腺苷酸活化蛋白激酶在缺血预处理诱导的神经保护中的作用

Effects of adenosine 5'monophosphate-activated protein kinase on europrotection induced by ischemic preconditioning

目的评估腺苷酸活化蛋白激酶(AMPK)及其活化型-磷酸化AMPK(p AMPK)在缺血预处理(IPC)中的作用,通过药理学方法控制p AMPK水平,评价该通路对脑梗死面积的影响。方法对雄性大鼠行短暂(3min)大脑中动脉闭塞处理(MCAO)诱导IPC,4h或72h后再行MCAO 90min,检测IPC后AMPK及p AMPK的水平;应用AMPK药物激动剂二甲双胍或抑制剂复合物C(CC)进行处理,观察IPC与AMPK信号传导的相关性。结果 IPC预处理(72h)可使MCAO模型大鼠大脑皮质、半球及总梗死面积明显减少(P<0.05),神经功能缺损评分(NDS)明显降低(P<0.05);单纯MCAO(90min)处理后4h可明显增加p AMPK的表达,IPC预处理(4h)可使诱导的p AMPK增加明显下调(P<0.05)。应用CC腹腔注射可减少MCAO所致的大鼠脑梗死面积;IPC预处理(72h)联合CC并不能进一步减少大鼠脑梗死面积。IPC预处理(72h)行MCAO同时给予二甲双胍,二甲双胍可明显阻断IPC诱导的大脑半球、皮层及纹状体梗死面积的减少(P<0.05)。结论 AMPK及p AMPK信号在IPC介导的神经保护作用中发挥重要作用,IPC的神经保护作用可能与下调p AMPK水平有关。

Objective To investigate the effects of adenosine 5’-monophosphate-activated protein kinase（AMPK） and phosphated AMPK（p AMPK） signals in ischemic preconditioning（IPC）, and the effect of pharmacological intervention of AMPK on infarct size of the brain. Methods A brief（3min） middle cerebral artery occlusion（MCAO） was employed to induce IPC in male rat, and another 90-min MCAO was performed 4 or 72 h later. The levels of AMPK and p AMPK were assessed after IPC. A pharmacological activator metformin, or inhibitor compound C of AMPK, was used to analyze the correlation of IPC to AMPK signaling in MCAO rats. Results The infarct size of total cerebral hemisphere and cortex was significantly decreased in MCAO animals by IPC for 72h（P〈0.05, n=8）, and the neurological deficit scores（NDS） of MCAO rats were also improved（P〈0.05, n=8）. There was a significant increase in p AMPK expression after a 90 min MCAO（P〈0.05, n=6）, and a significant decrease in induced p AMPK expression（P〈0.05, n=6） achieved only by a 72 h IPC treatment. Intraperitoneal injection of an AMPK inhibitor, compound C, could decrease the infarct size in MCAO rats（P〈0.05, n=6）, but combined IPC（72h） and injection of compound C did not result in further decrease of the infarct size（P〉0.05, n=6）. The AMPK activator metformin can significantly reverse the protective effect of IPC（P〈0.05, n=6）. Conclusions The signals of AMPK and p AMPK play an important role in neuroprotective effect of IPC on cerebral ischemic injury. The neuroprotective effect of IPC may be associated with the down-regulation of p AMPK.