Therapeutic potential of alpha-pinene in methotrexate-induced testicular toxicity: focus on apoptosis, oxidative stress, and inflammatory pathways.

PURPOSE: Methotrexate (MTX), a widely used chemotherapeutic agent, induces testicular toxicity via oxidative stress, inflammation, and apoptosis. This study aimed to investigate the protective effects of alpha-pinene (APN) against MTX-induced testicular damage in male rats.

METHODS

Animals were divided into four groups: vehicle control (VHC), toxicity group (MTX), APN treatment group (APN), and combined group (APN + MTX). Key assessments included body weight changes (BWCs), relative testis weight (RTW), epididymal sperm count (ESC), sperm motility and viability, histopathology, oxidative stress index (OSI), mRNA expression levels of Nrf2, Keap1, and Hmox1, inflammatory cytokines (TNF-α, IL-1, IL-6, and IL-10), and apoptotic markers (Caspase 3 and the BAX/BCL-2 ratio).

RESULTS

MTX significantly reduced BWC (d = -1.84), RTW (d = -3.00), ESC (d = -3.08), sperm motility (d = -7.53), and viability (d = -3.37) while increasing OSI (d = 2.21), TNF-α (d = 2.31), IL-1 (d = 1.97), Caspase 3 (d = 2.43), and BAX/BCL-2 (d = 2.68) (p < 0.05). APN preserved testicular structure and reduced OSI (d = 2.14), TNF-α (d = 2.12), and IL-1 (d = 2.72). Nrf2 expression increased with APN (vs. MTX, d = 1.35), while IL-6, IL-10, and Hmox1 remained statistically unchanged (p > 0.05), despite a large effect size for Hmox1 (d = 1.49).

CONCLUSION

APN attenuated MTX-induced testicular damage by reducing oxidative stress, inflammation, and apoptosis. The unchanged IL-6 and IL-10 levels suggest that APN preserves MTX's immunomodulatory effects while offering protection against fertility impairment.