Regulation Of SDF-1/CXCR4 Axis On The Ovarian Development And Function

Objective:To explore weather the SDF-1 /CXCR4 axis dynamic regulation would be involved in the process of gradual maturation and improvement of ovarian.This study intends to detect the expression of SDF-1 and CXCR4 in the ovaries of female mice at different developmental stages,and establish a mouse model of premature ovarian failure(POF)to explore the relationship between SDF-1 /CXCR4 axis and ovarian function.Methods:1.Female ICR mice were divided into three groups according to the typical development period: pre-sexual maturity group(4 weeks),sexual maturity group(7weeks)and reproductive age group(10 weeks),with 10 mice in each group.Only 5of each group were used to collect ovaries,and the expression of SDF-1 /CXCR4 mRNA was detected by qPCR after RNA extraction.Follicular count was performed after HE staining.Localization of SDF-1 /CXCR4 expression was detected by immunohistochemistry.The remaining 5 were used to obtaine COCs and isolated oocytes and cumulus granulosa cells after ovulation induction.RNA was extracted and qPCR was used to detect the expression of SDF-1 /CXCR4 mRNA.2.20 female ICR mice about 7 weeks old were used to construct the POF model and were divided into control group,low-dose group,medium-dose group and high-dose group,with 5 mice in each group.The low-dose group,medium-dose group and high-dose group wre dividually received 140 mg/kg CTX and 35 mg/kg,160 mg/kg CTX and 40 mg/kg Bus,the 200 mg/kg CTX and 50 mg/kg Bus intraperitoneal injection.The control group was intraperitoneally injected with equal volume solvents.Observing the estrous cycle changes of mice.Two weeks later,the ovaries of the mice were taken,the organ coefficient was determined,the follicle count was performed after HE staining,and the expression of SDF-1 /CXCR4 mRNA was detected by qPCR.Results:1.Compared with the pre-sexual maturity group,the expression of SDF-1mRNA in the ovary of the sexual maturity group and the reproductive age group was decreased(P<0.05),and the expression of CXCR4 mRNA in the ovary was significantly increased(P<0.01).2.The expression of ovarian SDF-1 mRNA in the sexual maturity group and the reproductive age group was significantly lower than that in the pre-sexual maturity group(P < 0.05),and the CXCR4 mRNA expression was significantly higher than that in the presexual maturity group(P < 0.01).2.HE staining showed normal follicles at all levels was in the ovaries of the three groups.The number of total of follicles primary follicles in the reproductive age group were significantly higher than the other two groups(P<0.01).Compared with the sexual maturity group,the number of secondary follicles in the reproductive age group were increased significantly(P < 0.01).3.Immunohistochemistry showed that SDF-1 and CXCR4 were expressed in all levels of ovarian follicles in the three groups of mice,and they were mainly located in follicular granulosa cells and oocyte cytoplasm.4.In COCs,the SDF-1 mRNA expression of cumulus granulosa cells in the reproductive age group was significantly higher than that in the other two groups(P< 0.01).The expression of SDF-1 mRNA in oocytes of the sexual maturation group was significantly higher than that of the pre-sexual maturation group(P < 0.05).CXCR4 mRNA of oocyte granulosa cells in the pre-sexual maturation group was significantly lower than that in the other two groups(P < 0.05).5.After intraperitoneal injection of chemotherapeutic drugs,the estrous cycle of mice was disordered.After two weeks,the ovarian organ coefficients of the groups accepted chemotherapy drugs treatment were significantly lower than those of the control group(P<0.01),and the number of total follicles and primary follicles decreased(P<0.01).The ovarian tissue structure was destroyed,the interstitium and cavity increased,and the granulosa cell arrangement was loose.The gap between ovarian granulosa cells widened in the medium and high dose groups.6.With the increase of chemotherapy dosage and the aggravation of ovarianinjury,the mRNA levels of SDF-1 and CXCR4 increased first and then decreased,but there was no significant difference compared with the control group.Conclusion:SDF-1 and its receptor CXCR4 may promote ovarian development and functional maturation by regulating follicular granulosa cell and oocyte function,as well as ovulation.SDF-1 and CXCR4 may have the effect of repairing chemotherapy-induced ovarian functional injury,and the repairing ability of SDF-1/CXCR4 axis may be suppressed when the ovaries suffered severe damage.