Protective role of sodium propionate against glycerol or fractionated doses of gamma rays-induced acute kidney injury via ATF5-induced mitophagy in rats

Acute kidney injury (AKI), whether induced by nephrotoxins like glycerol or by gamma radiation, is characterized by severe oxidative stress and subsequent mitochondrial dysfunction. We investigated the protective mechanism of sodium propionate (SP) against AKI in a rat model. Six experimental groups were established: (I) control rats were given saline; (II) rats were administered SP (37.5 mg/kg, p.o.) for two weeks; (III) rats were given an intramuscular injection of glycerol 10 mL/kg body weight; (IV) rats were given glycerol followed by SP treatment for two weeks; (V) rats were exposed to fractionated gamma-radiation (8 Gy; delivered as 2 Gy x 4 times); and (VI) γ-irradiated rats were treated with SP for two weeks. In comparison to AKI rats, SP treatment significantly preserved renal function, reduced serum urea and creatinine, and improved histopathological features. Biochemically, SP reduced lipid peroxidation and protein oxidation (malondialdehyde MDA, protein carbonyl PC, and lipofuscin) while restoring antioxidant defenses as reduced glutathione (GSH) and methionine sulfoxide reductase A (MSRA). SP restored mitophagy flux by increasing microtubule-associated protein light chain 3 (LC3II/LC3I) ratio and PTEN-induced putative kinase 1 (PINK-1) levels, promoting p62 clearance, and downregulating the mitochondrial stress marker, activating transcription factor 5 (ATF5), relative to the untreated AKI groups. These findings demonstrate that SP confers protection against AKI by attenuating oxidative stress and re-establishing mitochondrial quality control through re-establishment of autophagic flux. Hence, SP represents a promising candidate for therapeutic intervention in nephrotoxin- and γ-radiation-induced renal injury.