Protective action of melatonin on diabetic rat testis at cellular, hormonal and immunohistochemical levels

[Display omitted] •Simultaneous melatonin could ameliorate hyperglycemia in diabetic rats.•Antioxidant enzymes were increased by treatment with melatonin at a dose of 10 mg/kg in diabetic rats.•Inflammatory cytokine levels were decreased with melatonin treatment in experimental diabetes.•Melatonin protects the testicles of diabetes animals against oxidative stress.•Melatonin protects against morphometric alterations and decrease plasmatic testosterone. The aim of the present study was to analyze the effects of melatonin treatment on diabetic rat testes. Fifty albino rats were divided into the following groups: CG: control group; GD: placebo-induced and placebo-treated mice; GDI: insulin-induced and post-confirmation diabetes-induced rats; GDM: diabetes-induced and melatonin-treated post-confirmation mice and GDMS: diabetes-induced and melatonin-treated mice simultaneously. Melatonin was administered at a dose of 10 mg/kg in drinking water every day for 20 days at night. Diabetes was induced by streptozotocin (60 mg/kg) and confirmed after the fifth day of induction. Insulin was administered at 5 IU (international units)/day at different times of the day for 20 days. The testes were submitted to histopathological, morphometric, immunohistochemical and oxidative stress analysis. Melatonin moderately decreased glycemic levels, protected weight loss and morphometric changes in the testicles, increased antioxidant enzyme levels and stabilized plasma testosterone and androgen receptor levels and decreased inflammatory markers in the testicles. Showing its potential to mitigate diabetes effects.