Saiko-ka-Ryukotsu-Borei-To inhibits intimal thickening in carotid artery after balloon endothelial denudation in cholesterol-fed rats

Abstract

Oral administration of Saiko-ka-Ryukotsu-Borei-To (SRB), a traditional Chinese formulation, dose dependently inhibited intimal thickening in carotid artery injured by balloon endothelial denudation in cholesterol-fed rats. SRB also inhibited vascular smooth muscle cell (VSMC) proliferation, which is assessed by counting the VSMCs immunoreactive with antiproliferating cell nuclear antigen (PCNA) antibody in the intimal area. VSMC proliferation is considered to play a central role in the development of intimal thickening. SRB slightly, but not significantly, reduced serum total cholesterol and low-density lipoprotein cholesterol. These results indicate that the suppressive effect of SRB on intimal thickening may result from its inhibitory effect against VSMC proliferation, but does not depend on lowering of lipid levels. The balloon injury model used in this study has similar pathological processes to restenosis after percutaneous coronary intervention (PCI). Therefore the present results may provide a new therapeutic strategy using SRB to reduce restenosis after PCI in the treatment of patients with ischemic coronary artery disease. Furthermore, since it is considered that artery restenosis after balloon injury in PCI is "accelerated atherosclerosis," SRB may have beneficial effects in atherosclerosis that develops over a long clinical course in hyperlipidemia, diabetes, etc.