The Effect Of Crocin On In Vitro Maturation And Early Embryonic Development Of Mouse Oocytes

Crocin,as an extract of saffron crocus,has excellent antioxidant effect.It can reduce the content of reactive oxygen species in the cytoplasm of oocytes,increase the content of glutathione,and increase the expression of antioxidant and anti apoptotic genes,so as to improve the maturation rate and subsequent development ability of oocytes in vitro.This study investigated the effects of crocin on the in vitro maturation,in vitro fertilization and early embryonic development of Kunming white mouse oocytes by adding different concentrations of crocin in the oocyte maturation fluid and embryo development fluid,to provide experimental data and theoretical references for the selection of antioxidant systems and antioxidants in the production process of in vitro embryos.The results showed that the first polar excretion rate of oocytes increased with the increase of crocin concentration in mature solution compared with the control group,and the first polar body discharge rate of oocytes increased significantly when the concentration of crocin was 10 and 15 μM(P<0.05).When the concentration of crocin added continued to increase,the first polar discharge rate of oocytes began to decrease,When the concentration was 25 μM,or higher,the polar body excretion rate of oocytes decreased significantly(P<0.05).Adding Crocin into the IVM solution can reduce the content of ROS in the cytoplasm.Compared with the control group,when the Crocin concentration reached 10 and 15 μM,the ROS content was significantly reduced(P<0.05).When the concentration of 20 μM was added,the ROS level of oocytes showed an upward trend,indicating a higher concentration of Crocin It has a negative effect on cell cytoplasm.Glutathione(GSH)content in cytoplasm:Adding Crocin into the IVM solution can increase the content of GSH in the cytoplasm.Compared with the control group,when the Crocin concentration reached 10 and 15 μM,the GSH content was significantly increased(P<0.05),when the concentration further increased,the GSH content in the cytoplasm began to decrease,affecting the quality of the cells.The effect of adding different concentrations of Crocin to the maturation fluid on subsequent embryo development:Compared with the control group,except for 10 μM Crocin,which can increase the fertilization rate and cleavage rate of oocytes,there is no significant difference in the rate of blastocysts(P>0.05).Adding Crocin had no beneficial effect on early embryonic development.Increased concentration would significantly reduce the rate of oocyte fertilization and blastocyst development(P<0.05).Add 0,10,20,30,40,50 μM Crocin into oocyte maturation solution in vitro.The results showed that:with the increase of crocin concentration in 20 μM,The polar body abnormality was observed in MII oocytes(P<0.05),As the concentration continued to increase,the abnormal rate of polar bodies among other groups increased significantly(P<0.05),with large polar bodies,symmetrical division,and cell fragmentation.Add 0,1,2.5,5,and 7 μM Crocin into embryonic development fluid.The results showed that with the increase in the concentration of Crocin in the embryonic development fluid,there was no significant difference in the cleavage rate between the groups compared with the control groups(P>0.05).The blastocyst rate began to decrease after the concentration increased,at 7 μM The growth of fertilized eggs in the Crocin addition group was stagnated in the 2-cell and 4-cell states,and did not develop to blastocysts.Adding Crocin in embryonic development fluid was no significant difference in the number of blastocyst cellss(P>0.05).The results showed that under the condition of this experiment,10 and 15 μM were added to the in vitro maturation fluid of Kunming white mouse oocytes,GSH content in the cytoplasm,and reduced the ROS content.There was no significant effect on cleavage rate and blastocyst rate after IVF.Adding a concentration of 20 μM Crocin or higher to the maturation fluid will significantly increase the rate of polar body abnormalities.The addition of Crocin in embryonic development fluid will not significantly affect the fertilization rate and cleavage rate,but will significantly reduce the blastocyst rate as the concentration increases.At 7 μM Crocin,the development of fertilized eggs is stagnated in 2-cell nucleus 4-cell.