Abstract WP159: Acute Administration of Ethanol Reduced Brain Apoptosis by Regulating Expression of Apoptotic Proteins in Ischemic Stroke

Objectives: In our recent studies, acute ethanol administration appears to play a neuroprotective role after the onset of ischemic stroke by reducing infarct volume and behavioral dysfunction ( Stroke. 2012 43(1):205-10 ). In the present study, we sought to identify whether the ethanol-derived neuroprotection is associated with a reduction in apoptosis. Methods: Ethanol was given by intraperitoneal injections to Sprague-Dawley rats after 2 hours of middle cerebral artery (MCA) occlusion, followed by reperfusion. The actual degree of apoptotic cell death in control, ischemic rats, and ischemic rats treated with 1.5 g/kg ethanol was determined by the Cell Death Detection ELISA Assay (Roche). Levels of pro-apoptotic (Caspase-3, Bcl-2-associated X “BAX”, and Apoptosis-Inducing Factor “AIF”) and anti-apoptotic proteins (Bcl-2 and Bcl-xL) were determined by Western blot at 3 and 24 hours after reperfusion. Results: Rats treated with ethanol at the 1.5 g/kg dosage demonstrated significantly reduced cell death as compared to those of stroke without treatment. Acute ethanol administration at the 1.5 g/kg dose significantly promoted the expression of anti-apoptotic factors and decreased the expression of pro-apoptotic proteins at 3 hours after reperfusion. This effect was maintained at 24 hours for Caspase-3 and AIF, but not for Bcl-2, Bcl-xL, and Bax. We further demonstrated that administration of low dose of ethanol at 0.5 g/kg was not as effective in regulating protein expression as the 1.5 g/kg dose (1.5 g/kg dose being equivalent to the legal driving limit). Conclusions: Our study suggests that administration of ethanol at a 1.5 g/kg dosage after onset of stroke reduces apoptosis by creating a differential protein profile, with increased expression of anti-apoptotic proteins and decreased expression of pro-apoptotic ones. This study helps in validating ethanol as a new therapeutic approach in neuroprotection after stroke, and proposes a possible mechanism for its anti-apoptotic effect on neuronal cells.