Monocrotophos induced dysfunction on estrous cycle and follicular development in mice

Monocrotophos a organophosphate pesticide was administered orally at doses of 1.6, 3.3, 6.6, 10 and 13 mg/kg body weight/day to normal virgin Swiss albino mice for 30 days. The vaginal smear and body weight of the mice were recorded daily and mice were sacrificed on 31st day. The ovaries from each animal was serially sectioned and stained for follicular studies. Estrous cycle was affected by showing a significant decrease in the number of estrous cycle and duration of proestrus, estrus and metestrus with concomitant significant increase in the duration of diestrus in all the treated groups, except with 1.6 mg/kg body weight/day monocrotophos treated group. There were significant decrease in the small, medium, large and total number of healthy follicles and increase in the medium, large and total number of atretic follicles with 6.6, 10 and 13 mg/kg body weight/day monocrotophos treatment. However, there were no significant change in the number of healthy and atretic follicles with 1.6 and 3.3 mg/kg/bodyweight/day monocrotophos treatment. There was no change organs weight except for a significant decrease in weight of the ovary with 3.3, 6.6, 10 and 13 mg/kg body weight/day and uterus and body weight with 10 and 13 mg/kg body weight/day monocrotophos treatment. Interruption in estrous cycle, decrease in healthy follicles and increase in atretic follicles may be due to harmonal imbalance or toxic effects of monocrotophos, which adversely effects reproductive function, as it has also analgesic and sedative action.