Abstract: Objective To investigate the role of phospholipid transfer protein (PLTP) in cigarette smoke extract (CSE)-induced
apoptosis of rat alveolar type II cells (RLE-6TN) in vitro. Methods Rat alveolar epithelial cell line RLE-6TN were transfected
with a small interfering RNA (siRNA) targeting PLTP prior to exposure to different concentrations of CSE for 24 or 48 h. The
morphological changes of the apoptotic cells were observed by fluorescence microscopy with Hochest staining, and the cell
apoptosis rate was measured with flow cytometry. The expression level of PLTP and caspase-3 activity in the cells were
examined with Western blotting. Results Exposure to CSE significantly increased the cell apoptosis rate from (1.68±0.098)% to
(18.663±0.964)% (P<0.001). Hoechst staining revealed distinct apoptotic changes in CSE-treated cells, which showed increased
PLTP expression and caspase-3 activity. PLTP knockdown with the specific siRNA partly suppressed the SCE-induced enhancement
of caspase-3 activity in the cells. Conclusion PLTP may play a role in CSE-induced apoptosis of rat alveolar cells in vitro.