Pranlukast dose-and time-dependently protects against ischemic neuronal damage in the rat hippocampus

Objective Our previous studies showed that the neuroprotective effect of pranlukast,a cysteinyl leukotriene receptor-1(CysLT1)antagonist,on global cerebral ischemia in rats.This study was performed to evaluate dose-and time-dependent properties of pranlukast on CA1 neuron loss following transient global ischemia in rats.Methods Brain injury was induced by an improved four-vessel occlusion(4-VO)in rats.pranlukast(0.03-0.30 mg·kg-1)was injected intraperitoneally either as multiple doses(before or after ischemia)or as a single dose(30 min before ischemia),respectively.Physiological variables were monitored and neuron count was measured by computer-assisted imaging.Results The 4-VO model produced continuing postischemic neuronal death in CA1 region.Administration of pranlukast(0.1 and 0.3 mg·kg-1,30 min before ischemia and 1,24,48 and 72 h after ischemia)markedly reduced CA1 death.Treatment with a single dose of pranlukast(0.1 mg·kg-1,30 min before ischemia)also resulted in a significant increase in the number of healthy CA1 neurons at 3 days.Of interest is the finding that pranlukast(0.1 mg·kg-1)rescued CA1 neurons from ischemic death even when treatment was delayed until 30 min or 1 h after ischemia.Conclusions The present study confirms pranlukast has a dose-and time-dependent cerebroprotective effects on CA1 neuron loss following transient global ischemia in rats,with an effective dose range of 0.1-0.3 mg·kg-1 and a therapeutic window of 1 h.These findings further support the therapeutic potential of CysLT1 receptor antagonists in the treatment of global cerebral ischemia.