Effects Of Vitamin A On Oocyte Maturation And Early Embryonic Development In Pigs

At present,the efficiency of pig oocyte maturation in vitro is low and the quality is poor,which leads to the low development efficiency of late embryo production in vitro,which seriously affects the application of cloning technology in biomedical models and animal reproduction.Oocyte maturation in vitro is the main link of somatic cell nuclear transfer,in vitro fertilization and other technologies,which restricts the production efficiency of late embryonic development and is critical to the impact of embryonic development.This experiment mainly takes pig oocytes and parthenogenetic activation(PA),somatic cell nuclear transfer(SCNT),in vitro fertilization(IVF)blastocysts as the research objects,and aims to explore the role of vitamin A(VtiaminA,VA)in the in vitro culture system.Oocyte maturation in vitro and its influence on early embryonic developmentFirst,this experiment optimized the concentration of VA added to the porcine oocyte culture medium,and found that 20?g/ml VA can significantly improve the in vitro maturation rate of porcine oocytes(75%�2.13%vs 52%�3.26%)(***P<0.01,the difference is extremely significant).In addition,it was also found that the transcription level of RAR gene and GSH gene in M II stage oocytes in the VA-added group was significantly higher than that in the control group.The results of immunofluorescence staining of oocytes after maturation further confirmed that the antioxidant levels of ROS and GSH in M? phase cells in the VA added group were significantly higher than those in the control groupBased on the above results,this experiment was followed by an in-depth study on the effects of VA on the cleavage rate and blastocyst rate of PA,SCNT,and IVF early embryos.It was found that compared with the control group,the 2-cell cleavage rate(89.33%�2.89%vs 81.33%�2.53%)and 4-cell cleavage rate(81%�3.04%vs 70.33%�2.2%),8-cell cleavage(50%�2.13%vs 41.67%�2.18%)and embryo blastocyst rate(30%�3.16%vs 23.67%�2.29%)were significantly higher than the control group(*P<0.05,Significant difference);2-cell cleavage rate(60.33%�2.34%vs 50.67%�3.23%),4-cell cleavage rate(38.67%�3.54%vs 29.67%�2.27%),8 Cell cleavage rate(35.67%�2.73%vs 27.67%�3.18%)and embryo blastocyst rate(17.33%�3.29%vs 9.67%�3.16%)were also significantly higher than the control group(*P<0.05,the difference was significant),and the 2-cell cleavage rate(79.67%�2.34%vs 58.67%�3.23%),4-cell cleavage rate(59%�3.14%vs 49.67%�2.47%),8-cell egg The splitting rate(39.33%�2.33%vs 29.67%�3.58%)and the embryo blastocyst rate(21%�2.49%vs 17%�2.66%)were significantly higher than those in the control group(*P<0.05,significant difference)Finally,this experiment explored the effects of VA on the pluripotency,blastocyst number,and apoptosis of PA,SCNT,and IVF blastocysts.Immunofluorescence staining analysis found that compared with the control group,the expression levels of the pluripotency genes Oct4?Cdx2?Sox2,etc.in the VA added group blastocysts increased significantly,the number of blastocyst cells also increased significantly,and the VA added group The embryo apoptosis was significantly higher than the control groupIn summary,this experiment optimized the concentration of VA in the in vitro culture system of porcine oocytes and embryos,and proved that the optimized VA can significantly increase the in vitro maturation rate of porcine oocytes,and can also significantly increase Embryo cleavage rate and blastocyst rate.In addition,it was found that the VA addition group can enhance and increase the cell number and pluripotency of porcine blastocysts,and generally improve the efficiency of porcine oocyte maturation and embryo development in vitro.This study is conducive to better application of cloning technology in the fields of biomedical models and animal reproduction.