Beneficial effects of n-acetylcysteine on ischaemic brain injury

1 Nitric oxide (NO), peroxynitrite, formed from NO and superoxide anion,pol y (ADP-ribole) synthetase have been implicated as mediators of neuronal dam age following focal ischaemia. Here we have investigated the effects of a-a cetylcysteine (NAC) treatment in Mongolian gerbils subjected to cerebral is chaemia. 2 Treatment of gerbils with NAC (20 mg kg(-1) 30 min before reperfusion and 1, 2 and 6 h after reperfusion) reduced the formation of post-ischaemic br ain oedema, evaluated by water content. 3 NAC also attenuated the increase in the brain levels of malondialdehyde ( MDA) and the increase in the hippocampus of myeloperoxidase (MPO) caused by cerebral ischaemia. 4 Positive staining for nitrotyrosine was found in the hippocampus in Mongo lian gerbils subjected to cerebral ischaemia. Hippocampus tissue sections f rom Mongolian gerbils subjected to cerebral ischaemia also showed positive staining for poly (ADP-ribose) synthetase (PARS). The degree of staining fo r nitrotyrosine and for PARS were markedly reduced in tissue sections obtai ned from animals that received NAC. 5 NAC treatment increased survival and reduced hyperactivity linked to neur odegeneration induced by cerebral ischaemia and reperfusion. 6 Histological observations of the pyramidal layer of CA1showed a reduction of neuronal loss in animals that received NAG. 7 These results show that N AC improves brain injury induced by transient cerebral ischaemia.