Lung and systemic oxidant and antioxidant activity after graded smoke exposure in the rat

We wanted to determine the effect of a graded smoke inhalation on lung and systemic oxidant stress, and its relationship to physiological and histological change. Male Wistar rats were given 12 breaths of 10 ml/kg (n = 8) (group 1) or 20 ml/kg (n = 8) (group 2) tidal volume, using cotton toweling smoke through the trachea using positive pressure. Rats were monitored, then killed at 24 hr. Data were compared to controls (n = 8). Peak group 1 and group 2 carboxyhemoglobins were 22 +/- 6 and 46 +/- 6%, with a mortality prior to 24 hr of 14% and 50%, respectively. Group 1 rats showed only moderate lung dysfunction but with severe airway inflammation and edema, alveolar inflammation and atelectasis, with a decrease in PaO2 from the control of 96 +/- 4 to 72 +/- 5 torr. No increase in lung, liver, or kidney oxidant-induced lipid peroxidation, measured as malondialdehyde lung, liver, or kidney oxidant-induced lipid peroxidation, measured as malondialdehyde (MDA), or decrease in the antioxidant defenses catalase was noted. Group 2 rats demonstrated severe airways edema, alveolar atelectasis, and alveolar edema, and a PaO2 decreasing below 60 torr, corresponding with a 3-fold increase in lung tissue MDA and 35% decrease in catalase. In addition, liver and kidney tissue MDA doubled, and catalase activity decreased by 40%. Increased oxygen consumption was also demonstrated.(ABSTRACT TRUNCATED AT 250 WORDS)