Inhibition of vascular smooth muscle cell migration by serum from rats treated orally with Saiko-ka-Ryukotsu-Borei-To, a traditional Chinese formulation

Abstract

Abstract Oral administration of Saiko-ka-Ryukotsu-Borei-To (SRB), a traditional Chinese formulation, has been found to prevent intimal thickening of the carotid artery after balloon endothelial denudation in cholesterol-fed rats. To clarify the mechanism of this effect, the present study investigated if SRB inhibits vascular smooth muscle cell (VSMC) migration, which plays an important role in the development of intimal thickening after endothelial injury. The serum (SRB serum) sampled from cholesterol-fed rats treated orally with SRB for 3 days before and 4 days after the injury dose-dependently inhibited the migration of cultured VSMCs. When added directly to cultured VSMCs, the SRB extract did not inhibit VSMC migration. It is remarkable that SRB serum, which may contain a much lower concentration of SRB ingredients compared with the SRB extract, inhibited cultured VSMC migration. The present testing system using serum obtained from animals treated orally with traditional Chinese formulations may be useful for clarifying the pharmacological efficacy of such drugs, including many non-absorbable components. Furthermore, it may be useful in the search for new active compounds in serum after oral administration of traditional Chinese formulations, the active metabolites of which have not been identified.