Melatonin abrogates cadmium induced oxidative stress related neurotoxicity in rats.

TLDR: Melatonin markedly reduced the Cd induced pathological changes and preserved the normal histological architecture of the brain tissue in rats, suggesting that melatonin may be beneficial in combating the cadmium induced oxidative neurotoxicity in the brain of rats.

Abstract: Background: Cadmium is a potent neurotoxic heavy metal, which induces oxidative stress and membrane disturbances in brain. Melatonin is an effective antioxidant and free radical scavenger against oxidative stress. The present study was designed to investigate the neuroprotective efficacy of melatonin in pro- tecting the Cd induced changes in the activity of acetylcholinesterase (AChE), levels of lipid per- oxidation, protein carbonyls, non-enzymatic an- tioxidant, enzymatic antioxidant status, mem- brane bound ATPases and histopathology in the brain of rats. Materials and Methods: Twenty four male albino rats were used. Cadmium induced oxida- tive neurotoxicity was induced by oral adminis- tration of Cd for four weeks. Melatonin was pre- treated along with Cd for four weeks to assess its neuroprotective activity against Cd intoxica- tion. Rats treated with vehicles alone were used as controls. Results: Rats intoxicated with cadmium (5 mg/kg/day) for 4 weeks significantly (p<0.05) reduced the AChE levels in the plasma and brain, elevated the levels of thiobarbituric acid reactive substances (TBARS), lipid hydroper- oxides and protein carbonyls along with the significant (p<0.05) decrease in the levels of non-enzymatic antioxidants (GSH, TSH and vit- amins C and E), enzymatic antioxidants super- oxide dismutase (SOD), catalase (CAT), glu- tathione peroxidase (GPx), glutathione S-trans- ferase (GST) and membrane bound ATPases in the brain tissue. Administration of melatonin (10 mg/kg/day) for 4 weeks in cadmium intoxi- cated rats significantly (p<0.05) diminished the levels of oxidative stress markers, lipid peroxi- dation and protein carbonyls in brain and sig- nificantly (p<0.05) elevated the levels of non- enzymatic and enzymatic antioxidants, brain and the activities of AChE, enzymatic antioxi- dants and ATPases in brain. The histopatho- logical studies in the brain of rats also sup- ported that melatonin markedly reduced the Cd induced pathological changes and preserved the normal histological architecture of the brain tissue. Conclusions: The results of the present study suggest that melatonin may be beneficial in combating the cadmium induced oxidative neu- rotoxicity in the brain of rats.