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

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 P0.01)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 P0.05) . Staining for PCNA was significantly higher (analysis of variance P0.01)at 1week compared with that at 6hr.Subsequently, PCNA staining progressively decreased., with a significant peak at 1week(analysis of variance P0.01). 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.