The Effect Of Oocyte Maturation Inhibitor On Porcine Oocyte Maturation

In Comparison with cattle, goat and other animals oocytes in vitro maturation , porcine oocytes in vitro maturation is poor in quality .which reflects in these aspects : poor cytoplasmic maturation highly polyspermy and poor embryo development. In recently years , many scholars studyed adding inhibitor to maturation medium to improve cytoplasmic maturation. Even though inhibitors contribute little to nuclear maturation, they can inhibit the nuclear maturtion and make oocytes stay at GV stage, which may promote nuclear and cytoplasmic maturation synchronization. Moreover, inhibitor cause oocytes nuclear maturation to concentrate and decrease aging oocyte proportion. In this experiment, we mainly detected and recorded oocytes germinal vesicle chromatine configuration, the first polar body proportion , cumulus expansion and cleavage rate after activated, we studyed inhibitors influence on oocytes maturation cumulus expansion and development, in order to choose one kind of inhibitor which could improve oocytes maturation quality.Experiment 1: The influence of different COCs condition, different storage temperature and collection time of ovary on oocytes germinal vesical chromatin configuration, we stained COCs with Hoechst 33342 after disposal, which came from integrity or not cumulus mass cell; different ovary storage temperature (25-30℃ and 31-34℃); different collection time (Aug-Sep and Nov-Dec) ,then observed oocytes germinal vesical chromatin configuration. Experiment results showed that: integrity cumulus mass cell had significantly high GVI-GVII oocytes proportion in comparison with non-integrity cumulus mass cell(74.46% vs 57.06%, P < 0.01),while these two groups had no significant distinction in GV oocytes proportion (90.98% vs 85.44%, P>0.05) ; ovary preserved at 31-34℃ had significantly lower GVI-GVII and GV oocytes proportion than ovary preserved at 25-30℃ (45.96% vs 74.46%, P < 0.01;77.62% Vs 90.98%, P < 0.01). Under different collecting time, each meiotic stage oocytes were basically in the similar proportions, except that GVI oocytes proportion was influenced by collecting time. In conclusion, integrity or not cumulus mass cell condition and ovary storage temperature could affect oocytes germinal vesical chromatin...