Study On Superovulation And Cryopreservation Of Wistar Rat Embryos

The purpose of this study was to examine the response of Wistar rats of different doses on superovulation.The treatment hormones were used into three groups,10IU,20IU, or30IU/rat with pregnant mare serum gonadotropin-human chorionic gonadotropin (PMSG-HCG). Then the treated each female was mated with a male. Embryos were resumed at different developmental stages and locations, and compared to determine the best dose for superovulation of rat.The tube method was used to study two different extenders to cryopreserve by vitrification the2-cell Wistar Rats embryos and morula embryos, which were DAP213and SDP0323.And the effects of different extenders on the average survival rates of frozen-thawed embryos and on average rates of the news born were discussed, for selection the best one which will be used to cryo-bank.Results:(1)The experiments were divided into3groups according to the three different dosages(10IU,20IU and30IU),after the injection of HCG, the treated each female was mating with a male. Embryos were resumed at different developmental stages and locations. The average number of two-cell embryos obtained from each rat in three groups were12.1±4.623.1±10.2,24.9±8.2, respectively; in above-mentioned,30IU/rat was considered to be the best one, and there are significant differences between20/30IU and10IU according to the Student’s Test(P<0.01); The average number of morula embryos obtained from the three groups were10.3±5,23.7±17.2,17.2±5.9; obviously,20IU/rat was considered to be the best one, and there are significant differences between20/30IU and10IU according to the Student’s Test(P<0.05).(2) Using the tube method.of87rat2-cell embryos were frozen with DAP213.45embryos were retrieved, the43embryos were transplanted into pseudo pregnant rats, and born15off springs; of81rat2-cell embryos were frozen with SDP0323,56embryos were retrieved, the56embryos were transplanted into pseudo pregnant rats, and born23off springs. Respectively, there are no significant differences between the two extenders using the Student’s-Test(P<0.05), but both the average survival rates and average new born rates with SDP0323were higher than that with DAP213.Of256rat morula embryos were frozen with DAP213,176embryos were retrieved, the174embryos were transplanted into pseudo pregnant rats, and born32off springs, of214rat morula embryos were frozen with SDP0323,172embryos were retrieved, the169embryos were transplanted into pseudo pregnant rats, and born32off springs. Respectively, there are no significant differences between the two extenders using the Student’s-Test(P<0.05), but both the average survival rates and average new born rates with SDP0323were higher than that with DAP213. The results also show that the tube method with DAP213and SDP0323for cryopreservation of the2-cell and morula rat embryos have been established successfully, and both the two extenders are suitability for the rat embryos-bank.