Name: cryopreservation of zebrafish spermatogonia by whole testes needle immersed ultra-rapid cooling
Uploaded: 2018-03-04T13:00:00
Description: Watch this Scientific Journal Video about Cryopreservation of Zebrafish Spermatogonia by Whole Testes Needle Immersed Ultra-Rapid Cooling at JoVE.com

Este estudio fue apoyado por la investigación, desarrollo e innovación oficina de Hungría (grant 116912 a ÁH), la oficina de costos (alimentación y agricultura costo acción FA1205: AQUAGAMETE), el programa de becas beca Hungaricum (ayuda a ZM) y el nuevo Húngaro nacional excelencia Beca Predoctoral (grant EK).

Todos los métodos aquí descritos han sido aprobados por la ley de Bienestar Animal Húngaro.
1. preparación del reactivo
<ol><li>Soluciones madre<ol>
<li>Preparar 1 M trehalosa agregando 0,378 g de trehalosa dihidrato en 1 mL de dH2O. mezcla bien hasta que se disuelva por completo.</li>
		<li>Preparar 1 M sacarosa añadiendo 0,342 g de sacarosa en 1 mL de dH2O. mezcla bien hasta que se disuelva por completo.</li>
		<li>Preparar 1 M HEPES añadiendo 0,238 g de HEPES y...

