| Abstract: | In order to evaluate the effect of paraquat on oxidative radical reactions in the lung, we studied MDA production and chemiluminescence (spontaneous and tBuOOH-induced) in the isolated rat lung. After 2 hr of perfusion with 3.0 mM paraquat, MDA content in lung homogenates was 16 +/- 7 nmol/gm dry weight higher than in control lungs (mean +/- S.E., n = 7, p less than 0.05 by paired test); during 30 min of perfusion, malondialdehyde efflux was 33 +/- 15 nmol/gm dry weight higher than in control perfusates (n = 6, p less than 0.05). Spontaneous chemiluminescence was not augmented by 2 hr of perfusion with concentrations of paraquat ranging from 0.75 to 6.0 mM. On the other hand, tBuOOH-induced chemiluminescence was 17% +/- 3 higher immediately after the addition of hydroperoxide and reached a 16% +/- 6 higher plateau for the paraquat-perfused lungs than for control lungs (n = 10, p less than 0.05). Spectral analysis of the light emitted during induced chemiluminescence demonstrated peak intensity between 630 and 730 nm for both control and paraquat-treated lungs. Increased MDA production and increased induced chemiluminescence indicate that perfusion with paraquat enhances lipid peroxidation in the isolated rat lung. |
