cAMP/PKA-pCREB信号通路介导康复训练促进脑缺血大鼠运动功能恢复的探讨

cAMP /PKA-pCREB signal transduction pathway may mediate a promoting effect of rehabilitation training on motor function after ischemic stroke in rats

目的探讨cAMP/PKA-pCREB信号通路是否在康复训练促进的缺血性脑卒中大鼠运动功能的恢复方面发挥作用。方法采用Longa改良线栓法制备大鼠大脑中动脉缺血再灌注模型(middle cerebral artery ischemia-reperfusion model,MCAO),造模成功的大鼠随机分为自然恢复组(n=24)、自然恢复+Rp-cAMP组(n=24)、康复训练组(n=18)和康复训练+Rp-cAMP组(n=18)。同时设立假手术组(n=12)。于侧脑室注射RpcAMP后立即进行MCAO模型的制备。训练组大鼠于术后48 h开始每天给予平衡木、转棒及滚筒训练。采用平衡木试验评定大鼠的运动功能。酶联免疫法(ELISA)检测缺血灶周围的脑组织内PKA表达,蛋白免疫印迹法(Western blot)检测pCREB蛋白表达,同时采用免疫组化法对pCREB进行定位检测。结果 (1)运动功能评分结果揭示,自然恢复+Rp-cAMP组大鼠的运动功能低于自然恢复组,提示Rp-cAMP可抑制脑缺血大鼠运动神经功能的恢复;康复训练组大鼠的运动功能明显高于自然恢复组,也高于康复训练+Rp-cAMP组,提示Rp-cAMP明显减弱康复训练促进脑缺血大鼠运动神经功能的恢复;(2)于术后2 d、7 d、14 d、21 d检测缺血灶周围的脑组织PKA、pCREB的蛋白表达结果显示:康复训练组明显高于自然恢复组,同时高于康复训练+Rp-cAMP组,提示康复训练促进脑缺血大鼠的PKA、pCREB蛋白的表达,且Rp-cAMP明显抑制了康复训练促进脑缺血大鼠的PKA、pCREB蛋白的表达。结论 cAMP/PKA-pCREB信号通路可能介导康复训练促进的脑缺血大鼠运动功能的恢复。

Objective To explore whether the cAMP-PKA-pCREB signal pathway plays a role in promoting the recovery of motor function after rehabilitation training in cerebral ischemia-reperfusion rats .Methods The middle cerebral artery occlusion model （ MCAO） was established by modified Longa nylon occlusion method in adult male Sprague -Dawley rats.The 84 MCAO rats were selected and randomly assigned to four groups：the natural recovery group without any special training （group B, n=24）,natural recovery group with Rp-cAMP （group C, n=24）, rehabilitation training group （group D, n=18） and rehabilitation training with Rp-cAMP （group E, n=18）, and in addition a control group （group A, n =12）.To establish rat MCAO models immediately after injection of Rp-cAMP into the lateral ventricle of the brain .The rats in the groups D and E were trained by balance beam , bar rotating and rolling exercises started at 48 h after MCAO.The ex-pression of PKA was determined by enzyme-linked immunosorbent assay （ ELISA） and the pCREB protein expression was detected by Western blot assay .Motor function was assessed by balance beam test .Results （1） The motor function score in the group C was significantly higher than that of group B , suggesting that Rp-cAMP inhibited the recovery of motor func-tion in the cerebral ischemia-reperfusion rats .The score of group D was significantly lower than that of groups B and E , in-dicating that Rp-cAMP inhibited the promoting effect of rehabilitation training on motor function in the cerebral ischemia -reperfusion rats.（2） The expressions of PKA and pCREB proteins detected at 2nd, 7th, 14th, and 21th days after surgery showed that their expressions in the group D were significantly higher than those of the groups B and E , indicating that re-habilitation training promoted the expression of PKA and pCREB , and Rp-cAMP significantly inhibited the promoting effect of rehabilitation training on the expressions of PKA and pCREB proteins .Conclusion cAMP/PKA-pCREB signal trans-duction pathway may mediate a promoting effect of rehabilitation training on the recovery of motor function after ischemic stroke in rats.