Effects of various molecular weight dextrans on microvascular
ischemia-reperfusion injury in striated muscle.
Steinbauer, M., A. G. Harris, K. Messmer.
Institute for Surgical Research, University of Munich, Germany
APStracts 3:0512H, 1996.
The objectives of this study were 1) to elucidate the effect of
dextrans (Dx) at a non-hemodiluting dosage of 5 mg/kg on
ischemia/reperfusion (I/R) injury in striated muscle and 2) to
investigate, whether the effects are dependent upon the molecular
weight of Dx. We used the model of a 4 h pressure induced ischemia in
the hamster skinfold chamber. By means of intravital microscopy
following parameters were assessed: vessel diameter, red blood cell
velocity, rolling and adherent leukocytes, macromolecular
extravasation and functional capillary density (FCD). The animals
received a continuous infusion (total dose 5 mg/kg) of dextran of
different molecular weights or equivalent volumes of saline. Seven
groups were studied NaCl: (Control, n=6), Dx 1(n=6), Dx 40 (n=7), Dx
60 (n=6), Dx 70 (n=7), Dx 110 (n=7) and Dx 150 (n=7). Leukocyte
rolling was reduced by all Dx fractions - the difference to control
reaching significance level 0.5 h after reperfusion in the Dx 60, 70
and 110 group - whereas leukocyte adherence was attenuated by Dx of a
MW > 40,000 0.5 h after reperfusion. Concomitantly, FCD tended
to improve after Dx-treatment with a MW of 40.000 and higher.
However, all dextran fractions studied failed to reduce postischemic
macromolecular extravasation. These results provide evidence that a
dose of 5 mg/kg Dx attenuates postischemic microvascular
disturbances; this effect is molecular weight dependent.
Received 13 November 1995; accepted in final form 18 November
1996.
APS Manuscript Number H1059-5.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 31 December 1996