Evaluating the effect of silver nanoparticles on testes of adult albino rats (histological, immunohistochemical and biochemical study)

Silver nanoparticles (AgNPs) are widely used in medicine, however, they have toxic impacts on different organs. AgNPs distribution to the testes was reported, so, we aimed to study the effect of intraperitoneal injection of AgNPs, at different concentrations and different time durations, on adult rat testes. Sixty healthy adult male Wistar albino rats were divided into three groups; control group (Group I) and two experimental groups (Groups II & III), each of which were subdivided into two subgroups. Rats in group II were exposed for 7 days to low and high doses of AgNPs, respectively. Rats in group III were exposed for 28 days to low and high doses of AgNPs, respectively. Testicular sections were stained with H&E, Toluidine blue, Immunohistochemical staining for Ki-67 and CD68 and Electron microscope examination were performed. Serum testosterone level and Quantitative Real-Time PCR for spermatogenesis genes were measured. Group IIa & IIb showed thickened capsule studded with nanoparticles, congested blood vessels, disorganized seminiferous tubules (Sts) and detached germinal epithelium. Group IIIa & IIIb showed marked reduction in the germinal epithelium, and shrunken Sts with the absence of sperms in most of them, which was more evident with higher doses of AgNPs. Significant decrease in cell proliferation and increase in interstitial tissue macrophages were more detected in groups II & III than in the control group. Decreased serum testosterone and decreased expression levels of spermatogenesis genes in groups IIa, IIb & IIIa, IIIb than in the control group were observed. In conclusion: intraperitoneal injection of AgNPs adversely affected the structure of adult rat testes. The tissue damage was more manifested with increased dose and duration of exposure.