Melatonin supplementation preserves testicular function by attenuating lactate production and oxidative stress in high fat diet-induced obese rat model

Metabolic syndrome, including obesity has been documented as a critical factor in male reproductive dysfunction with subsequent reduction in male fertility. The therapeutic potential of melatonin has been demonstrated against oxidative stress-induced pathologies. Therefore, the present study investigated the effects of melatonin on testicular dysfunction associated with high fat diet (FD)-induced obese rat model, and the possible involvement of peroxisome proliferator-activated receptor-γ (PPAR-γ). Adult male Wistar rats (n = 6/group) were used: control group received vehicle (normal saline), obese group received 40% FD, melatonin-treated group received melatonin (4 mg/kg), and obese plus melatonin group received melatonin and 40% FD and the treatment lasted for 12 weeks. High fat diet caused increased body weight and testicular triglyceride, total cholesterol, malondialdehyde, γ-glutamyl transferase, lactate production and lactate/pyruvate ratio as well as decreased glutathione/glutathione peroxidase, nitric oxide and PPAR-γ and circulating testosterone. Nevertheless, all these alterations were attenuated when supplemented with melatonin. Taken together, these results demonstrates that FD-induced obesity causes testicular dysfunction. In addition, the results suggest that melatonin supplementation protects against obesity-associated testicular dysfunction and this effect is accompanied by upregulation of PPAR-γ.