Cellular and molecular mechanisms in vascular smooth muscle cells by which total saponin extracted from Tribulus terrestris protects against artherosclerosis.

BACKGROUND/AIMS Total saponin extracted from Tribulus terrestris (TSETT) has been reported to protect against atherosclerosis. We here investigate the cellular and molecular mechanisms of TSETT underlying protection against atherosclerosis. METHODS Cell proliferation was measured with Methyl thiazolyl tetrazolium (MTT); Intracellular H2O2 was measured with DCFH-DA, a fluorescent dye; Intracellular free Ca(2+) was measured with a confocal laser scanning microscopy; Genes expression was measured with gene array and real-time quantitative polymerase chain reaction (RT-PCR); Phosphorylation of extracellular signal-regulated kinase 1/2 (phospho-ERK1/2) was measured with cell-based enzyme-linked immunosorbent assay (ELISA) and western blotting. RESULTS TSETT significantly suppressed the increase in cells proliferation induced by angiotensin II, significantly suppressed the increase in the intracellular production of H2O2 induced by angiotensin II, significantly inhibited the increase in intracellular free Ca(2+) induced by H2O2, significantly inhibited the increase in phospho-ERK1/2 induced by angiotensin II; significantly inhibited the increase in mRNA expression of c-fos, c-jun and pkc-α induced by angiotensin II. CONCLUSION These findings provide a new insight into the antiatherosclerotic properties of TSETT and provide a pharmacological basis for the clinical application of TSETT in anti-atherosclerosis.