Name: collection and cryopreservation of hamster oocytes and mouse embryos
Uploaded: 2009-03-27T00:00:00.000+00:00
Duration: 13 min 36 s
Description: Watch this Scientific Journal Video about Collection and Cryopreservation of Hamster Oocytes and Mouse Embryos at JoVE.com

Este trabajo fue apoyado por el Ministerio español de Educación y Ciencia (BIO 2006 hasta 11.792) y la Generalitat de Catalunya (2005-SGR00437). Los autores desean agradecer a Marc Puigcerver y Lucas Jonatan por su asistencia técnica en la preparación de los medios de comunicación. Todo el personal de la Estabulari Servei d&#39;es reconocido por albergar a los animales y, especialmente, Juan José Martín y Javier Benito, por su contribución adicional sobre la grabación de parte de este video. BCN es un miembro de la Fundación un párrafo portugués Ciência e Tecnologia y SG es un compañero de la española Ministerio de Educación y Ciencia.

Cuidado de los animales y los procedimientos se realizaron de acuerdo a los lineamientos y reglamentos aprobados por el Comité de Ética en la investigación animal y humana de la Universitat Autònoma de Barcelona, ​​España. I. recolección de ovocitos <ol><li> Comprobar y seleccionar hamsters hembra (Mesocricetus auratus, 8-12 semanas de edad) de la cepa de oro de Siria a la presencia de una secreción espesa vaginal (flujo postovulatoria). </li><li> Inducir a las mujeres seleccionadas para superovular por inyección intraperitoneal de 40 UI de PMSG (gonadotropina sérica de yegua gestante), seguido de 40 UI de hCG (gonadotropina coriónica humana) 60 horas después. </li><li> Eutanasia hamsters mujer de 16 horas tras la administración de hCG en una cámara de dióxido de carbono. </li><li> Aislar a los oviductos de las hembras, como se muestra en el video y transferirlos a una gota de KSOM-H medio. </li><li> Recoger cúmulos ovocito complejos por romper la ampolla del oviducto bajo un microscopio estereoscópico en una gota de hialuronidasa (156 U / ml) a 37 ° C. Los ovocitos se libera de células del cumulus en aproximadamente 5 minutos. </li><li> Recoger óvulos de hialuronidasa y lavar dos veces en KSOM-H medio. </li></ol> Para la recogida de embriones de ratones, los ratones hembra (Mus musculus; 6-8 semanas de edad) son inducidos a superovular por inyección intraperitoneal de 5 UI de PMSG seguido de 5 UI de hCG 48 horas más tarde y se aparearon con ratones machos. Las hembras son sacrificadas por dislocación cervical en el 24-26, 44-46 o 54-56 horas después de la administración de hCG para la obtención de pronuclear, de 2 o 4 células de células de embriones etapa, respectivamente. Recolección de los embriones pronuclear se lleva a cabo exactamente como se describe en ovocitos de hámster. Embriones en las fases 2-célula y célula-4 son recogidos por el lavado del oviducto con KSOM-H medio [6]. Nota: Después de este protocolo de aproximadamente 20 a 30 ovocitos / embriones se pueden recoger de cada mujer. II. Preparación de congelación y descongelación de soluciones <ol><li> Prepare una solución de I diluyendo 0,57 ml de propilenglicol en 5 ml de KSOM-H (1,5 M de propilenglicol). </li><li> Prepare una solución de descongelación mediante la adición de 2 ml de KSOM-H a un tubo con 0,2052 g de sacarosa (0,3 M de sacarosa). </li><li> Preparar la solución de congelación mediante la adición de 2 ml de solución que a un tubo con 0,0684 g de sacarosa (1,5 M de propilenglicol y 0,1 M de sacarosa). </li></ol> Nota: la solución y la congelación y descongelación, y deben prepararse justo antes de su uso. Sin embargo, las cantidades especificadas de la sacarosa que se utilizará para la preparación de la congelación y descongelación de soluciones puede ser ponderada por adelantado y almacenado en tubos de 3 ml a temperatura ambiente durante varios meses. III. Protocolo de congelación <ol><li> Transferencia de ovocitos / embriones del medio KSOM-H a una gota de la solución I y se incuba durante 7-15 minutos a temperatura ambiente. </li><li> Mientras tanto, prepare una placa de Petri de 90 mm para cargar la paja mediante la colocación de l 90 gotas de congelación y descongelación de soluciones como se muestra en el video (1 gota