Attenuation of postischemic brain hypoperfusion and reperfusion injury by the cyclooxygenase—lipoxygenase inhibitor BW755C

Abstract

Arachidonic acid metabolites are believed to be important mediators of tissue injury during reperfusion after cerebral ischemia. To determine whether inhibiting the oxygen-dependent metabolism of arachidonic acid would reduce reperfusion injury, we administered the mixed cyclooxygenase-lipoxygenase inhibitor BW755C (3-amino-1-[m(trifluoromethyl)phenyl]-2-pyrazoline) near the time of reperfusion in a rat model of temporary focal ischemia. The duration of ischemia + reperfusion was 2 hours + 22 hours, 3 hours + 3 hours, or 3 hours + 21 hours. The effects of drug or saline treatment on infarct volume, blood-brain barrier permeability, and blood flow were determined. Cortical blood flow was monitored with laser Doppler flowmetry and blood-brain barrier permeability was evaluated by the Evans blue dye method. Infarct volume was determined in all groups by computerized image analysis of Nissl-stained sections. We found that BW755C treatment significantly attenuated delayed postischemic hypoperfusion in the 3 + 3 group (p < 0.05) and reduced the volume of Evans blue dye staining in the cortex (p < 0.01) and basal ganglia (p < 0.05). Hemispheric swelling was reduced in all treatment groups (p < 0.01), as was total infarct volume in the ischemic hemisphere (p < 0.05). These results support the hypothesis that arachidonic acid metabolites contribute to acute postischemic reperfusion injury and suggest that using a mixed cyclooxygenase-lipoxygenase inhibitor as an adjunct to thrombolytic or revascularization therapy could lengthen the ischemia time after which reperfusion is beneficial.