Abstract: Objective Under the circumstance of mechanical ventilation, we designed to explore the relationship between different airway pressure levels and expression of related cytokines to airway remodeling. Methods Fourty-two chronic obstructive pulmonary disease cases (COPD group) and thirty-three without chronic airway inflammatory dieases (control group) were collected. The above cases underwent mechanical ventilation in the period of general anesthesia. According to different levels of peak inspiratory pressur e (PIP) , above two groups, randomly and respectively, were divided into high PIP (HPIP, 24 cmH2O) group, moderate PIP (MPIP, 22 cmH2O ) group, low PIP (LPIP, 20 cmH2O ) group. All positive end expiratory pressure (PEEP) was set to 5 cmH2O. Then the collection of BALF was performed before and 3 hours after applying ventilator. The related factors to airway remodeling, such as fibroblast growth factor 2 (FGF-2) , transforming growth factor β1 (TGF-β1) and matrix metalloproteinase-9 (MMP-9) , were measured by enzyme-linked immunosorbent assay (ELISA) and Western blot. Results 1) Before mechanical ventilation, the levels of FGF-2, TGF-β1 and MMP-9 in COPD group were higher than control group (P<0.01) . 2) 3 hours after mechanical ventilation, we saw significant upregulated expression of FGF-2, TGF-β1, MMP-9 in HPIP subgroup in control group (P<0.05) and the 3 factors levels of COPD group were all increased (P<0.05) . Moreover, HPIP subgroup were significantly higher than MPIP and LPIP subgroup in COPD group (P<0.05) . 3) The expression of FGF-2, TGF-β1, MMP-9 in BALF had a positive correlation with the airway pressure levels in COPD group(P<0.01). Conclusions Under mechanical ventilation, sustained high airway pressure may enhance the expression of FGF-2, TGF-β1 and MMP-9 which could result in airway remodeling by mechanosensitive cation channel in bronchial epithelial cells, especially in COPD patients.

Key words: airway pressure airway remodeling chronic obstructive pulmonary disease