摘要：Tumor necrosis factor- α (TNF- α ) has been implicated in the pathogenesis of atherosclerosis through influence on vascular smooth muscle cell behavior. However, little is known about the expression and function of endogenous TNF- α in the cells. Dense and sparse cultures of bovine aortic smooth muscle cells were prepared and the expression of TNF- α and regulation of collagen synthesis by endogenous TNF- α were investigated. The results indicate that dense and sparse vascular smooth muscle cells express endogenous TNF- α that suppresses the synthesis of collagen (types I and III) only when the cell density is high; suppression was also observed in human and rabbit aortic smooth muscle cells. Transforming growth factor- β stimulated collagen synthesis in bovine aortic smooth muscle cells and the stimulation was significantly suppressed by endogenous TNF- α when cell density was high. The present data suggest that vascular smooth muscle cells express endogenous TNF- α that is involved in the suppressive regulation of collagen synthesis depending on the cell density.
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