We thank Amanda Fair, the CMI, and Kathy Sweet and the ORL at UM for assistance with &#181;CT imaging and analysis. Funding: BL Funded by 1K08GM109105-01 and Plastic Surgery Foundation National Endowment Award.

Declaração de ética: Todos os procedimentos com animais foram realizados em estrita conformidade com as boas práticas de animais, tal como definido nas orientações fornecidas no Guia para uso e cuidado de Animais de Laboratório: Oitava Edição do Instituto de Laboratório de Pesquisa Animal (ILAR de 2011) e foram aprovado pelo Comitê de Cuidado e Uso de Animal Institucional da Universidade de Michigan (PRO0001553). 1. mouse Procedimentos Cirúrgicos NOTA: Use 8-10 semanas de idade C57BL / 6 ratos. Outras idades, origens e linhagens de camundongos também pode ser usado para testar diferentes condições ou composição genética. Para a parte tenotomia do procedimento, manter condições estéreis, utilizando máscara facial, bonnet cabelo, e avental estéril, luvas e instrumentos. Locais cirúrgicos devem ser esterilizada preparada com iodopovidona e drapeados estéril. Evitar a hipotermia usando uma almofada de aquecimento e veterinária para o aquecimento de soluções de ressuscitação 37 ° C antes da adminis-ção. <ol><li> Anestesiar o rato usando 2,5% de isoflurano inalado. Use um cone do nariz para deixar o dorso e traseiras-membros de fácil acesso. Ajustar a taxa de administração de isoflurano para manter a taxa respiratória apropriada e coloração das mucosas e para garantir anestesia, verificando o tônus ​​muscular, toe pitada, e reflexo da córnea. Aplicar pomada oftálmica sem graça para os olhos do rato para evitar lesões do olho seco durante o procedimento. Manter a temperatura corporal adequada usando uma almofada de aquecimento veterinária ou circulador de água quente sob o campo cirúrgico. </li><li> Administrar buprenorfina, 0,1 mg / kg, por via subcutânea imediatamente antes da cirurgia para analgesia. </li><li> Intimamente raspar o local da cirurgia na pata traseira esquerda usando cortadores desde o calcanhar até o joelho. </li><li> Estreitamente raspar o dorso do rato, começando ao longo da coluna vertebral e que se estende a área rapada à esquerda da linha média dorsal, limpar uma área de pelo menos 2 cm x 3 cm para acomodar o ferimento de queimadura. </li><li>Prepara-se o local de cirurgia, incluindo a pata traseira ao joelho utilizando 3 alternadas esfrega povidona-iodo. </li><li> Realize uma incisão longitudinal ao longo do aspecto medial do tendão de Aquiles esquerdo. Estender a incisão para que o tendão de Aquiles pode ser facilmente visualizado; aproximadamente 0,5 cm. </li><li> Executar uma tenotomia de Aquiles com dissecção aguda de tendão no ponto médio com uma tesoura de tecido afiadas. Inserir uma lâmina da tesoura de tecido no plano do tecido abaixo do tendão e dissecar ao longo do plano até que a lâmina está no ponto central do tendão. Feche as lâminas da tesoura para cortar o tendão acentuadamente. NOTA: Certifique-se de inclusão de todos os tendões posteriores incluindo gastrocnêmio, sóleo, e tendões plantar. </li><li> Hemostasia, aplicando pressão com gaze estéril (deve haver sangramento mínimo) e fechar a incisão na pele com um ponto vicryl 5-0. </li><li> Realize o dorsal queimadura de espessura parcial com um bloco de alumínio com peso de 35 g com measuremen aproximadosTS 2 cm por 2 cm x 3 cm aquecida a 60 ° C num banho de água aplicada ao dorso rapada do ratinho durante 17 seg. NOTA: Atingir a profundidade de gravação apropriado colocando o bloco no topo do rato anestesiado, assegurando que toda a superfície do bloco está em contacto com o rato, no entanto, evitar a aplicação de qualquer pressão adicional para o bloco, ou seja, permitir que a gravidade seja a única força que prende o bloco no lugar. Um cabo de plástico fino ligado a um lado do bloco é conveniente para a manipulação, de estabilização, e recuperação a partir do banho de água quente. Isto irá criar uma área de superfície total do corpo queimar cerca de 30% em um 8-10 semanas de idade C57BL / 6 mouse. Este queimadura contato foi escolhido em detrimento de outros métodos (chama ou escaldão queimaduras), devido à uniformidade da profundidade da queimadura sobre a ferida e a reprodutibilidade entre os animais. </li><li> Seque o site queimadura com uma gaze e aplicar um curativo Tegaderm. </li><li> Administrar fluidos de ressuscitação aquecidos: solução de Ringer com lactato de 1 mlinjecção intraperitoneal e subcutânea de 0,5 ml. Esta administração única de reanimação é adequada para a recuperação da lesão por queimadura e tenotomia. NOTA: Não retornar ratos anestesiados para jaulas de habitação com outros ratos, casa individualmente em gaiolas limpas sob monitoramento até que os ratos são totalmente recuperado. A recuperação típica ocorre no prazo de 1-6 horas. Locais queimados geralmente curar dentro de 2-4 semanas e raramente são complicados por infecção da ferida se mantido em ambientes de habitação limpas. </li><li> Administrar Buprenorfina 0,1 mg / kg injecção subcutânea a cada 12 horas durante 3 dias após o procedimento. Monitorar o crescimento HO com varreduras μCT de série em intervalos apropriados. Crescimento ósseo ectópica é evidente pela primeira vez em torno de 3 semanas pós-operatório por μCT. NOTA: A maioria do desenvolvimento HO é completa por nove semanas de pós-operatório. Nós não observamos uma diferença de HO volume ou local com repetidas varreduras μCT bi-semanal, durante 15 semanas, em comparação a um único ponto-final μCT digitalizar em 15 semanas.No final das experiências, todos os ratinhos a eutanásia com CO2 inalação de acordo com as orientações institucionais e verificar a morte com deslocamento cervical depois de 10 min. </li></ol> 2. μCT Aquisição e Análise <ol><li> Prenda o rato anestesiado na mesa do scanner na posição prona. Tape os membros posteriores segurança para a cama para evitar respirar movimento artefato. Inclua o ar, a água, e hidroxiapatita contendo fantasma sob o mouse para calibração de imagem. </li><li> Abra o software de análise de osso e definir uma região de interesse (ROI) que engloba ambos os membros posteriores da articulação da anca proximal à ponta da pata traseira distalmente. Obter uma imagem usando os seguintes parâmetros:. 80 kV, 500 mA e 1.300 ms de exposição, 48 mm tamanho voxel 14,15 </li><li> Calibre a imagem para unidades Hounsfield (HU) pelo desenho de um ROI em cada uma das três câmaras fantasmas e introduzir a densidade média nos campos apropriados emo software. </li><li> Usando a ferramenta &quot;apanhando&quot; no software, re-orientar a imagem de modo a tíbia do membro posterior esquerdo é paralelo ao longo do eixo Z para permitir a mais clara vista anatômico para a delimitação das estruturas ósseas corticais ortotópicos e HO. </li><li> Começando na altura do joelho, desloque distalmente através das fatias de imagem até HO é encontrado. Usando a ferramenta de spline o manual, faça um ROI em torno do osso ectópico em cada 5 th fatia continua distalmente através da pata ou até HO foi ultrapassado. Use a ferramenta extrapolar para ampliar e costurar as ROIs juntos em um ROI que contém todas as HO. </li><li> Faça um ROI 3D e escolha o menu de análise. Calcule o volume ósseo, definindo os valores de limite inferior e superior que melhor mostram a janela do osso. Use os mesmos valores-limite fixados para todas as digitalizações. </li></ol>

