The effects of different exercise modes for preventing endothelial dysfunction of arteries and bone loss in ovariectomized rats

Purpose]

Several epidemiological studies have demonstrated that there are positive correlations between vascular disorders and bone loss in postmenopausal women. The aim of the present study was to examine the effect of different types of exercise (e.g., climbing and swimming) for preventing endothelial dysfunction of arteries and bone loss in ovariectomized rats.

Methods]

Twenty Sprague-Dawley female rats were randomly divided into three groups: ovariectomy (OVX) plus treatment with vitamin D₃ and nicotine (VDN) (control rats Con], n = 7), which is an animal model for endothelial dysfunction and bone loss; voluntary climbing resistance exercise with OVX plus VDN (climbing rats Clim], n = 6), and swimming exercise with OVX plus VDN (swimming rats Swim], n = 7). The period of exercise training was 8 weeks.

Results]

The endothelin-1 (ET-1) protein levels were significantly lower in the Clim and Swim groups than in the Con. The endothelial nitric oxide synthase protein levels were significantly higher in the Swim group than in the Con, but they did not differ between the Clim and Con groups. The cortical bone mineral density in the tibia and breaking energy of the femur were significantly higher in the Clim group than in the Con, but this positive effect was not seen in the Swim group.

Conclusion]

Voluntary climbing exercise decreased arterial ET-1 protein levels and prevented bone loss in a postmenopause-model rat combining OVX and VDN. Conversely, swimming suppressed endothelial dysfunction of the arteries but did not prevent bone loss. Thus, the type of exercise should be cautiously chosen for enhancing vascular function and bone status, especially in females after menopause.