Effect of dexmedetomidine pretreatment on focal cerebral ischemia-reperfusion injury in rats / 中华麻醉学杂志

ABSTRACT

ObjectiveTo investigate the effect of dexmedetomidine pretreatment on focal cerebral ischemia-reperfusion(I/R) injury in rats.MethodsOne hundred male SD rats weighing 290-310 g were randomly divided into 5 groups(n =20 each)sham operation group(group SH) ; focal cerebral I/R group; focal cerebral I/R + dexmedetomidine 100 μg/kg(group L); focal cerebral I/R+ dexmedetomidine 200 μg/kg (group M) and focal cerebral I/R + dexmedetomidine 400 μg/kg(group H).Focal cerebral I/R was produced by occlusion of middle cerebral artery for 60 min followed by 24 h of reperfusion.Dexmedetomidine 100,200 and 400 μg/kg were injected intraperitoneally 15 min before ischemia in groups L,M and H respectively.While equal volume of normal saline was injected intraperitoneally in group SH.Neurologic function was assessed and scored at 24 h of reperfusion.Then the animals were sacrificed and brains were removed for determination of cerebral infarct volume and microscopic examination.The expression of heat shock protein 70(HSP70) and activity of Na+ -K + -ATPase in ischemic cortex and activity of SOD and concentration of cortisol in plasma were determinationed at 24 h of reperfusion.ResultsCompared with group SH,neurologic deficit scores and plasma concentration of cortisol were significantly increased,activities of SOD and Na+ -K+ -ATPase decreased and expression of HSP70 was up-regulated in groups I/R,L,M and H( P ＜ 0.05).Compared with group I/R,neurologic deficit scores and plasma concentration of cortisol were significantly decreased,activities of SOD and Na+ -K+ -ATPase increased and expression of HSP70 was up-regulated in a dose-dependent manner ( P ＜ 0.05),and the pathological change was reduced in a dose-dependent manner in groups L,M and H.ConclusionDexmedetomidine pretreatment can attenuate focal cerebral I/R injury in a dose-dependent manner through improvement of brain cell energy metabolism and reduction of lipid peroxidation and stress reaction.