Effect of pirfenidone protecting against cigarette smoke extract induced apoptosis

INTRODUCTION: Apoptosis of lung structural cells is a significant upstream event involved in COPD pathogenesis. This study was designed to explore whether pirfenidone (PFD) was able to attenuate apoptosis induced by cigarette smoke extract (CSE). METHODS: A method of intraperitoneal CSE injection to BALB/C mice was used to establish emphysema mouse model. Terminal deoxynucleotidyl transferase dUTPnick end labeling (TUNEL) assay was applied to evaluate apoptotic cell ratio in mouse lung tissue. The cell viability of HBECs exposed to different concentrations of PFD was measured by Cell Counting Kit-8 (CCK-8) assay. The apoptosis index (AI) of HBECs was tested by flow cytometry. Levels of apoptosis-related protein were determined by Western blotting. RESULTS: PFD treatment significantly decreased the AI value in emphysema mouse lung tissue by TUNEL. In HBECs, flow cytometry showed that PFD could significantly reduce AI led by CSE. Both in vitro and in vivo, protein levels of Bax and Cleaved-caspase 3 in CSE group significantly increased in contrast with the control group; while Bcl-2 protein level in CSE group was significantly decreased; moreover, PFD significantly reversed protein level changes of Bcl-2, Bax, and Cleaved-caspase 3 led by CSE. CONCLUSIONS: This study reveals that PFD may potentially protect against CSE induced apoptosis.