Cardioprotective effect of spontaneous activity.
In the perspective of giving a better understanding of the cardioprotective effects attributable to the tandem low caloric intake and training, Lou/C rats would be an interesting model since these animals exhibit spontaneously these two characteristics for months, without any dietary manipulations or stressor stimuli. No information was so far available on their cardiac function. Therefore, the aim of this pilot study was (i) to document cardiac function before and after ischemia in this strain, and (ii) to investigate whether spontaneous wheel-running activity can improve the ability of cardiac muscle to recover its function after an ischemic period. Cardiac mechanical and metabolic functions were measured in isolated Langendorff hearts from Wistar sedentary, Lou/C sedentary, and Lou/C wheel-running male rats submitted to a 20-min low-flow ischemia and 20-min reperfusion. In Lou/C sedentary rats, rate-pressure product, an index of cardiac work, was decreased before ischemia as compared to Wistar sedentary animals (- 24 %, p < 0.05). After ischemia, cardiac mechanical function recovery did not significantly differ between these two groups. Nevertheless, flux of non-oxidative glycolysis was lower before and after ischemia in Lou/C sedentary animals than in Wistar sedentary rats. In Lou/C rats, during normoxic perfusion, wheel-running activity significantly decreased heart rate (- 15 %), oxygen consumption (- 2.2 %) and cardiac efficiency (- 37 %), whereas coronary flow and flux of non-oxidative glycolysis were significantly increased (+ 15 % and + 263 %, respectively). After ischemia, recovery of cardiac mechanical function and cardiac efficiency were improved in Lou/C wheel-running rats versus Lou/C sedentary animals (p < 0.05). In conclusion, the impact of ischemia-reperfusion is similar between Lou/C- and Wistar sedentary rats. Spontaneous wheel-running activity decreases cardiac efficiency before ischemia and confers a protection against ischemia- and reperfusion-induced injury in isolated Lou/C rat hearts.
Peltier
S
S
Unité de Formation et de Recherche en Activités Physiques et Sportives, Université Joseph Fourier, Grenoble, France. sepeltier@laposte.net
Novel-Chate
V
V
Malaisse
W J
WJ
Molnar
A
A
Leverve
X M
XM
Favier
R
R
D000704:Analysis of Variance; D000818:Animals; D006334:Heart Function Tests; D007773:Lactates / Q000378:metabolism; D008297:Male; D023421:Models, Animal; D017202:Myocardial Ischemia / Q000503:physiopathology* / Q000628:therapy; D010101:Oxygen Consumption / Q000502:physiology; D010805:Physical Conditioning, Animal; D010865:Pilot Projects; D051381:Rats; D011919:Rats, Inbred Strains; D017208:Rats, Wistar; D020127:Recovery of Function
D007773:Lactates