Investigation of the Effect of Polycystic Ovary Syndrome on the Expression of the Sirtuin-3 Gene in the Ovum of the NMRI Mice

Increasing levels of free radicals in the ova reduce the quality of their fertilization. Investigations have revealed the elevated production of tissue and serum-free radicals in women with polycystic ovary syndrome. Sirtuin-3 is located in mitochondria and plays an important role in the deactivation of free radicals. This study aimed to investigate the expression of the Sirtuin-3 gene in the ova of polycystic ovary syndrome affected mice.

Polycystic ovary syndrome was induced by the injection of estradiol valerate (40 mg/kg) in six NMRI mice (age: six weeks old; weight: 25±5); moreover, six mice were selected as a control group. Following the induction, the structure of the ovaries was examined using the histotechnique, and the serum levels of sex hormones were determined using ELISA. The ova were collected from the ovaries, and their RNA was extracted by a special kit and converted to cDNA. Real-Time PCR was performed to analyze the expression of Sirtuin-3, and the Gapdh gene was selected as an internal control.

In the mice with polycystic ovary syndrome, hydatid cysts were formed in the ovaries. Furthermore, serum FSH hormone levels decreased in the affected mice, while LH and testosterone levels elevated, compared to those in the control mice (P<0.001). The expression of Sirtuin-3 was reduced in the ova of mice with polycystic ovary syndrome, compared to that in healthy mice in the ratio of 0.18 (P<0.05).

The result of the present study showed that the expression of the Sirtuin-3 gene was decreased in the ovum of mice with polycystic ovary syndrome. Moreover, the disrupted expression of the Sirtuin-3 in the ovum can be suggested as one of the causes of reduced quality of the ovum in patients with polycystic ovary syndrome.