Role of mitochondrial ATP-sensitive potassium channels in attenuation of cerebral ischemia-reperfusion injury by dexmedetomidine in rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of mitochondrial ATP-sensitive potassium (mito-KATe) channels in attenuation of cerebral ischemia-reperfusion (I/R) injury by dexmedetomidine in rats.Methods One hundred and twenty healthy male Wistar rats,weighing 290-340 g,were randomly assigned into 5 groups (n =24 each) using a random number tablesham operation group (group S) ; group I/R; dexmedetomidine group (group D) ; 5-HD (a specific blocker of mito-KATPchannel) group and 5-HD + dexmedetomidine group (group 5-HD + D).The rats were anesthetized with intraperitoneal chloral hydrate.Focal cerebral I/R was produced by 2 h middle cerebral artery occlusion followed by reperfusion.In group D,dexmedetomidine 50 μg/kg was injected intraperitoneally before ischemia and after onset of reperfusion.In group 5-HD,5-HD 30 mg/kg was injected intraperitoneally at 1 h before ischemia.In 5-HD + D group,5-HD 30 mg/kg was injected intraperitoneally at 1 h before ischemia and the other procedures were similar to those previously described in group D.Twelve rats were chosen at 24 and 48 h of reperfusion to assess the neurological deficit score (NDS).The animals were then sacrificed and brains were removed for determination of cerebral infarct size by TTC staining.Results Compared with S group,NDS and cerebral infarct size were significantly increased at each time point in the other four groups (P ＜ 0.05).Compared with group I/R,NDS and cerebral infarct size were significantly decreased in D and 5-HD + D groups (P ＜ 0.05),and no significant change was found in the parameters mentioned above in 5-HD group (P ＞ 0.05).Compared with group D,NDS and infarct size were significantly increased in group 5-HD + D (P ＜ 0.05).Conclusion Mito-KATP channels are involved in reduction of I/R-induced cerebral injury by dexmedetomidine in rats.