转VEGF基因对血管损伤后平滑肌细胞增殖和表型的影响

Effects of phVEGF165 gene transfer on vascular smooth muscle cell (VSMC) proliferation and phenotypes

目的观察局部转染pAdTrack CMV-VEGF165对动脉粥样硬化兔血管损伤后平滑肌细胞增殖和表型转变的影响.方法90只新西兰大白兔分为3组,Ⅰ组(30只)单纯拉伤腹主动脉;Ⅱ组(30只)拉伤后局部转染真核表达质粒pAdTrack CMV;Ⅲ组(30只)拉伤后局部转染pAdTrackCMV-VEGF165;每组按实验终点(术后3 d、1周、2周、4周和8周)分为5个亚组,术前1周开始予高脂饮食至实验终点,取拉伤段血管用于3H-TdR掺入实验、病理学检测和电镜观察平滑肌细胞表型变化.结果3H-TdR掺人实验结果显示,Ⅰ组和Ⅱ组在血管拉伤后3d3H-TdR掺入量增加(P＜0.05),2周时达到高峰(P＜0.01),以后逐渐下降,8周时恢复至正常,而Ⅲ组血管组织术后3 d同样出现3H-TdR掺入增加(P＜0.05),术后1周时3H-TdR掺入值明显低于Ⅰ组和Ⅱ组(P＜0.01),术后4周时3H-TdR掺入量接近正常;透射电镜观察显示Ⅰ组和Ⅱ组从术后3d开始出现合成型VSMC,2周时达到高峰,80%以上为合成型,至4周时,仍以合成型平滑肌细胞为主(60%),而Ⅲ组血管组织术后3 d时可见少量合成型平滑肌细胞(10%),1周时合成型VSMC约占30%,术后2周时90%为收缩型平滑肌细胞,4周时已无合成型平滑肌细胞.结论局部转染VEGF165基因可抑制平滑肌细胞增殖和表型改变,缩短修复时程.

Objectives To investigate the effect of phVEGF165 gene transfer on vascular smooth muscle cells proliferation and morphologic characteristics. Methods 90 New Zealand winte rabbits were divided into 3 groups randomly: group I (balloon injury group), group II (pAdTrack CMV group) and group KpAdTrack CMV-VEGF165 group). All animals had been given hypercholesterol diet for 7 days before experiment and continued to receive hypercholesterol diet until killed. Each group were divided into five subgroups according to the sacrifice time (3 days, 1,2,4 and 8 weeks after operation). The injured abdominal arteries were harvested for 3H-TdR incorporation test and electric microscopy study. Results The capacities of abdominal arterial rings 3H-TdR incorporation became ingher in all groups on 3'* day after the operation (increased value: group I 712. 53 + 89.21, group II 801.56 +94.97, group I 601.73 + 79.03, P , 0. 05) . In group 1, the value decreased quickly and from 1 week after operation, the capacities of 3H-TdR incorporation were significantly lower than group I and II (301.76 + 53.22 vs 679.01+85.43 and 703.89 + 79.44, P < 0.01), and nearly normal at the end of 4 week time. Immunoinstochemical identified the main cell types of the proliferating intima were VSMC. Electric microscopy showed that the morphologic characteristics of VSMC changed from contractile to synthetic quickly after vascular injurying and at the end of 4 weeks, the main VSMC phenotype in group I and II were synthetic. However, in group III, at the end of 2 weeks after operation, the main phenotype of VSMC were contractile, and at 4 week time, no synthetic phenotype could be seen. Conclusions Local pAdTrack CMV-VEGF165 transfer could restrain VSMC proliferation and phenotype change.