Acute alcohol intake impairs lung inflammation by changing pro- and anti-inflammatory mediator balance

Abstract

Previous studies have shown that alcohol (ethanol [EtOH]) intoxication impairs lung immunity by affecting cytokines pivotal to the inflammatory process. The objective of this study was to test the hypothesis that acute alcohol intoxication impairs lung innate immunity by downregulating the expression of proinflammatory mediators while simultaneously upregulating anti-inflammatory mediators. EtOH was administered to the mice 0.5h prior to an intratracheal injection of Escherichia coli lipopolysaccharide (LPS). The animals were killed either 4 or 24h after LPS to recover plasma, lungs, and bronchoalveolar lavage fluid. Lung inflammatory cytokines tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1beta), IL-6, macrophage inhibitory factor (MIF), IL-10, TGF-beta, and receptors for TNF-alpha, IL-1beta, IL-6, and TGF-beta as well as glycoprotein (gp)130 and corticosterone (CS) levels were evaluated at mRNA and protein level. While the mRNA expression and the soluble TNF-Rp55 levels were significantly upregulated by EtOH, LPS-induced TNF-alpha activity, TNF-Rp55 mRNA expression, and soluble TNF-Rp55 levels were significantly suppressed. The LPS-induced expression of IL-1beta, IL-6, MIF, gp130, and receptors IL-1RI, IL-1RII, and IL-6Ralpha were also significantly impaired by EtOH. EtOH increased significantly the basal IL-10 activity at 3h, which continued to remain elevated even at 24h. The EtOH effect on IL-10 activity persisted even in LPS-challenged mice. EtOH and LPS augmented lung CS levels independently of each other. EtOH suppressed upregulation of TGF-beta1 mRNA expression by LPS and blocked completely LPS-induced TGF-beta1 secretion. In conclusion, the data suggest that the suppression of acute lung inflammation by EtOH intoxication is largely due to impairment by EtOH of proinflammatory cytokine signaling at the levels of cytokine expression and secretion as well as receptor expression and soluble receptor activity. The augmentation by EtOH of anti-inflammatory mediators' secretion most likely shifts the cytokine balance in the anti-inflammatory direction.

Fig. 1

Mouse lung TNF-α (A), TNF-Rp55 (C) and TNF-Rp75 (E) mRNA levels and BAL fluid TNF-α (B), TNF-Rp55 (D) and TNF-Rp75 (F) activities following alcohol and lipopolysaccharide treatment. Plotted are means ± SEM for 6 - 8 mice/group. Abbreviations: saline (sal); alcohol (EtOH); lipopolysaccharide (LPS). *) p < 0.05 vs. sal/sal; **) p < 0.05 vs. EtOH/sal; ***) p < 0.05 vs. sal/LPS; ****) p < 0.05 vs. similarly treated 3 h group.

Fig. 2

Mouse BAL fluid IL-1β (A) activity, lung Il-1RI (B) and IL-1RII (D) mRNA levels, and IL-1RI (C) protein expression. Plotted are means ± SEM for 6 - 8 mice/group. Abbreviations: saline (sal); alcohol (EtOH); lipopolysaccharide (LPS); arbitary units (AU). *) p < 0.05 vs. sal/sal; **) p < 0.05 vs. EtOH/sal; ***) p < 0.05 vs. sal/LPS; ****) p < 0.05 vs. similarly treated 3 h group.

Fig. 3

Mouse lung Il-6 (A), IL-6Rα (C) and gp130 (E) mRNA levels, BAL fluid IL-6 (B) activity, and IL-6Rα (D) protein expression. Plotted are means ± SEM for 6 - 8 mice/group. Abbreviations: saline (sal); alcohol (EtOH); lipopolysaccharide (LPS); arbitrary units (AU). *) p < 0.05 vs. sal/sal; **) p < 0.05 vs. EtOH/sal; ***) p < 0.05 vs. sal/LPS; ****) p < 0.05 vs. similarly treated 3 h group.

Fig. 4

Mouse lung MIF (A) mRNA levels and MIF (B) protein expression. Plotted are means ± SEM for 6 - 8 mice/group. Abbreviations: saline (sal); alcohol (EtOH); lipopolysaccharide (LPS); arbitary units (AU). *) p < 0.05 vs. sal/sal; **) p < 0.05 vs. EtOH/sal; ***) p < 0.05 vs. sal/LPS; ****) p < 0.05 vs. similarly treated 3 h group.

Fig. 5

Mouse BAL fluid IL-10 (A), corticosterone (B) and TGF-β1 (C) activities, and lung TGF-β1 (D), TGF-βR1 (E), TGF-β2 (F), TGF-βRII (H) and TGF-β3 (I) mRNA levels. *) p < 0.05 vs. sal/sal; **) p < 0.05 vs. EtOH/sal; ***) p < 0.05 vs. sal/LPS; ****) p < 0.05 vs. similarly treated 3 h group.