the most relevant mediators of cell death following focal cerebral ischemia. Moreover, using animal models of cerebral ischemia, important concepts, diagnostic modalities, and therapeutic approaches have been developed and validated (e.g., "penumbra" and thrombolysis)11.
The availability of experimental stroke models, combined with non-invasive imaging modalities (e.g., magnetic resonance imaging (MRI), computed tomography, or laser speckle contrast analysis), enables the researcher to investigate hyperacute and chronic pathophysiological changes induced by the ischemic insult in a longitudinal manner12. Along with studying the spatiotemporal profile of the evolving lesion, changes resembling neuronal plasticity can be investigated and correlated to functional outcomes and histological findings. Within the last few years, further methodological advances have been made using the combination of cerebral ischemia models and in vivo microscopy via cranial windows13. These new techniques allow investigators to analyze the neurovascular unit at the cellular and molecular level, with great analytic power in the acute, subacute, and chronic phases following focal cerebral ischemia14. Moreover, in vivo microscopy imaging of microcirculatory dynamics has revealed novel aspects of cerebral microvasculature function and angioarchitecture, with significant pathophysiological relevance15-17. 
In this protocol, we present how to perform a chronic CW preparation lateral to the sagittal sinus and how to surgically induce a distal stroke underneath the window. This mouse model can be applied to sequential imaging of acute, subacute, and chronic changes following focal cerebral ischemia via epi-illuminating, confocal laser scanning, and two-photon intravital microscopy.

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Binocular surgical microscope</td>
			<td>Zeiss</td>
			<td>Stemi 2000 C</td>
			<td></td>
		</tr>
		<tr>
			<td>Light source for microscope</td>
			<td>Zeiss</td>
			<td>CL 6000 LED</td>
			<td></td>
		</tr>
		<tr>
			<td>Heating pad with rectal probe</td>
			<td>FST</td>
			<td>21061-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Stereotactic frame</td>
			<td>Kopf</td>
			<td>Model 930</td>
			<td></td>
		</tr>
		<tr>
			<td>Anaethesia system for isoflurane</td>
			<td>Draeger</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Isoflurane</td>
			<td>Abott</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont forceps #5</td>
			<td>FST</td>
			<td>11251-10</td>
			<td></td>
		</tr>
		<tr>
			<td>Dumont forceps #7</td>
			<td>FST</td>
			<td>11271-30</td>
			<td></td>
		</tr>
		<tr>
			<td>Bipolar Forceps</td>
			<td>Erbe</td>
			<td>20195-501</td>
			<td></td>
		</tr>
		<tr>
			<td>Bipolar Forceps&#160;</td>
			<td colspan="2">Erbe&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; 20195-022</td>
			<td></td>
		</tr>
		<tr>
			<td>Microdrill</td>
			<td colspan="2">FST&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; 18000-17&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;</td>
			<td></td>
		</tr>
		<tr>
			<td>Needle holder</td>
			<td>FST</td>
			<td>12010-14</td>
			<td></td>
		</tr>
		<tr>
			<td>5-0 silk suture</td>
			<td>Feuerstein, Suprama</td>
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			<td>7-0 silk suture</td>
			<td>Feuerstein,Suprama</td>
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			<td>8-0 silk suture</td>
			<td>Feuerstein, Suprama</td>
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			<td>Veterinary Recovery Chamber</td>
			<td>Peco Services</td>
			<td>V1200</td>
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lateral chronic cranial window preparation enables in vivo observation following distal middle cerebral artery occlusion in mice

