COMPARISON OF ANTIOXIDANT SUBSTANCES IN BRONCHOALVEOLAR LAVAGE CELLS AND FLUID FROM HUMANS, GUINEA-PIGS, AND RATS

Antioxidants located in the lining layer of the respiratory tract may be important in determining sensitivity of lung tissues to inhaled pol lutants. This study addressed species differences in the amounts of as corbic acid (AH-2), glutathione (GSH), uric acid (UA), and alpha-tocop herol (AT) in bronchoalveolar lavage (BAL) fluid and cells of humans, guinea pigs, and rats. Protein and lipid phosphorus (lipid P) were use d as normalizing factors. More than 90% of the lavageable AH-2, UA, GS H, protein, and lipid P was present in the extracellular fraction of B AL in rats and guinea pigs, while over 95% of the lavageable AT was lo cated in the BAL cells. BAL fluid AH-2/protein in rats was 7- to 9-fol d higher than in humans and guinea pigs. However, human BAL fluid had 2- to 8-fold higher UA/protein, GSH/protein, and AT/protein ratios tha n rats and guinea pigs. In BAL cells, rats had higher AH-2/protein and AT/protein ratios than guinea pigs and humans, and both rats and guin ea pigs had higher GSH and AT/protein ratios than humans. Individual v ariability among humans in the BAL fluid and cellular antioxidants was generally greater than in the laboratory animals. These data demonstr ate that some large species differences exist in BAL fluid and cellula r antioxidants which could affect susceptibility to oxidant pollutants .