Inhibitory effect of Wendan decoction on formation of foam cells induced by ox-LDL

AIM To explore the anti-atherosclerotic mechanism of Wendan decoction based on formation of foam cells. METHODS The optimal concentrations of Wendan decoction without cytotoxity to cells were selected by MTT assay. After Wendan decoction treatment， the formation of foam cells was examined by oil red O staining. The cholesterol efflux， cholesterol level， free cholesterol level and cholesterol esterification rate were analyzed using cholesterol efflux assay， total cholesterol assay and free cholesterol assay. The expression levels of macrophage membrane proteins， including CD36， scavenger receptor class A （SR-A）， ATP-binding cassette transporter A1 （ABCA1） and scavenger receptor class B type I （SR-BI）， were quantified by Western blot. RESULTS The optimal concentrations of Wendan decoction without cytotoxity to the cells were 0~6 g/L. Wendan decoction at the concentrations of 1.5， 3 and 6 g/L were selected for the experiments. Wendan decoction at these concentrations inhibited the formation of foam cells induced by oxidized low-density lipoprotein （ox-LDL）， and reduced the accumulation of intracellular lipids in a concentration-dependent manner （P<0.05 or P<0.01）. Wendan decoction also reduced intracellular total cholesterol level， cholesterol ester level and cholesterol esterification rate （P<0.05 or P<0.01）， promoted efflux of intracellular cholesterol （P<0.01）， and decreased the protein level of CD36 in THP-1 cell-derived macrophages （P<0.01） in a concentration-dependent manner. Wendan decoction at the concentration of 6 g/L significantly reduced the protein level of SR-A in THP-1 cell-derived macrophages （P<0.05）. At the concentrations of 3 and 6 g/L， Wendan decoction significantly increased the protein levels of ABCA1 and SR-BI in THP-1 cell-derived macrophages （P<0.05 or P<0.01）. CONCLUSION Wendan decoction significantly inhibits ox-LDL-induced formation of foam cells by reducing cholesterol deposition and promoting cholesterol efflux， and its mechanism may be related to the down-regulation of CD36 and SR-A and the up-regulation of ABCA1 and SR-BI.