Journal of Applied Physiology, Vol 42, Issue 4 501-507, Copyright © 1977 by American Physiological Society
Myocardial Feulgen-DNA levels and capillary vascularization in hypoxia-exposed rats
A. J. Stere and A. Anthony
Male abino rats were exposed to simulated altitude of 18,000 ft (380 Torr)
for 1 day to 8 wk. Histological sections of heart ventricles were stained
by the Feulgen technique and amounts of Feulgen-DNA were determined
cytophotometrically. Heart weights, relative to body weights, increased
over controls at all exposure periods, as did myocardial capillary
vascularization. Ninety percent of cardiac muscle nuclei were found to
contain tetraploid amounts of DNA. All nuclei exhibited a high degree of
chromatin dispersion in exposed and unexposed rats, which reflects a highly
reactive metabolic state of cardiac cells in both groups. There was no
evidence of increased ploidy or increased DNA synthesis associated with
hypertrophy after acute or chronic hypoxia exposure. The data suggest that
an initial event which could facilitate augmented protein synthesis during
hypoxia acclimation appears to be an increased availability of oxygen
and/or nutrients brought about by an expansion of the capillary bed and
vascular proliferation.
