EFFECTS OF DI-(2-ETHYLHEXYL) PHTHALATE ON RAT OVARIAN FUNCTION

This study aimed to evaluate the effects of di-(2-ethylhexyl) phthalate (DEHP) on estrous cycle, sex hormone levels and ovary histological features. A total of 80 female SD rats were randomly divided into 8 groups (n = 10 per group): short-course control group, short-course low-dose group, short-course medium-dose group, and short-course high-dose group, long-course control group, long-course low-dose group, long-course medium-dose group and long-course high-dose group. Intragastrical DEHP was administrated at 1000 mg/kg/d (low dose), 2000 mg/kg/d (medium dose) and 3000 mg/kg/d (high dose) independently for 14 days (short course) or 28 days (long course). Rats in control groups were untreated. Vaginal smearing was used to detect the estrous cycle and rats were weighed at every Monday and Thursday to evaluate the growth status. At the end of study, rats were sacrificed and bilateral ovaries were obtained for histological examination. In addition, ELISA determined levels of serum progesterone, estradiol, testosterone, follicle stimulating hormone and luteinizing hormone. DEHP treatment limited body weight gain (P < 0.05), prolonged the estrous cycle (P < 0.05), decreased the ovarian mass index (P < 0.05) and ovarian weight. No evident degeneration, necrosis or other pathological features were found in the ovaries. The testosterone levels were decreased by DEHP treatment in a dose dependent manner. DEHP treatment could increase serum testosterone level, inhibit ovulation and prolong the estrous cycle of rats, exerting reproductive toxicity in a dose dependent manner. We speculate DEHP can affect the endocrine regulatory function of the ovary and limit the body weight gain, resulting in chronic toxicity.