Tebuconazole Toxicity in the Parotid Gland of Adolescent Rats

This study aims to investigate the effects of subchronic exposure to Tebuconazole (TEB) on the parotid salivary gland of adolescent rats. These animals were exposed daily to TEB (10, 20, and 50 mg/kg, orally) or vehicle for 30 days. The parotid glands were evaluated by histopathological (hematoxylin-eosin staining and histomorphometry), histochemical (Periodic Acid-Schiff [PAS] for glycoconjugates and Picrosirius Red for collagen fibers) and immunohistochemical analysis for markers of oxidative stress (8-OHdG), inflammation (COX-2), apoptosis (caspase-3), epithelial remodeling (CK7), and cell proliferation (Ki-67). Histopathological results showed dose-dependent morphological changes, including architectural disorganization of the glandular parenchyma, cytoplasmic vacuolation, and inflammatory infiltrate. PAS results showed a significant reduction in labeling in the 50- and 20-mg/kg groups in relation to the 10 mg/kg and control groups, evincing a reduction in cell activity. The immunostaining of 8-OHdG (p < 0.05 at the 50 mg/kg dose), caspase-3 (p < 0.05 at all doses), CK7 (p < 0.05 at the 20- and 50-mg/kg doses), and COX-2 (p < 0.05 at all doses) significantly increased. The expression of the proliferation marker Ki-67 showed no significant alteration, whereas the histomorphometric analysis confirmed a progressive and significant reduction in cell density (p < 0.05). Moreover, the Picrosirius Red staining technique showed an increase in fibrotic tissue within the glandular parenchyma. In conclusion, this study found that the subchronic exposure to TEB induces dose-dependent toxicity in the parotid gland of adolescent rats.