NO/PKG On ABCA1 Expression And Cholesterol Content In THP-1 Momocyte-derived Macrophages

Objective: To explor the changes of NO/PKG during the process of THP-1 momocyte-derived macrophages form foam cells and the effect of NO/PKG on macrophages ABCA1 expression and cholesterol content.Methods : THP-1 derived macrophages(THP-1 cells were induced to become the macrophages by 160nM PMA)were incubated with ox-LDL for 48h or 72h,then cellular lipid accumlation was detected by Oil Red O staining,and total nitric oxide concentration in the cell cultured supernatant was detected by Total Nitric Oxide Assay Kit.THP-1 derived macrophages were incubated with nitric oxide donor (SNP or L-arginine)and PKG agonist(8-Br-cGMP),then ABCA1 mRNA and celluar lipid accumulation were detected by reverse trancriptase-polmerase chain reaction and high performance liquid chromatography analysis, repectively. Results: Cellular lipid was stained deeper red and occupied a large proportion of cell size in the treating group of THP-1 derived macrophages when incubated with Ox-LDL(25mg/L,50mg/L,100 mg/L,200 mg/L).The lipid accumulation in the treating group with Ox-LDL increased obviously than that in the control group. NO release had concentration and time effect, compare with control group , other groups increase NO release obviously(P<0.05). The release of NO in group 50mg/L,100mg/L and 200mg/L highly than that in group 25mg/L(P<0.05). After treated with macrophages, 8-Br-cGMP can up-regulated the expression of ABCA1 mRNA (P<0.05).SNP, L-arginine or EGTA have no effect on the expression of ABCA1 mRNA. L-arginine, SNP can reduce the content of cellular cholesterol compare with control group (P<0.05) after treated with macrophages. Conclusions: The NO/PKG pathway has a function on decreasing cellular cholesterol, the possible mechanism may concern with the up-regulated expression of ABCA1 mRNA by PKG, prompt the effluence of cholesterol,and decrease cellular lipid accumulation .