Protective Role Of Sulforaphane And N-Acetyl-Cysteine On Alveolar Epithelial Cells Against Injury Caused By Cigarette Smoke Extract And The Alteration Of IGFBP-3in The Process

Objective To investigate and study the protective role of Sulforaphane and N-acetylcysteine in the A549cells’injury caused by cigarette smoke extract and the expression change of insulin-like growth factor binding protein-3in this process for the deep mechanism.Method Diveded A549cells into four groups:Control,20%CSE group,5μ M SFN+20%CSE group,1mM NAC+20%CSE group. MTT assay was used to evaluate cell viability, flow cytometry was used to study the A549cell cycle in each group and the apoptotic cell proportion detected by AnnexinV-FITC/PI double-labelled flow cytometry. By incubation with fluorescent indicator DCFH-DA, intracellular reactive oxygen species (ROS) level was evaluated. Furthermore, using real-time quantitative RT-PCR as well as western blot methods, expression of insulin-like growth factor binding protein-3(IGFBP-3) in A549cells treated with CSE was discussed at both transcriptional and protein levels.Result it was observed that SFN or NAC could restore the viability of CSE inhibited A549cells; As the result of flow cytometry, SFN or NAC antagonized against the phase Gl block of A549cell cycle caused by CSE, and significantly reduced the apoptotic cell proportion compared with CSE group. at the same time SFN or NAC also prevented A549cell from apoptosis related morphological changes such as chromatin condensation and fragmentation. High expression of insulin-like growth factor binding protein-3(IGFBP-3) in A549cells treated with CSE was found at both transcriptional and protein levels, and concomitant with the restoration of cell growth after treatment with SFN or NAC, down regulation of IGFBP-3was observed.Conclusions In conclusion, our study demonstrates that20%CSE can induce A549cells injury which is related to cell cycle arrest and increasing apoptotic rate. Sulforaphane or N-acetylcysteine can protect A549cells from injury caused by cigarette smoke extract, markly decreased the intracellular reactive oxygen speices,reduced the CSE-induced apoptosis and eliminated the cell cycle arrest in some way.Meanwhile IGFBP-3probably play an important role in this process, it indicates that IGFBP-3may be a target in various relevant therapies.