Determination of biochemical and histopathological changes on testicular and epididymis tissues induced by exposure to insecticide Imidacloprid during postnatal development in rats.

Background: Imidacloprid is a neonicotinoid insecticide belonging to the chloronicotinyl nitroguanidine chemical family. Toxicity of IMD for mammals in scientific studies has shown high mutagenic, immunotoxic, teratogenic and neurotoxic effects. The present study was designed to assess the toxic effects of imidacloprid (IMD) on the testicular and epididymis tissues as well as testosterone levels of neonatal male rats.

Methods: Neonatal male rats from postnatal day (PND) 1 to PND 26 were consecutively administered with different concentrations of IMD (1, 5 and 10 mg/kg) subcutaneously. The effect of IMD on body and organ weight, lipid profile, histopathological alterations, oxidative stress and altered testosterone levels were assessed in the testis and plasma.

Results: The results of body weight gain showed a significant difference in group 4 (10 mg/kg) animals as compared to the control. A significant increase in total cholesterol and triglycerides, while a decrease in high-density lipoprotein concentrations was evident. Similarly, a significant decrease in concentrations of antioxidant enzymes (CAT and SOD) among all the IMD-treated groups was evident, when compared to the control. Increased production of ROS was also noticed in the highest-dose treatment group. Further, we observed that IMD-treated rats indicated histopathological changes in the testis and epididymis along with a significant decrease in the plasma testosterone concentrations among IMI-treated groups in contrast to the control. Histological examination of the testis of IMD-treated neonatal male rats also showed decreased spermatogenesis in the treated groups when compared to the control. Furthermore, an increase in lumen diameter and a decrease in epithelial height of seminiferous tubules were also observed in IMD-treated rats in comparison with the control.

Conclusion: It is concluded that sub-chronic exposure to IMD in neonatal male rats may induce histopathological changes in reproductive tissues and damage normal testicular functions via inducing oxidative stress, decrease in body weight, disturbing normal blood lipid profile and testosterone concentration. IMD exposure can induce pathophysiological effects calls for further evaluation of this widely used insecticide.