Toxicological impact of technical imidacloprid on ovarian morphology, hormones and antioxidant enzymes in female rats

Technical imidacloprid was evaluated for its effect on ovarian morphology, hormones and antioxidant enzymes in female rats after 90 days oral exposure. Luteinizing hormone (LH), follicle stimulating hormone (FSH) and progesterone levels were estimated in serum of rats and activity of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and level of reduced glutathione (GSH) and lipid peroxidation (LPO) were estimated in ovary after oral administration of imidacloprid (5, 10, and 20 mg/kg/day) for 90 days. Decreased ovarian weight together with significant patho-morphological changes in follicles, antral follicles and atretic follicles were observed at 20 mg/kg/day. Imidacloprid at 5 and 10 mg/kg/day has not produced any significant changes in ovarian morphology, hormones and antioxidant status of ovary. However 20 mg/kg/day dose has produced significant alterations in the levels of LH, FSH and progesterone. Similarly significant changes in SOD, CAT, GPx, GSH, and LPO were observed at 20 mg/kg/day dose level. Therefore, it is concluded that imidacloprid at 20 mg/kg/day dose level has produced significant toxicological impact on ovary of female rats as evident by pathomorphological changes, hormonal imbalance and generating oxidative stress and can be considered primarily as Lowest Observed Effect Level (LOEL) for chronic study.

► We have evaluated ovarian toxicity of imidacloprid (5, 10 and 20 mg/kg/day) in female rats after 90 days oral exposure. ► Significant changes in ovarian weight, histopathology, antioxidant profile and hormones were observed. ► Data revealed that 20 mg/kg/day have produced significant toxicological impact on ovary. ► Hence 20 mg/kg/day dose may be considered as Lowest Observable Effect Level for chronic study.