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L., 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=Alk2+regulates+early+chondrogenic+fate+in+fibrodysplasia+ossificans+progressiva+heterotopic+endochondral+ossification.">Alk2 regulates early chondrogenic fate in fibrodysplasia ossificans progressiva heterotopic endochondral ossification.</a> Stem Cells. 32 (5), 1289-1300 (2014).</li><li>Dinther, M., 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=ALK2+R206H+mutation+linked+to+fibrodysplasia+ossificans+progressiva+confers+constitutive+activity+to+the+BMP+type+I+receptor+and+sensitizes+mesenchymal+cells+to+BMP-induced+osteoblast+differentiation+and+bone+formation.">ALK2 R206H mutation linked to fibrodysplasia ossificans progressiva confers constitutive activity to the BMP type I receptor and sensitizes mesenchymal cells to BMP-induced osteoblast differentiation and bone formation.</a> J Bone Miner Res. 25 (6), 1208-1215 (1359).</li><li>Peterson, J. 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D. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterotopic+ossification+after+extremity+blast+amputation+in+a+Sprague-Dawley+rat+animal+model.">Heterotopic ossification after extremity blast amputation in a Sprague-Dawley rat animal model.</a> J Orthop Trauma. 25 (8), 506-510 (2011).</li><li>Tannous, O., 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=Heterotopic+bone+formation+about+the+hip+undergoes+endochondral+ossification:+a+rabbit+model.">Heterotopic bone formation about the hip undergoes endochondral ossification: a rabbit model.</a> Clin Orthop Relat Res. 471 (5), 1584-1592 (2013).</li><li>Peterson, J. R., 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=Treatment+of+heterotopic+ossification+through+remote+ATP+hydrolysis.">Treatment of heterotopic ossification through remote ATP hydrolysis.</a> Sci Transl Med. 6 (255), 255ra132 (2014).</li><li>Peterson, J. R., 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=Early+detection+of+burn+induced+heterotopic+ossification+using+transcutaneous+Raman+spectroscopy.">Early detection of burn induced heterotopic ossification using transcutaneous Raman spectroscopy.</a> Bone. 54 (1), 28-34 (2013).</li><li>Perosky, J. E., 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=Early+detection+of+heterotopic+ossification+using+near-infrared+optical+imaging+reveals+dynamic+turnover+and+progression+of+mineralization+following+Achilles+tenotomy+and+burn+injury.">Early detection of heterotopic ossification using near-infrared optical imaging reveals dynamic turnover and progression of mineralization following Achilles tenotomy and burn injury.</a> J Orthop Res. 32 (11), 1416-1423 (2014).</li><li>Peterson, J. R., 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=Effects+of+Aging+on+Osteogenic+Response+and+Heterotopic+Ossification+Following+Burn+Injury+in+Mice.">Effects of Aging on Osteogenic Response and Heterotopic Ossification Following Burn Injury in Mice.</a> Stem Cells Dev. , (2014).</li><li>Alfieri, K. A., Forsberg, J. A., Potter, B. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Blast+injuries+and+heterotopic+ossification.">Blast injuries and heterotopic ossification.</a> Bone and Joint Research. 1 (8), 174-179 (2012).</li><li>Hunt, J. L., Arnoldo, B. D., Kowalske, K., Helm, P., Purdue, G. F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Heterotopic+ossification+revisited:+a+21-year+surgical+experience.">Heterotopic ossification revisited: a 21-year surgical experience.</a> J Burn Care Res. 27 (4), 535-540 (2006).</li><li>Ring, D., Jupiter, J. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Operative+release+of+ankylosis+of+the+elbow+due+to+heterotopic+ossification.+Surgical+technique.">Operative release of ankylosis of the elbow due to heterotopic ossification. Surgical technique.</a> J Bone Joint Surg Am. 86-A, 2-10 (2004).</li><li>Crane, N. J., Polfer, E., Elster, E. A., Potter, B. K., Forsberg, J. A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Raman+spectroscopic+analysis+of+combat-related+heterotopic+ossification.">Raman spectroscopic analysis of combat-related heterotopic ossification.</a> Bone. 57 (2), 335-342 (2013).</li></ol>

