Effects Of Resveratrol On In Vitro Maturation And Early Embrvonic Development Of Sheep Oocytes

This study by discussing different concentrations of Resveratrol(RES)of sheep oocytes in vitro maturation,in vitro fertilization and early embryo development of ovine oocytes,as well as the antioxidant capacity of oocytes and the content of steroid hormone(Estradiol and Progesterone)secreted cumulus cells were investigated.It was found that RES had positive effects on in vitro maturation and embryo development of sheep oocytes.In order to further optimize the in vitro culture environment system of sheep oocytes,and further improve the in vitro maturation and embryo development efficiency of sheep oocytes,provide theoretical basis for the in vitro development mechanism of sheep in vitro fertilization embryos.The main results are as follows:Ⅰ.Effects of different concentrations of RES on in vitro maturation of sheep oocytesDifferent concentrations of RES 0,0.5,2.0 and 5.0 μmol/L were added to the in vitro maturation fluid of oocytes,respectively.The results showed that compared with the control group and the treated group with each concentration of RES,the 0.5 μmol/L RES group significantly improved the formation of the first polar body of oocytes and the GSH level(P<0.05),and significantly reduced the ROS level in the oocyte cytoplasm(P<0.05).the treated group of 5.0 μmol/L RES significantly decreased the cumulus expansion rate and formation rate of the first polar body,and the intracellular GSH level(P<0.05).Therefore,0.5 μmol/L RES was added to the IVM solution of sheep oocytes to reduce the level of cytoplasmic ROS and increase the level of GSH,so as to improve the quality of in vitro maturation of sheep oocytes.Ⅱ.Effects of RES at different concentrations on antioxidant enzyme activity and hormone content in vitro maturation medium of sheep oocytesThe results showed that the addition of 0.5 μmol/L and 2.0 μmol/L RES in the in vitro maturation fluid of oocytes increased the activity of SOD and GSH-Px,but there was no significant difference(P>0.05)and significantly decreased the content of MDA(P<0.05).5.0 μmol/L RES significantly reduced the activity of antioxidant enzymes SOD and GSH-Px and increased the content of MDA(P<0.05).In addition,RES of different concentrations had a certain inhibitory effect on E2 secreted by cumulus cells,which gradually decreased with the increase of concentration,and the concentration of 5.0 μmol/L RES significantly decreased E2 content(P<0.05).Meanwhile,compared with the control group,0.5μmol/L RES significantly increased the secretion of P4(P<0.05),and there was no significant difference between the experimental groups(P>0.05).Ⅲ.Effects of different concentration of RES on in vitro fertilization and early embryo development of sheep oocytesDifferent concentrations of RES 0,0.5,2.0,and 5.0 μmol/L were added to the IVM solution of sheep oocytes.It was found that adding 0.5 μmol/L RES could promote the development potential of in vitro fertilization embryos,and the fertilization rate,cleavage rate and blastocyst rate increased compared with the control group,but there was no significant difference(P>0.05).The optimal concentration of 0.5 μmol/L RES was added to IVM/IVC solution to promote embryo development in vitro,and significantly increased the embryo cleavage rate and blastocyst rate(P<0.05).The addition of 0.5 μmol/L RES to the in vitro maturation solution of sheep oocytes significantly improved the formation rate of the first polar body of oocytes,the intracellular GSH level and reduced the ROS level,thus improving the in vitro maturation quality of oocytes.0.5 mol/L RES can promote in vitro maturation efficiency of oocytes by improving antioxidant enzyme activity and increasing the content of P4 secreted by cumulus cells.In addition,0.5 mol/L RES significantly improved the ability of early embryo development of sheep.High concentration of 5.0 μmol/L RES had adverse effects on in vitro maturation and early embryonic development of oocytes.