Focal cerebral ischemia (i.e., ischemic stroke) may cause major brain injury, leading to a severe loss of neuronal function and consequently to a host of motor and cognitive disabilities. Its high prevalence poses a serious health burden, as stroke is among the principal causes of long-term disability and death worldwide1. Recovery of neuronal function is, in most cases, only partial. So far, treatment options are very limited, in particular due to the narrow time window for thrombolysis2,3. Determining methods to accelerate recovery from stroke remains a prime medical goal; however, this has been hampered by insufficient mechanistic insights into the recovery process. Experimental stroke researchers frequently employ rodent models of focal cerebral ischemia. Beyond the acute phase, stroke research is increasingly focused on the sub-acute and chronic phase following cerebral ischemia. Most stroke researchers apply permanent or transient occlusion of the MCA in mice or rats. In patients, occlusions of the MCA are among the most frequent causes of ischemic stroke4. Besides proximal occlusion of the MCA using the filament model, surgical occlusion of the distal MCA is probably the most frequently used model in experimental stroke research5. Occlusion of a distal (to the branching of the lenticulo-striate arteries) MCA branch typically spares the striatum and primarily affects the neocortex. Vessel occlusion can be permanent or transient. High reproducibility of lesion volume and very low mortality rates with respect to the long-term outcome are the main advantages of this model. Here, we demonstrate how to perform a chronic cranial window (CW) preparation lateral to the sagittal sinus, and afterwards how to surgically induce a distal stroke underneath the window using a craniotomy approach. This approach can be applied for sequential imaging of acute and chronic changes following ischemia via epi-illuminating, confocal laser scanning, and two-photon intravital microscopy.

The timeline and representative results are shown in Figures 2 and 3. The cranial window preparation, with a small cranial window lateral to the superior sagittal sinus (Figure 2 B, C, D) results in a very low mortality and morbidity rate when performed by an experienced surgeon. All of the 10 animals survived, and all chronic CW could be used for high-quality imaging, even 28 days after surgery. There was no problem with wound infections...

Watch this Scientific Journal Video about Lateral Chronic Cranial Window Preparation Enables In Vivo Observation Following Distal Middle Cerebral Artery Occlusion in Mice at JoVE.com

Lateral Chronic Cranial Window Preparation Enables In Vivo Observation Following Distal Middle Cerebral Artery Occlusion in Mice

Surgical occlusion of a distal middle cerebral artery branch (MCAo) is a frequently used model in experimental stroke research. This manuscript describes the basic technique of permanent MCAo, combined with the insertion of a lateral cranial window, which offers the opportunity for longitudinal intravital microscopy in mice.

Lateral Chronic Cranial Window Preparation Enables In Vivo Observation Following Distal Middle Cerebral Artery Occlusion in Mice

Focal cerebral ischemia (i.e., ischemic stroke) may cause major brain injury, leading to a severe loss of neuronal function and consequently to a host of ...

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11.5K Views.  Charité-Universitätsmedizin. Surgical occlusion of a distal middle cerebral artery branch (MCAo) is a frequently used model in experimental stroke research. This manuscript describes the basic technique of permanent MCAo, combined with the insertion of a lateral cranial window, which offers the opportunity for longitudinal intravital microscopy in mice.

Video: Lateral Chronic Cranial Window Preparation Enables In Vivo Observation Following Distal Middle Cerebral Artery Occlusion in Mice

Focal Cerebral Ischemia Model by Endovascular Suture Occlusion of the Middle Cerebral Artery in the Rat

Stroke is the leading cause of disability and the third leading cause of death in adults worldwide1. In human stroke, there exists a highly variable clinical state; in the development of animal models of focal ischemia, however, achieving reproducibility of experimentally induced infarct volume is essential. The rat is a widely used animal model for stroke due to its relatively low animal husbandry costs and to the similarity of its cranial circulation to that of humans2,3. In humans, the middle cerebral artery (MCA) is most commonly affected in stroke syndromes and multiple methods of MCA occlusion (MCAO) have been described to mimic this clinical syndrome in animal models. Because recanalization commonly occurs following an acute stroke in the human, reperfusion after a period of occlusion has been included in many of these models. In this video, we demonstrate the transient endovascular suture MCAO model in the spontaneously hypertensive rat (SHR). A filament with a silicon tip coating is placed intraluminally at the MCA origin for 60 minutes, followed by reperfusion. Note that the optimal occlusion period may vary in other rat strains, such as Wistar or Sprague-Dawley. Several behavioral indicators of stroke in the rat are shown. Focal ischemia is confirmed using T2-weighted magnetic resonance images and by staining brain sections with 2,3,5-triphenyltetrazolium chloride (TTC) 24 hours after MCAO.

