The Effect Of PLTP On CSE-induced IL-8 Production In A549 Cells

Objective:Cigarette smoke exposure is the cause of one of the important risk factors in the lung injury, and plasma lipid disorders have been shown to contribute to surfactant dysfunction in lung injury. Cigarette smoking can cause the expression of PLTP increase in the lung. The relationship between PLTP and lung injury caused by cigarette smoking has not been reported. Therefore, this study mainly discusses the effect of PLTP on the expression of IL-8 in A549 cells.Methods : This experiment adopted in vivo experiment and cell culture method. In vivo, SD rats were exposured to air and cigarette smoke for 6 hours/day on 3 consecutive days, then the lungs were sectioned and examined by methods of H&E staining and IHC, the number of total white blood cell and differential white blood cells in BALF were counted. In vitro, the different concentrations of CSE co-cultured with A549 cells for 24 hours. Cells growth was detected by MTT assay. Expression levels of PLTP mRNA and IL-8 mRNA were examined by RT-PCR, protein of PLTP was investigated by Western blotting, and production of IL-8 was examined by ELISA.Results:After exposure to CSE for 3 days, the lungs were edematous and hyperemic. H&E staining showed the destruction of the lung tissue, thinning of the alveolar walls, and enlargement of the alveolar spaces. The number of white blood cells in the BALF was significantly higher in the CSE-exposed rat lung than in the control lung, and the neutrophils and macrophages were clearly elevated. The expression of PLTP and IL-8 in rat alveolar cells were detected with IHC. CSE exposure significantly increased the expression of PLTP and IL-8 in the alveolar cells compared with the control cells. MTT assay showed that the proliferation of A549 cell line was stimulated by the 0.125% CSE, while the proliferation of A549 cell tends to decrease at high concentrations of CSE(2.0% CSE and 4.0% CSE),and in this middle concentrations of CSE(0.25% CSE, 0.5% CSE and 1.0% CSE),the proliferation of A549 cell was not significantly affected. Our studys suggested that PLTP and IL-8 release were induced by CSE in a concentration-dependent and time-dependent manner, and expression levels of IL-8 obviously increased after silence PLTP gene.Conclusion:Those results suggest that CSE can cause acute lung inflammation and IL-8 expression. PLTP siRNA can increased CSE-induced IL-8 production in human alveolar epithelial cells(A549).