The authors have nothing to disclose

Heterotopic ossification represents a major functional impairment faced by patients that sustain trauma, burns, and invasive musculoskeletal procedures. The most at-risk population are soldiers in modern conflicts with major blast injuries from mechanisms such as improvised explosive devices (IED).18 Improved body armor and forward positioned medical units allows for improved survival of major extremity injury. After initial stabilization and repair of their extremity injury, these patients are at high risk of developing HO.18 Notwithstanding its prevalence and medical burden, relatively little is known about the details of HO development. Specifically, questions regarding the precise receptors and signaling pathways involved and the cell lineage responsible for HO are important current lines of inquiry. Some similarity to FOP and other forms of congenital HO are expected and supported by recent reports.8,14,17 A reliable model of endogenously produced HO in response to trauma is a key tool in this endeavor. 
Of particular interest is the development of novel diagnostic modalities that can detect where HO is forming at early stages when preventative treatment is viable. Current treatment modalities rely on surgical excision and radiation therapy which carry significant comorbidities and high rates of recurrence.5,19,20 This is largely due the fact that HO can only be identified after it has already formed and can then be detected by conventional imaging such as radiographs or CT scans. Spectroscopic studies including near-infrared imaging and Raman spectroscopy have shown some promising preliminary results but are still in developmental phases.15,16,21
One major advantage of the mouse model described herein is the reliability and predictability of where HO will form. This factor is key in the analysis of early HO development and the preceding events that allow for reactive bone formation. Because there is no preparation or application of exogenous substances, this protocol is relatively straightforward. Critical steps include maintaining sterile technique to avoid infection of the tenotomy site, ensuring uniform contact between the aluminum block and mouse skin while creating the contact burn, and ensuring that the Gastrocnemius, Soleus, and Plantaris tendons are severed when performing the tenotomy. While one advantage of this model is its ability to induce ectopic bone in response to trauma/burn only, it is also limited by excluding other injuries that cause of HO such as fractures, traumatic brain injury, and amputations. Also, while this model has been proven to be successful in mice, it has not yet been validated in larger animals that may more accurately mimic the amount of bone that is seen in human patients. 
Like all anabolic processes, ectopic bone formation is a multifactorial coordination between many different factors and players in the local environment and at the cellular level. It has been shown that HO develops in an endochondral process, however the specific precursor cell is still in question.8,14,17 Having a well-defined time-course and location of HO development is also useful in the trialing of potential preventative therapies for HO. Limiting bone morphogenetic protein (BMP) signaling or reducing inflammation following trauma/burn injuries with ATP hydrolysis have shown a significant reduction in reactive bone formation in this model.14 Further refinement and exploration of diagnostic and therapeutic modalities is certainly warranted. Key to that effort is a reliable mouse model of endogenously produced HO that mimics the processes that occur in patients that suffer the complications of HO.

