Effects of melatonin on ischemic brain injury

Here we have investigated the effects of melatonin treatment in Mongolian gerbils subjected to cerebral ischemia. Treatment of gerbils with melatonin (10 mg/kg 30 minutes before reperfusion and 1, 2 and 6 hours after reperfusion) reduced the formation of post-ischemic brain oedema, evaluated by water content. Melatonin also attenuated the increase in the brain levels malondialdehyde (MDA) and the increase in the hippocampus of myeloperoxidase (MPO) caused by cerebral ischemia. Hippocampus tissue sections from Mongolian gerbils subjected to cerebral ischemia also showed positive staining for PARS. The degrees of staining for PARS was markedly reduced in tissue sections obtained from animals that received melatonin. Melatonin treatment increased survival and reduced hyperactivity linked to neurodegeneration induced by cerebral ischemia and reperfusion. These results show that melatonin improves brain injury induced by transient cerebral ischemia.