Chrysin-loaded casein nanoparticles protect against chlorfenapyr-induced renal injury through modulation of Nrf2/HO-1, NF-κB, and mitochondrial bioenergetics.

BACKGROUND: Chlorfenapyr (CFP) is a pesticide that induces nephrotoxicity through oxidative stress, mitochondrial dysfunction, inflammation, and apoptosis. Casein nanoparticles may enhance the therapeutic efficacy of chrysin (CY). OBJECTIVE: This study evaluated the protective effects of free CY and chrysin-loaded casein nanoparticles (CY-CasNPs) against CFP-induced renal histopathological and ultrastructural injury and investigated the underlying mechanisms. METHODS: Sixty male Wistar rats were randomly assigned to six groups: control, CY, CY-CasNPs, CFP, CFP/ CY, and CFP/ CY-CasNPs. CY (50 mg/kg) and CFP (180 mg/kg) were administered orally for 30 days. Histopathological and ultrastructural examinations served as the primary outcome measures. Renal function, oxidative stress, mitochondrial respiratory enzyme activities, ATP, inflammatory and apoptotic markers, and gene expression were evaluated to support the morphological findings. RESULTS: CFP induced marked glomerular and tubular injury, accompanied by severe ultrastructural abnormalities, as well as renal dysfunction, oxidative stress, mitochondrial impairment, inflammation, apoptosis, and increased Kim-1 and NF-κB expression. Free CY partially attenuated these alterations, whereas CY-CasNPs provided significantly greater protection. CY-CasNPs preserved renal tissue architecture and ultrastructure, restored renal function, activated the Nrf2/HO-1 pathway, reduced lipid peroxidation and nitric oxide, improved mitochondrial respiratory enzyme activities and ATP homeostasis, suppressed Kim-1, NF-κB, Bax, and caspase-3, and increased Bcl-2 expression. CONCLUSION: CY-CasNPs effectively preserved renal morphology at both histopathological and ultrastructural levels. The accompanying improvements in oxidative stress, mitochondrial dysfunction, inflammation, apoptosis, and renal function provide mechanistic support for the observed structural protection, highlighting casein-based nanoencapsulation of chrysin as a promising strategy for preventing pesticide-induced renal injury.