Esta pesquisa foi apoiada pelas bolsas F31DC017053-01A1 (Lenell, PI) e K23DC014517 (Johnson, PI) do Instituto Nacional de Surdez e outros Transtornos de Comunicação dos Institutos Nacionais de Saúde.

Este estudo foi realizado em conformidade com o Comitê Institucional de Cuidados e Uso de Animais da Faculdade de Medicina da Universidade de Nova York.
1. Disseca laringe de rato
<ol><li>Eutanize rato de acordo com o protocolo institucionalmente aprovado. Raspe o pescoço ventral da mandíbula para o manúbrio e cotonete com álcool para evitar a contaminação de peles nos espécimes teciduais.</li>
	<li>Sob um escopo de dissecação com 10x de ampliação, extirpar toda a laringe, criando uma incisão do pescoço médio com um bisturi até que a traqueia seja exposta.</li>
	<li>Separe os músculos laríngeos extrínsecos ventral na linha média para expor a laringe usando fórceps e dissecando tesouras ou um bisturi.</li>
	<li>Corte a traqueia caudal até o terceiro anel traqueal e faça uma rostral incisão ao osso hioide para extirpor toda a laringe usando tesoura dissecando.</li>
	<li>Remova os tecidos laríngeos extrínsecos (esôfago, glândula tireoide e músculos laríngeos extrínsecos) da laringe usando ferramentas de microdisseção (pinças, pinos e microscisores) sob ampliação.</li>
	<li>Com microscisores, bissecção a laringe dorsalmente entre os aritóides usando a linha média entre os músculos cricoarytenoides posteriores como um marco. Fixar paredes laterais da laringe para expor as dobras vocais e, em seguida, bissect ventrally através da linha média da cartilagem tireoide entre a comissura anterior das dobras vocais com microscisores (Figura 1). NOTA: Esta etapa pode ser opcional; ele pode ser pulado para manter a laringe inteira. A biseção de laringes permite múltiplas técnicas de imunossuagem usando separadamente os lados direito e esquerdo da mesma laringe.</li>
	<li>Enxágüe cada hemi-laringe em solução tamponada de fosfato (PBS) por ~10 s e seque delicadamente com um limpador de tarefas para reduzir a formação de cristais de gelo durante o congelamento.</li>
</ol>2. Fixar e/ou congelar o tecido laríngeo
NOTA: A fixação pode não ser ideal para todos os protocolos de imunossuagem. Muitas vezes os tecidos laríngeos são congelados imediatamente após a dissecção. Pule a etapa 2.1 para congelar o tecido laríngeo sem fixação.
<ol><li>Para fixar hemi-laringes coloque tecidos em tubo de centrífuga preenchido com 4% de formaldeído em PBS por 1 h à temperatura ambiente em um agitador orbital a 70 rpm. Transfira tecidos para um tubo de centrífuga limpo e enxágue 3x por 20 min em PBS. Em seguida, transfira para um tubo de centrífuga limpo e submerse em uma solução de 20% de sacarose/5% de glicerol (~18 h ou até que o tecido afunde) a 4 °C. ATENÇÃO: O formaldeído é perigoso e deve ser usado em um capô de fumaça, juntamente com equipamentos de proteção individual adequados.</li>
	<li>Coloque todas as hemi-larynges em uma posição uniforme em um molde crio-mold cheio com composto de temperatura de corte ideal (OCT). Para um hemilarnox, coloque o tecido com a superfície medial da dobra vocal voltada para a parte inferior do criomold e o aspecto longitudinal da dobra vocal paralela à borda inferior da abertura criomold. Para laringes inteiros, coloque o tecido com os cricoarytenoides posteriores voltados para a parte inferior do criomold e o aspecto longitudinal da dobra vocal paralela à borda inferior da abertura criomold. NOTA: A orientação laríngea consistente dentro do composto OCT é fundamental para a crioseção da dobra vocal do rato. Uma vez que o hemilarynx esteja embutido e congelado, ele deve ser descongelado para mudar sua orientação, introduzindo assim riscos de danos teciduais de múltiplos ciclos de congelamento de degelo.</li>
	<li>Tecidos de congelamento de flash usando isopentano (2-metilbutano) refrigerados em um béquer de aço cercado por nitrogênio líquido. NOTA: A isopentane atinge a temperatura ideal para congelamento de tecidos quando precipitações brancas começam a se formar nas laterais e na parte inferior do béquer13. Isopientano é usado porque tem uma condutividade térmica maior do que o nitrogênio líquido, o que ajuda a evitar a quebra do bloco tecidual durante o congelamento rápido. Para obter uma descrição mais detalhada do tecido de congelamento em OTC consulte Kumar et al.13.</li>
