Changes in Titin and Collagen Modulate Effects of Aerobic and Resistance Exercise on Diabetic Cardiac Function

Diastolic dysfunction is a common complication that occurs early in diabetes mellitus. Titin and collagen are two important regulators of myocardial passive tension, which contributes to diabetic myocardial diastolic dysfunction. Exercise therapy significantly improves the impaired diabetic cardiac function, but its benefits appear to depend on the type of exercise used. We investigated the effect of aerobic and resistance exercise on cardiac diastolic function in diabetic rats induced by high-fat diet combined with low-dose streptozotocin injection. Interestingly, although resistance training had a more pronounced effect on blood glucose control than did aerobic training in type 2 diabetic rats, improvements in cardiac diastolic parameters benefited more from aerobic training. Moreover, aerobic exercise did significantly increase the expression levels of titin and decrease collagen I, TGFβ1 expression level. In summary, out data suggest that aerobic exercise may improve diabetic cardiac function through changes in titin-dependent myocardial stiffness rather than collagen-dependent interstitial fibrosis.