双下肢远端缺血后适应减轻SD大鼠脑缺血再灌注损伤及相关VEGF、MMP-9表达的影响

Effect of limb remote ischemic post-conditioning on cerebral ischemia-reperfusion injury and expression of VEGF and MMP-9 in SD rats

目的:通过建立大鼠大脑中动脉闭塞模型,探讨肢体远端缺血后适应(limb remote ischemic postconditioning,RIP)对脑缺血再灌注损伤(ischemic/reperfusion,I/R)的影响。方法:将98只SD雄性大鼠随机分组,分为3大组:假手术组(n=14),对照组(缺血再灌注模型组,n=42),RIP组(缺血再灌注+肢体远端缺血后适应组,n=42),对照组和RIP组根据缺血再灌注之后不同时间再次分为12、24、72 h组,每组各14只。Longa评分法对其进行评分,HE染色、磁共振弥散加权像计算梗死体积百分比。测定缺血半暗带周围血管内皮生长因子(vascular endothelial growth factor,VEGF)、基质金属蛋白酶-9(matrix metalloproteinase-9,MMP-9)表达变化。结果:RIP组大鼠24 h后Longa评分较对照组有统计学意义(P=0.000)、RIP组大鼠HE染色脑梗死百分比在12、24、72 h均较对照组减少,差异有统计学意义(P=0.000)。免疫组织化学显示RIP组12、24、72 h在缺血半暗带周围VEGF表达均较对照组高,MMP-9表达均低于对照组,差异均有统计学意义(P=0.000)。结论:RIP减少缺血再灌注后24 h神经功能评分,减少梗死体积,具有减轻脑缺血再灌注损伤作用;远端缺血后适应明显增加缺血半暗带VEGF的表达,减少MMP-9的表达,表明RIP的神经保护作用与脑梗死后VEGF、MMP-9表达密切相关。

Objective：To explore the neuro-protective effect of limb remote ischemic post-conditioning（RIP）on middle cerebral artery occlusion（MCAO）after RIP. Methods：Totally 98 healthy adult male SD rats were randomly divided into three groups：sham group（n=14）,control group（n=14）and limb remote ischemic post-conditioning group（RIP group,n=14）. After ischemia and reperfusion,control group and RIP group were further divided into three subgroups：12,24,72 h groups. The neuro-protective effects of limb remote ischemic post-conditioning was assessed using Longa way of neurological deficit scores at 12,24,72 h. The percent of cerebral infarction volume at each point were also determined in time by HE staining and magnetic resonance imaging. Vascular endothelial growth factor（VEGF）and matrix metalloproteinase-9（MMP-9）expression in ischemic penumbra was detected by immunohistochemistry staining. Results：The neurological function scores were decreased in 24 h group than in control group（P=0.000）. The volume of cerebral infarction in RIP groups reduced at 12,24,72 h after ischemic compared with that in control group. VEGF expression was significantly increased but MMP-9 expression was significantly decreased in RIP group than in control group（P=0.0000;P=0.000）.Conclusion：RIP reduces neurological deficit scores at 24 h,decreases percent of infarction volume from 12 h to 72 h after ischemia,thus alleviates cerebral ischemia reperfusion injury. Significantly lower expressions of MMP-9 and higher expressions of VEGF after MCAO are observed in ischemic penumbra in RIP group,suggesting that decreased MMP-9 and increased VEGF expressions are tightly associated with the neuro-protective effect of RIP.