Study On Low Doses Of Nitric Oxide On Meiotic Maturation Of Mouse Cumulus Cell-enclosed Oocytes In Vitro And Its Mechanism

Objective: to investigate the effect of nitric oxide(NQ) ,we observe the influence of different doses of Sodium nitroprusside (SNP,an NO donor) and N^W-nitro-L-arginine methyl ester(l-NAME,nitric oxide synthase inhibitor)on maturation of germinal vesicle stage oocyte in vitro; cultured with special dose of NO,or/and L-NAME,or/and dbcAMP,or/and progesterone, We observed oocyte maturation and analysed the relationship between them; co-treateded with special dose of NO,or/and L-NAME,or/and dbcAMP,or/and progesterone,c-erbB₂mRNA expression change in oocyte was explored by RT-PCR and activated-MPF,activated MAPK change was detected by western-blotting.Methods: We used exogenous PMSG to induce Kunming mouse superovulate. After 48h, we killed the mouse by decapitation, took out of hibateral ovaries, and lacerate egg by needle under the inverted microscope. Then we used mouth haustorial tube to blow CEO and collected DO,we placed 40～50 COC or DO to the wells of a 4-well dish containing 950ul M199 medium and cultured at 37℃ in 100% humidity air with 5%CO₂, At different time , we examine effects of different treated factor on oocyte maturation.Results: 1)Treatments of low concentration of SNP(10^-4～10^-6mol/L)have no influence on CEO meiotic maturation . compared with the control group, 10^-4 mol/L, 10^-5 mol/L,10^-6 mol/L SNP exhibited no effect on on GVBD Percentage after 4 hours culture and on PB1 rate after 12 hours culture in oocyte 2)L-NAME(10^-3mol/L) inhibited CEO meiotic maturation .Compared with the control group, the GVBD Percentage and PB1 rate of 10^-2 mol/L, 10^-3 mol/L L-NAME group significantly...