Carnosic acid ameliorates methotrexate-induced male infertility: targeting testicular redox imbalance and nitric oxide/CGMP signaling.

PURPOSE: Methotrexate (MTX), a folate antagonist used in the treatment of cancer and autoimmune disorders, unfortunately, induces testicular toxicity and impairs male fertility. Although the tissue-protective properties of Carnosic acid (CAR) are known, its effectiveness in mitigating MTX-induced reproductive toxicity has not been adequately studied. This study explores the protective role of CAR against the toxicity of MTX in rat testes.

METHODS

Forty male Wistar rats were divided into four groups: control, MTX (20 mg/kg i.p., day 7), MTX + low-dose CAR (20 mg/kg p.o., 14 days), and MTX + high-dose CAR (40 mg/kg p.o., 14 days). On day 15, testicular tissue and serum were analyzed for oxidative stress markers (GSH, GPx, MDA), NO/cGMP pathway components (iNOS, NO, cGMP), inflammatory markers (NF- κB, IL-6), steroidogenesis parameters (total cholesterol, 3β-HSD, 17β-HSD), and hormonal levels (GnRH, FSH, LH, testosterone, estradiol). Histopathological examinations were conducted on testicular sections.

RESULTS

MTX significantly reduced antioxidant levels, increased lipid peroxidation, disrupted NO/cGMP signaling, elevated inflammation, impaired steroidogenesis, and altered hormone levels, with evidence of histological changes. CAR, especially at higher doses, mitigated these effects, restoring antioxidant status, normalizing NO/cGMP signaling, reducing inflammation, enhancing steroidogenesis, and improving testicular morphology.

CONCLUSION

CAR ameliorates MTX-induced adverse effects in the testes of rats via controlling redox balance, NO/cGMP signaling, inflammation, and steroidogenesis, with the potential of CAR to be used as a treatment to protect male reproductive function during therapy with MTX.