Chaired Posters PresentationObjectives: Left ventricular hypertrophy (LVH) associated with obesity
increases the morbidity and mortality of cardiovascular disease, which could
be attenuated by exercise in overweight and hypertensive patients. The
lysosomal degradation pathway − autophagy is reportedly mediated the
beneficial effect of exercise on glucose and lipid homeostasis. The present
study aimed to investigate the involvement of autophagy in the effect of
exercise on LVH induced by high fat diet in rats.
Methods: Female adult SD rats were divided into 4 groups namely: (i) high
fat diet (HFD), (ii) HFD+exercise, (iii) exercise, (iv) control. Rats in the
HFD groups were orally fed with high-fat chow (30% fat) daily for 12 weeks,
and rats in the exercise groups had exercise with a motorized wheel in the
last 4 weeks. Noninvasive measures of systolic pressure and fat composition
were assessed, respectively by tail cuff and MRI. The expression of markers
for cardiac hypertrophy and the protein expression in autophagic pathway
were determined by quantitative real time-PCR and western blot, respectively.
Statistical significance was at p<0.05 with ANOVA analysis followed by
post-hoc tests.
Results: Rats fed with HFD had LVH (increased heart weight and LV/
RV+septum ratio) with higher levels of body weight, arterial pressures and
fat composition than that of the control rat. In addition, the QTc interval and
the diameter and disarray of ventricular myocytes were significantly
increased in the HFD group, supported by elevated levels of the expression
of hypertrophic markers (ANP, BNP, β-MHC). These parameters were
attenuated by exercise in the HFD-fed rats. Moreover, we found elevated
levels of LC3II in the HFD heart, which were also attenuated by exercise,
suggesting an involvement of autophagy in the beneficial effect of exercise.
Furthermore, the expression level of AMPKα was also increased in the
exercise groups.
Conclusion: We demonstrated that exercise lowers the body weight and
attenuates the HFD-induced LVH in rats, which probably involves autophagy.
Future studies will focus on the role of autophagy in the pathogenesis.published_or_final_versio