	<li>Enrole cada molde em papel alumínio pré-rotulado e coloque em um saco de congelador individual para evitar a desidratação e armazene imediatamente em gelo seco até ser transferido para armazenamento em um congelador de -80 °C.</li>
</ol>3. Criosection hemilarynx em avião transversal
<ol><li>Ajuste a temperatura da câmara no criostato para -20 °C, que está no meio da faixa de temperatura (15-25 °C) recomendada para seção de tecido muscular pelo manual do fabricante.</li>
	<li>Defina a espessura da seção criostata para seções de 10 μm de espessura. NOTA: Para a análise transversal da fibra muscular, as seções de 10 μm de espessura são ideais para permitir a coloração completa e intensidade de imagem robusta das fibras musculares rotuladas para análise de digitação de fibras14,15,16. Alguns protocolos podem exigir espessura de seção diferente dependendo de alvos neuromusculares.</li>
	<li>Transfira tecidos para a câmara criostat, adicione uma camada uniforme de composto OCT no disco da amostra criostat (chuck) e coloque o bloco de tecido incorporado em cima do composto OCT no disco da amostra. Para obter seções transversais da dobra vocal para análise de fibra muscular tireonitoide (TA), afixe a amostra no mandril para que a cartilagem da tireoide ventral enfrente a lâmina criostat e a cartilagem aritóide enfrente o disco da amostra. NOTA: É fundamental notar que esses marcos não são visíveis nesta fase, devido ao composto OCT tornar-se branco e opaco quando congelado. Essa falta de visibilidade é a razão pela qual é fundamental notar a orientação do hemilarynx durante a fase de congelamento do flash.</li>
	<li>Corte o composto OCT avançando a cabeça da amostra em 100 μm até que a porção ventral da cartilagem da tireoide apareça.</li>
	<li>Em seguida, aparar e acompanhar seções de 30 μm desde o início da cartilagem tireoide até que a lavíria propria, os músculos M medial e o músculo TA lateral sejam expostos. NOTA: Os marcos laríngeos devem ser rastreados e observados desde o início da cartilagem da tireoide a cada 100 μm para garantir que o ângulo de secção não seja oblíquo. A Figura 2 representa os dois conjuntos de marcos laríngeos no plano transversal a 10x de ampliação.</li>
	<li>Uma vez alcançado o músculo TA alvo, colete seções em slides carregados positivamente a 10 μm.</li>
	<li>Armazene seções em PBS a 4 °C para reter a umidade até que estejam prontas para serem manchadas. NOTA: O tecido fixo pode ser armazenado em PBS até uma semana, dependendo do alvo IHC, enquanto o tecido não fixado deve ser imediatamente processado.</li>
</ol>4. Criosection hemilarynx em avião longitudinal
<ol><li>Com a câmara criostata novamente definida para -20 °C, mude a espessura da seção para 30 μm. NOTA: Para a análise do NMJ, uma espessura tecidual entre 30-60 μm pode ser usada para capturar vários NMJs completos dentro dos músculos laríngeos sem fragmentação do terminal nervoso ou da placa final do motor11,12,17.</li>
	<li>Para obter seções longitudinal de dobra vocal para análise nmj do músculo TA, afixar os espécimes ao mandril de modo que a epiglote é orientada para a lâmina criostata e o lúmen traqueal voltado para baixo em direção ao disco do espécime.</li>
	<li>Corte o composto OCT avançando a cabeça da amostra em 100 μm até que a cartilagem da tireoide apareça.</li>
	<li>Seções de corte e faixa de 30 μm desde o início da tireoide até que a álmina propria e divisões medial e lateral do músculo TA sejam expostas. NOTA: Cinco conjuntos de marcos laríngeos no plano longitudinal são recomendados para rastrear a progressão da profundidade tecidual em direção ao músculo TA alvo. A Figura 3 representa os marcos laríngeos no plano longitudinal a 10x de ampliação.</li>
	<li>Uma vez alcançado o músculo TA alvo, colete seções em slides carregados positivamente a 30 μm.</li>
	<li>Armazene seções em PBS a 4 °C para reter a umidade até que estejam prontas para serem manchadas.</li>
</ol>

