Orally administered melatonin reduces oxidative stress and proinflammatory cytokines induced by amyloid-β peptide in rat brain:: a comparative, in vivo study versus vitamin C and E

To determine the efficacy of antioxidants in reducing amyloid-beta -induced oxidative stress, and the neuroinflammatory response in the central nervous system (CNS) in vivo, three injections of fibrillar amyloid-beta (fAbeta ) or artificial cerebrospinal fluid (aCSF) into the CA1 region of the hippocampus of the rat were made. Concomitantly, one of the three free radical scavengers, i.e. melatonin, vitamin C, or vitamin E was also administered. Besides being a free radical scavenger, melatonin also has immunomodulatory functions. Antioxidant treatment reduced significantly oxidative stress and pro-inflammatory cytokines. There were no marked differences between melatonin, vitamin C, and vitamin E regarding their capacity to reduce nitrites and lipoperoxides. However, melatonin exhibited a superior capacity to reduce the pro-inflammatory response induced by fAbeta .