Attenuation of phosphorylated connexin-43 protein levels in diabetic rat heart by regular moderate exercise

High blood glucose levels increase the ratio of phosphorylated to non-phosphorylated connexin-43 amounts, which leads to the decomposition of the hyperphosphorylated connexin-43. This can cause heart arrhythmia in diabetic patients. Considering the effective role of exercise in diabetic patients, and because there are few studies regarding the effect of exercise on phosphorylated connexin-43 protein levels, in the present study the impact of different periods of moderate regular exercise on phosphorylated Connexion-43 levels were examined.

Sixty (60) male Wistar rats (300 ± 50 g) were randomly divided into six groups (n = 10). A week after induction of diabetes by injection of streptozotocin, one hour treadmill exercise, 5 days a week with 22 (m/min) speeds was undertaken. Left ventricles of hearts were isolated and immediately frozen. Finally, phosphorylated connexin-43 protein levels were measured by ELISA method.

The means of blood glucose levels were significantly decreased (P < 0/05) by increasing days of exercise. The means of blood glucose levels were significantly decreased (P < 0/05) by increasing days of exercise. Regular moderate exercise reduced the connexin-43 levels by increasing days of exercise (P < 0.01).

It is concluded that regular moderate exercise reduces the amount of phosphorylated connexin-43 protein levels in the ventricular myocardium, by reducing blood glucose levels. This can result in partial inhibition of cardiac arrhythmia observed in diabetic patients. This research was done in Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran.