Effects Of Endurance Exercise Training On The Cardiac Function Quantification By Echocardiography In STZ-DM Rats

Abstract

Many studies have demonstrated that diabetes mellitus (DM) is associated with cardiac dysfunction. Exercise training is beneficial for the treatment of chronic heart failure. PURPOSE: the aim of the present study was to evaluated effects of endurance exercise training (EX) on cardiac function quantification by echocardiography in DM rats. We also evaluated the levels of connexin 43 of the heart. METHODS: the Sprague-Dawley (SD) male rats were divided into 3 groups as two experimental groups and one control group. The first groups as a control group received adjuvant. The second and third groups were the DM groups, received 150 mg/kg STZ by intraperitoneal injection. After one week, EX was carried out in the third group (DM-EX group) for four weeks. The cardiac functions of those animals were evaluated by echocardiography method. The animals were sacrificed; the connexin 43 of heart was evaluated by western blot. The tissues of heart were stained by H&E or Masson’s trichrome stain. The morphology and fibrosis of cardiac cells were analyzed. RESULTS: the results show that the distances of interventricular septal and left ventricular (LV) posterior wall were shorter in DM and DM-EX groups than in control group (P<0.05). The LV diameter was longer in DM-EX group than in control group (P<0.05). The weights of rat’s body, heart and LV mass were lower in DM and DM-EX groups than in control group (P<0.05). The values of heart and LV mass weighted by body mass were higher in DM group than in control group (P<0.05). The heart connexin 43 was lowest in DM group than in control and DM-EX group (P<0.05). The length of cardiomyocyte diameter was longer in DM and DM-EX group than in control group (P<0.05). The percent of fibrotic area in heart tissue was highest in DM group than in others (P<0.05). The fibrotic area of heart was smaller in DM-EX group than in DM group (P<0.05). CONCLUSIONS: those results suggested that EX may decrease cardiac dysfunction from DM damage through connexin 43 increasing and lower myocardial fibrosis.