<ol>
	<li>Mazur, P., Leibo, S. P., Seidel, G. R. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cryopreservation+of+the+germplasm+of+animals+used+in+biological+and+medical+research:+Importance,+impact,+status,+and+future+directions.">Cryopreservation of the germplasm of animals used in biological and medical research: Importance, impact, status, and future directions.</a> Biol. Reprod. 78 (1), 2-12 (2008).</li><li>Carmichael, C., Westerfield, M., Varga, Z. M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cryopreservation+and+In+Vitro+Fertilization+at+the+Zebrafish+International+Resource+Center.">Cryopreservation and In Vitro Fertilization at the Zebrafish International Resource Center.</a> Methods Mol. Biol. 546, 45-65 (2009).</li><li>Yang, H., Carmichael, C., Varga, Z. M., Tiersch, T. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Development+of+a+simplified+and+standardized+protocol+with+potential+for+high-throughput+for+sperm+cryopreservation+in+zebrafish+Danio+rerio.">Development of a simplified and standardized protocol with potential for high-throughput for sperm cryopreservation in zebrafish Danio rerio.</a> Theriogenology. 68 (2), 128-136 (2007).</li><li>Morris, J. P., Berghmans, S., Zahrieh, D., Neuberg, D. S., Kanki, J. P., Look, A. T. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Zebrafish+sperm+cryopreservation+with+N,N-dimethylacetamide.">Zebrafish sperm cryopreservation with N,N-dimethylacetamide.</a> Biotechniques. 35 (5), 956-968 (2003).</li><li>Yoshizaki, G., 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=Spermatogonial+transplantation+in+fish:+A+novel+method+for+the+preservation+of+genetic+resources.">Spermatogonial transplantation in fish: A novel method for the preservation of genetic resources.</a> Comp. Biochem. Physiol. Part D: Genomics Proteomics. 6 (1), 55-61 (2011).</li><li>Gao, D., Critser, J. K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Mechanisms+of+cryoinjury+in+living+cells.">Mechanisms of cryoinjury in living cells.</a> ILAR J. 41 (4), 187-196 (2000).</li><li>Asturiano, J. F., Cabrita, E., Horv&#225;th, &. #. 1. 9. 3. ;. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Progress,+challenges+and+perspectives+on+fish+gamete+cryopreservation:+A+mini-review.">Progress, challenges and perspectives on fish gamete cryopreservation: A mini-review.</a> Gen. Comp. Endocrinol. 245, 69-76 (2017).</li><li>K&#225;sa, 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=Development+of+sperm+vitrification+protocols+for+freshwater+fish+(Eurasian+perch,+Perca+fluviatilis)+and+marine+fish+(European+eel,+Anguilla+anguilla).">Development of sperm vitrification protocols for freshwater fish (Eurasian perch, Perca fluviatilis) and marine fish (European eel, Anguilla anguilla).</a> Gen. Comp. Endocrinol. 245, 102-107 (2017).</li><li>Cuevas-Uribe, R., Leibo, S. P., Daly, J., Tiersch, T. R. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+channel+catfish+with+sperm+cryopreserved+by+rapid+non-equilibrium+cooling.">Production of channel catfish with sperm cryopreserved by rapid non-equilibrium cooling.</a> Cryobiology. 63 (3), 186-197 (2011).</li><li>Wang, Y., Xiao, Z., Li, L., Fan, W., Li, S. W. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+needle+immersed+vitrification:+A+practical+and+convenient+method+with+potential+advantages+in+mouse+and+human+ovarian+tissue+cryopreservation.">Novel needle immersed vitrification: A practical and convenient method with potential advantages in mouse and human ovarian tissue cryopreservation.</a> Hum. Reprod. 23 (10), 2256-2265 (2008).</li><li>Liu, J., Cheng, K. M., Silversides, F. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Production+of+Live+Offspring+from+Testicular+Tissue+Cryopreserved+by+Vitrification+Procedures+in+Japanese+Quail+(Coturnix+japonica).">Production of Live Offspring from Testicular Tissue Cryopreserved by Vitrification Procedures in Japanese Quail (Coturnix japonica).</a> Biol. Reprod. 88 (5), 124 (2013).</li><li>Liu, J., Cheng, K. M., Silversides, F. G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Novel+needle-in-straw+vitrification+can+effectively+preserve+the+follicle+morphology,+viability,+and+vascularization+of+ovarian+tissue+in+Japanese+quail+(Coturnix+japonica).">Novel needle-in-straw vitrification can effectively preserve the follicle morphology, viability, and vascularization of ovarian tissue in Japanese quail (Coturnix japonica).</a> Anim. Reprod. Sci. 134 (3-4), 197-202 (2012).</li><li>Lee, S., Yoshizaki, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Successful+cryopreservation+of+spermatogonia+in+critically+endangered+Manchurian+trout+(Brachymystax+lenok).">Successful cryopreservation of spermatogonia in critically endangered Manchurian trout (Brachymystax lenok).</a> Cryobiology. 72 (2), 165-168 (2016).</li><li>Marques, L. S., 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=Viability+of+zebrafish+(Danio+rerio)+ovarian+follicles+after+vitrification+in+a+metal+container.">Viability of zebrafish (Danio rerio) ovarian follicles after vitrification in a metal container.</a> Cryobiology. 71 (3), 367-373 (2015).</li><li>Luji&#263;, J., 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=First+successful+vitrification+of+salmonid+ovarian+tissue.">First successful vitrification of salmonid ovarian tissue.</a> Cryobiology. 76, 154-157 (2017).</li><li>Bono-Mestre, C., Cardona-Costa, J., Garc&#237;a-Xim&#233;nez, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+on+cell+viability+of+three+zebrafish+testicular+cell+or+tissue+cryopreservation+methods.">Effects on cell viability of three zebrafish testicular cell or tissue cryopreservation methods.</a> CryoLetters. 30 (2), 148-152 (2009).</li><li>Marinovi&#263;, Z., 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=Cryosurvival+of+isolated+testicular+cells+and+testicular+tissue+of+tench+Tinca+tinca+and+goldfish+Carassius+auratus+following+slow-rate+freezing.">Cryosurvival of isolated testicular cells and testicular tissue of tench Tinca tinca and goldfish Carassius auratus following slow-rate freezing.</a> Gen. Comp. Endocrinol. 245, 77-83 (2017).</li><li>P&#353;eni&#269;ka, M., Saito, T., Rodina, M., Dzyuba, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cryopreservation+of+early+stage+Siberian+sturgeon+Acipenser+baerii+germ+cells,+comparison+of+whole+tissue+and+dissociated+cells.">Cryopreservation of early stage Siberian sturgeon Acipenser baerii germ cells, comparison of whole tissue and dissociated cells.</a> Cryobiology. 72, 119-122 (2016).</li><li>Lee, S., Iwasaki, Y., Shikina, S., Yoshizaki, G. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Generation+of+functional+eggs+and+sperm+from+cryopreserved+whole+testes.">Generation of functional eggs and sperm from cryopreserved whole testes.</a> Proc. Nati. Acad. Sci. USA. 110 (5), 1640-1645 (2013).</li></ol>

