In vivo assessment of naringenin-mediated amelioration of lead-induced testicular injury in rats: regulation of Nrf2/Keap1 and PINK1/Parkin pathways.

Abstract

This study investigated the protective effects of naringenin (Nar) against lead (Pb)-induced testicular injury in rats, focusing on the Nrf2/Keap1 antioxidant pathway and PINK1/Parkin-mediated mitophagy. To this end, male SD rats were exposed to Pb (60 mg/kg) and co-treated with Nar (50 mg/kg) for 8 consecutive weeks, followed by assessments via biochemical detection, oxidative stress (OS) evaluation, hematological examination, histopathological observation, qPCR, WB, and IHC analyses. Pb exposure caused hematological disturbances, reduced serum LH and T levels, and OS imbalance (lower GSH, SOD, CAT; higher MDA), aggravating testicular damage. Meanwhile, it suppressed the Nrf2/NQO1 pathway, elevated Keap1, impaired autophagy (elevated p62, declined LC3‑II/LC3‑I ratio), and induced aberrant accumulation of PINK1/Parkin. Co-treatment with Nar mitigated these alterations, ameliorating testicular injury, restoring redox homeostasis and serum reproductive hormone levels, and normalizing key molecular expressions in both pathways. In conclusion, Nar alleviates Pb-induced rat testicular damage by reactivating the Nrf2/Keap1 axis to suppress OS, and by restoring autophagic flux to facilitate PINK1/Parkin-mediated clearance of damaged mitochondria.