Abstract: ObjectiveTo investigate the effect of low density lipoprotein(LDL) and oxidized low density lipoprotein(ox-LDL) on the secretion of endothelin(ET) and whether LDL to be oxidized and modified by ox-LDL in vitro.MethodsEndothelial cell strain ECV-304 was incubated with different concentration of LDL(50 and 100 mg/L),ox-LDL(50 and 100 mg/L) or LDL+ox-LDL(50mg/L) for 24 hours,then cells and cultured medium were collected.ET in cells and cultured medium were detected with radioimmunoassay.ResultsBoth of LDL and ox-LDL enhanced the secretion of ET in cultured endothelial cells;the effect of ox-LDL was more markedly than LDL.LDL+ox-LDL had a greater effect than any of the two lipoproteins alone.ConclusionLDL and ox-LDL may have the ability to promote the secretion of ET in cultured endothelial cells and LDL can be oxidized and modified by ox-LDL in vitro.

Key words: low density lipoprotein, oxidized low density lipoprotein, endothelial cell, endothelin