de cada solución / paja). </li><li> Transferir la cantidad deseada de los ovocitos / embriones de las gotas de solución de congelación. Nota: Por lo general, la transferencia de entre 5 y 30 ovocitos o embriones / drop. </li><li> Adjunte una paja a un sistema de aspiración controlada y la boca de carga es el siguiente orden: solución que yo, el aire, la caída de la congelación de los ovocitos, el aire, la caída de la descongelación, el aire. </li><li> Una vez que la paja se ha cargado, mantener la aspiración hasta que la gota introdujo por primera vez (solución I) alcanza el polímero en el extremo superior de la paja y las juntas este fin. Termo-sellar el otro extremo de la paja o el sello con un tapón de plástico. </li><li> Encienda el congelador programable y seleccione el programa de congelación. El programa de congelación utilizado en este protocolo se basa en la velocidad de enfriamiento, publicada originalmente por Lassalle et al. [7]: <ul><li> 2 ° C / min desde la temperatura ambiente a -7 ° C 0 ° C / min durante 10 minutos para permitir el equilibrio de temperatura y la inducción de la siembra (ver más abajo) </li><li> 0,3 ° C / min de -7 ° C a -30 ° C 0 ° C / min durante 2 minutos para permitir el equilibrio de temperatura </li><li> 35 ° C / min desde -30 ° C a -130 ° C </li></ul></li><li> La carga de la paja en las ranuras de la titular de la nevera programable, asegurándose de que la parte de la paja con la gota de solución de descongelación es hacia el exterior. Iniciar el programa de congelación. </li><li> Cuando la temperatura de la muestra llega a -7 ° C y el enfriamiento está en espera, lleve a cabo la siembra manual: hundir el fórceps en nitrógeno líquido, tire de los titulares de un poco fuera del congelador para exponer la parte de las pajillas que contienen las gotas de la solución de descongelación, y de inmediato tocar esta parte de la paja con las pinzas. Repita este procedimiento para cada titular y la paja en el soporte de cada uno, y luego dejar que el programa de congelación hasta el final. </li><li> Cuando el programa se ha completado, los titulares de la caída en nitrógeno líquido. </li><li> Quitar la paja deltitulares y transferirlos a un gobelet etiquetados. </li><li> Finalmente, coloque la gobelet dentro de un tanque de nitrógeno líquido. </li></ol> IV. Descongelación protocolo <ol><li> Quitar la paja del tanque de nitrógeno líquido. </li><li> Mantener la paja a temperatura ambiente durante 40 segundos. </li><li> Remoje la paja en un baño de agua a 30 ° C durante 40 segundos. </li><li> Retire el tapón de la paja o cortar la punta de la termo-selladas. </li><li> Vaciar la paja en un plato de petri de 35 mm y mezcle suavemente las dos gotas que contienen el congelamiento y descongelamiento soluciones. </li><li> Deja los ovocitos / embriones en la mezcla durante 15 minutos a temperatura ambiente. </li><li> La transferencia de ovocitos / embriones a una caída fresca de KSOM-H por 15 minutos a 37 ° C. </li><li> Los ovocitos / embriones están listos para su posterior manipulación. </li></ol> Nota: En los pasos 6 y 7 que usted debe ver que los ovocitos descongelados / embriones poco a poco se hinchan debido a la rehidratación. V. Los resultados representativos El uso del protocolo de criopreservación que aquí resulta en una tasa de supervivencia de aproximadamente el 95% de los ovocitos de hámster y de&gt; 90%, 85% y 80% para el ratón B6CBAF1 embriones en el pronuclear, dos etapas de las células y de 4 celdas, respectivamente. Cuando los embriones de ratón se cultivaron in vitro en KSOM después de la descongelación, por lo menos 70 a 80% debería llegar a la etapa de blastocisto, en condiciones óptimas de cultivo. Se recomienda que se incluye un grupo de control (paja) de los ovocitos / embriones en cada experimento de congelación y deshielo que este grupo antes que el resto de los ovocitos / embriones se usan para otras manipulaciones. Si las tasas de supervivencia para el grupo control son inferiores a lo esperado, descongelar otra paja del mismo lote. Si las tasas de supervivencia de este segundo grupo son también bajas, desechar la paja que queda de este lote de congelación.

