The Combination of Nigella sativa Oil-Based Nanoemulsion and Quercetin Alleviates Oxidative Stress From Exogenous...

Exogenous testosterone therapy induces testicular oxidative stress and inflammation, suppressing spermatogenesis. Chronic restraint and high-intensity exercise stress exacerbate reproductive dysfunction. Quercetin (Qu) and black seed oil (BSO) possess potent antioxidant and anti-inflammatory properties.

This study evaluates the efficacy of Qu-loaded BSO (Qu-BSO) nanoemulsion in mitigating testosterone-induced testicular damage in rats subjected to exercise and restraint stress, as well as to testosterone and finasteride administration.

A Qu-BSO nanoemulsion was prepared and characterized. Thirty-six male Wistar rats were divided into six groups (n = 6): control (C), testosterone (T) at 20 mg/kg weekly via subcutaneous injection, testosterone + finasteride (TF) at 1 mg/kg 5 days a week, testosterone + high-intensity treadmill exercise (TE) for 50 min daily, testosterone + chronic restraint stress (TI) for 3 h daily and testosterone + Qu-BSO (TQBSNE) for 6 weeks. Serum testosterone, LH, testicular antioxidants (SOD, CAT and GPx), lipid peroxidation (MDA), inflammatory cytokines (TNF-α and IL-1β mRNA), and histopathology were assessed.

The T, TF and TI groups exhibited significant testicular damage with elevated oxidative stress and inflammation. The T and TF groups exhibited the highest serum testosterone. TE showed partial protection. The TQBSNE treatment group provided superior protection, with significantly higher SOD, CAT and GPx activities, the lowest MDA levels and reduced TNF-α and IL-1β expression. TQBSNE also partially restored LH levels.

The high-intensity exercise group showed a partial protective effect. Chronic restraint stress exacerbated testicular damage caused by testosterone. Qu-BSO nanoemulsion effectively counteracted testosterone-induced testicular damage through antioxidant and anti-inflammatory mechanisms, representing a promising therapeutic strategy.