AIM: To investigate the apoptosis of endothelial cells (EC) induced by oxysterols and to examine the effect of amlodipine on the apoptosis induced by oxysterols.METHODS: Light microscope, electron microscope, DNA agarose gel electrophoresis and flow cytometry were used to detect the apoptosis of EC.RESULTS: The characteristic morphological features of apoptosis were observed under light and electron microscope; DNA electrophoresis showed"DNA Ladder"; Flow cytometry showed the sub-G1 peak, apoptotic rate is 32.25% and 23.04% in Triol-treated and 25-OH-treated groups, respectively. While treated EC with amlodipine at the same time, the apoptotic rate decreased significantly. CONCLUSION: Both Triol and 25-OH can induce apoptosis of EC, which can be inhibited by amlodipine.

AIM: To investigate the effects of oxysterols on matrix metalloproteinase (MMP) and tissue inhibitor of metalloproteinase-1 (TIMP-1) expression in vascular smooth muscle cells. METHODS: Rabbit aortic vascular smooth muscle cells were cultured in vitro and incubated with cholesterol, Triol and 25-hydroxycholesterol (25-OH), respectively. Slot blot was used to detect the mRNA expression level of TIMP-1 in vascular smooth muscle cells (VSMCs); meanwhile the protein expression level of MMP-9 and TIMP-1 was detected by immunohistology. RESULTS: Triol and 25-OH inhibited the expression of TIMP-1 compared with control and cholesterol, but have no effect on expression of MMP-9. CONCLUSION: Both Triol and 25-OH downregulated TIMP-1 expression in VSMCs .