Fig. 6

Photomicrographs of the testicle of rats stained by HE (bar = 100 μm) (a) Control group showing the normal histological structure of active mature functioning seminiferous tubules (Sts) associated with complete spermatogenic series. (b, c, d, e, f, g) SiO₂-NPs-treated group showing vacuolar degeneration of the germinal epithelium (red arrows), sloughing of the germinal epithelium into the lumen of seminiferous tubules (black arrows) beside shrunken, buckled, disorganized seminiferous tubules (black arrowheads), small-sized seminiferous tubules with no - or single - germinal cell layers (black star), hyalinization of the luminal contents (yellow star), necrotic seminiferous tubules (red stars) and faint eosinophilic albuminous interstitial edema (blue stars). (h) Thymol-treated group showing the normal histological structure of seminiferous tubules (Sts) (i) SiO₂-NPs + Thymol-treated group showing the normal histological structure of seminiferous tubules (Sts).