Heterotopic ossification (HO) is the formation of ectopic bone in which osteo-potent cells are aberrantly induced to form endochondral bone outside of the skeleton. While the details of the HO formation pathway are still largely unknown, an accepted paradigm includes three key factors: an inflammatory inciting incident, a permissive niche, and mesenchymal stem cells capable of forming bone.1-3 HO is a common comorbidity complicating over 60% of major burn injuries, 65% of combat-related injuries, and 10% of invasive orthopaedic surgery cases.4,5 However, it is often difficult to predict where HO will form because it can occur at sites of local injury or at distant locations that may be otherwise uninjured. This variability in location makes it difficult to intervene prophylactically to prevent reactive bone formation in a locally targeted manner. There are also congenital forms of HO such as fibrodysplasia ossificans progressiva (FOP) in which patients are prone to the development of robust HO in response to minor trauma or inflammatory insult. Powerful animal models using transgenic mice have reproduced this phenotype and provided insight to the molecular pathways that may also be important in trauma induced HO.6-9 Translational research into the pathogenesis of non-congenital HO has used a wide variety of constructs ranging from injury alone to the implantation of exogenous osteo-inductive materials and/or cells.10-13
In our prior work we have validated a simple and reliable model of HO formation in mice which does not require the administration of any exogenous material.14-17 This model created two key conditions to initiate HO: local trauma and global inflammation. This was achieved through the use of an Achilles tenotomy (local trauma) combined with a distant burn injury (global inflammation). Mice received both treatments concurrently and were found to develop a robust amount of HO that could be analyzed by histologic, radiologic, and molecular means. Interestingly, concurrent burn injury significantly increased the amount of HO that formed and accelerated its developmental time-course.14-16 HO developed at predictable sites around the calcaneus, ankle joint, and tibia/fibula of the limb that received the tenotomy. The reliability of HO development at a known location allowed for focused examination of molecular and histologic features in the early stages of ectopic ossification.14,17 To date, 100% of mice (over 50 animals) with a tenotomy and concurrent burn injury have developed HO. Additionally, longitudinal 2D and 3D imaging and spectroscopic analysis were conducted to examine the growth pattern and biochemical make-up of HO.15,16

<table border="0" cellpadding="0" cellspacing="0">
	<tbody>
		<tr>
			<td>C57BL/6 mice</td>
			<td>Jackson Laboratory</td>
			<td align="right">664</td>
			<td>8-10 weeks old</td>
		</tr>
		<tr>
			<td>Isoflurane &#8211; Fluriso</td>
			<td>VET one, Boise, ID</td>
			<td>V1 501017</td>
			<td></td>
		</tr>
		<tr>
			<td>Buprenorphine &#8211; Buprenex</td>
			<td>Reckitt Benckiser Healthcare</td>
			<td>NDC 12496-0757-1</td>
			<td>0.3 mg/ml solution</td>
		</tr>
		<tr>
			<td>Betadine</td>
			<td>Owens and Minor, Mechanicsville, VA</td>
			<td>2047PVP202</td>
			<td></td>
		</tr>
		<tr>
			<td>5-0 Vicryl sutures</td>
			<td>Ethicon, Summerville, NJ</td>
			<td>J493</td>
			<td></td>
		</tr>
		<tr>
			<td>Tegaderm Film, 6cm x 7cm</td>
			<td>3M</td>
			<td>1624W</td>
			<td>Cut in half to properly cover burn site</td>
		</tr>
		<tr>
			<td>&#181;CT - GE eXplore Locus SP</td>
			<td>GE Healthcare Pre-Clinical Imaging, London, ON, Canada</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Microview 2.2 Advanced Bone Analysis Application</td>
			<td>GE Healthcare Pre-Clinical Imaging, London, ON, Canada</td>
			<td></td>
			<td></td>
		</tr>
	</tbody>
</table>

direct mouse trauma/burn model of heterotopic ossification

Heterotopic ossification (HO) is the formation of bone outside of the skeleton which forms following major trauma, burn injuries, and orthopaedic surgical procedures. The majority of animal models used to study HO rely on the application of exogenous substances, such as bone morphogenetic protein (BMP), exogenous cell constructs, or genetic mutations in BMP signaling. While these models are useful they do not accurately reproduce the inflammatory states that cause the majority of cases of HO. Here we describe a burn/tenotomy model in mice that reliably produces focused HO. This protocol involves creating a 30% total body surface area partial thickness contact burn on the dorsal skin as well as division of the Achilles tendon at its midpoint. Relying solely on traumatic injury to induce HO at a predictable location allows for time-course study of endochondral heterotopic bone formation from intrinsic physiologic processes and environment only. This method could prove instrumental in understanding the inflammatory and osteogenic pathways involved in trauma-induced HO. Furthermore, because HO develops in a predictable location and time-course in this model, it allows for research to improve early imaging strategies and treatment modalities to prevent HO formation.

