Long-term ethanol consumption leads to lung tissue oxidative stress and injury

Background: Alcohol abuse is a systemic disorder. The deleterious health effects of alcohol consumption may result in irreversible organ damage. By contrast, there currently is little evidence for the toxicity of chronic alcohol use on lung tissue. Hence, in this study we investigated long-term effects of ethanol in the lung. Results: Though body weight of rats increased significantly with duration of exposure compared to its initial weight, there was no significant change in relative weight (g/100 g body weight) of lung due to ethanol exposure. The levels of thiobarbituric acid reactive substances (TBARS), nitrite, protein carbonyl, oxidized glutathione (GSSG), redox ratio (GSSG/GSH) and GST activity elevated; while reduced glutathione (GSH) level and activities of glutathione reductase (GR), glutathione peroxidase (GPx), catalase, superoxide dismutase (SOD) and Na(+)K(+)ATPase reduced significantly with duration of ethanol exposure in the lung homogenate compared to the control group. Total matrix metalloproteinase activity elevated in the lung homogenate with time of ethanol consumption. Histopathologic examination also demonstrated that severity of lung injury enhanced with duration of ethanol exposure. Methods; 16-18 week-old male albino Wistar strain rats weighing 200-220 g were fed with ethanol (1.6 g/kg body weight/day) up to 36 weeks. At the end of the experimental period, blood samples were collected from reteroorbital plexus to determine blood alcohol concentration and the animals were sacrificed. Various oxidative stress-related biochemical parameters, total matrix metalloproteinase activity and histopathologic examinations of the lung tissues were performed. Conclusions: Results of this study indicate that long-term ethanol administration aggravates systemic and local oxidative stress, which may be associated with lung tissue injury.