Effects of hyperglycemia and oxidized low density lipoprotein on differentiation of macrophage derived THP-1 monocytes / 上海第二医科大学学报

ABSTRACT

Objective To explore the effects of hyperglycemia and oxidized low density lipoprotein (ox-LDL) on the differentiation of macrophage derived THP-1 monocytes. Methods THP-1 human monocytic leukemia cell line was cultured in vitro, and the differentiation of THP-1 cells into macrophages was induced by phorbol esters. The macrophages were then incubated with the absence of D-glucose and ox-LDL (control group), 30 mmol/L D-glucose (hyperglycemia group), 100 μg/mL ox-LDL (ox-LDL group) or 30 mmol/L D-glucose and 100 μg/mL ox-LDL(G-ox-LDL group) for 24 h. High performance liquid chromatography was used for qualitative and quantitative analysis of intracellular cholesterol and cholesteryl esters. Both light microscope with red oil O staining technique and transmission electron microscope were employed to observe the morphology of treated and control THP-1 cells. Results A large number of intracellular red oil O stained granules and lipid vacuoles were observed in ox-LDL group and G-ox-LDL group, the contents of total cholesterol and cholesteryl esters were significantly higher than those of control group (P<0.05), and the contents of cholesteryl esters were higher than 50% of total cholesterol in both groups. However, only a few intracellular red oil O stained granules and lipid vacuoles were observed in control group and hyperglycemia group, there was no significant difference in the contents of total cholesterol and choleateryl esters between control group and hyperglycemia group (P>0.05), and the contents of cholesteryl esters were less than 50% of total cholesterol in both groups. Conclusion Foam cells form when THP-1 cells are incubated with ox-LDL, while hyperglycemia alone can not convert THP-1 cells to foam cells, indicating that ox-LDL is necessary for the macrophages derived THP-1 monocytes to turn into foam cells.