Protective effects of Rhus coriaria L. fruit extract against experimental calcium oxalate nephrolithiasis via modulation of oxidative stress and renal injury
摘要
Calcium oxalate nephrolithiasis is strongly associated with oxidative stress, renal tubular injury, and inflammation. Natural products rich in polyphenols may serve as promising complementary preventive strategies. This study investigated the antiurolithiatic and renoprotective effects of Rhus coriaria fruit extract in an ethylene glycol-induced rat model of nephrolithiasis. Forty-two male rats were randomized into seven groups (n = 6): control, ethylene glycol (EG), EG + potassium citrate, R. coriaria 250 mg/kg/day, R. coriaria 500 mg/kg/day, EG + R. coriaria 250 mg/kg/day, and EG + R. coriaria 500 mg/kg/day. Nephrolithiasis was induced with 1% ethylene glycol for 28 days. Serum biochemistry, urinary lithogenic parameters, oxidative stress markers including total antioxidant status (TAS), total oxidant status (TOS), superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA), histopathology, and immunohistochemical expression of kidney injury molecule-1 (KIM-1) and osteopontin (OPN) were evaluated. Phytochemical characterization of the extract was performed by high-performance liquid chromatography coupled with diode-array detection (HPLC-DAD). Gallic acid was identified as the predominant phenolic constituent, together with smaller amounts of protocatechuic acid and ellagic acid. Ethylene glycol significantly increased urinary lithogenic parameters, oxidative stress indices, crystal deposition, tubular injury, and OPN expression. Treatment with R. coriaria significantly reduced urinary oxalate and calcium levels, improved TAS, SOD, and CAT levels, lowered TOS and MDA concentrations, and markedly attenuated crystal deposition, inflammation, and tubular dilatation. OPN expression was substantially decreased in treated groups, whereas KIM-1 showed a decreasing trend. Protective effects were more pronounced at the 500 mg/kg/day dose. R. coriaria fruit extract exerted significant antiurolithiatic and renoprotective effects in experimental calcium oxalate nephrolithiasis. These findings suggest that R. coriaria may represent a potential adjunctive strategy for calcium oxalate stone disease.