El objetivo principal de este estudio fue adaptar la aguja inmerso en procedimiento de enfriamiento ultra rápido desarrollado para especies de aves y mamíferos10,11,12 a la crioconservación de testículo de pez (pez cebra como modelo organismo). La mayoría de los estudios anteriores con respecto a la criopreservación de los recursos genéticos del pez cebra se centraron principalmente en criopreservación de esperma de pez ...

Nuevas tendencias en la ciencia y la biotecnología han llevado a la creación de miles de nuevas líneas mutantes de Drosophila, pez cebra, ratones y otras especies usadas como organismos modelo en biomedicina y otras ciencias1. Además, como nuevas tecnologías se desarrollan y se convierten en disponibles, los números de líneas mutantes aumentan constantemente2. Esto conduce a la necesidad de un almacenamiento seguro de los recursos genéticos más allá de las prácticas comunes de mantener colonias de cría. Como un método que permite el almacenamiento seguro de los recursos genéticos por un período indefinido de tiempo, criopreservación ofrece muchas ventajas tales como extensión de la temporada reproductiva, evita la necesidad de un mantenimiento continuo de los reproductores, y es más costo - y mano de obra eficiente2.
Protocolos de criopreservación de esperma desarrollado durante los últimos varios años2,3,4 ofrecen la oportunidad para el almacenaje acertado del material genético masculino de pez cebra. Sin embargo, la criopreservación de óvulos o embriones de peces todavía no es posible debido a su compleja estructura y grandes cantidades de material de la yema de huevo. Recientemente, la práctica del trasplante de células de germen primordiales (PGCs) o las células madre espermatogonias (SSCs) ofrece un puente a esta barrera mediante el desarrollo funcional de la esperma y huevos después de trasplante5. Por lo tanto, la criopreservación de SSCs ofrece una nueva frontera en la conservación de los recursos genéticos raros y valiosos.
A pesar de que la criopreservación ofrece muchas ventajas, el proceso de congelación lenta tasa genera varias condiciones que pueden llevar a daño de la célula2. Estos incluyen la formación de hielo intracelular y extracelular, deshidratación y toxicidad del crioprotector. Hielo daña las células, hielo extracelular puede conducir a trituración mecánica de las células, mientras que la difusión de agua desde las células durante la tasa lenta de congelación puede conducir a deshidratación6. Recientemente, se ha aplicado vitrificación como una técnica que evita los efectos negativos de la formación de hielo en la criopreservación de gametos de peces7,8,9. Presenta una técnica de enfriamiento ultra rápida a través del cual los medios de comunicación internos y externos se convierten en un estado amorfo/vidrioso sin crystalizing en hielo7,10. Éxito vitrificación de tejido ovárico y testicular ha sido evidenciado en especies de aves y mamíferos10,11,12, abriendo posibilidades para su aplicación en los peces, así.
En este estudio, presentamos el procedimiento de vitrificación (NIV) aguja sumergido para la criopreservación de los testículos todo pez cebra. Demostrar un método confiable para el aislamiento de las células de germen incipiente pez cebra sin contaminación y un proceso de criopreservación que produce cantidades relativamente altas de células de germen incipiente con una baja presencia de otras células, especialmente de espermatozoides. A lo mejor de nuestro conocimiento, éste es el primer estudio en demostrar un protocolo detallado visualizado para el enfriamiento ultra rápido de tejido gonadal de peces y pez cebra del germline células. Además, la repetibilidad del método se demuestra en cinco cepas diferentes de pez cebra: AB tipo salvaje, casper (roy- / -; nácar- / -), leopardo (leot1/t1), vasa [Tg (vas::eGFP)] y línea transgénica de Wilms tumor [Tg (wt1b::eGFP 1)].

