Abstract: AIM: To study the protective effects of a leukotriene receptor antagonist zafirlukast on focal cerebral ischemia reperfusion injury (CIRI) in rats and its possible mechanisms.METHODS: Reversible middle cerebral artery occlusion(MCAO) model was produced by intraluminal suture technique, and reperfusion was begun after 2 h of occlusion.Zafirlukast was intragastrically administrated at 0 and 12 h of the reperfusion.After 24 h reperfusion the infarct volume of the brain, the cerebral edema degree and the permeability of blood brain barrier were estimated.The activity of myeloperoxidase (MPO), the contents of maleic dialdehyde (MDA), glutathione peroxidase (GSH-PX), nitric oxide (NO) and inducible nitric oxide synthase (iNOS) in the brain tissue were measured. RESULTS: Zafirlukast could decrease the infarct volume of the brain, lessen the degree of cerebral edema and reduce permeability of blood brain barrier.It could also decrease the content of MDA, the level of NO, the activity of iNOS and increase the activity of GSH-PX in the brain tissue significantly.The 40 mg·kg ^-1 dose of zafirlukast could reduce the activity of MPO.CONCLUSION: The highly selective leukotriene receptor antagonist zafirlukast can prevent cerebral ischemia reperfusion injury by depressing permeability of the blood brain barrier, inhibiting inflammation reaction, decreaseing lipid peroxidation and reducing toxic action of NO.

Key words: zafirlukast, reperfusion injury, blood brain barrier, inflammation, lipid peroxidation