. Melatonin prevents aluminum-induced oxidative damage and cytotoxicity in the medulla oblongata of mouse brain

We examined the daily melatonin (Mel) supplementation on oxidative damage and cytotoxicity induced by Aluminum (Al) in medulla oblongata of mice. Al induced pro-oxidant activity and
the protective role of melatonin was determined in the medulla oblongata of mice following administration of Al and/or melatonin. Two groups of male mice were intraperitoneally injected with
Al (as Al acetate) or melatonin only, at doses of 3.5 and 7 mg/kg/day, respectively, for 6 weeks. During this period, a third group of animals received Al (3.5 mg/kg/day) plus melatonin (7mg/
kg/day). At the end of the treatment medulla oblongata were isolated and the oxidative stress markers: superoxide dismutase (SOD), catalase (CAT) and thiobarbituric acid-reactive substances
(TBA-RS) were carried out. Protective effects of Mel against Al were also observed at microscopic level. Light microscopy of Al administered medulla oblongata showed severe hemorrhagic
areas, congested blood vessels, karyopycnosis of nucleus and vacuolated cells which are antagonized by Mel supplementation. Ultra structural studies revealed degenerated nerve fibres and
complete cytoarchitectural loss of neurons in medulla oblongata of Al treated which showed improvement following Mel. The results show that the biochemical and ultra structural changes
observed in this tissue indicate that Al acts as pro-oxidant agent, while melatonin exerts antioxidant action.