不同时程电针预处理对脑缺血再灌注大鼠血脑屏障基质金属蛋白酶-9、血管内皮生长因子的影响

目的:观察"百会""水沟"穴不同时程电针预处理对脑缺血再灌注大鼠血脑屏障血管内皮生长因子(VEGF)和基质金属蛋白酶-9(MMP-9)表达的影响,探讨电针预处理诱导脑缺血耐受的可能机制。方法:雄性SD大鼠随机分为假手术组、模型组、电针预处理7d组、电针预处理15d组。Zea Longa改良线栓法复制大鼠大脑中动脉栓塞模型。电针预处理7d组和15d组取"百会""水沟"进行电针预处理,分别于预处理7d和15d后进行造模。采用免疫组化法、荧光定量PCR法检测血脑屏障MMP-9阳性细胞、MMP-9mRNA、VEGF mRNA的表达。结果:模型组MMP-9阳性细胞、MMP-9 mRNA、VEGF mRNA表达较假手术组明显增多(P0.001);电针预处理各组MMP-9阳性细胞、MMP-9mRNA、VEGF mRNA表达较模型组明显减少(P0.01),且电针预处理15d组比电针预处理7d组减少更为明显(P0.01,P0.05)。结论:"百会""水沟"穴不同时程电针预处理可抑制脑缺血再灌注大鼠血脑屏障MMP-9阳性细胞及MMP-9mRNA、VEGF mRNA的表达;其效应均以电针预处理15d为佳。电针预处理诱导脑缺血耐受可能是通过调节脑缺血再灌注后血脑屏障MMP-9、VEGF表达实现的。

The Impact of Different Duration of EA-pretreatment on Expression of MMP-9 and VEGF in Blood-brain Barrier in Rats with Cerebral Ischemia-reperfusion Injury

Objective To observe the impact of preconditioning of EA stimulation of"Baihui"(GV 20)and"Shuigou"(GV 26)in different duration on expression of matrix metalloproteinase(MMP)-9and vascular endothelial growth factor(VEGF)in blood-brain barrier(BBB)tissues in rats with cerebral ischemia-reperfusion injury(CI/RI).Methods Sixty-four male SD rats were randomly allocated to sham-operation(sham),model,EA-pretreatment 7days(pre-t-7d)and EA-pre-t-15dgroups(16rats/group,8rats for immunohistochemistry and 8for RT-PCR).The CI/RI model was established by occlusion of the middle cerebral artery for 90 min and reperfusion.EA(2Hz/15 Hz,1mA)was applied to GV 20 and GV 26 for 30min,once daily for 7days and 15 days respectively before modeling.Immunohistochemical staining and fluorescence quantitative RT-PCR were employed to detect the expression of MMP-9protein,MMP-9mRNA and VEGF mRNA in the BBB tissues(choroid plexus).Results Compared with the sham group,the number of MMP-9immuno-reaction positive cells,and the expression of MMP-9mRNA and VEGF mRNA in the model group were significantly increased(P<0.001),while compared with the model group,the number of MMP-9positive cells,and expression levels of MMP-9mRNA and VEGF mRNA in the EA-pre-t-7dand EA-pre-t-15 dgroups were significantly reduced(P<0.01),and the effects of EA-pre-t-15 dwere markedly superior to those of EA-pre-t-7d(P<0.01,P<0.05).Conclusion EA-pretreatment of GV 20 and GV 26 can effectively restrain CI/RI-induced increase of expression of MMP-9protein,MMP-9mRNA and VEGF mRNA in blood-brain barrier in CI/RI rats,which may contribute to its protective effect of ischemic cerebral tissue.Longer EA-pretreatment is relatively better.