Evaluation of the beneficial impact of propolis extract against testicular toxicity induced by monosodium glutamate in male rats

This study investigated whether propolis extract (PE), a natural antioxidant-rich bee product, could attenuate testicular damage induced by monosodium glutamate (MSG) in adult male rats. Twenty-four rats were randomly divided into four groups: control, PE (100 mg/kg/day), MSG (1 g/kg/day), and MSG+PE. All treatments were administered orally for 42 consecutive days. Compared with the control, MSG significantly reduced reproductive hormone levels, including follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone. It also impaired sperm quality by decreasing sperm count, motility, and viability while increasing abnormal sperm forms. In addition, MSG induced marked oxidative stress in the testes, as indicated by decreased antioxidant enzyme activities (SOD, CAT, GPx, and GST), reduced glutathione (GSH) levels, and increased malondialdehyde (MDA). Histological examination revealed structural damage, enhanced apoptosis, and increased inflammatory changes in testicular tissue. Co-administration of PE with MSG was successfully restored the reproductive hormone levels and sperm parameters toward normalcy. PE also enhanced the antioxidant defense system, reduced lipid peroxidation, preserved normal testicular histoarchitecture, and suppressed apoptosis by increasing Bcl-2 and Ki-67 expression. Furthermore, PE reduced inflammation by inhibiting COX-2 expression. Overall, the findings suggest that propolis extract exerts modulatory effects against MSG-induced testicular injury through its antioxidant, anti-apoptotic, and anti-inflammatory properties.