A protein from Cajanus indicus Spreng protects liver and kidney against mercuric chloride-induced oxidative stress

Mercuric chloride (HgCl2) is a widespread environmental toxin that affects mainly liver and kidney. The present stud), has been carried out to investigate the protective action of a protein (the CI protein) isolated from the herb, Cajanus indicus Spreng against HgCl2 induced renal and hepatic toxicities in mice. Intraperitoneal administration of HgCl2 at a dose of 5 mg/kg body weight for 1 d significantly reduced the activities of antioxidant enzymes like superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx). Moreover, it also depleted the glutathione to oxidized glutathione (GSH/GSSG) ratio. In addition, HgCl2 increased the activities of serum marker enzymes (namely, glutamate pyruvate transaminase, GPT and alkaline phosphatase, ALP), creatinine, blood urea nitrogen and serum tumor necrosis factor alpha (TNF-alpha) level along with hepatic and renal lipid peroxidation. Besides, application of HgCl2 to hepatocytes increased reactive oxygen species production and reduced the total antioxidant activity of the treated hepatocytes. Treatment with the CI protein intraperitonealy at a dose of 2 mg/kg body weight before or after HgCl2 administration showed that it could scavenge free radicals in vitro and protect the alterations of the antioxidant molecules and the other parameters used in this particular study. Histological studies also revealed a milder lesion in kidney and liver samples of the CI protein treated mice compared to mice treated with HgCl2 alone. Effects of a known antioxidant N-acetylcysteine have been used to compare its action to that of the CI protein.