Voluntary running exercise attenuates the progression of endothelial dysfunction and arterial calcification in ovariectomized rats

Aim: Loss of oestrogen synthesis capacity after menopause contributes to increases in arterial stiffness and calcification. Exercise training improves arterial stiffness and calcification. However, the mechanism of exercise training-induced improvement of arterial stiffness and calcification remains unclear. Method: We examined the mechanism by using aortas of sham-operated rats (sham control; SC), ovariectomized rats (OVX control; OC), OVX plus treatment with vitamin D₃ plus nicotine (VDN) rats (OV sedentary; OVSe), which is an animal model of endothelial dysfunction and arterial calcification, and voluntary running wheel exercise for 8 weeks plus OVX plus VDN rats (OV exercise; OVEx). Results: The arterial tissue calcium and endothelin-1 (ET-1: a vasoconstrictor peptide and a potent regulator of arterial calcification) levels were significantly higher in OVSe rats compared with the SC and OC rats, whereas these levels in the OVEx rats were significantly lower than in the OVSe rats. Additionally, arterial expression of endothelial nitric oxide synthase (eNOS), which is an enzyme that produces nitric oxide (NO: a vasodilator substance), was reduced in OVSe rats. However, exercise training prevented the decrease in eNOS expression. Moreover, there was a significant positive correlation between arterial calcium level and arterial ET-1 level. Conclusion: These findings suggest that exercise training-induced improvement of ET-1 and NO prevents the impairment of endothelial function after menopause in females, and this improvement may result in less arterial calcification.