No presente estudo, o protocolo é descrito para o modelo de rato previamente publicado de trauma / queimadura induzida HO 14-17. Isto envolve a criação de concomitante lesão musculoesquelética localizada com uma tenotomia Aquiles e insulto inflamatório global, com uma espessura parcial queimaduras. Isto resulta na formação fiável do osso no local reactivo Tenotomia que pode ser seguido com imagens em série. Até à data, todos os ratinhos (mais de 50) que sofreram ambos Aquiles Tenotomia e lesão por queimadura desenvolveram uma quantidade mensurável de HO no local Tenotomia. Para quantificar a formação de osso ectópico, um protocolo de imagem μCT calibrado é usado em cada ponto de tempo desejado. A adição de um ferimento de queimadura em combinação com o Tenotomia Aquiles provou ser a chave para a indução de HO significativa. Com ambas as lesões que ocorrem simultaneamente, há um aumento significativo na quantidade de osso ectópico que é formado no local Tenotomia comparação com AcHilles Tenotomia sozinho (Figura 1). 17 <img alt="Figura 1" src="/files/ftp_upload/52880/52880fig1.jpg" /> Figura 1. desenvolvimento HO seguinte Aquiles tenotomia com ou sem ferimento de queimadura concorrente. Todos os ratinhos receberam uma tenotomia de Aquiles do membro posterior esquerdo, metade dos ratos também receberam uma TBSA espessura parcial de 30% queimar lesão no dorso. scans μCT foram concluídas em 5 dias e 3, 5, 7, 9, e 15 semanas após a lesão. (UMA). Reconstruções 3D representativos são mostrados com osso orthotopic branco e HO cor azul. Os círculos vermelhos indicam niduses de HO. Óssea ectópica desenvolve na área da Tenotomia, bem como locais distais e proximais para o local da lesão no membro inferior. Semelhante a HO visto clnically, este óssea reativa pode ser contígua com osso esquelético ou desenvolver remotamente em tecidos moles. (B). Quantificação de HO foi COMpletou com um protocolo de imagem calibrada e mostrado no gráfico. HO persiste para além das 15 semanas, no entanto planaltos de desenvolvimento entre 9-15 semanas, com a maior velocidade de crescimento tipicamente vistos entre 5-9 semanas. Os dados são médias +/- SD, n = 4 por grupo, teste t de Student, * P &lt;0,05 (Por favor note que este é, dados modificados de 17 publicado anteriormente). <a href="https://www-jove-com.remotexs.ntu.edu.sg/files/ftp_upload/52880/52880fig1large.jpg" target="_blank">Por favor clique aqui para ver uma versão maior desta figura.</a>

Watch this Scientific Journal Video about Direct Mouse Trauma/Burn Model of Heterotopic Ossification at JoVE.com

Direct Mouse Trauma/Burn Model of Heterotopic Ossification

An Achilles tenotomy and burn injury model of heterotopic ossification allows for the reliable study of trauma induced ectopic bone formation without the application of exogenous factors.

Direto Rato Trauma / Burn Modelo de ossificação heterotópica

Heterotopic ossification (HO) is the formation of bone outside of the skeleton which forms following major trauma, burn injuries, and orthopaedic surgical ...

direct-mouse-traumaburn-model-of-heterotopic-ossification

Nanyang Technological University

Research

JoVE Journal

Medicine

10.0K visualizações.  University of Michigan Medical School. An Achilles tenotomy and burn injury model of heterotopic ossification allows for the reliable study of trauma induced ectopic bone formation without the application of exogenous factors.

Vídeo: Direct Mouse Trauma/Burn Model of Heterotopic Ossification

A Modified Method for Heterotopic Mouse Heart Transplantion

Mice are often used as heart transplant donors and recipients in studies of transplant immunology due to the wide range of transgenic mice and reagents available. A difficulty is presented due to the small size of the animal and the considerable technical challenges of the microsurgery involved in heart transplantation. In particular, a high rate of technical failure early after transplantation may result from recipient death and post-operative complications such as hind limb paralysis or a non-beating heart. Here, the complete technique for heterotopic mouse heart transplantation is demonstrated, involving harvesting the donor heart and its subsequent implantation into a recipient mouse. The donor heart is harvested immediately following in situ perfusion with cold heparinized saline and transection of the ascending aorta and pulmonary artery. The recipient operation involves preparation of the abdominal aorta and inferior vena cava (IVC), followed by end-to-side anastomosis of the donor aorta with the recipient aorta using a single running 10-0 microsuture and a similar anastomosis of the donor pulmonary artery with the recipient IVC. Following the operation the animal is injected with 0.6 ml normal saline subcutaneously and allowed to recover on a 37&#160;&#176;C heating pad. The results from 227 mouse heart transplants are summarized with a success rate at 48 hr of 86.8%. Of the 13.2% failures within 48 hr, 5 (2.2%) experienced hind limb paralysis, 10 (4.4%) had a non-beating heart due to graft ischemic injury and/or thrombosis, while 15 (6.6%) died within 48 hr.

