The histologic observation of the effect of quercetin on the experimentally generated adult rat testis hyperthyroidism model

Objective: In our study, it was aimed to investigate histochemical, immunohistochemical, ultrastructural and biochemical effects of quercetin, a potent antioxidant against testicular damage, in experimental hyperthyroid rats. Method: In this study, male rats of Wistar strain were separated into 5 groups (n=7). I. Control group, II. Sham group; treated with only 2 cc maize oil (21 days oral gavage), III. Quercetin group; treated with 20 mg/kg/day quercetin dissolved in 2 cc of maize oil (21 days oral gavage), IV. Hyperthyroid group; treated with 0.3 mg/kg/day L- thyroxine (21 days ip) and V. Hyperthyroidism+Quercetin group; treated with 0.3 mg/kg ip L-thyroxine+20 mg/kg/day quercetin dissolved in 2 cc of corn oil. At the end of 21 days, all the test subjects were sacrificed. The sections obtained for light microscopic examinations were stained with Hematoxylin & Eosin (H&E), Periodic Acid Schiff (PAS) and Masson Trichrome. Johnsen score, seminiferous tubule diameter and basal membrane thickness were evaluated in these sections. In order to detect apoptosis, TUNEL and active caspase- 3 staining were performed. The testis structure was also examined ultrastructurally. For biochemical analyzes TSH, T3, T4 and testosterone levels in blood samples, and superoxide dismutase (SOD), glutathione peroxidase (GPx) and malondialdehyde (MDA) levels in testicular tissue were examined. Results: Microscopic and ultrastructural examinations showed normal testicular structure in the control group. In the hyperthyroid group, irregularity in spermatogenic serial cell viability, germ cell loss and vakoulization in seminiferous tubules, with decrease in basal membrane thickness and diameter while increase in connective tissue in interstitial region were observed. In the hyperthyroid+quercetin group, the testis showed almost normal morphology. On the immunohistochemical studies, the numbers of cells with TUNEL positive and active caspase-3 immunoprecipitated in the seminiferous tubules were increased in the hyperthyroid group compare to control group, whereas the number of immunopositive cells in the hyperthyroidism+quercetin group were decreased. In the biochemical analysis, hyperthyroidism group showed T3 and T4 levels were increased and TSH level was decreased compare to the control group. However, the levels of hyperthyroidism+quercetin groups were not changed statistically significant. Also testosterone levels were not statistically significant. A significant increase in MDA levels and a significant decrease in SOD levels were observed when the control group and hyperthyroid group were compared in testicular tissue. Significant decrease in MDA levels and a significant increase in SOD levels were observed in hyperthyroidism+quercetin group compared to hyperthyroidism group. There was no statistical significance in GPx levels. Conclusion: Based on the obtained results, we found that hyperthyroidism caused testicular tissue damage, increased oxidative stress and apoptosis, and that Quercetin appears to reduce tissue damage and biochemical changes. Key Words: testis, hyperthyroidism, quercetin, rat