The Regulation And Mechanism Of Adiponectin Deletion On The Reproductive Ability Of Female Mice

Objective To study the effect of adiponectin deficiency on fertility as well as the underlying molecules mechanisms in adiponectin herozygotic(APN+/-)and adiponectin homozygotic(APN-/-)mouse models.Methods 1)To assess the fertility of female APN+/-mouse and APN-/-mouse mating with B6 male mouse.2)To compare the collected the oocytes from three genotype mouse after intraperitoneal injections of PMSG and HCG.3)Morphology of all follicles composed of primordial,primary,preantral,antral and atretic follicles were assessed by microscope and they all were expressed as percentages of the total number of follicles in every twelfth section.4)Vaginal smears combined with toluidine blue stain were used to test the estrous cycle of adiponectin deficient mouse.5)Detection of the hormones related to mouse ovarian function(FSH,LH,progesterone,E2)by using ELISA.6)To detect the m RNA levels of FSHR,LHR and some genes invoved in follicular development and atresia.Results 1)Homozygotic deletion of adiponectin gene in female mice led to significant reduction in litter sizes compared with the control group respectively(17.8 vs 30.3,P<0.05).Haploid deficiency of adiponectin demonstrated a downward trend in producing offspring compared with the wild type mice,whereas the decrease did not reach statistical significance.2)Adiponectin null mice showed a sharp decrease in ovulated oocytes(5.4 vs 28.8 in APN+/+,P<0.001),and adiponectin haploid deficiency also led to significant reduction in the number of oocytes following PMSG/ HCG treatment(21.0 vs 28.8 in APN+/+,P<0.05).3)Adiponectin null female mice clearly showed a substantial increase in the percentages of atretic follicles compared to APN+/+ females(19.3% vs 8.5%,P<0.001),accordingly,the percentages of preantral and antral follicles exhibited a markedly decrease(P<0.01).4)Adiponectin deficient females exhibited abnormal estrous cycles,especially shown in APN-/-mice with presenting significant changes in four stages of estrus cycle which characterized by extended periods of diestrus(22.4 days vs 10.6 days,p<0.001)and shortened time of estrus(4.8 days vs 10.6 days,p<0.001).5)FSH levels were significantly decreased in both adiponectin haploid deficient and null mice relative to that of the wild-type controls(p<0.05).In contrast,LH levels were significantly higher in the female null mice than that in the controls(p<0.05).APN-/-mice exhibited reduced progesterone levels compared with APN+/+ mice(p<0.05).6)Real-time PCR and immunohistochemical analysis showed LHR expression was sharply decreased not only in m RNA levels but also protein levels,whereas FSHR expression showed no difference among the three genotypes.In addition,the expression of Bax and IGFBP-4 were significantly increased in the ovaries of adiponectin null mice compared to the controls(P<0.01),while CYP11A1 expression was significantly lower in adiponectin haploid deficient and null mice than in wild-type mice(P<0.05).Conclusion This study has demonstrated for the first time the critical function of adiponectin in ovarian follicular development and fertility in mouse.