Surgical induction of ischemic brain damage in the rat is a widely used model for stroke research. Here we demonstrate the induction of focal cerebral ischemia by occlusion of the middle cerebral artery. Visualization of the resulting infarct by histological staining and magnetic resonance imaging is also shown.

Stroke is the leading cause of disability and the third leading cause of death in adults worldwide1. In human stroke, there exists a highly variable ...

Dual Electrophysiological Recordings of Synaptically-evoked Astroglial and Neuronal Responses in Acute Hippocampal Slices

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs through activation of their ion channels and neurotransmitter receptors, and process information in part through activity-dependent release of gliotransmitters. Furthermore, astrocytes constitute the main uptake system for glutamate, contribute to potassium spatial buffering, as well as to GABA clearance. These cells therefore constantly monitor synaptic activity, and are thereby sensitive indicators for alterations in synaptically-released glutamate, GABA and extracellular potassium levels. Additionally, alterations in astroglial uptake activity or buffering capacity can have severe effects on neuronal functions, and might be overlooked when characterizing physiopathological situations or knockout mice. Dual recording of neuronal and astroglial activities is therefore an important method to study alterations in synaptic strength associated to concomitant changes in astroglial uptake and buffering capacities. Here we describe how to prepare hippocampal slices, how to identify stratum radiatum astrocytes, and how to record simultaneously neuronal and astroglial electrophysiological responses. Furthermore, we describe how to isolate pharmacologically the synaptically-evoked astroglial currents.

The preparation of acute brain slices from isolated hippocampi, as well as the simultaneous electrophysiological recordings of astrocytes and neurons in stratum radiatum during stimulation of schaffer collaterals is described. The pharmacological isolation of astroglial potassium and glutamate transporter currents is demonstrated.

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs ...

Piezo High Accuracy Surgical Osteal Removal (PHASOR): A Technique for Improved Cranial Window Surgery in Mice

Multiphoton microscopy has been widely adapted for imaging neurons in vivo. Repeated imaging requires implantation of a cranial window or repeated thinning of the skull. Cranial window surgery is typically performed with a high speed rotary drill, and many investigators find it challenging to prevent the drill from damaging the delicate dura and blood vessels. Extensive training and practice is required to remove the bone without damage to underlying tissue and thus cranial window surgery can be difficult, time consuming, and produce tissue damage. Piezoelectric surgery, which is extensively used for maxillofacial and dental surgery, utilizes ultrasonic vibrations to remove bone without damaging soft tissues. We have developed a method applying piezoelectric surgery to improve cranial window surgery in mice in preparation for multiphoton imaging. Comparisons within our lab find that the method requires less surgery time and has a lower average rate of complications due to dural bleeding than cranial window surgery with a rotary drill.

Piezo High Accuracy Surgical Osteal Removal PHASOR: A Technique for Improved Cranial Window Surgery in Mice

Piezoelectric surgery has led to improvements in human maxillofacial and dental surgery. We have developed a protocol to optimize piezoelectric surgery for cranial window surgery in mice.

Multiphoton microscopy has been widely adapted for imaging neurons in vivo. Repeated imaging requires implantation of a cranial window or repeated ...