A technique is demonstrated for the microsurgical procedure for heterotopic transplantation of hearts in mice, including simplified methods for donor harvesting and recipient vessel anastomosis.

Um método modificado para heterotópico Rato coração transplante

Mice are often used as heart transplant donors and recipients in studies of transplant immunology due to the wide range of transgenic mice and reagents ...

Medicina

Heterotopic Mucosal Engrafting Procedure for Direct Drug Delivery to the Brain in Mice

Delivery of therapeutics into the brain is impeded by the presence of the blood-brain barrier (BBB) which restricts the passage of polar and high molecular weight compounds from the bloodstream and into brain tissue. Some direct delivery success in humans has been achieved via implantation of transcranial catheters; however this method is highly invasive and associated with numerous complications. A less invasive alternative would be to dose the brain through a surgically implanted, semipermeable membrane such as the nasal mucosa that is used to repair skull base defects following endoscopic transnasal tumor removal surgery in humans. Drug transfer though this membrane would effectively bypass the BBB and diffuse directly into the brain and cerebrospinal fluid. Inspired by this approach, a surgical approach in mice was developed that uses a donor septal mucosal membrane engrafted over an extracranial surgical BBB defect. This model has been shown to effectively allow the passage of high molecular weight compounds into the brain. Since numerous drug candidates are incapable of crossing the BBB, this model is valuable for performing preclinical testing of novel therapies for neurological and psychiatric diseases.

A mouse model of human endoscopic skull base reconstruction has been developed that creates a semipermeable interface between the brain and nose using nasal mucosal grafts. This method allows researchers to study delivery to the central nervous system of high molecular weight therapeutics which are otherwise excluded by the blood-brain barrier when administered systemically.

Heterotópico mucosa enxertando Procedimento para entrega da droga direto para o cérebro em ratos

Delivery of therapeutics into the brain is impeded by the presence of the blood-brain barrier (BBB) which restricts the passage of polar and high ...

Murine Heterotopic Heart Transplant Technique

It is now over forty years since this technique was first reported by Corry, Wynn and Russell. Although it took some years for other labs to become proficient in and utilize this technique, it is now widely used by many laboratories around the world. A significant refinement to the original technique was developed and reported in 2001 by Niimi. Described here are the techniques that have evolved over more than a decade in the hands of three surgeons (Plenter, Grazia, Pietra) in our center. These techniques are now being passed on to a younger generation of surgeons and researchers.
Based largely on the Niimi experience, the procedures used have evolved in the fine details - details which we will endeavor to relate here in such a way that others may be able to use this very useful model. Like Niimi, we have found that a video aid to learning is a priceless resource for the beginner.

The manuscript describes the steps required to perform the heterotopic heart transplant in the mouse.

Técnica de transplante heterotópico Murino Coração

It is now over forty years since this technique was first reported by Corry, Wynn and Russell. Although it took some years for other labs to become ...

Transplantation of Pulmonary Valve Using a Mouse Model of Heterotopic Heart Transplantation

Tissue engineered heart valves, especially decellularized valves, are starting to gain momentum in clinical use of reconstructive surgery with mixed results. However, the cellular and molecular mechanisms of the neotissue development, valve thickening, and stenosis development are not researched extensively. To answer the above questions, we developed a murine heterotopic heart valve transplantation model. A heart valve was harvested from a valve donor mouse and transplanted to a heart donor mouse. The heart with a new valve was transplanted heterotopically to a recipient mouse. The transplanted heart showed its own heartbeat, independent of the recipient&#8217;s heartbeat. The blood flow was quantified using a high frequency ultrasound system with a pulsed wave Doppler. The flow through the implanted pulmonary valve showed forward flow with minimal regurgitation and the peak flow was close to 100 mm/sec. This murine model of heart valve transplantation is highly versatile, so it can be modified and adapted to provide different hemodynamic environments and/or can be used with various transgenic mice to study neotissue development in a tissue engineered heart valve.

In order to understand the cellular and molecular mechanisms underlying neotissue formation and stenosis development in tissue engineered heart valves, a murine model of heterotopic heart valve transplantation was developed. A pulmonary heart valve was transplanted to recipient using the heterotopic heart transplantation technique.

O transplante de válvula pulmonar Usando um modelo do rato de Heterotópica Transplante de Coração

Tissue engineered heart valves, especially decellularized valves, are starting to gain momentum in clinical use of reconstructive surgery with mixed ...

