Effects of cigarette smoke on phagocytosed function of monocyte-derived macrophage in chronic obstructive pulmonary disease patients

Abstract

To explore the effects of cigarette smoke extract (CSE) on phagocytosizing function of monocyte-derived macrophages (MDMs) in patients with chronic obstructive pulmonary disease (COPD). From January 2012 to March 2013, peripheral blood monocytes were isolated from 32 stable COPD patients and 32 healthy controls at First Hospital, Lanzhou University. MDM was induced and cultured from monocytes in vitro. The MDMs from COPD patients and healthy controls were divided into 4 groups of COPD non-CSE (conventional culture), COPD CSE (4% CSE treatment for 6 h), healthy non-CSE (conventional culture) and healthy CSE (4% CSE treatment for 6 h). Flow cytometry (mean fluorescence intensity, MFI) and laser scanning confocal microscopy (fluorescence grey level) were applied to detect the ability of MDM phagocytosed fluorescein-labeled Escherichia coli (FITC-E.coli). Total antioxidative capacity (TAC) was measured by o-phenanthroline colorimetry. Malondialdehyde (MDA) was measured by thiobarbituric acid colorimetry and glutathione peroxidase (GSH-PX) by 5, 5'-dithiobis-2-nitrobenzoic acid (DTNB) method. MFI and fluorescence grey level in COPD non-CSE group (20.2 ± 2.2, 51.5 ± 5.8) significantly decreased than those in healthy non-CSE group (56.9 ± 6.7, 87.3 ± 7.3). And in COPD CSE (7.6 ± 0.7, 14.1 ± 3.4) and healthy CSE groups (48.0 ± 5.4, 69.7 ± 6.0) decreased more than those in COPD non-CSE and healthy non-CSE groups (all P < 0.01). The levels of TAC and GSH-PX in COPD non-CSE group ((4.1 ± 0.5), (47.1 ± 4.1) U/ml) were lower than those in healthy non-CSE group ((5.1 ± 0.6), (88.4 ± 2.3) U/ml). And in COPD CSE and healthy CSE groups ((3.1 ± 0.4), (26.8 ± 6.2) U/ml) and (4.5 ± 0.4), (72.3 ± 5.1) U/ml) were respectively lower than those in COPD non-CSE and healthy non-CSE groups (all P < 0.01). The content of MDA in COPD non-CSE group was higher than that in healthy non-CSE group [(4.8 ± 0.5) vs (2.1 ± 0.4) µmol/L)]. And in COPD CSE and healthy CSE groups ((7.7 ± 0.9), (3.0 ± 0.6)µmol/L) were higher than those in COPD non-CSE and healthy non-CSE groups (all P < 0.01). At basic status, positive correlations existed between MFI and TAC, GSH-PX (r = 0.523, 0.818, P = 0.038, 0.001) while negative correlations between MFI and MDA (r = -0.501, P = 0.048) in COPD patients and after CSE treatment, the above relationships still existed (r = 0.704, 0.716, -0.522, P = 0.002, 0.002, 0.038). Cigarette smoke can reduce the phagocytosizing ability of MDM in COPD patients. And it may be related with oxidative stress.