Modeling Stroke in Mice: Transient Middle Cerebral Artery Occlusion via the External Carotid Artery

Stroke is the third most common cause of mortality and the leading cause of acquired adult disability in developed countries. To date, therapeutic options are limited to a small proportion of stroke patients within the first hours after stroke. Novel therapeutic strategies are being extensively investigated, especially to prolong the therapeutic time window. These current investigations include the study of important pathophysiological pathways after stroke, such as post-stroke inflammation, angiogenesis, neuronal plasticity, and regeneration. Over the last decade, there has been increasing concern about the poor reproducibility of experimental results and scientific findings among independent research groups. To overcome the so-called &#8220;replication crisis&#8221;, detailed standardized models for all procedures are urgently needed. As an effort within the &#8220;ImmunoStroke&#8221; research consortium (https://immunostroke.de/), a standardized mouse model of transient middle cerebral artery occlusion (MCAo) is proposed. This model allows the complete restoration of the blood flow upon removal of the filament, simulating the therapeutic or spontaneous clot lysis that occurs in a large proportion of human strokes. The surgical procedure of this &#8220;filament&#8221; stroke model and tools for its functional analysis are demonstrated in the accompanying video.

Different models of middle cerebral artery occlusion (MCAo) are used in experimental stroke research. Here, an experimental stroke model of transient MCAo via the external carotid artery (ECA) is described, which aims to mimic human stroke, in which the cerebrovascular thrombus is removed due to spontaneous clot lysis or therapy.

Stroke is the third most common cause of mortality and the leading cause of acquired adult disability in developed countries. To date, therapeutic options ...

Implantation of a Cranial Window for Repeated In Vivo Imaging in Awake Mice

To fully understand the cellular physiology of neurons and glia in behaving animals, it is necessary to visualize their morphology and record their activity in vivo in behaving mice. This paper describes a method for the implantation of a chronic cranial window to allow for the longitudinal imaging of brain cells in awake, head-restrained mice. In combination with genetic strategies and viral injections, it is possible to label specific cells and regions of interest with structural or physiological markers. This protocol demonstrates how to combine viral injections to label neurons in the vicinity of GCaMP6-expressing astrocytes in the cortex for simultaneous imaging of both cells through a cranial window. Multiphoton imaging of the same cells can be performed for days, weeks, or months in awake, behaving animals. This approach provides researchers with a method for viewing cellular dynamics in real time and can be applied to answer a number of questions in neuroscience.

Implantation of a Cranial Window for Repeated In Vivo Imaging in Awake Mice

Presented here is a protocol for the implantation of a chronic cranial window for the longitudinal imaging of brain cells in awake, head-restrained mice.

To fully understand the cellular physiology of neurons and glia in behaving animals, it is necessary to visualize their morphology and record their ...

Construction and Implementation of Carbon Fiber Microelectrode Arrays for Chronic and Acute In Vivo Recordings

Multichannel electrode arrays offer insight into the working brain and serve to elucidate neural processes at the single-cell and circuit levels. Development of these tools is crucial for understanding complex behaviors and cognition and for advancing clinical applications. However, it remains a challenge to densely record from cell populations stably and continuously over long time periods. Many popular electrodes, such as tetrodes and silicon arrays, feature large cross-diameters that produce damage upon insertion and elicit chronic reactive tissue responses associated with neuronal death, hindering the recording of stable, continuous neural activity. In addition, most wire bundles exhibit broad spacing between channels, precluding simultaneous recording from a large number of cells clustered in a small area. The carbon fiber microelectrode arrays described in this protocol offer an accessible solution to these concerns. The study provides a detailed method for fabricating carbon fiber microelectrode arrays that can be used for both acute and chronic recordings in vivo. The physical properties of these electrodes make them ideal for stable and continuous long-term recordings at high cell densities, enabling the researcher to make robust, unambiguous recordings from single units across months.

Construction and Implementation of Carbon Fiber Microelectrode Arrays for Chronic and Acute In Vivo Recordings

This protocol describes a procedure for constructing carbon fiber microelectrode arrays for chronic and acute in vivo electrophysiological recordings in mouse (Mus musculus) and ferret (Mustela putorius furo) from multiple brain regions. Each step, following the purchase of raw carbon fibers to microelectrode array implantation, is described in detail, with emphasis on microelectrode array construction.

Multichannel electrode arrays offer insight into the working brain and serve to elucidate neural processes at the single-cell and circuit levels. ...

