[Protection of azithromycin against pulmonary II epithelial cell injuries induced by cigarette smoke extract and relevant mechanisms].

OBJECTIVE: Cigarette smoke extract (CSE) can induce injuries of pulmonary II epithelial cells, activate nuclear factor-kappaB and increase tumor necrosis factor-alpha(TNF-alpha) secretion. This study aimed to investigate whether azithromycin can protect pulmonary II epithelial cells from injuries induced by CSE and relevant mechanisms. METHODS: Pulmonary II epithelial cells (A549 cells) were cultured in vitro. After 48 hrs of culture the cells were randomly treated with serum-free DMEM only (blank control group), azithromycin + serum-free DMEM, CSE+ serum-free DMEM or CSE+azithromycin. Eight hours later the morphology of A549 cells, the activity of NF-kappaB and the levels of TNF-alpha were measured by inverted microscope, immunohistochemistry and ELISA. RESULTS: The morphology and structure of A549 cells were changed, NF-kappaB activity increased (dark brown staining ) and TNF-alpha levels (0.307 +/- 0.036 pg/mL vs 0.234 +/- 0.028 pg/mL)increased in the CSE+ serum-free DMEM group compared with the blank control group (P < 0.01). CSE together with azithromycin treatment recovered partly the morphological injuries of A549 cells. It also attenuated NF-kappaB staining and decreased TNF-alpha levels from 0.307 +/- 0.036 pg/mL (CSE+serum-free DMEM group) to 0.269 +/- 0.009 pg/mL (P < 0.05). CONCLUSIONS: Azithromycin may inhibit NF-kappaB activity, decrease TNF-alpha secretion and thus lessen cytotoxicity of CSE to A549 cells.