<table border="0" cellpadding="0" cellspacing="0" width="948">
	<tbody>
		<tr height="24">
			<td height="24" style="height:24px;width:232px;">Leibovitz media (L-15)</td>
			<td style="width:220px;">Sigma-Aldrich</td>
			<td style="width:200px;">L1518</td>
			<td style="width:296px;">Supplemented with L-glutamine</td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:232px;">Fetal bovine serum (FBS)</td>
			<td style="width:220px;">Sigma-Aldrich</td>
			<td style="width:200px;">F9665</td>
			<td style="width:296px;"></td>
		</tr>
		<tr height="21">
			<td height="21" style="height:21px;width:232px;">Tricaine methanesulfonate (MS-222)</td>
			<td style="width:220px;">Sigma-Aldrich</td>
			<td>E10521</td>
			<td style="width:296px;"></td>
		</tr>
		<tr height="22">
			<td height="22" style="height:22px;width:232px;">HEPES</td>
			<td style="width:220px;">Sigma-Aldrich</td>
			<td style="width:200px;">H3375</td>
			<td style="width:296px;"></td>
		</tr>
		<tr height="19">
			<td height="19" style="height:19px;width:232px;">Sucrose</td>
			<td style="width:220px;">Acros Organics</td>
			<td>57-50-1</td>
			<td style="width:296px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:232px;">Trehalose</td>
			<td style="width:220px;">Acros Organics</td>
			<td>99-20-7</td>
			<td style="width:296px;">Dihydrate</td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:232px;">Methanol</td>
			<td style="width:220px;">Reanal</td>
			<td style="width:200px;">20740-0-08-65</td>
			<td style="width:296px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:232px;">Propylene glycol</td>
			<td style="width:220px;">Reanal</td>
			<td style="width:200px;">08860-1-08-65</td>
			<td style="width:296px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:232px;">Dimethyl sulfoxide</td>
			<td style="width:220px;">Reanal</td>
			<td style="width:200px;">00190-1-01-65</td>
			<td style="width:296px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:232px;">Collagenase</td>
			<td style="width:220px;">Gibco</td>
			<td style="width:200px;">9001-12-1</td>
			<td style="width:296px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:232px;">Trypsin</td>
			<td style="width:220px;">Sigma-Aldrich</td>
			<td style="width:200px;">T8003</td>
			<td style="width:296px;"></td>
		</tr>
		<tr height="24">
			<td height="24" style="height:24px;width:232px;">DNase I</td>
			<td style="width:220px;">Panreac AppliChem</td>
			<td style="width:200px;">A3778</td>
			<td style="width:296px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:232px;">Trypan blue</td>
			<td style="width:220px;">Sigma-Aldrich</td>
			<td style="width:200px;">T6146</td>
			<td style="width:296px;"></td>
		</tr>
		<tr height="20">
			<td height="20" style="height:20px;width:232px;">Phospate buffered saline (PBS)</td>
			<td style="width:220px;">Sigma-Aldrich</td>
			<td>P4417</td>
			<td>Tablets for preparation of 200 ml PBS solution</td>
		</tr>
	</tbody>
</table>

cryopreservation of zebrafish spermatogonia by whole testes needle immersed ultra-rapid cooling

