冠状动脉旁路移植术再狭窄中PCNA蛋白表达的研究

Expression of PCNA oncogenes to restenosis in a rabbit model of vein grafting

目的 研究 PCNA基因片段对冠状动脉旁路移植术再狭窄的作用。方法 2 5只健康纯种新西兰大耳白兔随机分五组 ,每组 5只。将颈外静脉移植于同侧颈总动脉 ,分别在术后 6 h,2 d,7d,14 d,2 8d取材。应用免疫组化和形态学分析观察不同时间 PCNA阳性细胞数的表达 ,采用计算机图象分析法测量静脉桥管腔内膜 ,中膜厚度及其比值。结果 实验过程中无实验动物死亡。吻合完成时各吻合口均通畅。在 7d时内膜和中膜厚度较 6 h明显增厚 ,有显著性差异 (P<0 .0 1)。而在 14 d、2 8d时内膜和中膜厚度较 7d没有明显变化 ,无显著性差异 (P>0 .0 5 )。移植后 6 h至 7d,在血管平滑肌细胞 (VSMC)中 ,PCNA蛋白逐渐增多 ,于 7d达高峰 (P<0 .0 1)。移植后 14 d PCNA蛋白在 VSMC中开始下降 ,与 7d相比差异有显著意义 (P<0 .0 1)。结论 PCNA阳性细胞数在移植后 7d达高峰。与内膜迅速增殖的高峰期相吻合。提示 PCNA蛋白表达与内膜增殖有密切联系 。

Objectives To study the effect of expression of PCNA oncogenes to restenosis in a rabbit model of vein grafting. The change of PCNA protein expression in vascular smooth muscle cell after coronary bypass grafting vvere observed. Methods Twenty-five New Zealand rabbits were randomized into five groups(five in each).External jugular vein were interposed beween ipsilateral common carotid arteries.The vein grafts were harvested at 6h, 2days, 1week, 2weeks, 4weeks after grafting.Immunohistochemical labeling and morphologic analysis of vein graft sections were used to identify PCNA positive cells.Intimal and medial thickness of perfusion fixed vein grafts were measured with a computer digitized system. Results 50 randomized animals survived the experiment;no difference in animal survival or graft patency among the groups were observed.Intimal and medial thicking peaked at 1 week and were significantly thicker(analysis of variance P<0.01)than the same region at 6hr after graft implantation .While intimal and medial thickness at 2 weeks and 4 weeks have no difference compared with 1 week.( analysis of variance P>0.05) . Staining for PCNA was significantly higher (analysis of variance P<0.01)at 1week compared with that at 6hr.Subsequently, PCNA staining progressively decreased., with a significant peak at 1week(analysis of variance P<0.01). Conclusion PCNA oncoprotein is expressed early after experimental vein grafting,with peak expression at 1week.This occurs during a period of maximal intimal thickening.Intimal thicking significantly correlated with PCNA positive cells.Expression of PCNA protooncogene may contribute to the induction and regulation VSMC proliferation producing intimal hyperplasia. Expression of PCNA protooncogene may be an earlier index to determine the intimal hyperplasia.