Capillary perfusion pattern and microvascular geometry in heterogeneous
hypoxic areas of hypoperfused rat myocardium .
Vetterlein, Friedrich, Michael Prange, Detlef Lubrich, Joachim Pedina, Marion
Neckel, and Gerhard Schmidt, Zentrum Pharmakologie Und Toxikologie Der
Universit[umlaut]at G[diaeresis]ottingen, Germany.
F. Vetterlein, Zentrum Pharmakologie und Toxikologie, Robert-Koch-Stra[beta]e
40, D-37075-G[diaeresis]ottingen, Germany, Phone: -551 395308, Fax -551 399652
APStracts 2:0002H, 1995.
The origin of heterogeneities in tissue oxygenation due to low-flow ischemia
was studied in hypoperfused myocardium of anesthetized rats. In frozen
sections of myocardial biopsies the localization of increases in NADH
fluorescence, an indicator of tissue hypoxia, was compared with microvascular
flow distribution and capillary geometry. The latter parameters were
accomplished through capillary labeling with indicator dyes in vivo and
enzyme-histochemical staining in vitro, respectively. Most NADH-fluorescent
areas were found to have developed despite sustained capillary flow. When the
fractions of arterial, venous, and intermediate capillary segments were
analysed within circumscribed hypoxic fields (<200 [mu]m diam.), frequencies
of 30.7+/-6.1%, 35.3+/-5.3%, and 30.8+/-5.0%, respectively, were found. In
contrast, a significantly higher fraction of arterial segments (63.2+/-3.3%)
and a lower percentage of venous segments (16.4+/-2.5%) were determined in
non-hypoxic islands enclosed by hypoxic tissue. These results support the view
that the latter zones are located near the arterial portion of the capillary
bed where their oxygenation is favored during low-flow states. This effect
appears to contribute to the supply heterogeneities in hypoperfused
myocardium.
Received 22 April 1994; accepted in final form 5 January 1995.
APS Manuscript Number H0356-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 24 February 1995.