<ol>
	<li>Connor, N. P., Suzuki, T., Lee, K., Sewall, G. K., Heisey, D. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Neuromuscular+junction+changes+in+aged+rat+thyroarytenoid+muscle.">Neuromuscular junction changes in aged rat thyroarytenoid muscle.</a> Annals of Otology, Rhinology and Laryngology. 111 (7), 579-586 (2002).</li><li>Suzuki, 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=Age-Related+Alterations+in+Myosin+Heavy+Chaing+Isoforms+in+Rat+Intrinsic+Laryngeal+Muscles.">Age-Related Alterations in Myosin Heavy Chaing Isoforms in Rat Intrinsic Laryngeal Muscles.</a> Annals of Otology, Rhinology and Laryngology. 111 (11), 962 (2002).</li><li>Johnson, A. M., Grant, L. M., Schallert, T., Ciucci, 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=Changes+in+Rat+50-kHz+Ultrasonic+Vocalizations+During+Dopamine+Denervation+and+Aging:+Relevance+to+Neurodegeneration.">Changes in Rat 50-kHz Ultrasonic Vocalizations During Dopamine Denervation and Aging: Relevance to Neurodegeneration.</a> Current Neuropharmacology. 13 (2), 211-219 (2015).</li><li>Wright, J. M., Gourdon, J. C., Clarke, P. B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Identification+of+multiple+call+categories+within+the+rich+repertoire+of+adult+rat+50-kHz+ultrasonic+vocalizations:+effects+of+amphetamine+and+social+context.">Identification of multiple call categories within the rich repertoire of adult rat 50-kHz ultrasonic vocalizations: effects of amphetamine and social context.</a> Psychopharmacology. 211 (1), 1-13 (2010).</li><li>Bowers, J. M., Perez-Pouchoulen, M., Edwards, N. S., McCarthy, M. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Foxp2+mediates+sex+differences+in+ultrasonic+vocalization+by+rat+pups+and+directs+order+of+maternal+retrieval.">Foxp2 mediates sex differences in ultrasonic vocalization by rat pups and directs order of maternal retrieval.</a> Journal of Neuroscience. 33 (8), 3276-3283 (2013).</li><li>Basken, J. N., Connor, N. P., Ciucci, 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=Effect+of+aging+on+ultrasonic+vocalizations+and+laryngeal+sensorimotor+neurons+in+rats.">Effect of aging on ultrasonic vocalizations and laryngeal sensorimotor neurons in rats.</a> Experimental Brain Research. 219 (3), 351-361 (2012).</li><li>Ciucci, M. 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=Reduction+of+dopamine+synaptic+activity:+degradation+of+50-kHz+ultrasonic+vocalization+in+rats.">Reduction of dopamine synaptic activity: degradation of 50-kHz ultrasonic vocalization in rats.</a> Behavioral Neuroscience. 123 (2), 328-336 (2009).</li><li>Ciucci, M. R., Vinney, L., Wahoske, E. J., Connor, N. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+translational+approach+to+vocalization+deficits+and+neural+recovery+after+behavioral+treatment+in+Parkinson+disease.">A translational approach to vocalization deficits and neural recovery after behavioral treatment in Parkinson disease.</a> Journal of Communication Disorders. 43 (4), 319-326 (2010).</li><li>Nagai, H., Ota, F., Konopacki, R., Connor, N. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Discoordination+of+laryngeal+and+respiratory+movements+in+aged+rats.">Discoordination of laryngeal and respiratory movements in aged rats.</a> American Journal of Otolaryngology. 26 (6), 377-382 (2005).</li><li>Ma, S. T., Maier, E. Y., Ahrens, A. M., Schallert, T., Duvauchelle, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Repeated+intravenous+cocaine+experience:+development+and+escalation+of+pre-drug+anticipatory+50-kHz+ultrasonic+vocalizations+in+rats.">Repeated intravenous cocaine experience: development and escalation of pre-drug anticipatory 50-kHz ultrasonic vocalizations in rats.</a> Behavioural Brain Research. 212 (1), 109-114 (2010).</li><li>Inagi, K., Schultz, E., Ford, C. N. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=An+anatomic+study+of+the+rat+larynx:+establishing+the+rat+model+for+neuromuscular+function.">An anatomic study of the rat larynx: establishing the rat model for neuromuscular function.</a> Otolaryngology and Head and Neck Surgery. 118 (1), 74-81 (1998).</li><li>Lenell, C., Newkirk, B., Johnson, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Laryngeal+Neuromuscular+Response+to+Short-+and+Long-Term+Vocalization+Training+in+Young+Male+Rats.">Laryngeal Neuromuscular Response to Short- and Long-Term Vocalization Training in Young Male Rats.</a> Journal of Speech, Language, and Hearing Research. 62 (2), 247-256 (2019).</li><li>Kumar, A., Accorsi, A., Rhee, Y., Girgenrath, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Do's+and+don'ts+in+the+preparation+of+muscle+cryosections+for+histological+analysis.">Do's and don'ts in the preparation of muscle cryosections for histological analysis.</a> Journal of Visualized Experiments. (99), e52793 (2015).</li><li>McMullen, C. A., Andrade, F. H. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Functional+and+morphological+evidence+of+age-related+denervation+in+rat+laryngeal+muscles.">Functional and morphological evidence of age-related denervation in rat laryngeal muscles.</a> Journals of Gerontology. Series A: Biological Sciences and Medical Sciences. 64 (4), 435-442 (2009).</li><li>McMullen, C. A., 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=Chronic+stimulation-induced+changes+in+the+rodent+thyroarytenoid+muscle.">Chronic stimulation-induced changes in the rodent thyroarytenoid muscle.</a> Journal of Speech, Language, and Hearing Research. 54 (3), 845-853 (2011).</li><li>Lenell, C., Johnson, A. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Sexual+dimorphism+in+laryngeal+muscle+fibers+and+ultrasonic+vocalizations+in+the+adult+rat.">Sexual dimorphism in laryngeal muscle fibers and ultrasonic vocalizations in the adult rat.</a> Laryngoscope. 127 (8), 270-276 (2017).</li><li>Johnson, A. M., Ciucci, M. R., Connor, N. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Vocal+training+mitigates+age-related+changes+within+the+vocal+mechanism+in+old+rats.">Vocal training mitigates age-related changes within the vocal mechanism in old rats.</a> Journals of Gerontology. Series A: Biological Sciences and Medical Sciences. 68 (12), 1458-1468 (2013).</li><li>Feng, X., Zhang, T., Ralston, E., Ludlow, C. L. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Differences+in+neuromuscular+junctions+of+laryngeal+and+limb+muscles+in+rats.">Differences in neuromuscular junctions of laryngeal and limb muscles in rats.</a> Laryngoscope. 122 (5), 1093-1098 (2012).</li></ol>

