Histomorphometric Comparison of Induction of Polycystic Ovary Syndrome by Exposure to Constant Light in Primiparous and Nulliparous Rats

Abstract

Different animal models of polycystic ovary syndrome (PCOS) are introduced but most of them are induced by exogenous chemical or hormonal manipulation. The aim of the present study was to evaluate histomorphometric characteristics of ovaries in primiparous and nulliparous PCOS rats which were exposed to 90 days constant fluorescent light. Twenty-four adult female primiparous and nulliparous rats were divided into two subgroups of light exposure and control (n = 6). Both light exposure groups were exposed to 90 days constant 24 h per day light with the intensity of 350 Lx to 1 m2 on floor. Ovaries of all rats were histomorphometrically evaluated after 90 days. The following indices were calculated and compared between groups: ovary volume, stroma volume, total follicular volume, number of secondary follicle, number of tertiary follicle, mean of tertiary follicle volume, corpus luteum volume, number of corpus luteum, and mean of corpus luteum volume. Serum testosterone concentrations were measured. In both primiparous and nulliparous rats, ovary volume and number and volume of corpora lutea of control groups were more than of light exposure groups (P < 0.05). While, total follicular volume and volume of single tertiary follicle of light exposure rats were more than control ones (P < 0.05). Concerning serum testosterone concentrations both light exposure groups showed hyperandrogenemia. In conclusion, induction of PCOS with the same characteristics of PCOS ovary of women was observed after 90 days exposure to constant light in both primiparous and nulliparous rats.