Rapid Publications Intact Human Erythrocytes Prevent Hydrogen Peroxide-mediated Damage to Isolated Perfused Rat Lungs and Cultured Bovine Pulmonary Artery Endothelial Cells

Portions ofthe work were presented by Ms. Toth at the Annual Meeting ofthe Western Society for Clinical Investigation, where she was awarded the Western Section-American Federation of Clinical Research Medical Student Pulmonary Subspecialty Prize. The work has also been selected for presentation at meetings of the American Society for Clinical Investigation and at the National Medical Student Research Forum. Address correspondence to Dr. Repine. Received for publication 24 February 1984. 1. Abbreviations used in this paper: ARDS, adult respiratory distress syndrome; AMT-catalase, 3-amino-1:2:4-triazole; DDC-RBC, diethyldithiocarbamic acid pretreated RBC; DMTU, dimethylthiourea; RBC, erythrocyte; GLUT-RBC, glutaraldehyde pretreated RBC; H202, hydrogen peroxide; HX, hypoxanthine; LDH, lactatedehydrogenase; M199, serum-free medium 199; SOD, superoxide dismutase; XO, xanthine oxidase. recent evidence suggests that toxic oxygen metabolites may contribute to endothelial cell injury and acute edematous lung injury (1). The source of these 02 metabolites is unclear, but they may be made by lung cells and/or by neutrophils that have been recruited to the lung and activated (1). Erythrocytes (RBC) are also commonly seen in intravascular, interstitial, and alveolar spaces during the development of ARDS but their significance is unknown (1-3). However, since RBC contain large amounts of superoxide dismutase (SOD), catalase, glutathione peroxidase, and reduced hemoglobin, which could scavenge 02 metabolites (4-10), we hypothesized that RBC could decrease acute edematous lung injury that was caused by 02 metabolites. We tested this premise in three systems. First, we perfused isolated rat lungs with varying concentrations of human RBC and then exposed these lungs to superoxide anion and hydrogen peroxide (H202), which were generated by hypoxanthine (HX) and xanthine oxidase (XO). Second, we measured the effect of adding RBC on H202-mediated damage to cultured bovine pulmonary artery lung endothelial cells. Third, we assessed the influence of RBC on H202-dependent oxidation of reduced cytochrome C in vitro. Our results show that RBC decrease acute edematous injury in isolated lungs that were perfused with HX and XO, decrease damage to cultured endothelial cells treated with H202, and decrease oxidation of cytochrome C by H202 in vitro.