The Effects Of Exercise Training On Hypertensive Heart Function And Its Mechanism

Objective:To investigated the effects of exercise training on blood pressure,heart function,cardiomyocyte contractility and myofilament Ca2+ sensitivity in hypertensive rats.Methods:The rats were divided into four groups randomly:hypertension group,hypertension exercise group,sham operation group,sham operation group.Hypertension is induced by angiotensin II.Noninvasive blood pressure multiple animal tail cuff technique was used to monitor blood pressure in rats.The left ventricular ejection fraction was detected by cardiac ultrasound.Isolated Myocardial cells were detected by IonOptix single cell shrinkage detection system.It is showed that contractile properties of cardiomyocytes and the sensitivity of cardiac muscle filament calcium.Results:(1)Blood pressure:There was statistically different in systolic blood pressure in the exercise training group compared with the sham group after exercise training 2weeks(P<0.05).Systolic blood pressure was significantly controlled in the exercise training group.There was no obvious difference between the sham groups in systolic pressure(P>0.05).There were significant difference between diastolic hypertension group and diastolic hypertension exercise training group(P<0.05),the diastolic pressure of hypertension group was obviously controlled.There was also have no significant difference in diastolic blood pressure between the sham group(P>0.05);(2)Left ventricular ejection fraction(LVEF):After exercise training,there were significant differences in LVEF between them(P<0.05).The left ventricular ejection fraction was higher in the exercise training hypertension group than in the hypertensive group rats group;LVEF in rats increased significantly after exercise training;(3)myocardial contractility:After exercise training,there was significant difference between the myocardial contractility and the contraction of myocardium in the hypertensive exercise group(P<0.05).This shows that after exercise training,the myocardial contractility of rats is obviously restored;(4)myofilament Ca2+ sensitivity:After exercise training,the length of sarcomere shortening Ca2+ concentration curve to the left in the exercise training group.EC50 hypertension group and hypertension exercise after exercise training group there were significant differences between EC 50,(P<0.05),and the EC50 shorten in exercise training.Conclusion:Exercise training could control hypertension systolic and diastolic blood pressure of rats effectively;Exercise training could improve contractility and cardiac function of myocardial cells by restoring the sensitivity of Ca2+ in myocardial cells...