Effect of microRNA-409 on the pathogenesis of polycystic ovary syndrome

Y.-L. Teng, S.-Y. Lin, H.-Y. Yang, L.-H. Meng, R. Yu, L.-C. Zeng

Reproductive Center, The First Affiliated Hospital of Wenzhou Medical University, Wenzhou, China. yplb53@163.com

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• Gynecology

OBJECTIVE: To explore the expression level of microRNA-409 in PCOS (polycystic ovary syndrome) rats, as well as its potential effects on fertility of PCOS rats and phenotypes of offspring rats.

MATERIALS AND METHODS: PCOS model in rats was established by Letasazole administration. Follicular development of rats was evaluated by the percentages of the cystic follicle (FC) and corpus luteum (CL) of all follicles. The enzyme-linked immunosorbent assay (ELISA) was conducted to detect serum levels of hormones in rats, including LH, LH/FSH, T, INS, FSH, and E2. Subsequently, PCOS rats received a subcapsular injection of microRNA-409 mimics. The expression level of microRNA-409 in ovary was determined by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Serum levels of LH, LH/FSH, T, INS, FSH, and E2 in PCOS rats with microRNA-409 overexpression were accessed by enzyme-linked immunosorbent assay (ELISA) as well. PCOS rats were mated with male rats for recording pregnancy rate. At 6-week-old of offspring, they were sacrificed for detecting microRNA-409 level, percentages of FC and CL, as well as serum levels of hormones.

RESULTS: PCOS rats showed irregular estrous cycle and they were mainly in the anestrum. Rats in the control group were in a regular estrous cycle. A higher percentage of FC and a lower percentage of CL were seen in PCOS rats compared with those of controls. ELISA data revealed higher serum levels of LH, LH/FSH, and T in PCOS rats compared with those of controls. However, levels of FSH and E2 were lower in PCOS rats. Although INS level increased in PCOS rats, we did not observe a significant difference in INS level between PCOS rats and control rats. MicroRNA-409 was lowly expressed in ovaries of PCOS rats than those of controls. After injection of microRNA-409 mimics into rat ovary, microRNA-409 expression remarkably upregulated than those PCOS rats without injection. Rats in PCOS+microRNA-409 mimics group showed the largest body weight compared with those in the PCOS group and control group. PCOS rats showed a lower pregnancy rate than those of controls, which was markedly increased after administration of microRNA-409 mimics. Rats in PCOS+microRNA-409 mimics group presented lower levels of LH, LH/FSH, T, and INS, but higher levels of FSH and E2 than those in PCOS group.

CONCLUSIONS: MicroRNA-409 is lowly expressed in the ovary of PCOS rats. Overexpression of microRNA-409 could improve hormone levels and pregnancy rate in PCOS rats, as well as affect clinical phenotypes of their offspring.

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