Manganese neurotoxicity and protective effects of resveratrol and quercetin in preclinical research

Background exposure to mn results in a neurological syndrome known as manganism. methods we examined how 4-week mn exposure (20 mg/kg mncl2 po,5 days/week) induces neurotoxic effects in rats. oxidized-to-reduced glutathione ratio (gssg/gsh),malondialdehyde (mda),superoxide dismutase (sod) activity,catalase (cat) activity,vitamin e content and caspase-3 activity were measured in several rat brain structures. further,we examined protective effects of the polyphenols: resveratrol (r) or quercetin (qct) against mn-induced neurotoxicity. results after exposure to mn,we found a rise in gssg/gsh ratio and a reduction in sod activity in the rat striatum (str),while in the nucleus accumbens (nac) decreases in alpha-tocopherol content and in sod activity were noted. in the frontal cortex (fcx),an enhancement in gssg/gsh ratio and a reduction in sod and cat activities were observed. in the cerebellum (cer),a significant increase in the caspase-3 activity paralleled a rise in the gssg/gsh ratio and a diminution of sod activity. in the rat hippocampus (hip),mn evoked an enhancement in gssg/gsh ratio. there were no changes in the mda levels. pretreatment with r and qct protected against the mn-induced (i) enhancement in gssg/gsh ratio in the str,(ii) decreases in the nac alpha-tocopherol content and (iii) reduction in sod activity in fcx,nac and cer. conclusion repeated mn administration induces toxic effects in several rat brain structures and treatment with r and qct may be a potential therapeutic strategy to attenuate the metal neurotoxicity. © 2016