[Effects of nitric oxide on the oocyte and embryo development in mice]

To evaluate the effects of exogenous nitric oxide on mouse oocyte maturation in vivo, in vitro fertilization and embryo development.

By intraperitoneal injection, the experimented female mice were administered separately with sodium nitroprusside (SNP) of dosages at 1.0 mg/kg, 5.0 mg/kg and 10.0 mg/kg when stayed in period of superovulation,and at the same time, the control mice were administered with equal volume of saline solution. At 15 hours after injected intraperitoneally with hCG, the mice were killed by cervical dislocation, of which the oocytes in the oviducts were collected for in vitro fertilization, and also the oocyte maturation, the embryo development and morphological change were observed.

(1) In 5.0 mg/kg SNP group, the rates of MI and MII oocytes with no fertilization were higher than those in the control group and 1.0 mg/kg SNP group (P < 0.05, P < 0.01),but the fertilization rate of oocytes was lower in 5.0 mg/kg SNP group than in the control group and 1.0 mg/kg SNP group (P < .01), all mice in 10.0 mg/kg of SNP group died of 20 minutes after administration. (2) The cleavage rate of embryos after 2-cell stage was lower in 5.0 mg/kg SNP group when compared separately with that in the control group and 1.0 mg/kg SNP group (P < 0.01), none of the embryos developed to blastocyst stage in 5.0 mg/kg SNP group. (3) The rate of the fragment formation in embryos during progress was higher in 5.0 mg/kg SNP group than in the control group and 1.0 mg/kg SNP group (P < 0.01).

The higher concentration of nitric oxide inhibits oocyte maturation in vivo, in vitro fertilization and embryo development,and affects the embryo quality.