Ameliorative Effects of Vitamin C on Heat Stress-Induced Testicular Dysfunction in Wistar Rats.

Abstract

Objective: To evaluate the effects of repeated heat exposure on testicular function and sperm quality in Wistar rats and to determine whether vitamin C mitigates heat stress-induced reproductive damage.

Methods: Twenty-four Wistar rats were allocated to four groups and treated for 28 days: (i) control, (ii) heat exposure (40°C for 4 hours/day), (iii) vitamin C (50 mg/kg), and (iv) vitamin C plus heat exposure. Antioxidant status (superoxide dismutase, catalase, reduced glutathione), oxidative/nitrosative stress markers (malondialdehyde, nitric oxide), reproductive hormones (testosterone, follicle-stimulating hormone, luteinizing hormone), testicular function markers (alkaline phosphatase, acid phosphatase, glycogen, protein), testicular cortisol and cholesterol, histological structure, body and testis weights, and sperm parameters (concentration, total count, motility profile) were assessed.

Results: Heat exposure significantly reduced antioxidant defenses (superoxide dismutase, catalase, reduced glutathione), increased malondialdehyde and nitric oxide levels, and disrupted reproductive hormones (decreased testosterone with increased follicle-stimulating and luteinizing hormones). Heat stress also decreased alkaline and acid phosphatase activities, glycogen, and protein levels, increased testicular cortisol and cholesterol, induced histological damage, and reduced body and testis weights. Sperm quality was impaired, with lower sperm concentration, total count, and fast motility, and higher slow and non-motile sperm fractions. Vitamin C co-treatment partially attenuated these effects, improving catalase activity, Nrf-2 levels, glycogen, testosterone, alkaline and acid phosphatase, and lessened lipid peroxidation.

Conclusion: Repeated heat exposure induced oxidative stress, hormonal imbalance, impaired sperm quality, and structural testicular injury in Wistar rats. Vitamin C provided partial protection against heat-induced testicular dysfunction, supporting its potential role as an adjunct antioxidant strategy; further studies should evaluate additional antioxidants and include gene expression analyses to clarify mechanisms and fertility outcomes.