The Study On The Regulation Of Meiotic Of Goat Oocyte

Mammalian oocytes grow and undergo meiosis within ovarian follicles. Oocytes are arrested at the first meiotic prophase, held in meiotic arrest by the surrounding follicle cells until a surge of LH from the pituitary stimulates the immature oocyte to resume meiosis. In this experiment, during the the process of goat oocyte IVM, by adding different concentration cumulus cell and its surrounding granular cell ,we study the inhibitive effects and its mechanism of follicular cells on meiosis of oocytes; Calcium signal is important for the regulation of meiotic cell cycle in oocytes, but Calcium signal weather as start signal in meiotic resumption and play what role after GVBD is not well known. In this study ,The functional roles ofcalcium/calmodulin-dependent protein kinase II (CaMKII) in meiotic maturation of sheep oocytes were studied by by adding some concentration CaMKII inhibitor KN-93 , CaM antagonist W7 or L-type Ca2+ channel blocker Nifedipine. The results were showed bellow:1. The IVM rate of oocyte was not being affected considerably after adding 105 cell/mL and 106 cell/mL cumulus cells or surrounding granular cells, contrast to control group(P>0.05), but were significantly higher than that of 5×10⁶ cell/mL(41.2%),107cell/mL(24.6%) cumulus cells and 5×10⁶cell/mL(38.5%),107cell/mL(23.8%) surrounding granular cells (P<0.05). In adding 5×10⁶ cell/mL,107 cell/mL cumulus cells group and surrounding granular cells group, the cumulus could not expand . Nuclear Status Examination, the meiosis of oocytes was maintained in GV stage. During the process of oocyte IVM, adding some concentration cumulus cells and surrounding granular cells would maintain oocytes meiotic arrest.2. Rp-cyclic adenosine monophosphothioate, a membrane-permeable antagonist to cAMP, induced the oocyte IVM rate of 107 cell/mL cumulus cells group(71.6%) and surrounding granular cells group(71.3%) which there was no significant difference among the control group (P>0.05). Adding some concentration cumulus cells and surrounding granular cells would maintain meiotic arrest by increasing the cAMP level of oocyte. 3. The meiotic resumption of cumulus-enclosed oocytes was prevented by CaMKII inhibitor KN-93 , CaM antagonist W7 or L-type Ca2+ channel blocker Nifedipine treatment. Calcium signal may be a important signal in regulating meiosis maturation, as a key mediator of Ca²⁺ signal CaM and CaMKII play an important role in meiotic resumption.4. When the oocytes were treated with KN-93 or W7 after GVBD,the first polar body emission was inhibited, stay in prophase or MI stage but treated with Nifedipine the first polar body emission was not inhibited. CaM and CaMKII play an important role in emission of first polar body after GVBD.