AJP - Lung Cellular and Molecular Physiology, Vol 269, Issue 1 52-L58, Copyright © 1995 by American Physiological Society
Hypoxia and reoxygenation stimulate biphasic changes in endothelial monolayer permeability
C. A. Partridge
Department of Biochemistry and Molecular Biology, Albany Medical College, New York 12208, USA.
Incubation of bovine pulmonary microvascular endothelial (BPMVE) cells in
low O2 content (95% N2-5% CO2) for 4 h increased monolayer permeability to
dextran almost twofold and also increased the incidence of intercellular
gaps and intracellular actin stress fibers. Hypoxic incubation decreased
the extracellular matrix contents of fibronectin and vitronectin, proteins
that serve as anchorage points for the endothelial cells. This state was
reversed after 24 h of hypoxic incubation, and the BPMVE monolayer
permeability to dextran was less than that of normoxic controls. The
monolayer had fewer intercellular gaps and stress fibers, and the
extracellular matrix contained increased amounts of fibronectin,
vitronectin, and type I collagen. These alterations stimulated by 24 h of
hypoxic incubation were resolved within 4 h of reoxygenation in room air
supplemented with 5% CO2. These studies indicate that incubation of
endothelial monolayers in hypoxic conditions first increases and then
decreases monolayer permeability, through increased and decreased formation
of intercellular gaps.
