Short-term exercise training can improve myocardial tolerance to I/R without elevation in heat shock proteins.

Abstract

We examined the effects of 3 days of exercise in a cold environment on the expression of left ventricular (LV) heat shock proteins (HSPs) and contractile performance during in vivo ischemia-reperfusion (I/R). Sprague-Dawley rats were divided into the following three groups (n = 12/group): 1) control, 2) exercise (60 min/day) at 4 degrees C (E-Cold), and 3) exercise (60 min/day) at 25 degrees C (E-Warm). Left anterior descending coronary occlusion was maintained for 20 min, followed by 30 min of reperfusion. Compared with the control group, both the E-Cold and E-Warm groups maintained higher (P < 0.05) LV developed pressure, first derivative of pressure development over time (+dP/dt), and pressure relaxation over time (-dP/dt) throughout I/R. Relative levels of HSP90, HSP72, and HSP40 were higher (P < 0.05) in E-Warm animals compared with both control and E-Cold. HSP10, HSP60, and HSP73 did not differ between groups. Exercise increased manganese superoxide dismutase (MnSOD) activity in both E-Warm and E-Cold hearts (P < 0.05). Protection against I/R-induced lipid peroxidation in the LV paralleled the increase in MnSOD activity whereas lower levels of lipid peroxidation were observed in both E-Warm and E-Cold groups compared with control. We conclude that exercise-induced myocardial protection against a moderate duration I/R insult is not dependent on increases in myocardial HSPs. We postulate that exercise-associated cardioprotection may depend, in part, on increases in myocardial antioxidant defenses.

0100200'03'05'07'09'11'13'15'17
Citations per Year

910 Citations

Semantic Scholar estimates that this publication has 910 citations based on the available data.

See our FAQ for additional information.

Cite this paper

@article{Hamilton2001ShorttermET, title={Short-term exercise training can improve myocardial tolerance to I/R without elevation in heat shock proteins.}, author={Karyn L Hamilton and Scott K . Powers and Takayuki Sugiura and Sung-Hee Kim and Shannon L. Lennon and Nihal Tumer and Jay L. Mehta}, journal={American journal of physiology. Heart and circulatory physiology}, year={2001}, volume={281 3}, pages={H1346-52} }