Important role of TNF-alpha in inhibitory effects of Radix Sophorae Flavescentis extract on vascular restenosis in a rat carotid model of balloon dilatation injury.

The aim of this study was to determine the molecular mechanism underlying the inhibition of vascular restenosis by Radix Sophorae Flavescentis (RSF) extract after balloon dilatation injury. In a rat carotid model of balloon dilatation injury, the RSF extract showed a significant inhibitory effect on vascular restenosis. Immunohistochemistry showed that the expression of tumor necrosis factor-alpha (TNF-alpha) in the vascular focus was markedly reduced upon treatment with the RSF extract, whereas the expression of proliferating cell nuclear antigens (PCNA) was mostly unaffected. Colorimetric assays of methylene blue incorporation demonstrated that the proliferation of cultured vascular smooth muscle cells (VSMCs) was not inhibited with serum from rats treated with RSF extract. However, the expression of TNF-alpha in cultured VSMCs was significantly downregulated by serum from rats treated with RSF extract. These results suggested that RSF extract has an inhibitory effect on vascular restenosis after balloon dilatation injury which might be, in part, attributable to its inhibition of TNF-alpha expression. Georg Thieme Verlag KG Stuttgart, New York.