Os autores não têm nada a revelar.

Preparar dobras vocais de ratos para análise neuromuscular pode apresentar vários desafios. Não só os músculos laríngeos são pequenos e cercados por cartilagem, dificultando a extração direta do músculo alvo, a alta variabilidade também foi encontrada entre os animais na profundidade de marcos anatômicos laríngeos. Para o protocolo de plano transversal, as seções completas das dobras vocais apareceram entre 21-85 seções (10 μm por seção) após o aparecimento inicial da cartilagem da tireoide ventral, ...

A laringe de ratos é um modelo bem estabelecido para investigar adaptações de laringe neuromuscular estrutural e funcional para o desenvolvimento, envelhecimento, doença e agentes farmacológicos1,2,3,4,5. A consistência dos métodos histológicos é fundamental para essa linha de trabalho, pois há múltiplas complexidades envolvidas na preparação e análise muscular, bem como desafios associados ao tamanho, forma e topografia laríngeos dos músculos encapsulados dentro das cartilagens laríngeas1,6,7,8,9,10,11 . Devido ao pequeno tamanho dos músculos laríngeos intrínsecos do rato, incorporação sistemática, congelamento e criosecção são fundamentais para alcançar resultados consistentes e precisos. Por exemplo, ao seccionar a dobra vocal do rato no plano coronal, as junções neuromusculares (NMJs) de quatro dos músculos laríngeos intrínsecos estão localizadas dentro de menos de 1,8 mm de profundidade tecidual11. Portanto, o monitoramento preciso da anatomia muscular laríngea durante a criosecção é imperativo para identificar com precisão a seção de interesse e evitar o oversectioning do tecido. O oversectioning do músculo alvo pode resultar em identificação imprecisa do número e topografia de NMJs11 ou pode resultar em reduções globais no tamanho da amostra se o músculo alvo for descartado devido à confusão de orientação de marco12. À medida que novos modelos para o estudo do músculo laríngeo e suas respectivas adaptações são desenvolvidos, procedimentos operacionais padrão são essenciais para garantir que os resultados sejam precisos, confiáveis e reprodutíveis em todos os estudos.
O objetivo deste artigo é detalhar a preparação da dobra vocal de rato para uma análise longitudinal e transversal ideal. Métodos detalhados usados regularmente em nosso laboratório são descritos para identificar marcos musculares alvo durante a crioseção. Embora métodos semelhantes sejam usados em vários laboratórios, maiores detalhes são fornecidos aqui do que na literatura para garantir uma replicação confiável e precisa quando implementado por investigadores iniciantes. O objetivo deste tutorial é fornecer uma metodologia padrão para avaliação imunohistoquímica (IHC) da dobra vocal de ratos para melhorar a consistência entre laboratórios e investigações.

<table>
	<tbody>
		<tr>
			<td>2-Methylbutane Certified</td>
			<td>Fisher Chemical</td>
			<td>35514</td>
			<td></td>
		</tr>
		<tr>
			<td>Aluminum Foil</td>
			<td>Fisherbrand</td>
			<td>1213101</td>
			<td></td>
		</tr>
		<tr>
			<td>Cryo Tongs SS</td>
			<td>Thermo Scientific</td>
			<td>11679123</td>
			<td></td>
		</tr>
		<tr>
			<td>Cryostat</td>
			<td>Leica Biosystems</td>
			<td>CM3050</td>
			<td></td>
		</tr>
		<tr>
			<td>Cryostat blades</td>
			<td>C.L. Sturkey D554X50</td>
			<td>22-210-045</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable Base Molds 15mm x 15mm</td>
			<td>Thermo Scientific</td>
			<td>41-741</td>
			<td></td>
		</tr>
		<tr>
			<td>Disposable Underpads</td>
			<td>Medline</td>
			<td>23-666-062</td>
			<td></td>
		</tr>
		<tr>
			<td>Dissection kit</td>
			<td>Thermo Scientific</td>
			<td>9996969</td>
			<td></td>
		</tr>
		<tr>
			<td>DPBS - Dulbecco&#39;s Phosphate-Buffered Saline</td>
			<td>Gibco</td>
			<td>14190136</td>
			<td></td>
		</tr>
		<tr>
			<td>Frozen Section Medium</td>
			<td>Fisher Healthcare</td>
			<td>23-730-571</td>
			<td></td>
		</tr>
		<tr>
			<td>Ice Bucket</td>
			<td>Bel-Art</td>
			<td>11999054</td>
			<td></td>
		</tr>
		<tr>
			<td>Immunostain Moisture Chamber</td>
			<td>Ted Pella Inc</td>
			<td>NC9425474</td>
			<td></td>
		</tr>
		<tr>
			<td>Needle holders</td>
			<td>Assi</td>
			<td>ASSI.B148</td>
			<td></td>
		</tr>
		<tr>
			<td>Non-Woven Sponges, 4 Ply</td>
			<td>Quick Medical</td>
			<td>9023</td>
			<td></td>
		</tr>
		<tr>
			<td>Orbital shaker</td>
			<td>Troemner</td>
			<td>02-217-987</td>
			<td></td>
		</tr>
		<tr>
			<td>Pap pen</td>
			<td></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Paraformaldehyde, 16% w/v aq. soln., methanol free</td>
			<td>Alfa Aesar</td>
			<td>50-00-0</td>
			<td></td>
		</tr>
		<tr>
			<td>Premium Microcentrifuge Tubes</td>
			<td>Fisherbrand</td>
			<td>5408129</td>
			<td></td>
		</tr>
		<tr>
			<td>Specimen Storage Bags</td>
			<td>Fisherbrand</td>
			<td>19240093</td>
			<td></td>
		</tr>
		<tr>
			<td>Stainless Steel Graduated Measure 32 oz/100 mL</td>
			<td>Polar Ware</td>
			<td>114231B</td>
			<td></td>
		</tr>
		<tr>
			<td>Superfrost Plus Microscope Slides</td>
			<td>Fisherbrand</td>
			<td>12-550-15</td>
			<td></td>
		</tr>
		<tr>
			<td>Task wiper</td>
			<td>Kimberly-Clark Professional&#8482; 34155</td>
			<td>06666A</td>
			<td></td>
		</tr>
		<tr>
			<td>Timer</td>
			<td>Fisherbrand</td>
			<td>2261840</td>
			<td></td>
		</tr>
		<tr>
			<td>Vannas Pattern Scissors</td>
			<td>Assi</td>
			<td>ASSI.SAS15RV</td>
			<td></td>
		</tr>
		<tr>
			<td colspan="4">NOTE: For all supplies, these are examples of equipment to purchase. The exact model is not necessary to complete our methods.</td>
		</tr>
	</tbody>
</table>

