Alcohol-induced exacerbation of ischemic brain injury: Role of NAD(P)H oxidase

Background: Chronic alcohol consumption increases ischemic stroke and exacerbates ischemic brain injury. We determined the role of NAD(P)H oxidase in exacerbated ischemic brain injury during chronic alcohol consumption.Methods: Sprague Dawley rats were fed a liquid diet with or without alcohol (6.4% v/v) for 8 weeks. We measured the effect of apocynin on 2-hour middle cerebral artery occlusion (MCAO)/24-hour reperfusion-induced brain injury. In addition, superoxide production and expression of NAD(P)H oxidase subunit, gp91phox, in the peri-infarct area were assessed.Results: Chronic alcohol consumption produced a larger infarct volume, worse neurological score, and higher superoxide production. Acute (5 mg/kg, ip, 30 minutes before MCAO) and chronic treatment with apocynin (7.5 mg/kg/d in the diet, 4 weeks prior to MCAO) reduced infarct volume, improved neurological outcome, and attenuated superoxide production in alcohol-fed rats. Expression of gp91phox at basal conditions and following ischemia/reperfusion was greater in alcohol-fed rats compared to non-alcohol-fed rats. In addition, neurons are partially responsible for upregulated gp91phox during alcohol consumption.Conclusions: Our findings suggest that NAD(P)H oxidase may play an important role in exacerbated ischemic brain injury during chronic alcohol consumption.