The Effects Of Nitric Oxide On The Development Of Porcine Preantral Follicle Cultured In Vitro

Preantral follicle was the early development of mammalian ovarian follicle,but they can't be fully used because most of them became atresia or degeneration before developed to antrum.To study preantral follicles,there is very important significance on oogenesis and follicular development.And make the best of ovary resources to promote animal breeding,preserve endangered species and human reproduction health.Recently,many studies demonstrated that nitric oxide,as a signal molecular, also has its key role in the control of growth and development of ovarian follicle in mammalian reproductive system,such as its involvement in follicular development, oocyte maturation,ovulation and sex hormone synthesis and so on.In order to observe the follicular survival,antrum formation,changes in oocyte diameter and development of follicle oocyte and granulose apoptosis at the end of the culture, porcine preantral follicles diameter between 200-300μm were used and NCSU23 was used as basal cultural medium supplemented with 7.5%FBS,2.5mg/ml FSH, 3.5μg/ml insulin,10μg/ml apo-transferrin and 100μg/ml ascorbic acid,the treatments were:NO donor of SNP(sodium nitroprusside)(0,0.001,0.01,0.1 and 1mmol/L).The effect of SNP on porcine preantral follicles cultured in vitro were as follows:(1)There were no difference on the growth during cultural period with all treatments showed increasement in follicle diameter(P＞0.05);(2)There showed difference of follicle survival rate in the 2 days and 4 days period,the follicle survival rate of 0.001mmol/L SNP was significantly higher than that of 1mmol/L SNP(85.28%vs70.6%,P＜0.05),and there were no significant difference with other treatments(P＞0.05);(3) The antrum formation showed no significant difference on day 2 and showed significant difference on day 4,with highest antrum formation of 0.001mmol/L SNP reach to 79.81%.in addition,the antrum formation rate of 0.001mmol/L SNP was significantly higher than that of 1mmol/LSNP (79.81%vs55.22%,,P＜0.05);(4) At the end of the culture,from the oocyte normal rate,apart from 1mmol/L SNP significantly lower than that of 0.001mmol/L SNP of 50.93%(P＜0.05),there were no significant difference among other treatments(P＞0.05);About the COC recovery rate,0.001mmol/L SNP was significantly higher than other treatments(P＜0.05);(5)granulosa apoptosis rate with all treatments, 1mmol/L SNP is significantly higher than other treatments(P＜0.05),0.001mmol/L SNP is significantly lower than other treatments(P＜0.05).We concluded that the important of NO during the porcine preantral follicles cultured in vitro,its involvement in follicular development,antrum formation,oocyte maturation and granulose apoptosis.The low concentrations of SNP was beneficial to the follicles,the high concentrations of SNP has toxic effect.