Effects Of APS On Cholesterol Contnet And The Expression Of ABCA1in RAW264.7Macrophage-derived Foam Cells

Objective:to investigate the effect of astragalus polysaccharides(Aps) on cholesterol content and the expression of ABCA1in RAW264.7macrophage-derived foam cells,and explore the possible mechanism.Method:1. preparation of OX-LDLof using GuSO4oxidation.2. The mouse RAW264.7cells were induced into foam cells by incubation with50mg/L oxidized low density lipoprotein(ox-LDL). Transmission light microscope(using red oil O staining technique) was applied to appraise the morphology and change of foam cells.3. After APS of different concentrations((0,10,20,50,100mg/L) were incubated with RAW264.7macrophage-derived foam cells for24h and100mg/L APS was incubated with RAW264.7macrophage-derived foam cells for0,6,12,24,48h, the cholesterol content of foam cells was measured by enzyme assay.4. After exposed to Aps at different doses,cholesterol efflux and ABCA1protein leves in cultured RAW264.7macrophage-derived foam cells were determined by enzyme assay.ATP binding cassette transport Al(ABCAl) expression in the macrophages was quantitates by TR-PCR and enzyme-linked immunoabsobant assay(FLISA).Results: 1. Ox-LDL was successfully preparated. After the LDL oxidation, It is measured at532nm blank reference substance, standards, and samples of the absorption value of0.0013,0.1420,0.0165, the protein concentration of50mg/L, on the basis of calculated associates content is21.61? Mol/g,2. Foam cell model were observed under inverted microscope showed that adherent growth more macrophages with round and irregular polygon is given priority to, generally containing one or two nuclear, pseudopodia, smaller cell the cell body, cells grow quickly,5to6days can fusion; Ox-LDL after48h of phagocyte cells visible volume increased obviously, intracellular lipid droplets of visible size; After oil red O staining, cell plasma within a large number of red dye (about88%)3. After APS of different concentrations((0,10,20,50.100mg/L) were incubated with RAW264.7macrophage-derived foam cells for24h,the cholesterolester content of foam cells was45.15±3.57,37.67±2.26,34.59±3.51、28.57±10.34.15.92±3.86nmol/mg(P<0.01);100mg/L APS was incubated with RAW264.7macrophage-derived foam cells for0,6,12,24,48h, the cholesterol content of foam cells was55.35±15.07,33.05±6.12,22.33±5.54,13.51±2.76、15.76±3.89nmol/mg(p<0.01).4.After APS of different concentrations(0,10,20.50,100mg/L) were incubated with RAW264.7macrophage-derived foam cells for24h, ATP binding cassette transport Al(ABCAl) expression in the macrophages was quantitates by TR-PCR, OD ratio of ABCAl andβ-actin were0.41±0.028,0.59±0.032,0.64±0.0820.77±0.109、0.95±0.069(P<0.01)。5.After APS of different concentrations(0,10,20,50,100mg/L) were incubated with RAW264.7macrophage-derived foam cells for24h, ABCA1expression in the macrophages was quantitates by enzyme-linked immunoabsobant assay(ELISA).the OD±SD value was0.3053±0.0055,0.3251±0.0083、0.3603±0.0127,0.3792±0.0092、 0.3993±0.012.Conclusion:1. Application GuSO4oxidation process could be successfully become ox-LDL oxidative modification of LDL.2.The results showed that APS could significantly decreased the cholesterolester contnet of foam cells in a concentration-dependent and time-dependent manner.3. APS may reduce the cholesterolester contnet of foam cells via upregulating the expression of ABCA1in the mRNA and protein, This may be one of its occurrence and development of resistance to atherosclerosis mechanism.