preparation of the rat vocal fold for neuromuscular analyses

O objetivo deste tutorial é descrever a preparação da dobra vocal de rato para o estudo neuromuscular histoquímico. Este protocolo descreve procedimentos para dissecção laríngea de ratos, congelamento de flash e criosectioning das dobras vocais. Este estudo descreve como criosecção dobras vocais em planos longitudinais e transversais. Uma novidade deste protocolo é o rastreamento laríngeo durante a criosecção que garante a identificação precisa dos músculos laríngeos intrínsecos e reduz a chance de perda de tecido. Os números demonstram a crioseção progressiva em ambos os planos. Vinte e nove hemi-laringes de ratos foram criosectionados e rastreados desde o surgimento da cartilagem tireoide até o aparecimento da primeira seção que incluía a dobra vocal completa. A dobra vocal completa foi visualizada para todos os animais em ambos os planos. Houve alta variabilidade na distância do aparecimento da cartilagem tireoide ao aparecimento da dobra vocal completa em ambos os planos. O peso não foi correlacionado à profundidade dos marcos laríngeos, sugerindo que a variabilidade individual e outros fatores relacionados à preparação tecidual podem ser responsáveis pela alta variabilidade no aparecimento de marcos durante a secção. Este estudo detalha uma metodologia e apresenta dados morfológicos para a preparação da dobra vocal de ratos para investigação neuromuscular histoquímica. Devido à alta variabilidade individual, os marcos laríngeos devem ser acompanhados de perto durante a crioseção para evitar a perda de tecido e tecido overfando. O uso de uma metodologia consistente, incluindo a preparação adequada do tecido e a conscientização de marcos dentro da laringe de ratos, auxiliará em resultados consistentes em estudos e ajudará novos pesquisadores interessados em usar a dobra vocal de ratos como modelo para investigar mecanismos neuromusculares laríngeos.

Os resultados representativos foram parte de uma investigação contínua dos efeitos do exercício vocal no sistema neuromuscular laríngeo. Vinte e nove ratos Fischer 344/marrom da Noruega (12 de 9 meses, 17 24 meses) foram pesados e eutanásia com inalação de CO2 seguida de uma toracotomia bilateral.
Os procedimentos seguiram o protocolo delineado para rotular NMJs e tamanho de fibra dos músculos TS lateral e medial. A distância entre os marcos laríngeos foi rastreada em pla...

Watch this Scientific Journal Video about Preparation of the Rat Vocal Fold for Neuromuscular Analyses at JoVE.com

Preparation of the Rat Vocal Fold for Neuromuscular Analyses

Este protocolo descreve métodos usados para preparar dobras vocais de ratos para estudo neuromuscular histoquímico.

Preparação da Dobra Vocal do Rato para Análises Neuromusculares

The purpose of this tutorial is to describe the preparation of the rat vocal fold for histochemical neuromuscular study. This protocol outlines procedures ...

preparation-of-the-rat-vocal-fold-for-neuromuscular-analyses

Research

JoVE Journal

Neuroscience

2.6K visualizações.  New York University School of Medicine. Este protocolo descreve métodos usados para preparar dobras vocais de ratos para estudo neuromuscular histoquímico.

Vídeo: Preparation of the Rat Vocal Fold for Neuromuscular Analyses

Morphometric Analyses of Retinal Sections

Morphometric analyses of retinal sections have been used in examining retinal diseases. For examples, neuronal cells were significantly lost in the retinal ganglion cell layer (RGCL) in rat models with N-methyl-D-aspartate (NMDA)&#x2013;induced excitotoxicity1, retinal ischemia-reperfusion injury2 and glaucoma3. Reduction of INL and inner plexiform layer (IPL) thicknesses were reversed with citicoline treatment in rats' eyes subjected to kainic acid-mediated glutamate excitotoxicity4. Alteration of RGC density and soma sizes were observed with different drug treatments in eyes with elevated intraocular pressure3,5,6. Therefore, having objective methods of analyzing the retinal morphometries may be of great significance in evaluating retinal pathologies and the effectiveness of therapeutic strategies.
The retinal structure is multi-layers and several different kinds of neurons exist in the retina. The morphometric parameters of retina such as cell number, cell size and thickness of different layers are more complex than the cell culture system. Early on, these parameters can be detected using other commercial imaging software. The values are normally of relative value, and changing to the precise value may need further accurate calculation. Also, the tracing of the cell size and morphology may not be accurate and sensitive enough for statistic analysis, especially in the chronic glaucoma model. The measurements used in this protocol provided a more precise and easy way. And the absolute length of the line and size of the cell can be reported directly and easy to be copied to other files. For example, we traced the margin of the inner and outer most nuclei in the INL and formed a line then using the software to draw a 90 degree angle to measure the thickness. While without the help of the software, the line maybe oblique and the changing of retinal thickness may not be repeatable among individual observers. In addition, the number and density of RGCs can also be quantified. This protocol successfully decreases the variability in quantitating features of the retina, increases the sensitivity in detecting minimal changes.
 	This video will demonstrate three types of morphometric analyses of the retinal sections. They include measuring the INL thickness, quantifying the number of RGCs and measuring the sizes of RGCs in absolute value. These three analyses are carried out with Stereo Investigator (MBF Bioscience &mdash; MicroBrightField, Inc.). The technique can offer a simple but scientific platform for morphometric analyses.

