Journal of Applied Physiology, Vol 64, Issue 2 689-696, Copyright © 1988 by American Physiological Society
Subcellular changes in capillary endothelial cells during repair of hyperoxic lung injury
J. P. Mastin, J. D. Shelburne and L. A. Thet
Department of Medicine, Duke University Medical Center, Durham, North Carolina.
We studied the changes in subcellular ultrastructure associated with the
hypertrophy of capillary endothelial cells during repair of hyperoxic (100%
O2) lung injury in rats. We used stereologic-morphometric measurements at
different magnifications to determine the absolute volume of each
subcellular compartment per average capillary endothelial cell. The
increases in this value during the first 3 days of postexposure repair were
118% for cytoplasm, 786% for polyribosomes, 310% for rough endoplasmic
reticulum, and 79% for mitochondria; the volume of pinocytotic vesicles did
not change. By day 7 of repair, only the polyribosomes and rough
endoplasmic reticulum were still increased; by day 14 all values were
normal. We conclude that the capillary endothelial cell hypertrophy that
develops during repair of hyperoxic lung injury is associated with large
and heterogeneous increases in subcellular organelles and is not merely due
to increases in the cytosol or to cellular edema. These increases seem to
be an integral part of the repair process and may be important in the
development of tolerance to subsequent oxygen exposure.
