Long-term passive wheel running-induced rat model of physiological cardiac hypertrophy

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(P0.01);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(P0.01).The left ventricle internal diameter at enddiastole 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(P0.01),indicating that the cardiac structures were significantly different betweenPWR 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(P0.05or P0.01).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(P0.05),and those in the TAC group were 1.98-fold and 2.03-fold those of the sham operation group(P0.05).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.