Melatonin protects against chromium induced oxidative stress-mediated changes in energy metabolism of rat hepatic, cardiac and renal tissues

Chromium (Cr) is one of the most prevalent and potentially hazardous heavy metal found in the environment that can cause carcinogenic, genotoxic, and organ-specific irreversible complications. The most severe adverse outcome of Cr on humans involves oxidative stress. Melatonin was evidenced to alleviate such stress with various mechanisms including antioxidative potential and metal chelation. Male Wistar rats were divided into 4 groups and treated for 14 days. The first group (control) was treated with vehicle; the second group was orally administered with melatonin (20 mg/kg b.w./day); the third group was injected with sodium dichromate dihydrate (5 mg/kg bw, s.c. every alternate day); and the fourth group was administered with melatonin, 30 min before Cr administration. The treatment of rats with Cr (VI) was found to affect the metabolic pathways by altering the activities of enzymes possibly through uncompetitively binding with them. The current study also demonstrated that melatonin efficiently preserved the glucose levels and blood lipid profile. Moreover, melatonin was further found to protect the activities of glycolytic, Krebs' cycle, and ETC enzymes. Further, melatonin pre-treatment reduced the production of O-2 center dot(-) anion free radical and Ca2+ overload to protect the mitochondria at the ultrastructural level and reduced DNA damage to some extent. Therefore, this research strongly recommends melatonin as a therapeutic molecule against Cr-induced oxidative stress-mediated liver, heart, and kidney disorders.