Preliminary Study On The Role Of Autophagy During Aging Of Mouse Oocytes

The post-ovulatory oocyte aging has marked detrimental effects on embryo development and offspring. oxygen free radical accumulation results in Mitochondria and endoplasmic reticulum dysfunction, Ca2+ imbalance, the activity of MPF and MAPK decrease, thus Oocyte activation sensitivity increase, the development of embryo decline. Autophagy is a general term for processes by which cytoplasmic materials including organelles reach lysosomes for degradation, in order to realize the metabolic needs of the cell itself and some organelles renewal. It is found that autophagy was essential for embryo development, but studies on the changes and effects of autophagy during oocyte aging were less. Thus we use mouse model, coming to study on changes of autophagy in vivo and in vitro and the effect of autophagy on aging of oocytes and embryo developmental competence.The results were as follows:1. Autophagy level gradually declined during oocytes in vivo aging, which decreased significantly in aging 24h. After aging 24h, autophagy has been decreased to the basal level.2. After adding H2O2CM, autophagy expression decreased; however, when adding MG132 aging 12h in vitro, autophagy expression increased.3. We found that when added autophagy activator rapamycin, autophagy level increased, the activation rate of oocytes reduced, and the developmental competence improved. The results were in contrast with RAP A when we added early autophagy inhibitor 3-MA.4. When oocytes aged 24h in vitro, autophagy level decreased significantly. After aging 24h, autophagy has been decreased to the basal level.5. Oocyte aging Oh or 24h adding 3-MA could inhibit fragmentation, but oocyte fragmentation did not change when oocyte aged 12h or 24h with 3-MA.6. Oocyte fragmentation did not change when we added rapamycin during aging.In conclude, autophagy gradually decreased in vitro or in vivo. After oocyte aged 24h, autophagy decreased to the base level. when we activated autophagy during oocyte aged 12h in vitro, autophagy inhibited oocyte aging and increased embryo developmental competence; The opposite results were found when we inhibited autophagy. autophagy did not affect oocyte fragmentation.