Interactive Effects Of Pyruvate And Low Temperature On Inhibition Of Aging Of Postovulatory Mouse Oocytes

In most mammals,matured oocytes are arrested at metaphase-Ⅱafter ovulation,and will not resume meiosis until they are activated by penetrating spermatozoa or other stimulations.If the MⅡoocytes are not fertilized or activated timely,they will occurs aging,the main features of the aging oocyte are the activity of MPF decline,sensitivity of activated increased,ability of development decreased.Like detention in the oviduct,in vitro culture of matured oocytes also led to oocyte aging.Many experimental designs in research involve culture of matured oocytes prior to micromanipulation or insemination.So the oocytes may occur the aging to reduce the subsequent capacity of the development.Therefore,it is necessary that we find a suitable way to inhibit the aging of oocytes.Our labortary has proved that Pyruvate plays an important role in inhibiting the aging of oocytes,the level of cell metabolism will decreased in Low temperature,so we believe that the low temperature may have inhibitory effects on the aging of oocytes.We studied the interaction between temperature and pyruvate on the aging of mouse oocytes.The results showed that:1 at the same temperature,the high concentration of pyruvate (10.27mM,5,27mM) compared to low concentrations of pyruvate(0.27mM), high concentrations can inhibit Oocytes sensitivity of activated to increase.2 in the same concentration of pyruvate,oocyte sensitivity of activated increased more slowly with the more lower temperature (5℃＜15℃＜25℃＜37℃).3 at various temperatures,high concentrations pyruvate can significantly improve the capacity of embryos developmental (10.27mM＞5.27mM＞0.27mM) after oocytes aging,oocytes age for 24h supplemented with high concentrations(10.27mM)of pyruvate at 25℃and 15℃,the capacity of embryonic development have no significant difference between supplemented with low concentration of pyruvate at 37℃for aging 6h.4,25℃compared to 15℃can cause the ability of fertilization of the aging oocytes to decline both supplemented with the high concentration(10.27mM) of pyruvate.5,5℃low temperature would cause the oocytes microtubule depolymerization,and can not be restored for aging 24h.6,after aging for 24 hours supplemented with high pyruvate at 25℃, zona occur hardening,and distribution of the cortical granules are abnormal, we thinked this cause the low rate of the fertilization.In short,in appropriate temperature supplemented with high concentration of pyruvate can effectively inhibit the aging of mouse oocytes, this method may be used for other animal and human clinical medicine with further study.