<ol>
	<li>Whittingham, D. G., Leibo, S. P., Mazur, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Survival+of+mouse+embryos+frozen+to+-196+and+-269+&#176;C.">Survival of mouse embryos frozen to -196 and -269 &#176;C.</a> Science. 178, 411-414 (1972).</li><li>Wilmut, I. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=The+effect+of+cooling+rate,+warming+rate,+cryoprotective+agent+and+stage+of+development+on+survival+of+mouse+embryos+during+freezing+and+thawing.">The effect of cooling rate, warming rate, cryoprotective agent and stage of development on survival of mouse embryos during freezing and thawing.</a> Life Sci. 11, 1071-1079 (1972).</li><li>Parkening, T. A., Tsunoda, Y., Chang, M. C. <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+various+low+temperatures,+cryoprotective+agents+and+cooling+rates+on+the+survival,+fertilizability+and+development+of+frozen-thawed+mouse+eggs.">Effects of various low temperatures, cryoprotective agents and cooling rates on the survival, fertilizability and development of frozen-thawed mouse eggs.</a> J. Exp. Zool. 197, 369-374 (1976).</li><li>Schneider, U. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cryobiological+principles+of+embryo+freezing.">Cryobiological principles of embryo freezing.</a> J. In Vitro Fert. Embryo Transf. 3, 3-9 (1986).</li><li>Vajta, G., Kuwayama, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Improving+cryopreservation+systems.">Improving cryopreservation systems.</a> Theriogenology. 65, 236-244 (2006).</li><li>Duselis, A. R., Vrana, 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=Retrieval+of+mouse+oocytes.">Retrieval of mouse oocytes.</a> JoVE. 3, (2007).</li><li>Lassalle, B., Testart, J., Renard, J. P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Human+embryo+features+that+influence+the+success+of+cryopreservation+with+the+use+of+1,2+propanediol.">Human embryo features that influence the success of cryopreservation with the use of 1,2 propanediol.</a> Fertil. Steril. 44, 645-651 (1985).</li><li>Ib&#225;&#241;ez, E., Grossmann, M., Vidal, F., Egozcue, J., Santal&#243;, 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+caprine+beta-lactoglobulin+transgenic+mouse+embryos.">Cryopreservation of caprine beta-lactoglobulin transgenic mouse embryos.</a> Cryobiology. 35, 290-298 (1997).</li><li>Dinnyes, A., Wallace, G. A., Rall, W. F. <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+genotype+on+the+efficiency+of+mouse+embryo+cryopreservation+by+vitrification+or+slow+freezing.">Effect of genotype on the efficiency of mouse embryo cryopreservation by vitrification or slow freezing.</a> Mol. Reprod. Dev. 40, 429-435 (1995).</li><li>Tateno, H., Kamiguchi, Y., Mikamo, K. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=A+freezing+and+thawing+method+of+hamster+oocytes+designed+for+both+the+penetration+test+and+chromosome+assay+of+human+spermatozoa.">A freezing and thawing method of hamster oocytes designed for both the penetration test and chromosome assay of human spermatozoa.</a> Mol. Reprod. Dev. 33, 202-209 (1992).</li><li>Biggers, J., McGuinnis, L. K., Raffin, M. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Amino+acids+and+preimplantation+development+of+the+mouse+in+the+protein-free+KSOM.">Amino acids and preimplantation development of the mouse in the protein-free KSOM.</a> Biol. Reprod. 63, 281-293 (2000).</li></ol>

Con este protocolo de ovocitos de hámster y de embriones de ratón pueden ser criopreservados con éxito. Una vez congelado, los ovocitos / embriones pueden ser almacenados en tanques de nitrógeno líquido por tiempo indefinido y se recuperó en cualquier momento o lugar deseado. Esto ofrece la ventaja de tener muestras de casi listo para su uso cuando sea necesario. Por otro lado, este protocolo también se puede utilizar para generar criobancos embrión a partir de cepas de ratón de gran valor (como las líneas de transgénicos), como ...

