Enhanced post-ischemic myocardial recovery following exercise
induction of hsp 72.
Locke, Marius, Robert M. Tanguay, Richard E. Klabunde, and C. David
Ianuzzo.
Deborah Research Institute, Browns Mills, NJ, 08015, USA and MGM,
Centre de recherches du CHUL and Laboratoire de
G[acute]en[acute]etique Cellulaire et d[acute]eveloppementale RSVS,
Pavillon C. E. Marchand, Universit[acute]e Laval, Ste Foy,
Qu[acute]ebec, G1K 7P4, Canada
APStracts 2:0103H, 1995.
The inducible isoform of the 70 kDa heat shock protein (HSP) family,
HSP 72, has been shown to protect cells from protein damaging
stressors and has been associated with myocardial protection. Since
exercise is capable of increasing HSP 72 content, we determined if
exercise induction of HSP 72 also provided myocardial protection.
Twenty-eight rats (n=7 per group) were divided in control, heat
shocked (15 min at 42 degrees C), and two exercised groups. Exercise
consisted of either one bout or three bouts (on three consecutive
days) of treadmill running for 60 min at 30 m/min. Twenty-four hours
after heat shock or exercise, hearts were placed on a Langendorff
apparatus and subjected to 30 min of global ischemia followed by 30
min of reperfusion. Left ventricular developed pressure (LVDP),
maximal rate of contraction and relaxation (+/-dP/dt), coronary flow,
catalase activity and HSP 72 content were determined. During
reperfusion, hearts from heat shocked animals and animals subjected
to 3 bouts of exercise, recovered a greater percentage of pre
-ischemic LVDP and +/-dP/dt compared to controls or animals that
exercised only once. Compared to hearts from controls, HSP 72 content
was significantly elevated in the hearts of heat shocked animals, and
in animals subjected to 3 bouts of exercise, but not in animals that
exercised only once. These results suggest that exercise induction of
HSP 72 can confer an enhanced post-ischemic recovery and may explain,
at least in part, the myocardial protection associated with exercise.
Received 15 November 1994; accepted in final form 1 February
1995.
APS Manuscript Number H1022-4.
Article publication pending Am. J. Physiol. (Heart Circ. Physiology).
ISSN 1080-4757 Copyright 1995 The American Physiological Society.
Published in APStracts on 4 April 1995.