| These experiments were carried out to clarify the kinds, the best concentration of the cryoprotectant which has no or little toxicity to embryos as well as suitable stage of the embryos' development by studying on the toxicity experiments of the mouse embryos, so that achieve the aim to improve viability of the frozen embryos.1. According to the crossbreed, the mice were divided into four groups-ICR Kunming , Kunming Kunming , ICR ICR and Kunming ICR . The oocytes of ovulation were 17.6, 13.4, 11.3 and 8.1 respectively. The effect of superovulation for the group of ICR Kunming was significantly higher than those of the groups of ICR ICR and Kunming ICR ( P<0.05), and the differences between other groups were not significant.2. The survival rates of early blastocyst treated with trehalose and sucrose, were 79.1%, and.77.1%, respectively; and the survival rates of morula were 46.3% , and 51.6%, respectively. The survival rate of blastocyst treated with trehalose were significantly higher than that of those treated with sucrose (P<0.05); while there was no significant difference between two groups in the survival rate of morula.3. The survival rates of mice early blastocyst and morula treated with 0.5M trehalose were 61.8% and 95.6% respectively; and treated with 0.25M trehalose were 35.5% and 67.2% respectively. The survival rates of both early blastocyst and morula treated with 0.5M trehalose were significantly higher than that of 0.25M trehalose treated ( P<0.05) .4.The survival rates of mouse morula for 0.5M trehalose added with O.OM, 2.0M, 2.5M, 3.0M and 3.5M glycerol were 51.3%,56.4%,63.7%,60.5%, and 70.8% respectively; the survival rates of blastocyst treated using thesame method were 97.09, 94.8% , 98.2%, 92.4% , and 96.1% respectively. There was no significant difference between control and treatments for morula and early blastocyst treated with different glycerol concentration.5. The survival rates of the early blastocyst and morula treated with 2.5M glycerol were 98.2% and 73.7% respectively. The survival rate of early blastocysts was significantly higher than that of the morula (P<0.05).6. In the experiment of researching the frozen effects on mouse embryos treated with different freezing methods, there were no significant difference in the number of normal embryos retrieved after thawing and the survival rate of embryos cultured 12 hours.7. In the experiment of freezing the mouse embryos treated with different concentration of ethylene glycol (EG), the number of normal embryos, the survival rates of blastocysts cultured 12 hours, 24 hours, 36 hours, and 48 hours and the hatching rates of the blastulas were compared. Except that the survivals rates of the contrast group and the cultured 12 hours group were significantly higher than those of the group with 10% EG(P<0.05), there were no significant difference between the contrast group and 10% group, 20% group in other aspects, but the contrast group was significantly higher than that of 30% group in every aspects.8. In the experiment of researching vitrification effect on mouse embryos crossed differently, there were no significant difference for the number of normal embryos thawed among Kunming Kunming , Kunming ICR , ICR Kunming and ICR ICR ; the blastocyst development rate of the embryo cultured 12 hours for the group of Kunming ICR was significantly higher than that of the group of ICR Kunming(p<0.05), and there were no significant difference between other groups; the blastocyst development rates of the embryos cultured for 24 hours and 36 hoursof the group of ICR Kunming were significantly higher than that of the other three groups(P<0.05); There were no significant difference among Kunming Kunming , Kunming ICR , ICR ICR ; the blastocyst development rate and hatching rate of the embryo cultured for 48 hours among four crossbred groups did not differ significantly. |
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