<table><tbody><tr><td>Material Name</td><td>Type</td><td>Company</td><td>Catalogue Number</td><td>Comment</td></tr><tr><td>French type mini-straw 0.25 ml</td><td></td><td>Mini-tub</td><td>13407/0010</td><td></td></tr><tr><td>hCG</td><td></td><td>Farma-Lepori, Spain</td><td>749036.4</td><td></td></tr><tr><td>Hyaluronidase</td><td></td><td>Sigma</td><td>H-3884</td><td></td></tr><tr><td>KSOM-H medium</td><td></td><td></td><td></td><td>Ref. [11]</td></tr><tr><td>Liquid Nitrogen </td><td></td><td>Air Liquide</td><td></td><td></td></tr><tr><td>Plastic plugs</td><td></td><td>Mini-tub</td><td>19046</td><td></td></tr><tr><td>PMSG</td><td></td><td>Intervet, Spain</td><td>1.614/8447</td><td></td></tr><tr><td>Propilenglycol</td><td></td><td>Fluka</td><td>82280</td><td></td></tr><tr><td>Sucrose</td><td></td><td>Merck</td><td>107687</td><td></td></tr><tr><td>Surgical Scissors</td><td></td><td>Aesculap</td><td>BC-060R; BG-061R</td><td></td></tr><tr><td>Thermo-sealer</td><td></td><td>SIZ</td><td>220</td><td></td></tr><tr><td>35 and 90 mm culture dishes</td><td></td><td>Nunc</td><td>153066; 150350</td><td></td></tr><tr><td>10 ml tubes</td><td></td><td>Greiner Bio-one</td><td>163160</td><td></td></tr><tr><td>Nitrogen tank</td><td></td><td>MVE, Cryogenics</td><td>XC 43/28</td><td></td></tr><tr><td>Programmable Freezer</td><td></td><td>Planner Products Ltd.</td><td>Kryo-10 Series III</td><td></td></tr><tr><td>Forceps</td><td></td><td>Aesculap</td><td>BD-331R; BD-053R; OC-020R</td><td></td></tr></tbody></table>

collection and cryopreservation of hamster oocytes and mouse embryos

Embriones y ovocitos criopreservados fueron los primeros con éxito más de 30 años, cuando Whittingham<i&gt; Et al.</i&gt;<sup&gt; 1</sup&gt; Wilmut y<sup&gt; 2</sup&gt; Descritos separadamente que los embriones de ratón podría ser congelado y almacenado a -196 ° C y, unos años más tarde, Parkening<i&gt; Et al</i&gt;.<sup&gt; 3</sup&gt; Reportó el nacimiento de crías vivas como resultado de la fertilización in vitro (FIV) de ovocitos criopreservados. Desde entonces, el uso de las técnicas de criopreservación se ha extendido rápidamente a convertirse en un componente esencial en la práctica de la reproducción asistida humana y animal y en la conservación de los recursos genéticos de los animales. En la actualidad, existen dos principales métodos utilizados para criopreservar óvulos y embriones: el congelamiento lento y la vitrificación. Una amplia variedad de enfoques se han utilizado para tratar de mejorar tanto las técnicas y los millones de animales y miles de niños han nacido a partir de embriones crioconservados. Sin embargo, subsisten deficiencias importantes asociados a la criopreservación todavía hay que superar, ya que la formación de cristales de hielo, los efectos de la solución y el shock osmótico parecen causar cryoinjuries varios descongelado después de ovocitos y embriones. La congelación lenta, con congelador programable tiene la ventaja de la utilización de bajas concentraciones de crioprotectores, que generalmente están asociados con la toxicidad química y el shock osmótico, pero su capacidad para evitar la formación de cristales de hielo en concentraciones bajas es limitado. La congelación lenta también induce efectos súper-que debe ser evitado el uso de la siembra manual o automático<sup&gt; 4</sup&gt;. En el proceso de vitrificación, las altas concentraciones de crioprotectores inhibir la formación de cristales de hielo y dar lugar a la formación de un estado semejante al vidrio vitrificado en el que el agua se solidifica, pero no ampliado. Sin embargo, debido a la toxicidad de cyroprotectants a las concentraciones utilizadas, los ovocitos / embriones sólo pueden ser expuestos a la solución de crioprotectores por un período muy corto de tiempo y en una solución de volumen mínimo, antes de sumergir las muestras directamente en nitrógeno líquido<sup&gt; 5</sup&gt;. En la última década, la vitrificación se ha vuelto más popular porque es un método muy rápido en el que no se requiere un equipo caro (congelador programable). Sin embargo, la congelación lenta sigue siendo el método más ampliamente utilizado para la criopreservación de ovocitos / embriones. En este video-artículo mostramos, paso a paso, cómo recoger y congelar lentamente ovocitos de hámster con altas tasas de supervivencia después de la descongelación. El mismo procedimiento se puede aplicar para congelar y descongelar con éxito embriones de ratón en las diferentes etapas de desarrollo de preimplantación.