A Model for Encephalomyosynangiosis Treatment after Middle Cerebral Artery Occlusion-Induced Stroke in Mice

There is no effective treatment available for most patients suffering with ischemic stroke, making development of novel therapeutics imperative. The brain's ability to self-heal after ischemic stroke is limited by inadequate blood supply in the impacted area. Encephalomyosynangiosis (EMS) is a neurosurgical procedure that achieves angiogenesis in patients with moyamoya disease. It involves craniotomy with placement of a vascular temporalis muscle graft on the ischemic brain surface. EMS has never been studied in the setting of acute ischemic stroke in mice. The hypothesis driving this study is that EMS enhances cerebral angiogenesis at the cortical surface surrounding the muscle graft. The protocol shown here describes the procedure and provides initial data supporting the feasibility and efficacy of the EMS approach. In this protocol, after 60 min of transient middle cerebral artery occlusion (MCAo), mice were randomized to either MCAo or MCAo + EMS treatment. The EMS was performed 3-4 h after occlusion. The mice were sacrificed 7 or 21 days after MCAo or MCAo + EMS treatment. Temporalis graft viability was measured using nicotinamide adenine dinucleotide reduced-tetrazolium reductase assay. A mouse angiogenesis array quantified angiogenic and neuromodulating protein expression. Immunohistochemistry was used to visualize graft bonding with brain cortex and change in vessel density. The preliminary data here suggest that grafted muscle remained viable 21 days after EMS. Immunostaining showed successful graft implantation and increase in vessel density near the muscle graft, indicating increased angiogenesis. Data show that EMS increases fibroblast growth factor (FGF) and decreases osteopontin levels after stroke. Additionally, EMS after stroke did not increase mortality suggesting that protocol is safe and reliable. This novel procedure is effective and well-tolerated and has the potential to provide information of novel interventions for enhanced angiogenesis after acute ischemic stroke.

The protocol aims to provide methods for encephalomyosynangiosis-grafting of a vascular temporalis muscle flap on the pial surface of ischemic brain tissue-for the treatment of non-moyamoya acute ischemic stroke. The approach's efficacy in increasing angiogenesis is evaluated using a transient middle cerebral artery occlusion model in mice.

There is no effective treatment available for most patients suffering with ischemic stroke, making development of novel therapeutics imperative. The ...

Assessment of Thermal Damage from Robot-Drilled Craniotomy for Cranial Window Surgery in Mice

Cranial window surgery allows for the imaging of brain tissue in live mice with the use of multiphoton or other intravital imaging techniques. However, when performing any craniotomy by hand, there is often thermal damage to brain tissue, which is inherently variable surgery-to-surgery and may be dependent on individual surgeon technique. Implementing a surgical robot can standardize surgery and lead to a decrease in thermal damage associated with surgery. In this study, three methods of robotic drilling were tested to evaluate thermal damage: horizontal, point-by-point, and pulsed point-by-point. Horizontal drilling utilizes a continuous drilling schematic, while point-by-point drills several holes encompassing the cranial window. Pulsed point-by-point adds a &#34;2 s on, 2 s off&#34; drilling scheme to allow for cooling in between drilling. Fluorescent imaging of Evans Blue (EB) dye injected intravenously measures damage to brain tissue, while a thermocouple placed under the drilling site measures thermal damage. Thermocouple results indicate a significant decrease in temperature change in the pulsed point-by-point (6.90 &#176;C &#177; 1.35 &#176;C) group compared to the horizontal (16.66 &#176;C &#177; 2.08 &#176;C) and point-by-point (18.69 &#176;C &#177; 1.75 &#176;C) groups. Similarly, the pulsed point-by-point group also showed significantly less EB presence after cranial window drilling compared to the horizontal method, indicating less damage to blood vessels in the brain. Thus, a pulsed point-by-point drilling method appears to be the optimal scheme for reducing thermal damage. A robotic drill is a useful tool to help minimize training, variability, and reduce thermal damage. With the expanding use of multiphoton imaging across research labs, it is important to improve the rigor and reproducibility of results. The methods addressed here will help inform others of how to better use these surgical robots to further advance the field.

