Effect Of IGF-1 On Ovarian Growth And Development In MEX3C Gene Knockout Mice

Objective The effect of MEX3C gene on IGF-1 protein expression and follicular development in mice was investigated in vivo.Methods The genotype of 4-week-old FVB mouse was identified by PCR,divided into the wild type and the homozygous type.On the basis of that,the four groups were designed,each group of six?n=6?,concluding wild-type group,MEX3C knockout mouse homozygotes?homozygous group?,homozygote+IGF-1 treatment group,homozygote+trehalose?treatment control group?.The homozygous+IGF-1 treatment group was intraperitoneally injected with IGF-1 at 8 am at a dose of 10ug/kg.d for 7 days,the treatment control group the same dose of trehalose.The weight of mouse was compared before and after IGF-1 injection in each group.The mouse were sacrificed at week 5,and the ovarian wet weight of the mouse was compared in each group.The expression of E₂ and FSH in serum of mouse were detected by ELISA?enzyme-linked immunosorbent assay?.The morphological changes and follicle counts of ovaries were observed by HE staining.The expression of MEX3C,insulin-like growth factor-1 receptor?IGF-1R?,proliferating cell nuclear antigen?PCNA?,and P-AKT?Ser473?were detected by immunohistochemistry.The expression of MEX3C,IGF-1R,PCNA,and P-AKT?Ser473?,concerned protein was detected by Western blotting.The SPSS22.0statistical software was used for statistic,and P<0.05 indicated statistically significant difference.Results The weight and ovarian wet weight of MEX3C^-/-mice significantly reduced,compared with the wild type group?P<0.001?.After IGF-1 injection,compared with the treatment control group,the weight and ovarian wet weight of the homozygous+IGF-1treatment group increased?P>0.05?.ELISA results showed that compared with the wild type group,E₂ and FSH in serum were significantly decreased in the homozygote group?P<0.01?,but E₂ and FSH in serum were significantly increased in the homozygote+IGF-1 group?P<0.01?,compared with the treatment control group.HE staining results showed that follicles at all levels were observed in the wild type group and mature follicles were present,however,the multiple atretic follicles were observed in the MEX3C^-/-mice;and the primary follicles and presinus follicles were observed in the homozygote+IGF-1 treatment group.Follicle count results showed that compared with the wild type group,the original follicles,primary follicles,pre-sinus follicles,and sinus follicles were significantly reduced in the ovary of the homozygous group?P<0.05?,and the atretic follicles were significantly increased?P<0.01?.Compared with treatment control group,the number of primordial follicle and primary follicles increased significantly in homozygous+IGF-1group?P<0.05?,and the number of atresia follicles decreased significantly?P<0.05?.Compared with the wild-type group,the relative expression levels of MEX3C,IGF-1R,PCNA and p-AKT were significantly decreased in the homozygous group?p<0.01?,while the expression levels of IGF-1R,PCNA and p-AKT were significantly increased in the homozygous+IGF-1 groupby western blot and immunohistochemistry.?p<0.05?.Conclusions 1.MEX3C and IGF-1 positively regulated follicular development.2.MEX3C mediates IGF-1 to promote AKT phosphorylation and thus follicular development.3.IGF-1promotes ovarian follicular development in MEX3C knockout mice by upregulating IGF-1R and p-AKT levels and increasing serum estrogen levels to promote follicular development.