Effects of IL-10 on SR-A expression in the oxidized LDL-induced foam cell formation of macrophages derived from human THP-1 Cells

Objective:To study the effects of interleukin-10(IL-10) on expression of scavenger receptor class A(SR-A) in macrophages treated with oxidized low density lipoprotein(ox-LDL) from THP-1 Cells.Method:Human THP-1 cells were cultured with 200 nmol/L PMA for 24 h in order to differentiate the cells to macrophages.The macrophages were incubated with ox-LDL(100 mg/L) for 24 h to form foam cells.We classified these cells to five groups:THP-1 cells,macrophages,macrophages with 20 mg /L IL-10,macrophages with ox-LDL(foam cells),macrophages with ox-LDL and 20 mg/L IL-10 group.RT-PCR and Western blotting analysis were used to detect expression of SR-A,and the formation of foam cells were evaluated by lipid granules formed in the cell by oil redo staining technique.Result:SR-A was highly expressed in the macrophages compared with the human THP-1 Cells.But the expression of SR-A was inhibited when macrophages was stimulated by 20 mg/L IL-10 for 24 h,and the expression of SR-A mRNA and protein was downregulate to 0.6 times and 0.7 times respectively comparcel to the levels before stinulation.The percentage of the foam cell formation was reduced to 0.6 times in the macrophages with IL-10 group compared with the macrophages group.The expression of SR-A was further elevated in the foam cell group compared with the macrophages group,and the expression of SR-A mRNA and protein were elevated to 1.5 times and 1.4 times respectively.Comparced to the levels before stinulation The percentage of the foam cell formation was increased to 1.7 times.When macrophages was stimulated by 100 mg/L ox-LDL and 20 mg/L IL-10 for 24 h,the expression of SR-A was further inhibited,the expression of SR-A on both protein and mRNA levels was depressed 0.4 times,and the percentage of the foam cell formation was fell 0.3 times in the macrophages with ox-LDL and IL-10 group compared with the foam cell group.Conclusion:IL-10 inhibits the SR-A expression in macrophages.IL-10 has pronineatly inhibitory effects on the expression of SR-A in macrophages treated with ox-LDL.The results suggest that IL-10 prevented atherosclerosis by inhibiting the SR-A protein expression.