Inhaled nitric oxide injures the pulmonary surfactant system of
lambs in vivo.
Matalon, S., V. Demarco, I. Y. Haddad, C. Myles, J. W. Skimming, S.
Sch[umlaut]urch, S. Cheng, and S. Cassin.
Departments of Pediatrics, Anesthesiology, and Physiology and
Biophysics, University of Alabama at Birmingham, Birmingham, Alabama
35233, Departments of Physiology and Pediatrics, University of
Florida, Gainesville, Florida, 32610 and Respiratory Research Group,
University of Calgary, Calgary, Alberta, T2N 4N, Canada
APStracts 2:0166L, 1995.
Nitric oxide (.NO) is a free radical, and as such may damage the
pulmonary surfactant system. To determine the potential toxicity of
.NO in vivo, we exposed 35 newborn lambs to 0, 20, 80 or 200 ppm .NO
in either 21% or 60% O2 for six h. At the end of the exposure, lambs
had normal values of arterial PO2, PCO2, and pH; total protein
concentration in the bronchoalveolar lavage was also at normal
levels. There were no differences in the surface properties of
surfactant among the air or 60% O2 groups. Pulmonary surfactant
samples, isolated from the bronchoalveolar lavage of lambs breathing
air or 20 ppm .NO, and reconstituted at a lipid concentration of 3
mg/ml, reached a low minimum surface tension (Tmin<3 mN/m) in an
pulsating bubble surfactometer. On the other hand, abnormal surface
properties were observed in 36% and 60% of surfactant samples
isolated from lungs of lambs that breathed 80 or 200 ppm .NO
respectively. These findings were confirmed using a captive bubble
surfactometer. Surfactant protein A, isolated from the lungs of lambs
that breathed 200 ppm .NO, exhibited decreased ability to aggregate
lipids in vitro. These data are consistent with injury to the
surfactant apoproteins during inhalation of either 80 or 200 ppm .NO
for 6 h.
Received 12 July 1995; accepted in final form 1 September 1995.
APS Manuscript Number L220-5.
Article publication pending Am. J. Physiol. (Lung Cell. Mol.
Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 23 September 1995.