D-Ribose-L-Cysteine mitigates copper-induced testicular toxicity in mice through modulation of redox, inflammation, and apoptosis mechanisms.

D-ribose-L-cysteine (DRc) has been shown to protect against copper-induced neurotoxicity. However, its potential protective effect against copper-induced testicular toxicity has not been previously investigated. The present study aimed to evaluate the protective efficacy of DRc against copper-induced gonadotoxicity and to elucidate the underlying mechanisms using complementary in vivo and in silico approaches. Male Swiss mice were administered oral treatments of copper sulfate [CuSO4 (100 mg/kg)] and/or DRc (10, 25, and 50 mg/kg) once a day for 28 days. After euthanization, the epididymal sperm were immediately subjected to semen analysis, and the excised testicular tissues were processed for biochemical and histomorphological assays. In parallel, network pharmacology analysis was performed to predict key molecular targets and pathways associated with DRc-mediated gonadoprotection. DRc significantly improved copper-induced reproductive toxicity, as evidenced by improvements in sperm count, motility, viability, morphology, gonadosomatic index, testosterone levels, and testicular histoarchitecture. These protective effects were accompanied by a marked reduction in oxidative stress (decreased levels of MDA and NO, and increased levels of GSH and SOD), inflammation (e.g., decreased IL-6 and TNF-α), and apoptosis (e.g., decreased caspase-3). Network pharmacology analysis identified 19 targets, including caspase-3 (CasP3), X-linked inhibitor of apoptosis protein (XIAP), nitric oxide synthase 1 (NOS1), Janus kinase 2 (JAK2), and DNA repair protein (RAD50), suggesting coordinated regulation of oxidative stress, inflammatory, apoptotic, and DNA repair pathways. Taken together, DRc mitigates copper-induced gonadotoxicity through modulation of oxidative-inflammatory, apoptotic, and DNA repair machinery.