Free SiO2 promotes the foaming of alveolar macrophages / 医学研究生学报

ABSTRACT

Objective Lipid metabolism disorders caused by cell foam plays an important role in atherosclerosis,but wheth-er it is involved in the development and progression of silicosis has not yet been elucidated. This study aimed to investigate the effect of free silica(SiO2) in inducing foam cell formation of NR8383 alveolar macrophages in rats. Methods NR8383 cells were cultured in vitro by the routine method (the control group) or in 50 μg/mL SiO2 (the SiO2group), 50 μg/mL ox-LDL (the ox-LDL group), or 50 μg/ml SiO2and ox-LDL (the model group), all for 36 hours. The survival rate of the cells was calculated with the cell proliferation and cytotoxicity assay (MTS),the lipid deposition observed by oil red O staining,the levels of total cholesterol (TC), free cholesterol (FC) and cholesterol esters(CE) measured by ELISA,and the mRNA and protein expressions of PPARγ and CD36 in the cells determined by RT-PCR and Western blot, respectively. Results Compared with the control group,the cells treated with ox-LDL showed a significantly increased survival rate, which reached the peak at 50 μg/mL ([1.501±0.201]%) (P<0.05). Foam cells were observed in the SiO2,ox-LDL and model groups,but most significantly in the model group. In comparison with the ox-LDL group,the model group exhibited remarkable increases in TC([14.195±2.260] vs[35.764±4. 226] μg/mg,P<0.05),FC([7.722±0.690] vs[10.049±0.698] μg/mg,P<0.05),CE([6.473±1.707] vs[25.715±4.243] μg/mg,P<0.05),and CE/TC (45.057% vs 71.642%, P<0.05). Conclusion Free SiO2promotes the lipid metabolism disorder in macrophages and enhances the foaming of the cells,in which PPARγ and CD36 may play an important role of regulation.