Watch this Scientific Journal Video about Collection and Cryopreservation of Hamster Oocytes and Mouse Embryos at JoVE.com

Collection and Cryopreservation of Hamster Oocytes and Mouse Embryos

En este video-artículo se presenta una demostración paso a paso sobre cómo recoger y criopreservar óvulos de hámster con altas tasas de supervivencia después de la descongelación. El mismo procedimiento se puede aplicar para congelar y descongelar con éxito embriones de ratón en las diferentes etapas de desarrollo de preimplantación.

Recolección y criopreservación de ovocitos de hámster y de embriones de ratón

Embryos and oocytes were first successfully cryopreserved more than 30 years ago, when Whittingham et al. 1 and Wilmut 2 separately described that mouse ...

collection-and-cryopreservation-of-hamster-oocytes-and-mouse-embryos

Universidad de Cartagena UDEC

Research

JoVE Journal

Biology

16.9K vistas.  Universitat Autonoma de Barcelona. En este video-artículo se presenta una demostración paso a paso sobre cómo recoger y criopreservar óvulos de hámster con altas tasas de supervivencia después de la descongelación. El mismo procedimiento se puede aplicar para congelar y descongelar con éxito embriones de ratón en las diferentes etapas de desarrollo de preimplantación.

Video: Collection and Cryopreservation of Hamster Oocytes and Mouse Embryos

Retrieval of Mouse Oocytes

To date, only a few studies have reported successful manipulations of Peromyscus embryogenesis or reproductive biology.  Together with the Peromyscus Genetic Stock Center (http://stkctr.biol.sc.edu), we are characterizing the salient differences needed to develop this system.  A primary goal has been to optimize oocyte/early embryo retrieval.

This protocol illustrates the technique for extracting oocytes or early-stage fertilized embryos from the oviduct of mice. The ability to identify the infindibulum and insert a blunt end needle into it is essential to correctly performing the procedure.

Recuperación de los ovocitos de ratón

To date, only a few studies have reported successful manipulations of Peromyscus embryogenesis or reproductive biology.  Together with the Peromyscus ...

Investigación

Biología

Derivation of Stem Cell Lines from Mouse Preimplantation Embryos

Mouse embryonic stem cell (mESC) derivation is the process by which pluripotent cell lines are established from preimplantation embryos. These lines retain the ability to either self-renew or differentiate under specific conditions. Due to these properties, mESC are a useful tool in regenerative medicine, disease modeling, and tissue engineering studies. This article describes a simple protocol to obtain mESC lines with high derivation efficiencies (60-80%) by culturing blastocysts from permissive mouse strains on feeder cells in defined medium supplemented with leukemia inhibitory factor. The protocol can also be applied to efficiently derive mESC lines from non-permissive mouse strains, by the simple addition of a cocktail of two small-molecule inhibitors to the derivation medium (2i medium). Detailed procedures on the preparation and culture of feeder cells, collection and culture of mouse embryos, and derivation and culture of mESC lines are provided. This protocol does not require specialized equipment and can be carried out in any laboratory with basic mammalian cell culture expertise.

This article describes a protocol to efficiently derive and culture pluripotent stem cell lines from mouse embryos at the blastocyst stage.

Derivación de líneas de células madre de embriones de preimplantación de ratón

Mouse embryonic stem cell (mESC) derivation is the process by which pluripotent cell lines are established from preimplantation embryos. These lines ...

Biología del Desarrollo

Use of Freeze-thawed Embryos for High-efficiency Production of Genetically Modified Mice

The use of genetically modified (GM) mice has become crucial for understanding gene function and deciphering the underlying mechanisms of human diseases. The CRISPR/Cas9 system allows researchers to modify the genome with unprecedented efficiency, fidelity, and simplicity. Harnessing this technology, researchers are seeking a rapid, efficient, and easy protocol for generating GM mice. Here we introduce an improved method for cryopreservation of one-cell embryos that leads to a higher developmental rate of the freeze-thawed embryos. By combining it with optimized electroporation conditions, this protocol allows for the generation of knockout and knock-in mice with high efficiency and low mosaic rates within a short time. Furthermore, we show a step-by-step explanation of our optimized protocol, covering CRISPR reagent preparation, in vitro fertilization, cryopreservation and thawing of one-cell embryos, electroporation of CRISPR reagents, mouse generation, and genotyping of the founders. Using this protocol, researchers should be able to prepare GM mice with unparalleled ease, speed, and efficiency.

