title: Short-term exercise training improves vascular function in hypercholesterolemic rabbit femoral artery.
abstract: Chronic exercise in healthy or hypercholesteremic animals for at least two months improves their vascular functions. This study is to examine whether short-term exercise training protocols can correct early-stage vascular dysfunction induced by high-cholesterol diet feeding. Male New Zealand White rabbits were fed for 2, 4 or 6 weeks with rabbit chow with or without the addition of 2% (w/w) cholesterol. They were further divided into control and exercise groups. Animals in exercise groups ran on a leveled treadmill for the same time periods as diet intervention. At the end of experiments, femoral arteries were dissected, loaded with fura 2-AM, and mounted in a tissue flow chamber. Phenylephrine-precontracted vessel specimens were exposed to acetylcholine. The endothelial intracellular calcium elevation and vasorelaxation were determined simultaneously under an epifluorescence microscope with ratio imaging capability. En face oil red O staining was used to evaluate fatty streak formation. Our results showed that 1) high-cholesterol diet feeding for > or = 4 weeks caused lipid deposition, reduced the acetylcholine-evoked endothelial calcium signaling, and impaired both endothelium-dependent and endothelium-independent vascular responses in a time-dependent manner; 2) vasorelaxation at given levels of endothelial intracellular calcium elevation decreased in hypercholesterolemia; 3) concomitant exercise program had reverse effects. We conclude that high-cholesterol diet intervention for as short as 4 weeks induces vascular structural changes, impairs endothelial intracellular calcium signaling and vasodilatation in rabbit femoral arteries. Short-term exercise training in parallel completely eliminates these adverse effects so long as the diet intervention is no more than 6 weeks.
authors.affiliation: Department of Physiology, College of Medicine, National Cheng Kung University, Tainan 701, Taiwan, ROC.
authors.forename: Chauying J
authors.initials: CJ
authors.lastname: Jen
authors.forename: Yu-Fan
authors.initials: YF
authors.lastname: Liu
authors.forename: Hsiun-Ing
authors.initials: HI
authors.lastname: Chen
mesh_terms: D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D020013:Calcium Signaling; D002791:Cholesterol, Dietary / Q000008:administration & dosage; D004730:Endothelium, Vascular / Q000378:metabolism; D005263:Femoral Artery / Q000503:physiopathology*; D006937:Hypercholesterolemia / Q000503:physiopathology*; D008297:Male; D009599:Nitroprusside / Q000494:pharmacology; D010656:Phenylephrine / Q000494:pharmacology; D010805:Physical Conditioning, Animal; D011817:Rabbits; D014664:Vasodilation / Q000187:drug effects
chemical_list: D002791:Cholesterol, Dietary; D009599:Nitroprusside; D010656:Phenylephrine; D000001:Calcimycin; D000109:Acetylcholine