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Updated: Sep 25, 2026
Methods for the Determination of Rates of Glucose and Fatty Acid Oxidation in the Isolated Working Rat Heart
Published on: September 28, 2016
Effect of exercise training on the ability of the rat heart to tolerate hydrogen peroxide
Ryan P Taylor1, Joseph T Ciccolo, Joseph W Starnes
1Cardiac Metabolism Laboratory, Department of Kinesiology and Health Education, 222 Bellmont Hall, The University of Texas at Austin, Austin, TX 78712, USA.
Objective:
The purpose of this study was to determine whether exercise training could precondition the myocardium against hydrogen peroxide (H(2)O(2))-induced damage.
Methods:
Male Fischer 344 rats ran on a treadmill for 9 weeks (60 min/day, 22 m/min, 6 degrees grade, 5 days/week). Isolated perfused working hearts from exercise trained (ET, n=8) and sedentary (SED, n=10) animals were perfused with 150 microM H(2)O(2).
Results:
Pre-H(2)O(2) baseline values for cardiac external work (COxSP), coronary flow (CF), and lactate dehydrogenase (LDH) release were similar between groups. At 5 min of H(2)O(2), COxSP was unchanged from baseline but CF was increased 30% in SED and 46% in ET (P<0.05 vs. SED). COxSP began to decline similarly thereafter in both groups, dropping to 20% of baseline at 20 min. CF in ET remained higher than SED throughout (P<0.05). LDH leakage remained near baseline during the first 15 min of H(2)O(2) exposure, but was elevated (P<0.05) 72% in SED and 40% in ET after 20 min, and was 2.2-fold greater in SED than ET (P<0.05) after 25 min. Heat shock protein 70 was 2.1-fold greater in ET than SED (P<0.05), but ET did not change catalase and glutathione peroxidase.
Conclusions:
The results of this study indicate that chronic moderate exercise will enhance coronary flow and attenuate the development of myocardial injury when exposed to H(2)O(2), but will not affect H(2)O(2)-induced decrease in pump function.
