Ischemic preconditioning attenuates postischemic leukocyte adhesion
and emigration.
Akimitsu, Tadafumi, Dean C. Gute, and Ronald J. Korthuis.
Department of Physiology and Biophysics, Louisiana State
University, School of Medicine in Shreveport, Shreveport, LA
71130
APStracts 3:0181H, 1996.
Intravital microscopy was used to determine whether ischemic
preconditioning (IPC, 5 min ischemia and 10 min reperfusion) would
attenuate leukocyte adhesion and emigration induced by subsequent
prolonged ischemia (60 min) and reperfusion (60 min) (I/R) in murine
cremaster muscle and whether adenosine produced during the period of
preconditioning ischemia and/or reperfusion contributed to these
beneficial effects. I/R elicited a marked increase in the number of
adherent and emigrated leukocytes as compared to the nonischemic
control muscles, effects that were largely prevented by IPC.
Superfusion of the cremaster with adenosine deaminase (ADA) only
during the period of preconditioning ischemia or only during 60-min
reperfusion attenuated the inhibitory effect of IPC on postischemic
leukocyte adhesion and emigration. On the other hand, the beneficial
effects of IPC were mimicked in cremasters preconditioned with
adenosine (topical application for 10 min beginning 20 min prior to
the onset of prolonged ischemia). Similar results were obtained in
experiments in which adenosine was topically applied to the cremaster
only during the 60 min reperfusion period. Our findings suggest that
the ability of IPC to attenuate postischemic leukocyte adhesion and
emigration may be mediated by adenosine released during
preconditioning ischemia and during reperfusion following prolonged
ischemia.
Received 9 February 1996; accepted in final form 18 April 1996.
APS Manuscript Number H132-6.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 8 May 96