家兔静脉移植桥血管内膜c-myc蛋白的表达

Expression of c-myc protein in vascular smooth muscle cell of vein graft rabbits

目的 :研究c -myc基因在冠脉旁路移植术静脉桥中的表达。方法 :2 5只新西兰大耳白兔随机分为 5组 ,每组 5只。将颈外静脉间置于同侧颈总动脉 ,分别在术后 6h ,2d ,7d ,14d ,2 8d取静脉桥。应用免疫组化和形态学方法观察不同时间c -myc蛋白的表达 ,采用计算机图像分析法测量静脉桥内膜、中膜厚度及其比值。结果 :7d时静脉桥内膜和中膜厚度较 6h明显增厚 ,差异有统计学意义 (P <0 .0 1)。 14d ,2 8d时静脉桥内膜和中膜厚度较7d没有明显变化 ,差异无统计学意义 (P >0 .0 5 )。移植后 6h至 7d ,c -myc蛋白血管平滑肌细胞逐渐增多 ,于 7d达高峰 (P <0 .0 1)。移植后 14d ,2 8dc -myc蛋白血管平滑肌细胞开始下降 ,与 7d相比差异有统计学意义 (P <0 .0 1)。结论 :c-myc蛋白表达与内膜增殖有密切联系 。

Aim: To study the expression of c-myc oncogenes in vascular smooth muscle cell (VSMC) in vein graft. Methods: A total of 25 New Zealand rabbits were randomly divided into five groups with five rabbits in every group.External jugular vein was interposed between ipsilateral common carotid arteries.The vein grafts were harvested after 6 h,2 days,1 week,2 weeks,4weeks.Immunohistochemical labeling and morphologic analysis of vein graft sections were used to identify c-myc positive cells.Intimal and medial thicknesses of perfusion fixed vein grafts were measured with a computer digitized system. Results: Intimal and medial thicknesses peaked after 7 days were significantly thicker than the same region at 6 h after graft implantation( P<0.01). While intimal and medial thicknesses after 2 weeks and 4 weeks had no difference compared to that of 1 week( P>0.05). Expression for c-myc was significantly higher at 1 week compared to that of 6 h(P<0.01).Subsequently,c-myc staining decreased with a significant peak at 1week(P<0.01). Conclusion: Expression of c-myc protein may contribute to the induction and regulation VSMC proliferation producing intimal hyperplasia, and may be an earlier index to determine the intimal hyperplasia.