脑缺血再灌注大鼠GAP-43和RhoA蛋白表达及NEP1-40对其的影响

Effects of NEP1-40 on GAP-43 and RhoA expression in rats of cerebral ischemic-reperfusion model

目的观察侧脑室注射NEP1-40对脑缺血再灌注大鼠轴突再生、患肢功能恢复和RhoA信号通路活动的影响,探讨其可能的机制。方法将60只成年雄性SD大鼠分为假手术组、脑缺血对照组、侧脑室注射PBS组和侧脑室注射NEP1-40组;采用线栓法制作大鼠大脑中动脉缺血再灌注模型;用Western blot方法检测缺血灶周边脑组织生长相关蛋白(GAP-43)和RhoA蛋白表达;用Montoya设计的"楼梯测试"方法对患肢运动功能进行测试。结果①侧脑室注射NEP1-40组大鼠缺血灶周边脑组织GAP-43在术后7d和14d均高于脑缺血对照组和侧脑室注射PBS组,以术后7d最显著。②侧脑室注射NEP1-40组大鼠缺血灶周边脑组织RhoA在术后各时相点显著低于脑缺血对照组和侧脑室注射PBS组。③侧脑室注射NEP1-40组大鼠在术后各时相点"楼梯测试"结果显著高于脑缺血对照组和侧脑室注射PBS组。结论NEP1-40能够促进脑缺血再灌注大鼠损伤后轴突再生和运动功能恢复,其机制可能与抑制RhoA信号通路活动有关。

Objective To study the effects of NEP1-40 on axon regeneration, motor function recovery of affected limbs and RhoA signal pathway in cerebral isehemia-reperfusion rats for exploring the possible mechanisms. Methods A total of 60 adult male Sprague-Dawley （SD） rats were equally divided into sham operation group （sham group）, cerebral ischemia-reperfusion control group （control group）, intra-lateral ventricle injection of PBS group （PBS group）, and intra-lateral ventricle injection of NEP140 group （NEP1 40 group）. The middle cerebral artery ischemia-reperfusion model （MCAI/R） was established by nylon monofilament occlusion method in rats. The changes in growth associated protein-43 （GAP-43） and RhoA expressions were determined by Western blotting technique. The motor function of affected limbs was tested by the ＂staircase test＂ of Mon- toya＇ s design. Results （1） The expression of GAP-43 in NEP1-40 group was higher than that in the control and the PBS groups at 7 d and 14 d after MCAI/R, peaking at 7 d; （2） The expression of RhoA in NEP1-40 group was significantly lower than that in the control and the PBS groups at each time point; （3） The results of ＂staircase test＂ in NEP1-40 group were much higher than those in the control group and the PBS groups at each time point after MCAI/R. Conclusion NEP140 can improve axon regeneration in cerebral ischemia-reperfu- sion rats and promote the recovery of motor function. The mechanism may be associated with the inhibition of RhoA signal pathway.