The Role Of Transforming Growth Factor Beta One In The Intima Stenosis Of Injured Arteries

BackgroundCoronary heat disease became one of the most serious threats to the public health. Percutaneous transluminal coronary angioplasty(PTCA) is a revolution in the treatment of coronary artery disease. It can obviously lessen stenosis in diseased vessel and amend blood supply and became the equiponderance way to cure coronary artery disease with medication and surgery operation. But the long-term success of PTCA is limited by the high rate of restenosis(RS), which occurs in 30%~50% vessels within 6 months after PTCA. Previous studies suggested that proliferation, migration and collagen synthesis of vascular smooth muscle cells(VSMCs) be a predominant mechanism of restenosis, which modulated by complex growth factors system. Transforming growth factor beta one (TGP- 1) is a 2.5 104 molecular weight pleiotropic growth factor which expressed in diverse adult mammalian tissues and have the function to modulate proliferation and differentiation of cells. Recent reports showed that TGP- 1 may promote the proliferation rate of fibroblast and vascular smooth muscle cells of injured vessel,may increase the synthesis of extracellular matrix(ECM) and inhibit their decomposition, may enhance the ability of ECM to link with cytoskeleton .In this article ,we study the role of TGF- 1 in collagen accumulation , VSMCs' proliferation after aortic injury, and the expression of integrin and FAK in order to explore more about themechanism and prevention on the process of vasal stenosis. Objective1. Stenosis models of ventral aorta after arterial intimal injury were established to evaluate the expression of TGP- 1 , type I, type III collagen and matrix metalloproteinase-9(MMP-9) in injured intima. Rat aortic SMCs inculture were incubated with TCP-Pi of different concentration to test secretion of collagen and MMP-2, MMP-9.2. To discuss the effect and the mechanism of TGF- 1 on the growth and propagating of the rat VSMCs in vitro.3. To discuss the effect of TCP-Pi on the expression of integrin and FAK. Methods1. Stenosis models of ventral aorta after arterial intimal injury were established in rabbits(to observe the pathological features in the injury arteries from 1 week to 4 month). Evaluate the expression of TGF- s1 , type I, type III collagen and MMP-9 in injured intima with Immunohistochemistry and in situ hybridization.2. Cells derived from rat vascular smooth muscle were cultured and identified by their characteristic immunocytochemical staining for smooth muscle myosin(monoclonal anti-smooth muscle myosin antibody ).Cultured VSMCs (passage 4~6) were incubated with TCP-Pi. Concentration of TCP- 1 were lng/ml, 5ng/mI, 10ng/ml respectivrly for 24 hours, and study collagen synthesis of VSMCs by 3H-proline incorporating into 3H-hydroxyproline. And substrate zymography was applied to test the activation of MMP-2 and MMP-9.3. Cultured VSMCs (passage 4-6) were incubated with TGF- 1. After treated with l~10ng/ml TGF- 1 for 6 hours, the proliferation of VSMCs was measured by Flow Cytometry DNA assay and the expression of PCNA was determined by immunohistochemical procedures.4. In situ hybridization was used to evaluate the expression of TGF-pi and FAK in injured intima. Rat aortic SMCs in culture were incubated with TCP- 1 of different concentration. Immunohistochemistry was applied to test the expression of integrin and FAK.5. The results of in situ hybridization and immunohistochemistry wereanalysed by Computer Image Analysis System NYD-1000. Result1. the vessel narrowness models models of rabbit after intimal injured was established and the expression of TGF- 1, type I, III collagen and MMP-9 was detected. The obvious expression of TCP- 1 and type I collagen started about 1 to 2 weeks after intimal injuring, and remained increasing in the following 4 months. The expression level of type III collagen was very low in normal aorta but increased rapidly at 1 week after intimal injury and the expression peak appeared at 4 weeks after injury .The expression of MMP-9 reach to...