CARD Rat IVF Medium

Rats are widely used in medical and life science research. In recent years, various strains of genetically modified rat have been produced worldwide thanks to the development of genome editing technologies. Moreover, it is predicted that even more genetically modified rats will be produced in the future. Therefore, there is a pressing need for effective preservation techniques for these genetically modified rat strains. Through sperm freezing, it is possible to quickly cryopreserve a large number of sperm taken from the cauda epididymis of a male rat. For this reason, sperm cryopreservation is expected to be an easier, more effective and most economically viable technique for the preservation of genetically modified rat strains than embryo cryopreservation. However, rat sperm is vulnerable to the effects of physical changes to pH, osmotic pressure, temperature and other similar factors. Moreover, it is difficult to maintain the motility of frozen-thawed sperm via conventional sperm cryopreservation methods, which means that it is not viable to use these sperm in in vitro fertilisation (IVF). Therefore, the establishment of rat sperm cryopreservation and rat IVF techniques was required to solve these issues. A research team led by Dr. Naomi Nakagata and Dr. Toru Takeo at the Institute of Resource Development and Analysis, Kumamoto University have developed a practical rat sperm cryopreservation technique and an IVF method using frozenthawed rat sperm. These techniques may offer a solution to the problem of genetically modified rat strain preservation.