Tendencias actuales en ciencia y biotecnología conducen a la creación de miles de nuevas líneas en organismos modelo lo lleva a la necesidad de nuevos métodos para el almacenamiento seguro de los recursos genéticos más allá de las prácticas comunes de mantener colonias de cría. El objetivo principal de este estudio fue adaptar la aguja inmerso en procedimiento de vitrificación (NIV) para criopreservar los testículos todo pez cebra. Criopreservación de células de germen incipiente por los testículos todo NIV ofrece posibilidades para el almacenamiento de pez cebra recursos genéticos, especialmente puesto que después maduran a gametos masculinos y femeninos. Los testículos fueron suprimidos, en una aguja de acupuntura, equilibrada en dos medios crioprotectores (solución de equilibrado que contiene 1,5 M metanol y glicol de propileno de 1.5 M; y solución de vitrificación que contiene dimetilsulfóxido de 3 M y 3 M propilenglicol) y sumergida en nitrógeno líquido. Las muestras fueron calentadas en una serie de tres soluciones de calentamiento consiguientes. Las principales ventajas de esta técnica son (1) la falta de espermatozoides después de la digestión de los testículos caliente facilitando manipulaciones posteriores; (2) ultra rápido de enfriamiento que permite la óptima exposición de los tejidos a nitrógeno líquido, por lo tanto maximizar la refrigeración y reducir la necesaria concentración de crioprotectores, reduciendo así su toxicidad; (3) exposición sincrónica de varios testículos crioprotectores y nitrógeno líquido; y repetibilidad (4) demostró mediante la obtención de la viabilidad de sobre el 50% en cinco cepas diferentes de pez cebra.

En promedio, el número de células de germen inicial aislada de un testículo de pez cebra dulce solo varió entre 40.000 y 200.000 células dependiendo del tamaño de los peces. Al digerir los testículos frescos de pez cebra en todas las 5 cepas, células germinales tempranas no eran las células sólo presentes en las suspensiones de la célula (figura 2). Al lado de las células de germen incipiente, numerosos espermatozoides fueron encontrados también....

Watch this Scientific Journal Video about Cryopreservation of Zebrafish Spermatogonia by Whole Testes Needle Immersed Ultra-Rapid Cooling at JoVE.com

Cryopreservation of Zebrafish Spermatogonia by Whole Testes Needle Immersed Ultra-Rapid Cooling

Criopreservación de espermatogonios de pez cebra por todo los testículos aguja inmerso enfriamiento ultra rápido

El objetivo principal de este estudio fue adaptar la aguja inmerso en procedimiento de vitrificación (NIV) para criopreservar los testículos todo pez cebra. Además, se evaluó la repetibilidad del método en cinco cepas diferentes de pez cebra.

Current trends in science and biotechnology lead to creation of thousands of new lines in model organisms thereby leading to the necessity for new methods ...