This video demonstrates three types of morphometric analyses of the retina, which include measuring the inner nuclear layer thickness, quantifying the number of retinal ganglion cells (RGCs) and measuring the sizes of RGCs. The technique can offer a simple but scientific platform for morphometric analyses.

Análises morfométricas de secções da retina

Morphometric analyses of retinal sections have been used in examining retinal diseases. For examples, neuronal cells were significantly lost in the ...

Neurociência

Sequential Photo-bleaching to Delineate Single Schwann Cells at the Neuromuscular Junction

Sequential photo-bleaching provides a non-invasive way to label individual SCs at the NMJ. The NMJ is the largest synapse of the mammalian nervous system and has served as guiding model to study synaptic structure and function. In mouse NMJs motor axon terminals form pretzel-like contact sites with muscle fibers. The motor axon and its terminal are sheathed by SCs. Over the past decades, several transgenic mice have been generated to visualize motor neurons and SCs, for example Thy1-XFP1 and Plp-GFP mice2, respectively.
Along motor axons, myelinating axonal SCs are arranged in non-overlapping internodes, separated by nodes of Ranvier, to enable saltatory action potential propagation. In contrast, terminal SCs at the synapse are specialized glial cells, which monitor and promote neurotransmission, digest debris and guide regenerating axons. NMJs are tightly covered by up to half a dozen non-myelinating terminal SCs - these, however, cannot be individually resolved by light microscopy, as they are in direct membrane contact3.
Several approaches exist to individually visualize terminal SCs. None of these are flawless, though. For instance, dye filling, where single cells are impaled with a dye-filled microelectrode, requires destroying a labelled cell before filling a second one. This is not compatible with subsequent time-lapse recordings3. Multi-spectral "Brainbow" labeling of SCs has been achieved by using combinatorial expression of fluorescent proteins4. However, this technique requires combining several transgenes and is limited by the expression pattern of the promoters used. In the future, expression of "photo-switchable" proteins in SCs might be yet another alternative5. Here we present sequential photo-bleaching, where single cells are bleached, and their image obtained by subtraction. We believe that this approach - due to its ease and versatility - represents a lasting addition to the neuroscientist's technology palette, especially as it can be used in vivo and transferred to others cell types, anatomical sites or species6.
In the following protocol, we detail the application of sequential bleaching and subsequent confocal time-lapse microscopy to terminal SCs in triangularis sterni muscle explants. This thin, superficial and easily dissected nerve-muscle preparation7,8 has proven useful for studies of NMJ development, physiology and pathology9. Finally, we explain how the triangularis sterni muscle is prepared after fixation to perform correlated high-resolution confocal imaging, immunohistochemistry or ultrastructural examinations.

Visualizing individual cells in densely packed tissues, such as terminal Schwann cells (SCs) at neuromuscular junctions (NMJs), is challenging. "Sequential photo-bleaching" allows delineating single terminal SCs, for instance in the triangularis sterni muscle explant, a convenient nerve-muscle preparation, where sequential bleaching can be combined with time-lapse imaging and post-hoc immunostainings.

Sequencial de foto-branqueamento de delinear células de Schwann individuais na junção neuromuscular

Sequential photo-bleaching provides a non-invasive way to label individual SCs at the NMJ. The NMJ is the largest synapse of the mammalian nervous system ...

Dissection of the Transversus Abdominis Muscle for Whole-mount Neuromuscular Junction Analysis

Analysis of neuromuscular junction morphology can give important insight into the physiological status of a given motor neuron. Analysis of thin flat muscles can offer significant advantage over traditionally used thicker muscles, such as those from the hind limb (e.g. gastrocnemius). Thin muscles allow for comprehensive overview of the entire innervation pattern for a given muscle, which in turn permits identification of selectively vulnerable pools of motor neurons. These muscles also allow analysis of parameters such as motor unit size, axonal branching, and terminal/nodal sprouting. A common obstacle in using such muscles is gaining the technical expertise to dissect them. In this video, we detail the protocol for dissecting the transversus abdominis (TVA) muscle from young mice and performing immunofluorescence to visualize axons and neuromuscular junctions (NMJs). We demonstrate that this technique gives a complete overview of the innervation pattern of the TVA muscle&#160;and can be used to investigate NMJ pathology in a mouse model of the childhood motor neuron disease, spinal muscular atrophy.

Dissection of the Transversus Abdominis Muscle for Whole-mount Neuromuscular Junction Analysis

In this video we demonstrate a protocol for dissection of the transversus abdominis muscle of the mouse and use immunofluorescence and microscopy to visualize neuromuscular junctions.

Dissecção do Músculo Transversus Abdominis para Análise de Junção Neuromuscular de Montagem Integral

Analysis of neuromuscular junction morphology can give important insight into the physiological status of a given motor neuron. Analysis of thin flat ...

Why Quantification Matters: Characterization of Phenotypes at the Drosophila Larval Neuromuscular Junction

Most studies on morphogenesis rely on qualitative descriptions of how anatomical traits are affected by the disruption of specific genes and genetic pathways. Quantitative descriptions are rarely performed, although genetic manipulations produce a range of phenotypic effects and variations are observed even among individuals within control groups.&#160;Emerging evidence shows that morphology, size and location of organelles play a previously underappreciated, yet fundamental role in cell function and survival. Here we provide step-by-step instructions for performing quantitative analyses of phenotypes at the Drosophila larval neuromuscular junction (NMJ). We use several reliable immuno-histochemical markers combined with bio-imaging techniques and morphometric analyses to examine the effects of genetic mutations on specific cellular processes. In particular, we focus on the quantitative analysis of phenotypes affecting morphology, size and position of nuclei within the striated muscles of Drosophila larvae. The Drosophila larval NMJ is a valuable experimental model to investigate the molecular mechanisms underlying the structure and the function of the neuromuscular system, both in health and disease. However, the methodologies we describe here can be extended to other systems as well.

