In vitro inhibition of proliferation of vascular smooth muscle cells by serum of rats treated with Dahuang Zhechong pill.

Dahuang Zhechong pill (DHZCP) is a famous and classical Chinese herbal prescription, which is clinically used to treat hepatic, gynecological and cardiovascular diseases in China. The aim of this study was to observe the effects of the serum of rats treated with DHZCP on the proliferation of cultured rat vascular smooth muscle cells (VSMCs) stimulated by platelet-derived growth factor (PDGF), oxidized low density lipoprotein (ox-LDL) and hyperlipidemic serum (HLS), and on DNA, protein and collagen syntheses of VSMCs induced by PDGF in vitro. VSMCs proliferation was assayed by measuring the cell viability with MTT method, and syntheses of DNA, protein and collagen were evaluated by detecting [(3)H]-thymidine, [(3)H]-leucine and [(3)H]-proline incorporations, respectively. The results showed that PDGF, ox-LDL and HLS stimulated the proliferation of rat VSMCs in vitro. The serum of rats treated with DHZCP significantly inhibited the proliferation of rat VSMCs induced by the above stimulants and the incorporations of [(3)H]-thymidine, [(3)H]-leucine and [(3)H]-proline into rat VSMCs induced by PDGF in comparison with the model control group (P<0.01). The data suggest that DHZCP is able to obviously inhibit VSMCs proliferation via interfering with syntheses of DNA and protein, and to decrease production of extracellular matrix by VSMCs through antagonizing collagen synthesis.