It is postulated that inhibition of cytosolic
phospholipase A(2) alpha (cPLA(2)α) can reduce severity of
stroke injury. This is supported by the finding that cPLA(2)α-deficient mice are partially protected from transient, focal
cerebral ischemia. The object of this study was to determine the effect of cPLA(2)α inhibition with
arachidonyl trifluoromethyl ketone (ATK) on
stroke injury in mice. Male C57BL/6 mice were subjected to 1h of focal
cerebral ischemia followed by 24 or 72 h of reperfusion. Mice were treated with ATK or vehicle by intermittent
intraperitoneal injection or continuous infusion via an implanted
infusion pump. ATK
injections 1h before and then 1 and 6h after the start of reperfusion significantly reduced
infarction volumes in striatum and hemisphere after 24h of reperfusion. ATK did not reduce injury if it was not administered before onset of
ischemia or was not administered after 6h of reperfusion. Intermittent doses of ATK failed to reduce
infarct volume after 72 h of reperfusion. Continuous infusion with ATK throughout 72h of reperfusion significantly reduced cortical and whole hemispheric
infarct volume compared to vehicle treatment. Following
ischemia and reperfusion, ATK treatment significantly reduced brain PLA(2) activity. These results are the first to demonstrate a
therapeutic effect of cPLA(2)α inhibition on
ischemia and
reperfusion injury and define a therapeutic time window. cPLA(2)α activity augments injury in the acute and delayed phases of
cerebral ischemia and
reperfusion injury. We conclude that cPLA(2)α inhibition may be clinically useful if started before initiation of
cerebral ischemia.