Heterotopic Cervical Heart Transplantation in Mice

The heterotopic cervical heart transplantation in mice is a valuable tool in transplant and cardiovascular research. The cuff technique greatly simplifies this model by avoiding challenging suture anastomoses of small vessels thereby reducing warm ischemia time. In comparison to abdominal graft implantation the cervical model is less invasive and the implanted graft is easily accessible for further follow-up examinations. Anastomoses are performed by pulling the ascending aorta of the graft over the cuff with the recipient&#8217;s common carotid artery and by pulling the main pulmonary artery over the cuff with the external jugular vein. Selection of appropriate cuff size and complete mobilization of the vessels are important for successful revascularization. Ischemia-reperfusion (I/R) injury can be minimized by perfusing the graft with a cardioplegic solution and by hypothermia. In this article, we provide technical details for a simplified and improved cuff technique, which should allow surgeons with basic microsurgical skills to perform the procedure with a high success rate.

The cuff technique shortens and facilitates the model of heterotopic cervical heart transplantation in mice by avoiding technically challenging suture anastomoses of small vessels. The technical details shown in this video paper should allow researches to establish this model in their laboratories.

Heterotopic Cervical Transplante Cardíaco em Ratos

The heterotopic cervical heart transplantation in mice is a valuable tool in transplant and cardiovascular research. The cuff technique greatly simplifies ...

Heterotopic Renal Autotransplantation in a Porcine Model: A Step-by-Step Protocol

Kidney transplantation is the treatment of choice for patients suffering from end-stage renal disease. It offers better life expectancy and higher quality of life when compared to dialysis. Although the last few decades have seen major improvements in patient outcomes following kidney transplantation, the increasing shortage of available organs represents a severe problem worldwide. To expand the donor pool, marginal kidney grafts recovered from extended criteria donors (ECD) or donated after circulatory death (DCD) are now accepted for transplantation. To further improve the postoperative outcome of these marginal grafts, research must focus on new therapeutic approaches such as alternative preservation techniques, immunomodulation, gene transfer, and stem cell administration.
Experimental studies in animal models are the final step before newly developed techniques can be translated into clinical practice. Porcine kidney transplantation is an excellent model of human transplantation and allows investigation of novel approaches. The major advantage of the porcine model is its anatomical and physiological similarity to the human body, which facilitates the rapid translation of new findings to clinical trials. This article offers a surgical step-by-step protocol for an autotransplantation model and highlights key factors to ensure experimental success. Adequate pre- and postoperative housing, attentive anesthesia, and consistent surgical techniques result in favorable postoperative outcomes. Resection of the contralateral native kidney provides the opportunity to assess post-transplant graft function. The placement of venous and urinary catheters and the use of metabolic cages allow further detailed evaluation. For long-term follow-up studies and investigation of alternative graft preservation techniques, autotransplantation models are superior to allotransplantation models, as they avoid the confounding bias posed by rejection and immunosuppressive medication.

Porcine models of organ transplantation provide an important platform to study mechanisms of organ preservation. This article describes a heterotopic porcine renal autotransplantation model, which allows investigating new approaches to improve the outcome of transplantation using marginal kidney grafts.

Heterotópico Renal autotransplante em um modelo suíno: Um Protocolo Passo-a-Passo

Kidney transplantation is the treatment of choice for patients suffering from end-stage renal disease. It offers better life expectancy and higher quality ...

Isometric Contractility Measurement of the Mouse Mesenteric Artery Using Wire Myography

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and drugs. It is widely used in many studies on the physiological functions of vascular smooth muscle, the pathogenesis of vascular diseases such as hypertension, and the development of smooth muscle relaxant drugs. The mouse is a widely used model animal with a large pool of disease models and genetically modified strains. We introduced this method to measure the isometric contraction of mouse mesenteric artery in detail. A 1.4-mm segment of mouse mesenteric resistance artery was isolated and mounted on a myograph chamber by passing two steel wires through its lumen. After equilibration and normalization steps, the vessel segment was potentiated by a high-K+ solution twice prior to the contraction assay. As an example of the application of this method in drug development, we measured the relaxant effect of a novel natural substance, neoliensinine, isolated from a Chinese herb, embryos of the lotus seed (Nelumbo nucifera Gaertn.) on mouse mesenteric arteries. The vessel segments mounted on the myograph chamber were stimulated with a high-K+ solution. When the force tension reached a stable sustained phase, cumulative doses of neoliensinine were added to the chamber. We found that neoliensinine had a dose-dependent relaxant effect on smooth muscle contraction, thus suggesting that it bears potential activity against hypertension. In addition, as the vessel segment can survive at least 4 hours after mounting and maintain contractility induced by the high-K+ solution for many times, we suggest that the wire myograph system may be used for the time-consuming process of drug screening.

The wire myograph technique is used to investigate vascular smooth muscle functions and screen new drugs. We report a detailed protocol for measuring the isometric contractility of the mouse mesenteric artery and for screening new relaxants of vascular smooth muscle.

Medição de contratilidade isométrica da artéria mesentérica Mouse usando fio miografia

The wire myograph technique is used to assess the contractility of vascular smooth muscles in response to depolarization, GPCR agonists/inhibitors and ...