Cranial windows have become a ubiquitously implemented surgical technique to allow for intravital imaging in transgenic mice. This protocol describes the use of a surgical robot that performs semi-automated bone drilling of cranial windows and can help reduce surgeon-to-surgeon variability and partially mitigate thermal blood-brain barrier damage.

Cranial window surgery allows for the imaging of brain tissue in live mice with the use of multiphoton or other intravital imaging techniques. However, ...

Establishing a Transcranial Middle Cerebral Artery Occlusion Mice Model

A Modified Transcranial Middle Cerebral Artery Occlusion Model to Study Stroke Outcomes in Aged Mice

In experimental stroke research, middle cerebral artery occlusion (MCAO) with an intraluminal filament is widely used to model ischemic stroke in mice. The filament MCAO model typically exhibits a massive cerebral infarction in C57Bl/6 mice that sometimes includes brain tissue in the territory supplied by the posterior cerebral artery, which is largely due to a high incidence of posterior communicating artery atresia. This phenomenon is considered a major contributor to the high mortality rate observed in C57Bl/6 mice during long-term stroke recovery after filament MCAO. Thus, many chronic stroke studies exploit distal MCAO models. However, these models usually produce infarction only in the cortex area, and consequently, the assessment of post-stroke neurologic deficits could be a challenge. This study has established a modified transcranial MCAO model in which the MCA at the trunk is partially occluded either permanently or transiently via a small cranial window. Since the occlusion location is relatively proximal to the origin of the MCA, this model generates brain damage in both the cortex and striatum. Extensive characterization of this model has demonstrated an excellent long-term survival rate, even in aged mice, as well as readily detectable neurologic deficits. Therefore, the MCAO mouse model described here represents a valuable tool for experimental stroke research.

Author Spotlight: Innovative Techniques and Future Directions in Stroke Research 

This protocol demonstrates a unique mouse stroke model with a medium-sized infarct and an excellent survival rate. This model allows preclinical stroke researchers to extend the ischemia duration, use aged mice, and assess long-term functional outcomes.

In experimental stroke research, middle cerebral artery occlusion (MCAO) with an intraluminal filament is widely used to model ischemic stroke in mice. ...

A Model of Transient Cerebral Ischemia by Occlusion of Middle Cerebral Artery

Transient Middle Cerebral Artery Occlusion Model of Stroke

Stroke stands as a major cause of death or chronic disability globally. Nevertheless, existing optimal treatments are limited to reperfusion therapies during the acute phase of ischemic stroke. To gain insights into stroke physiopathology and develop innovative therapeutic approaches, in vivo rodent models of stroke play a fundamental role. The availability of genetically modified animals has particularly propelled the use of mice as experimental stroke models.
In stroke patients, occlusion of the middle cerebral artery (MCA) is a common occurrence. Consequently, the most prevalent experimental model involves intraluminal occlusion of the MCA, a minimally invasive technique that doesn't require craniectomy. This procedure involves inserting a monofilament through the external carotid artery (ECA) and advancing it through the internal carotid artery (ICA) until it reaches the branching point of the MCA. After a 45 min arterial occlusion, the monofilament is removed to allow reperfusion. Throughout the process, cerebral blood flow is monitored to confirm the reduction during occlusion and subsequent recovery upon reperfusion. Neurological and tissue outcomes are evaluated using behavioral tests and magnetic resonance imaging (MRI) studies.

Author Spotlight: Assessing Ischemic Stroke Damage Through Middle Cerebral Artery Occlusion Model 

This protocol describes the model of transient focal cerebral ischemia in mice through intraluminal occlusion of the middle cerebral artery. Additionally, examples of outcome assessment are shown using magnetic resonance imaging and behavioral tests.

Stroke stands as a major cause of death or chronic disability globally. Nevertheless, existing optimal treatments are limited to reperfusion therapies ...