The effect of intravascular complement activation and brief episodes of hypoxia on protein in bronchoalveolar lavage fluid in C5 sufficient and deficient mice

Abstract

Our earlier investigations indicated that systemic complement activation with iv cobra venom factor (CVF) or infused zymosan-activated rabbit plasma or rabbit C5a does not significantly increase bronchoalveolar lavage albumin in rabbits (Am Rev Respir Dis 1982; 125:335-340); but that complement activation due to CVF combined with a brief episode of hypoxia increases lavage albumin and is associated with the presence of neutrophils for its expression (J Clin Invest 1985; 75:902-910). In order to determine if intravenous CVF and hypoxia cause similar alterations in mice, and to investigate the time course of the response as well as the importance of C5 fragments to the process, we challenged the B10.D2/nSn strain of C5 sufficient mice (C5+) and the congenic B10.D2/oSn strain of C5 deficient mice (C5-) with intravenous CVF, 15 min of 12% oxygen, or CVF followed by hypoxia. Neither C5+ nor C5- mice had significant increases in lavage protein after either CVF or hypoxia. However, the combined insults significantly increased lavage protein in C5+ but not C5- mice; polyacrylamide gel electrophoresis showed increased amounts of proteins of low and high molecular weights in lavage fluid from the C5+ strain. While the time course of abnormalities in mice was different from that in rabbits, both meclofenamate pretreatment and neutrophil depletion attenuated the increases in lavage protein after the combined insults in both animal species. Infusion of prostaglandin E2 (PGE2) with CVF in the C5+ mice also led to significant increases in lavage protein. We conclude that in mice, intravenous complement activation, as an isolated event, does not cause a significant increase in lavage protein.(ABSTRACT TRUNCATED AT 250 WORDS)