A Mouse Model of Vascularized Heterotopic Spleen Transplantation for Studying Spleen Cell Biology and Transplant Immunity

The spleen is a unique lymphoid organ that plays a critical role in the homeostasis of the immune and hematopoietic systems. Patients that have undergone splenectomy regardless of precipitating causes are prone to develop an overwhelming post-splenectomy infection and experience increased risks of deep venous thrombosis and malignancies. Recently, epidemiological studies indicated that splenectomy might be associated with the occurrence of cardiovascular diseases, suggesting that physiological functions of the spleen have not yet been fully recognized. Here, we introduce a mouse model of vascularized heterotopic spleen transplantation, which not only can be utilized to study the function and behavioral activity of splenic immune cell subsets in different biologic processes, but also can be a powerful tool to test the therapeutic potential of spleen transplantation in certain diseases. The main surgical steps of this model include donor spleen harvest, the removal of recipient native spleen, and spleen graft revascularization. Using congenic mouse strains (e.g., mice with CD45.1/CD45.2 backgrounds), we observed that after syngeneic transplantation, both donor-derived splenic lymphocytes and myeloid cells migrated out of the graft as early as post-operative day 1, concomitant with the influx of multiple types of recipient cells, thus generating a unique chimera. &#160;Despite relatively challenging techniques, this procedure can be performed with &#62;90% success rate. This model allows tracking the fate, longevity, and function of splenocytes during steady state and in a disease setting following a spleen transplantation, thereby offering a great opportunity to discover the distinct role for spleen-derived immune cells in different disease processes.

This protocol details the surgical steps of a mouse model of vascularized heterotopic spleen transplantation, a technically challenging model that can serve as a powerful tool in studying the fate and longevity of spleen cells, the mechanisms of distinct spleen cell populations in disease progression, and transplant immunity.

Um modelo de camundongo de transplante de baço heterotópico vascularizado para estudar a biologia celular do baço e a imunidade a transplantes

The spleen is a unique lymphoid organ that plays a critical role in the homeostasis of the immune and hematopoietic systems. Patients that have undergone ...

A Simplified Model for Heterotopic Heart Valve Transplantation in Rodents

There is an urgent clinical need for heart valve replacements that can grow in children. Heart valve transplantation is proposed as a new type of transplant with the potential to deliver durable heart valves capable of somatic growth with no requirement for anticoagulation. However, the immunobiology of heart valve transplants remains unexplored, highlighting the need for animal models to study this new type of transplant. Previous rat models for heterotopic aortic valve transplantation into the abdominal aorta have been described, though they are technically challenging and costly. For addressing this challenge, a renal subcapsular transplant model was developed in rodents as a practical and more straightforward method for studying heart valve transplant immunobiology. In this model, a single aortic valve leaflet is harvested and inserted into the renal subcapsular space. The kidney is easily accessible, and the transplanted tissue is securely contained in a subcapsular space that is well vascularized and can accommodate a variety of tissue sizes. Furthermore, because a single rat can provide three donor aortic leaflets and a single kidney can provide multiple sites for transplanted tissue, fewer rats are required for a given study. Here, the transplantation technique is described, providing a significant step forward in studying the transplant immunology of heart valve transplantation.

This protocol describes a simple and efficient method for the transplantation of aortic valve leaflets under the renal capsule to allow for the study of alloreactivity of heart valves.

Um modelo simplificado para transplante de válvula cardíaca heterotópica em roedores

There is an urgent clinical need for heart valve replacements that can grow in children. Heart valve transplantation is proposed as a new type of ...

A Modified Cuff Technique for Mouse Cervical Heterotopic Heart Transplantation Model

Cardiac allograft rejection limits the long-term survival of patients after heart transplantation. A mouse heart transplantation model is ideal for investigating the mechanism of cardiac allograft rejection in preclinical studies because of their high homology with human genes. This understanding would help develop unique approaches to improving patients&#39; long-term survival treated with cardiac allografts. In a mouse model, abdominal donor heart implantation is commonly performed with an end-to-end&#160;anastomosis to the recipient&#39;s aorta and inferior vena cava using stitches. In this model, the donor&#39;s heart is implanted by end-to-end anastomosis to the recipient&#39;s carotid artery and jugular vein by the modified-Cuff technique. The transplantation surgery is performed without stitching and thus may increase the survival of the recipient since there is no interference with the blood supply and venous reflux of the lower body. This mouse model would help investigate the mechanisms underlying the immunological and pathological (acute/chronic) rejection of cardiac allografts.

In the present protocol, a mouse heart transplantation model is used for investigating the mechanism of cardiac allograft rejection. In this heterotopic heart transplantation model, operation efficiency is improved, and the survival of cardiac grafts is ensured by a cervical end-to-end anastomosis of heart implantation using a modified Cuff technique.

Técnica de Cuff Modificada para Modelo de Transplante Cardíaco Heterotópico Cervical:

Cardiac allograft rejection limits the long-term survival of patients after heart transplantation. A mouse heart transplantation model is ideal for ...