Effects of silver nano-particles on sperm parameters, number of Leydig cells and sex hormones in rats

Background: Nano-particles are extensively employed in most industries. Several studies have been started to explore the probable detrimental effects of nano-particles on human reproduction. However, there is insufficient and controversially evident of effects of silver nano-particles on sperm parameters and other reproductive indices. Objective: Investigation of the effects of silver nano-particles on sperm parameters, sex hormones and Leydig cells in rat as an experimental model. Materials and Methods: In this experimental study, 75 male prepubertal Wistar rats were categorized in five groups including control group and 4 experimental groups (n=15 in each group). The rats in the experimental groups were fed silver nano-particles (60 nm in dimension) with concentrations of 25, 50, 100, and 200 mg/kg/day. After 45 days (about one duration of spermatogenesis in rat), samples of blood were taken from the rats for testosterone, leuteinizing hormone (LH), and follicle stimulating hormone (FSH) assessments. Afterwards, the epididymis and the testis of each rat were dissected for analyzing sperm parameters and Leydig cells. Results: The results demonstrated a statistically significant reduction in number of Leydig cells in experimental groups compared to control one. In addition, the data showed a reduction in testosterone and a rise in LH level which was more obvious in high doses (p<0.05); however, FSH level showed a reduction but it was not statistically significant. A significant decrease was also found in sperm motility and normal sperm morphology in the experimental groups compared to the control one. Conclusion: Our results demonstrated that silver nano-particles, in addition to interruption in functions of sex hormones, can diminish the number of Leydig cells and sperm parameter indices. It should be noted that the effects of nano-particles on reproductive indices are dose-dependent.