Why Quantification Matters: Characterization of Phenotypes at the Drosophila Larval Neuromuscular Junction

Morphology, size and location of intracellular organelles are evolutionarily conserved and appear to directly affect their function. Understanding the molecular mechanisms underlying these processes has become an important goal of modern biology. Here we show how these studies can be facilitated by the application of quantitative techniques.

Por Quantificação Matérias: Caracterização de fenótipos na<em&gt; Drosophila</em&gt; Larval Junção Neuromuscular

Most studies on morphogenesis rely on qualitative descriptions of how anatomical traits are affected by the disruption of specific genes and genetic ...

Microstate and Omega Complexity Analyses of the Resting-state Electroencephalography

Microstate and omega complexity are two reference-free electroencephalography (EEG) measures that can represent the temporal and spatial complexities of EEG data and have been widely used to investigate the neural mechanisms in some brain disorders. The goal of this article is to describe the protocol underlying EEG microstate and omega complexity analyses step by step. The main advantage of these two measures is that they could eliminate the reference-dependent problem inherent to traditional spectrum analysis. In addition, microstate analysis makes good use of high time resolution of resting-state EEG, and the four obtained microstate classes could match the corresponding resting-state networks respectively. The omega complexity characterizes the spatial complexity of the whole brain or specific brain regions, which has obvious advantage compared with traditional complexity measures focusing on the signal complexity in a single channel. These two EEG measures could complement each other to investigate the brain complexity from the temporal and spatial domain respectively.

This article describes the protocol underlying electroencephalography (EEG) microstate analysis and omega complexity analysis, which are two reference-free EEG measures and highly valuable to explore the neural mechanisms of brain disorders.

Microestado e análises de complexidade Omega de eletroencefalografia a estado descansando

Microstate and omega complexity are two reference-free electroencephalography (EEG) measures that can represent the temporal and spatial complexities of ...

Levator Auris Longus Preparation for Examination of Mammalian Neuromuscular Transmission Under Voltage Clamp Conditions

This protocol describes a technique to record synaptic transmission from the neuromuscular junction under current-clamp and voltage-clamp conditions. An ex vivo preparation of the levator auris longus (LAL) is used because it is a thin muscle that provides easy visualization of the neuromuscular junction for microelectrode impalement at the motor endplate. This method allows for the recording of spontaneous miniature endplate potentials and currents (mEPPs and mEPCs), nerve-evoked endplate potentials and currents (EPPs and EPCs), as well as the membrane properties of the motor endplate. Results obtained from this method include the quantal content (QC), number of vesicle release sites (n), probability of vesicle release (prel), synaptic facilitation and depression, as well as the muscle membrane time constant (&#964;m) and input resistance. Application of this technique to mouse models of human disease can highlight key pathologies in disease states and help identify novel treatment strategies. By fully voltage-clamping a single synapse, this method provides one of the most detailed analyses of synaptic transmission currently available.

Levator Auris Longus Preparation for Examination of Mammalian Neuromuscular Transmission Under Voltage Clamp Conditions

The protocol described in this paper uses the mouse levator auris longus (LAL) muscle to record spontaneous and nerve-evoked postsynaptic potentials (current-clamp) and currents (voltage-clamp) at the neuromuscular junction. Use of this technique can provide key insights into mechanisms of synaptic transmission under normal and disease conditions.

Músculo levantador Auris Longus Preparação para exame da transmissão Neuromuscular mamíferos sob condições de grampo de tensão

This protocol describes a technique to record synaptic transmission from the neuromuscular junction under current-clamp and voltage-clamp conditions. An ...

Dissection of Single Skeletal Muscle Fibers for Immunofluorescent and Morphometric Analyses of Whole-Mount Neuromuscular Junctions

The neuromuscular junction (NMJ) is a specialized point of contact between the motor nerve and the skeletal muscle. This peripheral synapse exhibits high morphological and functional plasticity. In numerous nervous system disorders, NMJ is an early pathological target resulting in neurotransmission failure, weakness, atrophy, and even in muscle fiber death. Due to its relevance, the possibility to quantitatively assess certain aspects of the relationship between NMJ components can help to understand the processes associated with its assembly/disassembly. The first obstacle when working with muscles is to gain the technical expertise to quickly identify and dissect without damaging their fibers. The second challenge is to utilize high-quality detection methods to obtain NMJ images that can be used to perform quantitative analysis. This article presents a step-by-step protocol for dissecting extensor digitorum longus and soleus muscles from rats. It also explains the use of immunofluorescence to visualize pre and postsynaptic elements of whole-mount NMJs. Results obtained demonstrate that this technique can be used to establish the microscopic anatomy of the synapsis and identify subtle changes in the status of some of its components under physiological or pathological conditions.

The ability to accurately detect neuromuscular junction components is crucial in evaluating modifications in its architecture because of pathological or developmental processes. Here we present a complete description of a straightforward method to obtain high-quality images of whole-mount neuromuscular junctions that can be used to perform quantitative measurements.