Cryopreservation offers the possibility of maintaining live cells and tissues at low temperatures for an infinite period of time, at least in human terms. Vitrification is a form of cryopreservation which involves ultra-rapid cooling into a glassy, amorphous state without the formation of crystalline ice and without the damages associated. In this video, we present the protocol for the vitrification of whole zebrafish testes, which allows their safe storage until their later use as a source of germ cells for transplantation into suitable recipients.The current vitrification protocol has one significant advantage over the slow-rate freezing protocols in regard to germ stem cell manipulations. And that is that after vitrification and warming, the spermatozoa die and they get adjusted so they are not present in the cell suspension. Therefore, there is no need for isolation of germ cells after warming.And that readily facilitates the downstream manipulations. Euthanize the fish by placing it into a dish containing 200 milligrams per liter of MS-222 at pH seven. Before continuing with the dissection, make sure that the gills have stopped moving, and at least 10 minutes have passed since that moment to ensure death by hypoxia.Dry the fish by patting it on a paper towel and place it on its dorsal side on a dissecting mat. Firstly, cut off the pelvic and pectoral fins for easier dissection. Horizontally snip the skin on the belly of the fish between the pectoral fins, and cut the skin and underlying muscle along the belly until the anal fin.Open the body cavity of the fish and pin the left and right body wall to the dissection mat with needles. Testes are located above the gastrointestinal organs on both sides of the swimming bladder. To prevent contamination, do not take out the gastrointestinal organs, but gently push them to one side and remove the testes from the opposing side.Testes are connected to the body wall, so remove them carefully and cut the connecting peritoneum by micro scissors. Additionally, in order to prevent contamination, firstly sterilize the testes by putting them into 70%ethanol for two seconds, and then place them in L-15 on 96-well plate on ice. Mark needles with appropriate labels, depending on the sample type, and prepare the equilibration and vitrification solutions.Transfer the testes to a larger-well plate or dish and pin three testes or more, depending on the size of the needle, on a sterile acupuncture needle. Firstly, position the testes on top of curved tweezers. Place the point of the needle in the middle of the testis and carefully pull the testis upward with the tweezers.After puncturing the testis, gently pull it upwards towards the top of the needle. Make sure the testes are separated from each other and they are not falling off or sliding down. Place the needles with pinned testes in a Tubulator Eppendorf tube filled with L-15 until vitrification at 25 degrees.The storage time should not exceed one hour. Transfer the needle with the testes into the equilibration solution and incubate for five minutes at 25 degrees. Transfer the needle into the vitrification solution and incubate for 30 seconds at 25 degrees.Remove the needle from the vitrification solution. Quickly and gently absorb the remaining solution from the tissue by a sterile paper towel. Use caution to avoid the testes sticking to the paper towel or falling off.Quickly place the needle into liquid nitrogen in a styrofoam box. Keep the needle in liquid nitrogen in a closed styrofoam box for five to 10 minutes. Pre-cool an opened 4.5 milliliter cryotube and its cap in the same box.After five to 10 minutes, transfer each needle into a separate cryotube under the surface of liquid nitrogen and close the cryotube. Place the cryotube onto a metal cane and place it in the cryobank canister as fast as possible. Store the samples in a canister storage drawer until further use.Warm each needle separately. All warming solutions should be at 25 degrees. Detach the cryotube from the metal cane and plunge it into liquid nitrogen stored in a styrofoam box.Open the cryotube in the liquid nitrogen vapor using forceps, and release the needle into the liquid nitrogen. Transfer the needle very fast into the first warming solution and incubate for one minute. Make sure to transfer the needle quickly to prevent it warming in the air during transfer.Transfer the needle into the second warming solution, and incubate for three minutes. Transfer the needle into the third warming solution and incubate for five minutes. Release the testes from the needle by sliding them downwards with curved tweezers.Place each warmed testis individually into a separate well filled with 250 microliters of L-15, supplemented with 10%FPS. Make sure that the wells are labeled according to the sample. Keep the well plate on ice until all samples are warmed, and until further work.Prepare 500 microliters of the dissociation solution for each sample in separate two-milliliter tubes. Label the tubes according to the code of the sample. Incubate the prepared dissociation solution for five minutes at room temperature.Add the warmed tissue into the digestion solution, and cut it into small pieces by at least 30 movements of small scissors. Incubate the tissue on a shaking plate for 90 minutes at 24 degrees. Stop the digestion process by adding 400 microliters of L-15 and 100 microliters of 10%FPS.Briefly shake the solution and incubate for one minute at room temperature. Filter the obtained solution through 50-micron filters into a 1.5 milliliter tube. Label the tubes accordingly.Centrifuge the filtered solution at 200 G for 10 minutes at 25 degrees. Carefully remove the supernatant and re-suspend the pellet in 20 microliters of L-15, supplemented with 10%FPS. Manually shake the tube until the pellet is completely dissolved.Keep the cell suspension on ice or at four degrees until further use. Mix five microliters of cell suspension and five microliters of 0.4%trypan blue solution in an appropriately-labeled 0.2 milliliter PCR tube. If different volumes are used, make sure that the dilution ratio of one to one remains.Incubate this suspension for one to three minutes at 25 degrees. Check the viability of each sample in a hemocytometer under a microscope. Count the number of live cells unstained by trypan blue in 15 fields.Calculate the total number of cells in 20 microliters of the cell suspension. The suspension is now ready for any downstream application. On average, the number of early-stage germ cells isolated from a single fresh zebrafish testis vary between 40, 000 and 200, 000 cells, depending on the size of the fish.In all zebrafish lines used in this study, the current vitrification protocol yielded average viability rates of 50%and higher. This indicates favorable viability and repeatability of the presented protocol. When digesting fresh zebrafish testes in all five strains, besides the early-stage germ cells, numerous spermatozoa were found as well.After digestion of cryo-preserved testes, there were far less spermatozoa, indicating that they do not survive this vitrification protocol, and that they are most likely eliminated during the digestion process. The needle-immersed vitrification protocol presented in this study offers several advantages in the cryopreservation of testicular pieces. Firstly, several pieces can be pinned to one needle, and therefore they can simultaneously be exposed to cryoprotectants and to the liquid nitrogen.Furthermore, this method enables that very low amounts of cryoprotectants are attached to the tissue pieces. And therefore, cooling and warming rates can be higher. One significant advantage is that spermatozoa do not survive this protocol, and therefore in the end, the cell suspensions are enriched spermatogonia, which will facilitate the downstream applications.But one thing that has to be taken into account is the possibility of cross-contamination through nitrogen. Therefore when using this method, liquid nitrogen should not be reused.

