Methyl Donor Ameliorates CCl4-Induced Nephrotoxicity by Inhibiting Oxidative Stress, Inflammation, and Fibrosis Through the Attenuation of Kidney Injury Molecule 1 and Neutrophil Gelatinase-Associated Lipocalin Expression

Abstract

Carbon tetrachloride (CCl₄), a volatile organic compound, is harmful to multi-organs, including the liver, lungs, muscles, and kidneys. Methyl donors, such as methionine, choline, betaine, and folic acid, are vital to one-carbon metabolism and have great potential to alleviate oxidative stress and inflammation, thus mitigating disease onset. Hence, the current study aims to examine the therapeutic effect of methyl donors against CCl₄-induced nephrotoxicity. Nephrotoxicity was developed in male Sprague Dawley rats using CCl₄ at a dose of 1 mL/kg (4-week model induction) twice a week via the intraperitoneal route. Thereafter, methyl donor treatments through oral gavage were given for the next 6 weeks with a continuation of CCl₄ administration. Biochemical, oxidative stress parameters, histopathological, and qRT-PCR analyses were done at the completion of the 10-week. Biochemical analyses revealed that CCl₄ induces nephrotoxicity, as evidenced by increased urea and creatinine levels and decreased albumin levels. These detrimental effects were significantly ameliorated by methyl donor treatment. Moreover, CCl₄ decreased the antioxidant enzyme activity (superoxide dismutase; SOD and catalase; CAT) while increasing oxidative stress markers (malondialdehyde; MDA and nitrite). Methyl donor treatment effectively mitigated these oxidative changes. Histopathological analysis demonstrated the nephroprotective effect of methyl donors against CCl₄-induced nephrotoxicity, showing reduced tissue damage and protection of renal architecture. At the molecular level, methyl donor treatment alleviated the CCl₄-induced increase in kidney injury biomarkers (Kidney injury molecule 1; KIM-1 and Neutrophil gelatinase-associated lipocalin; NGAL), as well as inflammatory (IL-6 and TNF-α) and fibrosis-related genes (Acta-2 and TGF-β). In conclusion, our findings suggest that methyl donors possess anti-inflammatory and anti-fibrotic properties. They protect against CCl₄-induced oxidative damage to renal cells, likely due to their reactive oxygen species scavenging capabilities and their ability to restore key early renal injury biomarkers (KIM-1 and NGAL). Methyl donors hold great promise as a cutting-edge therapy approach for preventing CCl₄-induced nephrotoxicity.