冠脉搭桥术再狭窄中c-myc蛋白表达的研究

Study of Expression of c-myc Oncogenes to Restenosis in Rabbit Model of Vein Grafting

目的 研究c -myc基因片段对冠脉搭桥术再狭窄的作用。方法 将 2 5只健康纯种新西兰大耳白兔按体重随机分 5组 ,每组 5只。将颈外静脉置于同侧颈总动脉 ,分别在术后 6h、2天、7天、14天、2 8天取材。应用免疫组化和形态学分析观察不同时间c -myc阳性细胞数的表达 ,采用计算机图象分析法测量管腔内膜、中膜厚度及其比值。结果 在 1周时内膜和中膜厚度较 6h明显增厚 (P <0 .0 1)。而在 14天、2 8天时内膜和中膜厚度较 7天没有明显变化 (P >0 .0 5 )。移植后 6h～ 7天 ,c -myc蛋白VSMC逐渐增多 ,于 7天达高峰 (P <0 .0 1)。在移植后 14天、2 8天c -myc蛋白VSMC开始下降 ,与 7天相比差异有显著意义 (P <0 .0 1)。结论 c -myc阳性细胞数在移植后 7天达高峰。与内膜迅速增殖的高峰期相吻合。提示c -myc蛋白表达与内膜增殖有密切联系 ,可做为一个早期指标反应血管损伤后内膜的增殖。

Objective To study the effect of expression of c-myc oncogenes to restenosis in a rabbit model of vein grafting. Methods 25 New Zealand rabbits were randomized into five groups(5 in each).External jugular vein were interposed beween ipsilateral common carotid arteries.The vein grafts were harvested at 6h,2days,1 week,2 weeks,4weeks after grafting. Immunohistochemical labeling and morphologic analysis of vein graft sections were used to identify c-myc positive cells.Intimal and medial thickness of vein grafts were measured with a computer system. Results Intimal and medial thicking peaked at 1 week and were significantly thicker(P <0.01)than the same region at 6h after graft implantation. While intimal and medial thickness at 2 weeks and 4 weeks have no difference compared with 1 week( P>0.05).Staining for c-myc VSMC was higher significantly (P<0.01)at 1week compared with 6h. Subsequently,c-myc VSMC staining progressively decreased in 2 weeks and 4 weeks compared with 1week(P<0.01). Conclusion c-myc oncoprotein is expressed early after experimental vein grafting with peak expression at 1week. Intimal thicking significantly correlated with c-myc positive cells. Expression of c-myc protooncogene may be an earlier index to determine the intimal hyperplasia.