脑脉通对老龄大鼠脑缺血/再灌注微血管生成及VEGF/VEGFR系统表达的影响

Effect of Naomaitong on cerebral angiogenesis and expressions of VEGF and VEGFR after cerebral ischemia/reperfusion in aged rats

目的:从血管内皮生长因子(VEGF)及其受体表达方面揭示脑脉通促进老龄大鼠脑缺血/再灌注血管生成的作用机制。方法:将SD雄性老龄大鼠随机分为假手术组、模型组、尼莫地平组、脑脉通组,运用免疫组化和原位杂交等方法测定MVD、血管场面积以及VEGF、Flt-1、Flk-1的蛋白与基因表达。结果:脑脉通组缺血(I)3h、缺血/再灌注(I/R)1d、3d、12dMVD和I3h、I/R3d、6d、12d血管场面积均较模型组升高(P<0.05,P<0.01)。脑脉通组各时间点VEGF、Flt-1、Flk-1表达均较模型组增强(P<0.05,P<0.01)。脑脉通组I3h、I/R3d、6d、12dVEGFmRNA以及各时间点Flt-1、Flk-1mRNA表达水平均较模型组增强(P<0.01)。结论:脑脉通可促进老年脑缺血/再灌注微血管生成,其机制与其提高VEGF/VEGFR系统蛋白与基因表达有关。

Objective：To reveal the mechanism of action of Naomaitong promoting angiogenesis after cerebral ischemia/ reperfusion in aged rats through VEGF and VEGFR.Methods：The aged male SD rats were randomly divided into sham operation group,model group,nimodipine group and Naomaitong group.To examine microvessel density（MVD）,microvessel area,and the expression of protein and mRNA of VEGF,Flt-1,Flk-1 by immunohistochemistry and hybridization in situ,etc.Results：I 3h,I/R 1d,3d,12d MVD,and I 3h,I/R 3d,6d,12d microvessel area in Naomaitong group were higher than those in model group（P0.05,P0.01）.MVD continued to decline since I 3h to I/R 12d;microvessel area reached the peak in the I/R 1d,I/R 1d and rapidly decreased to I/R 12d to a minimum in model group.In Naomaitong group,MVD I 3h significantly increased,I/R 1d reached the peak,after I/R 1d the MVD began to decline,I/R 6d reached the minimum,to I/R 12d MVD also increased significantly;microvessel area I 3h significantly increased,I/R 1d reached the minimum,I/R 3d then increased,to I/R 6d reduced again,and then increased again,I/R 12d returned to the level of I/R 3d.Compared with those in model group,expressions of VEGF,Flt-1,Flk-1 at different time points in Naomaitong group increased（P0.05,P0.01）.The expression of VEGF in model group,the peak appeared in the I/R 1d,I/R 1d^12d was gradually weaken trend;The expression of Naomaitong group began to increase in the I 3h,I/R 1d reached the peak,to I/R 12d expression slightly decreased.In model group,the expression of Flt-1,Flk-1 in I 3h began to increased,I/R 1d reached the peak,I/R 1d^12d rapidly declined;in Naomaitong group,expressions of Flt-1,Flk-1 were strong in the I 3h,Flt-1 reached the peak in the I/R 3d,then which expression decreased slightly,to I/R 12d was still at a high level of expression,while Flk-1 expression continued to increase until reached the peak in the I/R 6d,expression may also maintain the high level to I/R the 12d.The expression level of I 3h,I/R 3d,6d,12d VEGF mRNA and all time points of Flt-1,Flk-1 mRNA in Naomaitong group increased than those in model group（P0.01）.In model group,the expression of VEGF mRNA reached the peak in the I/R 1d,I/R 3d expression droped to the lowest,after the expression increased slightly;in Naomaitong group the expression of VEGF mRNA that was markedly enhanced in the I 3h,I/R 6d reached the peak and sustained to the I/R 12d was still a high expression.In model group,the expression of Flt-1,Flk-1 mRNA was strongest in the I/R 1d,I/R 1d^12d rapidly declined;in Naomaitong group,the expression of Flt-1,Flk-1 mRNA increased obviously in the I 3h,I/R 1d reached the peak,then gradually decreased,to I/R 12d still maintained a high level of expression.Conclusion：Naomaitong could promote angiogenesis after cerebral ischemia/reperfusion,its mechanism may be related to which enhances the expression of protein and gene of VEGF/VEGFR system.