Aim To explore the effects of niacin on LDL-C uptake and metabolism in HepG2 cells, and to clarify the functions of niacin in lipid-lowering and slowing the atherosclerosis process,thus to provide a scintific basis for niacin as a lipid-lowering drug in clinical development. Methods Oil red 0 staining was used to observe HepG2 cells after lipid uptake. Enzymatic method was used to determine the content of intracellular free cholesterol ( FC ) and total cholesterol (TC). The LDLR levels on the surface of cell membrane were detected by immunofluorescence flow cytometer. The mRNA and protein expr...