Effects of exercise training on myocardial fatty acid metabolism in rats with depressed cardiac function induced by transient ischemia

The effects of exercise training on metabolic and functional recovery after myocardial transient ischemia were investigated in a rat model. Male Wista r Kyoto rats were subjected either to a 30-min left coronary artery occlusi on followed by reperfusion or to a sham operation. At 4 weeks after operati on, the rats were randomly assigned either to sedentary conditions or to ex ercise training for 6 weeks. In the ischemic rats, pinhole SPECT (single ph oton emission computed tomography) imaging with thallium-201 (Tl-201) and I -123-(rho -iodophenyl)-3-R, S-methylpentadecanoic acid (BMIPP) showed a red uction of both myocardial perfusion and fatty acid metabolism in the risk z one of the left ventricle (LV). The LV was dilated and the ejection fractio n was decreased after ischemic injury. The severity score showed a signific ant decrease on both Tl-201 and BMIPP (Tl-201, from 19.9 +/- 2.7 to 17.0 +/ - 2.2, p < 0.05; BMIPP, from 21.5 <plus/minus> 2.4 to 18.6 +/- 1.9, p < 0.0 5) after exercise training in the ischemic trained rats, but did not change significantly in their sedentary counterparts, plasma levels of free fatty acids normalized in the ischemic trained rats, but elevated in the ischemi c sedentary rats (0.53 <plus/minus> 0.05 vs 0.73 +/- 0.06 mmol/L, p < 0.05) . Furthermore, the trained rats had a significant increase in LV stroke vol ume (0.25 <plus/minus> 0.02 vs 0.21 +/- 0.01 ml/beat, p < 0.05) and adaptiv e cardiac hypertrophy. These findings demonstrate that adaptive improvement s in myocardial perfusion, fatty-acid metabolism and LV function were induc ed by exercise training after transient ischemia.