Inhibitory effect of Salvia miltiorrhia BGE on matrix metalloproteinase-9 activity and migration of TNF-α-induced human aortic smooth muscle cells

The migration and matrix metalloproteinases (MMPs) production of vascular smooth muscle cells (VSMC) may play a key role in the development of atherosclerosis. The Radix of Salvia miltiorrhiza Bunge (Labiatae) (SM), an eminent herb, is often included as an ingredient in various herbal remedies recommended for vascular therapies and has been used to treat vascular diseases for many centuries. In this study, we investigated the inhibitory effect of SM on TNF-α induced human aortic smooth muscle cells (HASMC) migration and MMP-9 activity. Various extracts prepared from stems of SM were tested for cytotoxic activity on HASMC using the XTT assay method. The ethanol extract (IC50 > 100 μg/ml), water extract (IC50 > 100 μg/ml) and chloroform (IC50 = 90 μg/ml) fraction exhibited weak cytotoxic activity. However, buthanol (IC50 = 80 μg/ml) and ethyl acetate (EtOAc; IC50 = 70 μg/ml) fraction exhibited strongly cytotoxic activity. Also, the extracts and fractions were investigated the inhibitory effects on MMP-9 activity using gelatin zymography. Gelatin zymography showed that the TNF-α-treated HASMC secreted MMP, probably including MMP-9, which may be involved in HASMC migration. The EtOAc fraction showed stronger inhibitory effect of proteolytic activity than other fractions. The EtOAc fraction was able to decrease the proteolytic activity of MMP-9 in a concentration-dependent manner on zymography. The Matrigel migration assay showed that SM effectively inhibited the TNF-α induced migration of HASMC as compared with the control group in a dose-dependent manner (IC50 = 65 μg/ml) and that the EtOAc fraction effectively inhibited the migration of HASMC, as compared with the control group in a dose-dependent manner. These results suggest that SM could be used as potential anti-atherosclerotic agent for anti-migration in TNF-α treated HASMC.