Comparison of the protective effects of black seed oil, metformin and vitamin-E on fertility potential, testicular and spermatological character in experimental diabetic rats

In this study, we aimed to compare the possible effects of black seed oil, metformin and vitamin E against testicular damage of diabetic rats induced by STZ. Thirty male rats were divided into; Control, diabetes, diabetes+black seed oil, diabetes+metformin and diabetes+vitamin E groups. 4 groups were induced with a single dose of streptozotocin (45mg/kg) to induce diabetes. Diabetes+black seed oil group (2.5ml/kg/day) black seed oil, diabetes+metformin group (100mg/kg/day) metformin, diabetes+vitamin E group (100mg/kg/day) vitamin E were given orally. At the end of the eight-week experiment, blood glucose levels were analyzed. For histological examination, testes were dissected and taken for routine paraffin tissue protocol. Histopathological evaluation of H-E, PAS and Van Gieson, immunohistochemical determination of PCNA and caspase-3 and TUNEL-Assay were applied in the sections. In the Diabetes Group, irregularity, degeneration and atrophic tubules were observed in seminiferous tubules in all testicular sections. Testicular damage was very mild in the testicular sections of the black seed oil group. In the metformin group testicular sections, degenerated spermatogenic cells desquamated into the lumens, vascular congestion and interstitial edema were observed. In the immunohistochemical examination, some spermatogenetic cells in the Diabetes group were found to be decreased in PCNA expression, increased in Caspase-3 activity and increased in TUNEL Assay analysis. In the black seed oil group, the apoptotic index in spermatogenetic cells decreased more than Metformin and vitamin E groups. Metformin and vitamin E are partially beneficial for treatment of testes lesions in diabetic rats, yet black seed oil is more effective than those two.