Anti oxidant role of elevated apelin levels in rats with polycystic ovary

Background: polycystic ovary syndrome (PCOS), one of the most common causes of infertility with increased incidence of inflammatory state and oxidative stress. Apelin is unique among adipose tissue hormones in being up regulated in the obese state and exert antioxidant activity. Objective: This research aims to evaluate serum apelin Levels in Rat models of letrozole induced PCOS and asses its relation to oxidative stress markers, TNF- hormonal state, and insulin resistance. Design: 48 Adolescent healthy female albino rats were used. It was divided into two equal groups; group I (normal diet) and group II (high fat diet) for 12 weeks, after the ninth week each group was subdivided into group A (control) and group B (PCOS induced). Fasting serum levels of apelin, insulin, glucose, estradiol, progesterone, LH, FSH and TNF- were measured and ovaries oxidative stress markers were estimated. Results: Serum apelin levels are increased in Letrozole induced PCOS in lean and HFD obese rats. While serum apelin levels positively correlated with TNF-insulin, HOMA-IR, BMI and ovarian tissues antioxidant markers, it correlated negatively with ovarian tissues oxidant markers. Hyperandrogenemia, Irregular cycles, incidence of subcapsular ovarian cysts with a diminished granulosa cell layer were detected in PCOS groups. Conclusion: Inflammatory markers as TNF-  is one of the major mechanisms which increase apelin levels in lean and obese PCOS, beside the synergistic role of hypeinsulinemia. Increased serum apelin levels in PCOS can be considered as compensatory against risk factors of PCOS as it induced increase in ovarian antioxidant markers.