Journal of Applied Physiology, Vol 65, Issue 1 235-241, Copyright © 1988 by American Physiological Society
Superoxide dismutase and cytochrome oxidase in collapsed lungs: possible role in reexpansion edema
R. M. Jackson, A. L. Brannen, C. F. Veal and J. D. Fulmer
Birmingham Veterans Administration Medical Center 35233.
This study examined the effects of lung collapse, a condition that causes
relative hypoxia in lung tissues, on superoxide dismutase (SOD), cytochrome
oxidase (cyt ox), and pyruvate kinase (py ki) activities in rabbits.
Cyanide-insensitive respiration measurements were done in collapsed and
contralateral lungs, as an index of intracellular free radical production.
Rabbits' right lungs were collapsed for 7 days after which the animals were
killed. We found that control rabbit lungs contained approximately 25 SOD
units/mg DNA measured with 10(-5) M KCN (total SOD) and approximately 11
SOD units/mg DNA measured with 10(-3) M KCN (mitochondrial or MnSOD). Right
lung collapse caused a 25% decrease in mitochondrial SOD activity after 7
days (P less than 0.05), whereas no significant changes occurred in right
or left lungs' total SOD activity. In control rabbits cyt ox activity
averaged approximately 0.009 mumol ferrocytochrome c.min-1.mg DNA-1. Right
lung collapse caused a greater than 40% decrease in cyt ox activity after 7
days of collapse (P less than 0.05), whereas cyt ox activity in
contralateral left lungs did not change. Pyruvate kinase activity, a marker
for anaerobic glycolysis resulting from tissue hypoxia, increased 49% in
collapsed right lungs (P less than 0.01). Cyanide-insensitive respiration
was 83% higher in 7 day-collapsed lungs (2.28 +/- 0.66 microliters
O2.min-1.g-1) compared with contralateral lungs (1.24 +/- 0.34, P less than
0.05), indicating increased O2-. and H2O2 production in this tissue after
homogenization at normoxic PO2 (approximately 150 Torr).(ABSTRACT TRUNCATED
AT 250 WORDS)
