Effects Of TPA And PAI-1on Bovine Cumulus Oocyte Complexes During In Vitro Maturation

In order to understand the effects of tissue Plasminogen activator and Plasminogen activator in bovine cumulus oocyte complexes (COCs) maturation in vitro, real-time RT-PCR and ELISA techniques were used to detect the relative expression of Plasminogen gene and tPA activity changes in bovine COCs cultured with Oh,8h,16h and24h in vitro, the expression of Hyaluronan synthase2(HAS2) mRNA in cumulus cell freed from COCs treated with different concentration of tPA and PAI-1in maturation medium and cultured16h in vitro, and HAS2gene expression of cumulus cell from COCs, the relative gene expression changes of GDF-9and BMP-15in corresponding oocytes of COCs treated with the combination of tPA and PAI at16h maturation in vitro, as well as the differences in the degree of bovine cumulus cell expand. The results are as follows:1. In the process of COCs maturation, the relative expression of Plasminogen mRNA level was significantly higher at8h and24h compared to Oh and16h (P<0.05) in bovine cumulus cells, at the same, the tPA activity in cumulus cell was prominent higher at8h and24h than16h (P<0.05).2. COCs were treated with different concentrations of tPA (0,0.1,1and10ng/mL) and PAI (0,0.1,1and10ng/mL) in vitro mature system, cultured16h. The results showed that the HAS2mRNA relative expression in cumulus cell were significantly lower in tPA treatment group than the control group and was lowest in1ng/mL tPA group, but the HAS2mRNA level in lng/mL and10ng/mL group was eminently higher than control.3. After addtion of the different combination of tPA and PAI-1, the HAS2mRNA relative expression amount of cumulus cell in PAI-1group was significantly higher than the other treatment groups (P<0.05) and cumulus cell proliferation extent in PAI-1group was prominently greater than the control group and the tPA group when COCs were cultured16h in vitro. Moreover, BMP15mRNA relative expression levels of oocyte in tPA group was significantly higher than the PAI-1group (P<0.05) and GDF9mRNA level in tPA group was notable higher than the amount of added PAI and control group (P<0.05).In summary, these findings show that PAI-1positive regulates HAS2gene expression in bovine cumulus cell and the effect of tPA on HAS2mRNA expression is adverse to PAI-1. While in bovine oocyte, tPA promotes BMP-15and GDF-9gene expression, but PAI plays converse role. Therfore, PAI-1secreted by cumulus cell is regarded as the essential factor in regulating and promoting cumulus cell proliferation in oocyte maturation.