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Cryopreservation training course

Last week we held our popular four day cryopreservation course, designed to give animal technologists hands-on experience of embryo and sperm freezing and in vitro fertilization.

Cryopreservation allows long-term storage of embryos and sperm, providing a convenient way to preserve, protect and transport mouse lines for use in research. Here at MRC Harwell we have extensive experience of using cryopreservation techniques. By providing this course we aim to share our expertise with the wider scientific community.

The course runs over a period of three and a half days, this year from Monday 10 to Thursday 13 March, and is worth ten continuing professional development (CPD) points. It is led by MRC Harwell’s Frozen Embryo and Sperm Archive (FESA), part of the European Mutant Mouse Archive (EMMA), a collective effort by centres all across Europe to create a genetic archive for use by the international scientific community.

On Monday, the participants learnt how to freeze sperm in liquid nitrogen using plastic semen straws. While embryos can be stored ready to use, sperm cryopreservation has the advantage that, as long as you have enough oocytes for fertilisation, you can potentially recover over a thousand mice from the sperm of just one male.

Tuesday was all about embryo cryopreservation. The embryos were harvested, loaded into straws and frozen in the morning, and after lunch the group learnt how to thaw them out again. At the end of the day, everyone had the chance to get to know each other a little better at the course dinner.

The final day and a half of the course was set aside to give participants experience of a straightforward and robust in vitro fertilisation (IVF) procedure, with a demonstration of how these embryos can then be transferred into recipient females to establish a new pregnancy. The course concluded with a final review and recap.

In this way, the course allowed participants to gain experience of the entire process, from harvesting the embryos and sperm, to conducting IVF and transferring embryos into the female mouse. After a productive and enjoyable few days, they left fully equipped to put their newly acquired skills to use.

We will be running another cryopreservation course later in the year on 6-9 October 2014. Please contact Martin Fray ( for more details.

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