Here, we present a modified method for cryopreservation of one-cell embryos as well as a protocol that couples the use of freeze-thawed embryos and electroporation for the efficient generation of genetically modified mice.

Uso de embriones congelados descongelados para la producción de alta eficiencia de ratones modificados genéticamente

The use of genetically modified (GM) mice has become crucial for understanding gene function and deciphering the underlying mechanisms of human diseases. ...

Genética

Minimum Volume Vitrification of Immature Feline Oocytes

In wild animals&#8217; conservation programs, gamete banking is crucial to safeguard genetic resources of valuable individuals and rare species and to promote biodiversity preservation. In felids, most species are threatened with extinction, and domestic breeds are used as a model to increase the efficiency of protocols for germplasm banking. Among oocyte cryopreservation techniques, vitrification is more and more popular in human and veterinary assisted reproduction. Cryotop vitrification, which was at first developed for human oocytes and embryos, has demonstrated to be well-suited for cat oocytes. This method offers several advantages, such as the feasibility in field conditions and the speed of the procedure, which can be helpful when several samples need to be processed. However, the efficiency is strongly dependent on the operator&#8217;s skills, and intra- and inter-laboratory standardization are needed, as well as personnel training. This protocol describes minimum volume vitrification of immature feline oocytes on a commercial support in a step by step field-friendly protocol, from oocyte collection to warming. Following the protocol, preservation of oocyte integrity and viability at warming (as high as 90%) can be expected, although there is still room for improvement in post-warming maturation and embryonic development outcomes.

This manuscript describes a protocol for the minimum volume vitrification of immature cat oocytes with laboratory-made media on commercial supports. It covers every step from oocyte isolation from ex vivo gonads to vitrification and warming.

Vitrificación de Volumen Mínimo de Ovocitos Felinos Inmaduros

In wild animals&#8217; conservation programs, gamete banking is crucial to safeguard genetic resources of valuable individuals and rare species and to ...

Mouse Oocyte Microinjection, Maturation and Ploidy Assessment

Mistakes in chromosome segregation lead to aneuploid cells. In somatic cells, aneuploidy is associated with cancer but in gametes, aneuploidy leads to infertility, miscarriages or developmental disorders like Down syndrome. Haploid gametes form through species-specific developmental programs that are coupled to meiosis. The first meiotic division (MI) is unique to meiosis because sister chromatids remain attached while homologous chromosomes are segregated. For reasons not fully understood, this reductional division is prone to errors and is more commonly the source of aneuploidy than errors in meiosis II (MII) or than errors in male meiosis 1,2. 
In mammals, oocytes arrest at prophase of MI with a large, intact germinal vesicle (GV; nucleus) and only resume meiosis when they receive ovulatory cues. Once meiosis resumes, oocytes complete MI and undergo an asymmetric cell division, arresting again at metaphase of MII. Eggs will not complete MII until they are fertilized by sperm. Oocytes also can undergo meiotic maturation using established in vitro culture conditions 3. Because generation of transgenic and gene-targeted mouse mutants is costly and can take long periods of time, manipulation of female gametes in vitro is a more economical and time-saving strategy. 
Here, we describe methods to isolate prophase-arrested oocytes from mice and for microinjection. Any material of choice may be introduced into the oocyte, but because meiotically-competent oocytes are transcriptionally silent 4,5 cRNA, and not DNA, must be injected for ectopic expression studies. To assess ploidy, we describe our conditions for in vitro maturation of oocytes to MII eggs. Historically, chromosome-spreading techniques are used for counting chromosome number 6. This method is technically challenging and is limited to only identifying hyperploidies. Here, we describe a method to determine hypo-and hyperploidies using intact eggs 7-8. This method uses monastrol, a kinesin-5 inhibitor, that collapses the bipolar spindle into a monopolar spindle 9 thus separating chromosomes such that individual kinetochores can readily be detected and counted by using an anti-CREST autoimmune serum. Because this method is performed in intact eggs, chromosomes are not lost due to operator error.