Research

JoVE Journal

Biology

Transplantation of Whole Kidney Marrow in Adult Zebrafish

El trasplante de médula del riñón entero en adultos de pez cebra

Hematopoietic stem cells (HSC) are a rare population of pluripotent cells that maintain all the differentiated blood lineages throughout the life of an ...

Investigación

Biología

Zebrafish Whole Mount High-Resolution Double Fluorescent In Situ Hybridization

Zebrafish Whole Mount High-Resolution Double Fluorescent In Situ Hybridization

Pez cebra todo el montaje de alta resolución doble fluorescente In Situ La hibridación

Whole mount in situ hybridization is one of the most widely used techniques in developmental biology.  Here, we present a high-resolution double ...

Generating Chimeric Zebrafish Embryos by Transplantation

La generación de embriones quiméricos de pez cebra mediante un trasplante

One of the most powerful tools used to gain insight into complex developmental processes is the analysis of chimeric embryos. A chimera is defined as an ...

A High-Throughput Method For Zebrafish Sperm Cryopreservation and In Vitro Fertilization

A High-Throughput Method For Zebrafish Sperm Cryopreservation and In Vitro Fertilization

Un método de alto rendimiento para la crioconservación de esperma de pez cebra y In Vitro Fertilización

This is a method for zebrafish sperm cryopreservation that is an adaptation of the Harvey method (Harvey et al., 1982).  We have introduced two changes to ...

Making Gynogenetic Diploid Zebrafish by Early Pressure

Hacer pez cebra Gynogenetic diploides por presión inicial

Heterozygosity in diploid eukaryotes often makes genetic studies cumbersome. Methods that produce viable homozygous diploid offspring directly from ...

Isolation of Drosophila melanogaster Testes

Isolation of Drosophila melanogaster Testes

El aislamiento de Drosophila melanogaster Testículos

The testes of Drosophila melanogaster provide an important model for the study of stem cell maintenance and differentiation, meiosis, and soma-germline ...

Cryopreservation of Mouse Embryos by Ethylene Glycol-Based Vitrification

La criopreservación de embriones de ratón por el etileno a base de glicol vitrificación

Cryopreservation of mouse embryos is a technological basis that supports biomedical sciences, because many strains of mice have been produced by genetic ...

Imaging Centrosomes in Fly Testes

Los centrosomas de imagen en Fly Testículos

Centrosomes are conserved microtubule-based organelles whose structure and function change dramatically throughout the cell cycle and cell ...

Analysis of Apoptosis in Zebrafish Embryos by Whole-mount Immunofluorescence to Detect Activated Caspase 3

Análisis de la apoptosis en embriones de pez cebra en Todo el montaje de inmunofluorescencia para detectar la caspasa 3 activada

Whole-mount immunofluorescence to detect activated Caspase 3 (Casp3 assay) is useful to identify cells undergoing either intrinsic or extrinsic apoptosis ...

Flat Mount Preparation for Observation and Analysis of Zebrafish Embryo Specimens Stained by Whole Mount In situ Hybridization

Flat Mount Preparation for Observation and Analysis of Zebrafish Embryo Specimens Stained by Whole Mount In situ Hybridization

Preparativos Piso en observación y análisis de embrión de pez cebra muestras teñidas por todo el montaje<em&gt; In situ</em&gt; La hibridación

The zebrafish embryo is now commonly used for basic and biomedical research to investigate the genetic control of developmental processes and to model ...