Exercise training attenuates aging-associated increases in collagen and collagen crosslinking of the left but not the right ventricle in the rat

The purpose of this study was to compare the independent and interactive effects of age and exercise training on selected parameters of the right ventricle (RV), left ventricular septum (LVS) and left ventricular free-wall (LVFW) extracellular matrix. Specifically, we evaluated collagen and collagen crosslinking (hydroxylysylpyridinoline, HP) concentrations in the myocardial extracellular matrix in young adult, Y (5.5 months) and old, O (25.5 months) male Fischer 344 rats. Rats were assigned to either a sedentary control (YC, OC) or an exercise training group (YT, OT). Rats were trained for 45 min/day, 5 days/week, for 10 weeks at approximately equals 70% of maximal oxygen consumption. Following the training regimen, rats were sacrificed and their hearts were dissected into the RV, LVS and LVFW. Training resulted in a significant hypertrophy of the left ventricle (LV) but not RV relative to body weight. In young rats, collagen concentration was significantly higher (P