Studies have shown that metal nanoparticles induce toxicity in testicular tissue. One such nanoparticle, with applications in both therapy and industry, is bismuth oxide nanoparticle. There has been no extensive research investigating the effects of these nanoparticles on testicular histology. Therefore, in this study, we examined the effects of this substance on the testicular tissue of male NMRI mice. Mice were divided into 7 groups, with a treatment duration of 35 days. Groups 1 to 6 were treated with bismuth oxide nanoparticles at concentrations of 25, 50, 100, 200, 400, and 800 mg/kg, respectively, while group 7 served as the control group, receiving daily physiological saline. After 35 days, the mice were euthanized, and their testicular tissues were extracted, fixed in a specific fixative (MDF), and processed for sectioning and staining. Testicular changes were then evaluated using stereological techniques. The findings revealed a significant decrease in the total volume of testicular tissue, seminiferous tubules, and the number of spermatogonia, spermatocytes, spermatids, Sertoli cells, and Leydig cells in the bismuth-treated groups compared to the control group. Conversely, the volume of the interstitial tissue showed a significant increase compared to the control group. However, there were no significant changes in the length, diameter, and thickness of the basement membrane of seminiferous tubules compared to the control group. Therefore, bismuth oxide nanoparticles can cross the blood-testis barrier and induce toxicity in testicular tissue. It is recommended that future studies be conducted on human testicular tissue.
