An inhibitor of lipid peroxidation in rat lungs

Cellular and biochemical indices of bronchoalveolar lavage for detection of lung injury following insult by airborne toxicants

Cellular and biochemical profiles of bronchoalveolar lavage (BAL) material after inhalation or intratracheal exposure to various airborne toxicants clearly reflect that BAL has the potential of being a useful tool for the rapid screening of lung injury. The cellular and biochemical responses not only predict inflammation, extent of tissue damage and toxic nature of the substances, but could also help in understanding the molecular mechanisms of pathogenicity. Depending upon the changes of BAL in animals acutely exposed to a pulmonary toxicant, future in-depth studies along with complete histopathological evaluations could be made. Also, the assessment of macromolecules of pharmacological importance in the lavage, especially the secretory products of alveolar macrophages and other lung cell types, could be very useful in predicting the toxic potential of various airborne substances and could also serve as important indicators of developing chronic lung diseases and, therefore, necessitate further studies.

A highly sensitive gas chromatographic method does not detect exhalation of volatile hydrocarbons from isolated ventilated lungs under massive peroxidative stress

Lung lipid peroxidation is thought to be a basic pathophysiological phenomenon responsible for pulmonary damage in different types of oxidant attack. Measurement of volatile hydrocarbons, especially ethane and pentane, produced during peroxidative degradation of polyunsaturated fatty acids and exhaled into an animal housing chamber, has attracted increasing interest for the monitoring of in vivo lipid peroxidation. However, this approach cannot distinguish between pulmonary exhalation of hydrocarbons generated in different organs or even the intestinum and pulmonary generation of these lipid peroxidation markers. In the present study we developed a respiration and hydrocarbon trapping system for isolated, ventilated, and perfused lungs that avoided rebreathing and allowed complete sampling and gas chromatographic separation and quantification of exhaled alkanes and alkenes (C1-C5) in the absence of background levels. Using an "artificial lung," the recoveries of exogenously administered hydrocarbons ranged between 80 and 95% with good reproducibility (SD between 1.7 and 9.6%). The detection limit of the system was approximately 3 fmol of each alkane or alkene/g wet lung weight.min. However, neither under basal conditions nor during massive peroxidative stress by the application of high doses of H2O2, FeCl3/ascorbate, paraquat, or ozone was any material with a retention time similar to that of hydrocarbons exhaled from isolated rabbit lungs. We conclude that under the experimental conditions employed, there is only insignificant generation of hydrocarbons in intact lungs.

Detection of Organic Hydroperoxides in Rabbit Lung Lavage Fluid, but not in Lung Tissue Homogenate, Using GSH Peroxidase and GSH Reductase

A specific method for the detection of organic hydroperoxides in lung lavage fluid (lung surfactant system) and lung tissue homogenate is described. After the inactivation of endogenous GSH peroxidase and GSH reductase and preincubation with catalase, organic hydroperoxides are consumed by addition of GSH and GSH peroxidase. The increase of GSSG, compared to a blank without addition of GSH peroxidase, is measured in a second enzymatic step with GSH reductase. The recoveries of t-butyl hydroperoxide and of peroxidized, free fatty acids added to lavage fluid or to lung homogenate are higher than 85% in each case. The detection limits of this assay for organic hydroperoxides are 0.9 nmol/mg surfactant phospholipid (molar ratio of 0.00066) and 40 nmol/g wet lung weight. The assay detects organic hydroperoxides in the surfactant system of normal rabbit lungs, but not in lung tissue homogenate.