Experimental Study Of Rapamycin Prevent Restenosis Of Vein Graft In Rats

Objective:To investigate whether rapamycin can inhabit the intimal hyperplasia in a rats model of vein grafts.Methods:Twenty-four female SD rats(weighing200to250g) were randomly divided into2groups:Control group (only vein graft)and experimental group (vein graft and using rapamycin mixed fiber glue to the outer membrane of vein). The grafted vein (4rats) were obtained7,14, and28days after operation, HE staining was preformed for histological changes of grafted vein intimal membranes. Proliferating cell nuclear antigen(PCNA) immunohistochemistry staining was conducted for proliferation of smooth muscle cells of the grafted vein. The results were analysed by statistical methods.Results:H-E staining:the vein neointimal thickness in experimental group is less than that in control group. The hyperplasia in experimental group is different from control group at14d and28d postoperation(P<0.05). The average intimal thickness of control group is11.5±0.9μm(7d),20.2±1.6μm(14d),29.0±1.6μm(28d). Experimental group is10.7±0.7μm(7d),14.8±1.0μm(14d),19.4±1.3μm(28d).Immunohistochemistry:The percentage of PCNA-positive cells of control group vein is (15.5±1.9)%(7d),(24.9±1.4)%(14d),(16.4±1.5)%(28d). Experimental group is (10.0±1.6)%(7d),(17.0±1.5)%(14d),(11.3±0.9)%(28d). The percentage of PCNA-positive cells of the control group is superior to that of experimental group at7days,14days and28days. Conclusion:The application of rapamycin can inhabits intimal hyperplasia and proliferation of vascular smooth muscle cells. It can reduce restenosis in vein graft effectively. Saphenous vein have been used as bypass conduits for coronary artery disease for50years. This widely used treatment, however, is complicated by the development of changes in the vein graft, which resemble atherosclerosis. Graft restenosis seriously affects the long-term prognosis of the coronary artery bypass graft. The development of vein graft atherosclerosis differs from arterial atherosclerosis. Studies have examined the role of trauma, lipids, vasoactive mediators, smooth muscle cells mitogens, smooth muscle cells apoptosis, adhesion molecules and proteases. Therapies have been developed to prevent vein graft atherosclerosis based on these studies and have been tested using animal models and in patients. The purpose of this review is to summarize the knowledge in restenosis following saphenous vein graft, as well as promising new treatments for this disease.