Oocytes are prone to aneuploidy due to errors in chromosome segregation during meiotic maturation. Aneuploid eggs can cause infertility, miscarriages or developmental disorders like Down syndrome. Here, we describe methods to introduce materials of choice into oocytes and methods to study meiotic maturation and assess ploidy.

La microinyección de ovocitos de ratón, Maduración y Evaluación de ploidía

Mistakes in chromosome segregation lead to aneuploid cells.  In somatic cells, aneuploidy is associated with cancer but in gametes, aneuploidy leads to ...

Cryopreservation of Mouse Embryos by Ethylene Glycol-Based Vitrification

Cryopreservation of mouse embryos is a technological basis that supports biomedical sciences, because many strains of mice have been produced by genetic modifications and the number is consistently increasing year by year. Its technical development started with slow freezing methods in the 1970s1, then followed by vitrification methods developed in the late 1980s2. Generally, the latter technique is advantageous in its quickness, simplicity, and high survivability of recovered embryos. However, the cryoprotectants contained are highly toxic and may affect subsequent embryo development. Therefore, the technique was not applicable to certain strains of mice, even when the solutions are cooled to 4&deg;C to mitigate the toxic effect during embryo handling. At the RIKEN BioResource Center, more than 5000 mouse strains with different genetic backgrounds and phenotypes are maintained3, and therefore we have optimized a vitrification technique with which we can cryopreserve embryos from many different strains of mice, with the benefits of high embryo survival after vitrifying and thawing (or liquefying, more precisely) at the ambient temperature4.
Here, we present a vitrification method for mouse embryos that has been successfully used at our center. The cryopreservation solution contains ethylene glycol instead of DMSO to minimize the toxicity to embryos5. It also contains Ficoll and sucrose for prevention of devitrification and osmotic adjustment, respectively. Embryos can be handled at room temperature and transferred into liquid nitrogen within 5 min. Because the original method was optimized for plastic straws as containers, we have slightly modified the protocol for cryotubes, which are more easily accessible in laboratories and more resistant to physical damages. We also describe the procedure of thawing vitrified embryos in detail because it is a critical step for efficient recovery of live mice. These methodologies would be helpful to researchers and technicians who need preservation of mouse strains for later use in a safe and cost-effective manner.

An ethylene glycol-based vitrification method for mouse embryos is described. It is advantageous to other methods in its simplicity and low embryonic toxicity, and therefore can be broadly applicable to many strains of mice, including inbred and gene-modified mice.

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 ...

Mouse Sperm Cryopreservation and Recovery using the I&middot;Cryo Kit

Thousands of new genetically modified (GM) strains of mice have been created since the advent of transgenesis and knockout technologies. Many of these valuable animals exist only as live animals, with no backup plan in case of emergency. Cryopreservation of embryos can provide this backup, but is costly, can be a lengthy procedure, and generally requires a large number of animals for success. Since the discovery that mouse sperm can be successfully cryopreserved with a basic cryoprotective agent (CPA) consisting of 18&#37; raffinose and 3&#37; skim milk, sperm cryopreservation has become an acceptable and cost-effective procedure for archiving, distributing and recovery of these valuable strains.
 Here we demonstrate a newly developed I&bull;Cryo kit for mouse sperm cryopreservation. Sperm from five commonly-used strains of inbred mice were frozen using this kit and then recovered. Higher protection ratios of sperm motility (&gt; 60&#37;) and rapid progressive motility (&gt; 45&#37;) compared to the control (basic CPA) were seen for sperm frozen with this kit in 5 inbred mouse strains. Two cell stage embryo development after IVF with the recovered sperm was improved consistently in all 5 mouse strains examined. Over a 1.5 year period, 49 GM mouse lines were archived by sperm cryopreservation with the I&bull;Cryo kit and later recovered by IVF.

Here we demonstrate the newly developed I&#x2022;Cryo kit for mouse sperm cryopreservation. Two-cell stage embryo development with frozen-thawed sperm was improved consistently in 5 mouse strains with the use of this kit. Over a 1.5 year period, 49 genetically modified mouse lines were archived by sperm cryopreservation with the I&#x2022;Cryo kit and later successfully recovered by IVF.

Criopreservación de espermatozoides de ratón y de recuperación con el I · Kit de Cryo

Thousands of new genetically modified (GM) strains of mice have been created since the advent of transgenesis and knockout technologies.  Many of these ...

