Effects of green tea and vitamin E in the testicular tissue of streptozotocin-induced diabetic rats

OBJECTIVE: To investigate the possible therapeutic or protective effects of green tea in diabetic rat's testicular tissue, either as a single agent, or together with vitamin E.

METHODS: The present study was carried out at the Faculty of Medicine, Gazi University, Ankara, Turkey from May to August 2011 for 10 weeks. Forty-eight adult male Wistar albino rats, weighting 250-300 g, were divided into 8 groups: control; nondiabetic vitamin E (0.4 mg/kg/NG); nondiabetic green tea (300 mg/kg/NG); nondiabetic vitamin E plus green tea administered groups; diabetic group (60 mg/kg/IV streptozotocin); diabetic vitamin E; diabetic green tea; and diabetic vitamin E plus green tea administered groups. Proliferative and apoptotic indexes were determined using anti-PCNA antibody immunohistochemistry and TUNEL assays respectively. Tubule degeneration was evaluated using the Johnson's score and also seminiferous tubules diameters, epithelial thickness were measured.

RESULTS: Histopathological examination in diabetic group revealed degenerative changes in the seminiferous tubules together with a statistically significant decrease in PCNA positive cells, in epithelial thickness, diameter of the tubules and in Johnson's score, while exhibited an increase in the number of apoptotic cells. When all these findings are considered together, the most successful protective effects in diabetes were obtained in the combined antioxidant group.

CONCLUSION: Combined therapy of vitamin E and green tea in diabetes was more effective than monotherapy. Therefore, these antioxidants may be use as a supporting therapy for reproductive dysfunction.