| There are more evidence show that variouse stage of antral follicular oocyte before maturation culture in vitro, first reflected on the chromatin configuration of the nucleus , may account for the observed flaw of in vitro maturation system. In this experiment ,we studied the chromatin configuration changes during oogenesis and its relationship with ovulatio^ meiotic competence - fertilization and preimplantation development.The results are as follows:1) There are four types chromatin configuration in antral follicular oocyte isolated adult mouse.They are named S^NSN>pSN,pNSN.; SN>NSN type oocyte is more frequency than pSN> pNSN type oocyte;2) The appearance of SN-oocyte is first observed in 17-day-old mouse, the rate of SN-oocyte is significantly increased when the mouse age reached 18 and 19 days;3) Oocyte in diameter between 20um and 60um is found to be NSN-oocyte,but when oocyte in diameter reached 70um, SN-oocyte is first found and the rate of SN-oocyte is increased as the oocyte diameter reached 70-80um;There are more pSN ?0 pNSN-oocyte when the oocye in diameter is smaller than that of 70 urn;4) PMSG injection appeared to induce an increase of SN-oocyte in diameter 70~80um and an decrease of NSN-oocyte in diameter 6Q~70um;But hCG injection induce an decrease of SN-oocyte and back to a situation prior to PMSG injection.5) Both SN-oocyte and NSN-oocyte isolated from antral follicular can undergo GVBD and progress toup to metaphase II.But the meiotic competence of SN-oocyte is higher than that of NSN-oocyte;6) The fertilization rate is not significantly different in both groups of matured oocyte derived from SN-and NSN-oocyte;But the 2-cell development rate of SN-oocyte is higher than that of NSN-oocyte;7) The rate of SN-oocyte in antral follicular is not significantly different between 6-8 weeks old and 30-32 weeks old mouse;8) With ageing ,the rate of SN-oocyte isolated from antral follicular is increased . |
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