Mouse Embryonic Development in a Serum-free Whole Embryo Culture System

Mid-gestation stage mouse embryos were cultured utilizing a serum-free culture medium prepared from commercially available stem cell media supplements in an oxygenated rolling bottle culture system. Mouse embryos at E10.5 were carefully isolated from the uterus with intact yolk sac and in a process involving precise surgical maneuver the embryos were gently exteriorized from the yolk sac while maintaining the vascular continuity of the embryo with the yolk sac. Compared to embryos prepared with intact yolk sac or with the yolk sac removed, these embryos exhibited superior survival rate and developmental progression when cultured under similar conditions. We show that these mouse embryos, when cultured in a defined medium in an atmosphere of 95% O2 / 5% CO2 in a rolling bottle culture apparatus at 37 &#176;&#8203;C for 16-40 hr, exhibit morphological growth and development comparable to the embryos developing in utero. We believe this method will be useful for investigators needing to utilize whole embryo culture to study signaling interactions important in embryonic organogenesis.

Serum utilized in embryo cultures contains unknown components that can affect the outcome of experiments especially in studies involving signaling interactions. Here we utilized a serum-free oxygenated culture system and show that mid-gestation mouse embryos cultured for 16-40 hr&#160;exhibit morphological development comparable to embryos developing in utero.

Embriones de ratón con el desarrollo en todo un sistema de cultivo de embriones sin suero

Mid-gestation stage mouse embryos were cultured utilizing a serum-free culture medium prepared from commercially available stem cell media supplements in ...

Meiotic Spindle Assessment in Mouse Oocytes by siRNA-mediated Silencing

Errors in chromosome segregation during meiotic division in gametes can lead to aneuploidy that is subsequently transmitted to the embryo upon fertilization. The resulting aneuploidy in developing embryos is recognized as a major cause of pregnancy loss and congenital birth defects such as Down&#8217;s syndrome. Accurate chromosome segregation is critically dependent on the formation of the microtubule spindle apparatus, yet this process remains poorly understood in mammalian oocytes. Intriguingly, meiotic spindle assembly differs from mitosis and is regulated, at least in part, by unique microtubule organizing centers (MTOCs). Assessment of MTOC-associated proteins can provide valuable insight into the regulatory mechanisms that govern meiotic spindle formation and organization. Here, we describe methods to isolate mouse oocytes and deplete MTOC-associated proteins using a siRNA-mediated approach to test function. In addition, we describe oocyte fixation and immunofluorescence analysis conditions to evaluate meiotic spindle formation and organization.

Here, we present a protocol for specific siRNA-mediated mRNA depletion followed by immunofluorescence analysis to evaluate meiotic spindle assembly and organization in mouse oocytes. This protocol is suitable for in vitro depletion of transcripts and functional assessment of different spindle and/or MTOC-associated factors in oocytes.

Evaluación del huso meiótico en ovocitos de ratón por silenciamiento siRNA mediada

Errors in chromosome segregation during meiotic division in gametes can lead to aneuploidy that is subsequently transmitted to the embryo upon ...

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

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 for safe storage of genetic resources beyond the common practices of keeping breeding colonies. The main purpose of this study was to adapt the needle immersed vitrification (NIV) procedure to cryopreserve whole zebrafish testes. Cryopreservation of early-stage germ cells by whole testes NIV offers possibilities for the storage of zebrafish genetic resources, especially since after transplantation they can mature into both male and female gametes. Testes were excised, pinned on an acupuncture needle, equilibrated in two cryoprotective media (equilibration solution containing 1.5 M methanol and 1.5 M propylene glycol; and vitrification solution containing 3 M dimethyl sulfoxide and 3 M propylene glycol) and plunged into liquid nitrogen. Samples were warmed in a series of three consequent warming solutions. The main advantages of this technique are (1) the lack of spermatozoa after digestion of warmed testes thus facilitating downstream manipulations; (2) ultra-rapid cooling enabling the optimal exposure of tissues to liquid nitrogen therefore maximizing the cooling and reducing the required concentration of cryoprotectants, thereby reducing their toxicity; (3) synchronous exposure of several testes to cryoprotectants and liquid nitrogen; and (4) repeatability demonstrated by obtaining viability of above 50% in five different zebrafish strains.

The main purpose of this study was to adapt the needle immersed vitrification (NIV) procedure to cryopreserve whole zebrafish testes. Additionally, the repeatability of the method in five different zebrafish strains was tested.

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

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 ...