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(Arteriosclerosis, Thrombosis, and Vascular Biology. 2002;22:1219.)
© 2002 American Heart Association, Inc.

Atherosclerosis and Lipoproteins

Chronic Exercise Improves Endothelial Calcium Signaling and Vasodilatation in Hypercholesterolemic Rabbit Femoral Artery

Chauying J. Jen; Hung-Pin Chan; Hsiun-ing Chen

From the Department of Physiology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.

Correspondence to Prof Hsiun-ing Chen, Department of Physiology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan. E-mail hichen{at}mail.ncku.edu.tw

Objective— This study was to investigate the effects of chronic exercise on vasodilatation and endothelial intracellular calcium (EC [Ca²⁺]_i) signaling in atherosclerotic animals.

Methods and Results— For 8 weeks, male New Zealand White rabbits were fed rabbit chow with or without the addition of 2% cholesterol. They were further divided into control and exercise groups. Animals in the exercise groups ran on a leveled treadmill at 0.88 km/h for 10 to 60 minutes gradually for 5 days per week for a total of 8 weeks. At the end of experiments, femoral arteries were dissected, loaded with fura 2-AM, and mounted in a tissue flow chamber. PE-precontracted vessel specimens were exposed to acetylcholine (ACh). The EC [Ca²⁺]_i elevation and vasorelaxation were determined simultaneously under an epifluorescence microscope equipped with a ratio-imaging capability. Our results showed the following: (1) high cholesterol diet feeding caused lipid deposition on vascular surface, reduced the ACh-evoked EC [Ca²⁺]_i elevation, and impaired endothelium-dependent and endothelium-independent vascular responses, but chronic exercise had the opposite effects; (2) ACh-induced vasorelaxation was associated with EC [Ca²⁺]_i elevation in all groups; and (3) vasorelaxation at high levels of EC [Ca²⁺]_i elevation decreased in hypercholesterolemia.

Conclusions— Our data suggest that hypercholesterolemia induces vascular structural changes and impairs EC [Ca²⁺]_i signaling and vasodilatation, whereas chronic exercise partially reverses these adverse effects.

Key Words: chronic exercise • high cholesterol diet • nitric oxide • calcium signaling • vasodilators

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				A.-L. Yang, C. J. Jen, and H.-i. Chen Effects of high-cholesterol diet and parallel exercise training on the vascular function of rabbit aortas: a time course study J Appl Physiol, September 1, 2003; 95(3): 1194 - 1200. [Abstract] [Full Text] [PDF]