| Summary: | 碩士 === 中山醫學大學 === 生化暨生物科技研究所 === 93 === In developed countries, atherosclerosis and its complications are becoming a major cause of death. Several studies showed that free radical-mediated oxidation of low density lipoprotein leading to the production of oxidized LDL (OxLDL) is a key event in initiating endothelial cells proliferation and atherosclerosis plaque. Some natural antioxidants such as vitamin C, vitamin E, β-carotene have been revealed clearly to prevent the atherosclersis. As shown in previous studies, we found that the aqueous extract of Hibiscus Sabdariffa ( HSE ) and protocatechuic acid ( PCA ) could be able to inhibit the apoptosis of macrophage induced by OxLDL. In this study, we used the human monocyte, THP-1, to further detect the effects induced by OxLDL, and what kind of role could HSE and PCA play. Using TBAR, migration assay, flow cytometric DNA fluorescence and detecting apoptosis-related proteins, our results showed that increasing the dosage of HSE or PCA could inhibit monocyte apoptosis caused by OxLDL. At the high concentration of HSE and PCA, the concentrations of MDA produced from lipid peroxidation were inhibited up to 91% and 85%; the inhibitory percentage on migration were 70% and 76%; and the level of apoptosis was reduced to 81% and 93%. Taken the above, we concluded that the inhibitory mechanisms of HSE or PCA on atherosclerosis could also be contributed to the other pathway by inhibiting monocyte apoptosis and differentiation.
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