ABSTRACT
Objective: To explore the effect of exercise preconditioning (EP) on pathological cardiac hypertrophy and heart failure (HF) in pressure over-loaded experimental rats. Methods:A total of 60 SD rats at the age of 6 weeks were randomly divided into 3 groups, n=20 in each group. Sham-operation group, Transverse aortic constriction (TAC) group and EP + TAC group. The cardiac function and structure were evaluated by echocardiography, patholgical changes and HF biomarkers were examined for EP effect at 4 and 8 weeks after TAC. Results:Compared with Sham-operation group, the cardiac function and structure had obvious changes in the other 2 groups. Compared with TAC group, the ejection fraction in EP+ TAC group increased 15%, the heart weight index and left ventricular weight index decrease 15.7%and 20%respectively at 8 weeks after TAC, all P Conclusion: EP may improve cardiac pathological hypertrophy in pressure over-loaded rats at the early stage, and delay the heart failure process.
ABSTRACT
Objective: To explore a novel animal model of physiological cardiac hypertrophy induced by long-term passive wheel running. Methods: Forty male Sprague-Dawley rats were randomly divided into four groups (n=10): normal control group, passive wheel running(PWR) group, sham operation group, and transverse aortic constriction(TAC) group.PWR group received passive wheel movement training, TAC group received aortic arch narrow operation, sham operation group did not receive ligature thoracic aorta, and other treatments were similar to that of TAC group; no treatment was given to the normal control group. Five weeks after training or operation, a comparison was made between different groups. The modeling results of PWR were assessed by echocardiography, morphology, and molecular hypertrophic-markers for heart failure. Results: Echocardiography findings showed that thickness of the left ventricle wall in PWR group was significantly increased compared with the normal control group, and that in the TAC group was significantly increased compared with the sham operation group (P<0.01); the stroke volume and ejection fraction were also significantly different between PWR and normal control group and between the TAC group and sham operation group(P<0.01). The left ventricle internal diameter at end-diastole was not significantly different from that of normal control group, but that in the TAC group was decreased by 38% compared with the sham operation group (P<0.01), indicating that the cardiac structures were significantly different between PWR and TAC groups. Compared with the normal control group, the heart weight/body weight ratio, left ventricular weight/body weight ratio and lung weight/body weight ratio were increased by 25.0%, 37.3% and 23.8% in PWR rats, respectively; compared with the sham group, the above indicators were increased by 31.6%, 38.8% and 56.6% in TAC rats, respectively(P<0.05 or P<0.01). Compared with the normal control group, the expression levels of atria natriuretic peptide (ANP)and brain natriuretic peptide (BNP)were 0.67-fold and 0.48-fold of those in PWR group(P<0.05), and those in the TAC group were 1.98-fold and 2.03-fold those of the sham operation group (P<0.05). Conclusion: Long-term PWR training can induce physiological cardiac hypertrophy in rats, which may provide a novel way for establishing physiological cardiac hypertrophy animal models.