Dissecção de fibras musculares esqueléticas únicas para análises imunofluorescentes e morfométricas de junções neuromusculares de monte inteiro

The neuromuscular junction (NMJ) is a specialized point of contact between the motor nerve and the skeletal muscle. This peripheral synapse exhibits high ...

Expanding the Toolkit for In Vivo Imaging of Axonal Transport

Axonal transport maintains neuronal homeostasis by enabling the bidirectional trafficking of diverse organelles and cargoes. Disruptions in axonal transport have devastating consequences for individual neurons and their networks, and contribute to a plethora of neurological disorders. As many of these conditions involve both cell autonomous and non-autonomous mechanisms, and often display a spectrum of pathology across neuronal subtypes, methods to accurately identify and analyze neuronal subsets are imperative.
This paper details protocols to assess in vivo axonal transport of signaling endosomes and mitochondria in sciatic nerves of anesthetized mice. Stepwise instructions are provided to 1) distinguish motor from sensory neurons in vivo, in situ, and ex vivo by using mice that selectively express fluorescent proteins within cholinergic motor neurons; and 2) separately or concurrently assess in vivo axonal transport of signaling endosomes and mitochondria. These complementary intravital approaches facilitate the simultaneous imaging of different cargoes in distinct peripheral nerve axons to quantitatively monitor axonal transport in health and disease.

Expanding the Toolkit for In Vivo Imaging of Axonal Transport

Using transgenic fluorescent mice, detailed protocols are described to assess in vivo axonal transport of signaling endosomes and mitochondria within motor and sensory axons of the intact sciatic nerve in live animals.

Expansão do Kit de Ferramentas para Imagens In Vivo do Transporte Axonal

Axonal transport maintains neuronal homeostasis by enabling the bidirectional trafficking of diverse organelles and cargoes. Disruptions in axonal ...

Preparation of Rat Sciatic Nerve for Ex Vivo Neurophysiology

Ex vivo preparations enable the study of many neurophysiological processes in isolation from the rest of the body while preserving local tissue structure. This work describes the preparation of rat sciatic nerves for ex vivo neurophysiology, including buffer preparation, animal procedures, equipment setup and neurophysiological recording. This work provides an overview of the different types of experiments possible with this method. The outlined method aims to provide 6 h of stimulation and recording on extracted peripheral nerve tissue in tightly controlled conditions for optimal consistency in results. Results obtained using this method are A-fibre compound action potentials (CAP) with peak-to-peak amplitudes in the millivolt range over the entire duration of the experiment. CAP amplitudes and shapes are consistent and reliable, making them useful to test and compare new electrodes to existing models, or the effects of interventions on the tissue, such as the use of chemicals, surgical alterations, or neuromodulatory stimulation techniques. Both conventional commercially available cuff electrodes with platinum-iridium contacts and custom-made conductive elastomer electrodes were tested and gave similar results in terms of nerve stimulus strength-duration response.

Preparation of Rat Sciatic Nerve for Ex Vivo Neurophysiology

This protocol describes the preparation of rat whole sciatic nerve tissue for ex vivo electrophysiological stimulation and recording in an environmentally-regulated, two-compartment, perfused saline bath.

Preparação do Nervo Ciático de Ratos para Neurofisiologia Ex Vivo

Ex vivo preparations enable the study of many neurophysiological processes in isolation from the rest of the body while preserving local tissue structure. ...

Visualizing the Morphological Characteristics of Neuromuscular Junction in Rat Medial Gastrocnemius Muscle

The neuromuscular junction (NMJ) is a complex structure serving for the signal communication from the motor neuron to the skeletal muscle and consists of three essential histological components: the pre-synaptic motor axon terminals, post-synaptic nicotinic acetylcholine receptors (AchRs), and peri-synaptic Schwann cells (PSCs). In order to demonstrate the morphological characteristics of NMJ, the rat medial gastrocnemius muscle was selected as the target-tissue and examined by using multiple fluorescent staining with various kinds of biomarkers, including neurofilament 200 (NF200) and vesicular acetylcholine transporter (VAChT) for the motor nerve fibers and their pre-synaptic terminals, alpha-bungarotoxin (&#945;-BTX) for the post-synaptic nicotinic AchRs, and S100 for the PSCs. In this study, staining was performed in two groups: in the first group, samples were stained with NF200, VAChT, and &#945;-BTX, and in the second group, samples were stained with NF200, &#945;-BTX, and S100. It was shown that both protocols can effectively demonstrate the detailed structure of NMJ. Using the confocal microscope, morphological characteristics of the pre-synaptic terminals, post-synaptic receptors, and PSC were seen, and their Z-stacks images were reconstructed in a three-dimensional pattern to further analyze the spatial correlation among the different labeling. From the perspective of methodology, these protocols provide a valuable reference for investigating the morphological characteristics of NMJ under physiological conditions, which may also be suitable to evaluate the pathological alteration of NMJ, such as peripheral nerve injury and regeneration.

The protocol shows a method to examine spatial correlation among the pre-synaptic terminals, post-synaptic receptors, and peri-synaptic Schwann cells in the rat medial gastrocnemius muscle using fluorescent immunohistochemistry with different biomarkers, namely, neurofilament 200, vesicular acetylcholine transporter, alpha-bungarotoxin, and S100.

Visualizando as Características Morfológicas da Junção Neuromuscular no Músculo Gastrocnemius De Rato Medial

The neuromuscular junction (NMJ) is a complex structure serving for the signal communication from the motor neuron to the skeletal muscle and consists of ...