Effect of CSE on the expression of calreticulin and C/EBPα. (A) Proliferation of human ASMCs treated with 10% CSE for 24, 48 and 72 h was analyzed by an MTT assay. (A-E) Human ASMCs were treated with 10% CSE for 24 h. and cell apoptosis was analyzed using the FITC Annexin V/Dead Cell Apoptosis kit; (B) Bar chart showing the percentage of apoptotic cells with or without 10% CSE treatment for 24 h; (C) Reverse transcription-quantitative polymerase chain reaction and (D) western blots analyses were performed to detect mRNA and protein levels, respectively, of calreticulin and C/EBP-α in human ASMCs; (E) Immunostaining of ASMCs was performed using fluorescent-labeled antibodies against C/EBP-α (red); nuclei were counter-stained with DAPI (blue). Magnification, ×200). Values are expressed as the mean ± standard deviation. *P<0.05 vs. control. AMSC, airway smooth muscle cell; C/EBP-α, CCAAT/enhancer-binding protein alpha; CSE, cigarette smoke extract; FITC, fluorescein isothiocyanate; PI, propidium iodide.