Biochemical and histopathological investigation to study the impact of pyriproxyfen exposure on ovarian morphology and reproductive function in female rats.

BACKGROUND: Pyriproxyfen (PYR) is a pyridine-based broad-spectrum insect growth regulator and pesticide which works as an analogue of juvenile hormone. Its exposure to aquatic animals and crops is linked with various hazardous effects on biological functions. We aimed to find the possible reprotoxic effects of pyriproxyfen in adult female Sprague-Dawley rats through histological and biochemical approaches. METHODS: Adult female rats were assigned to four groups and were administered 0 mg/kg (Control), 62 mg/kg b.w, 124 mg/kg b.w, and 186 mg/kg b.w., of PYR dissolved in distilled water for 28 consecutive days. Body mass index, blood glucose levels, total protein concentration, lipid profile, ovarian histology and reproductive hormonal profiles were determined. RESULTS: There were no significant changes in body weight due to PYR exposure; however, slight alterations in ovarian and uterine weights were noted in the treatment groups. The 186 mg/kg b.w. treatment significantly affected estrous cyclicity. Furthermore, a non-significant increase in total protein levels and a significant (p < 0.05) rise in triglyceride and total cholesterol levels were recorded. However, a significant decline in high-density lipids was recorded in the high-dose treatment group (186 mg/kg bw) as compared to the control. A notable reduction in plasma concentration of estradiol, progesterone, and cortisol levels was recorded between the control and all the treated groups. Ovarian histomorphological analysis showed distorted basal membranes, increased empty spaces, tissue decompaction, degenerate follicles, and disassembled epithelium in the high-dose treated group (186 mg/kg b.w). CONCLUSION: Oral administration of PYR in adult female rats leads to altered organ weights, disturbed normal estrous cycle, increased triglycerides and total cholesterol, reduced high-density lipids concentrations, and damaged ovarian architecture, affecting biochemical and reproductive function in female rats.