Department of Biomedical Sciences, College of Veterinary Medicine, University of Missouri, Columbia, MO 65211, USA.
J Physiol. 2010 Apr 15;588(Pt 8):1293-307. doi: 10.1113/jphysiol.2009.186247. Epub 2010 Mar 1.
Exercise training is known to be an effective means of improving functional capacity and quality of life in patients with peripheral arterial insufficiency (PAI). However, the specific training-induced physiological adaptations occurring within collateral vessels remain to be clearly defined. The purpose of this study was to determine the effect of exercise training on vasomotor properties of isolated peripheral collateral arteries. We hypothesized that daily treadmill exercise would improve the poor vasodilatory capacity of collateral arteries isolated from rats exposed to surgical occlusion of the femoral artery. Following femoral artery ligation, animals were either kept sedentary or exercise trained daily for a period of 3 weeks. Hindlimb collateral arteries were then isolated, cannulated and pressurized via hydrostatic reservoirs to an intravascular pressure of either 45 or 120 cmH(2)O. Non-occluded contralateral vessels of the sedentary animals served as normal Control. Vasodilatory responses to acetylcholine (ACh; 1 x 10(9)-1 x 10(5)m) and sodium nitroprusside (SNP; 1 x 10(9)-1 x 10(4)m), constrictor responses to phenylephrine (PE; 1 x 10(9)-1 x 10(4)m), and flow-induced vasodilatation were determined. Endothelium-mediated vasodilatation responses were significantly greater to either ACh (P < 0.02) or intravascular flow (P < 0.001) in collateral arteries of trained rats. Neither blockade of cyclooxygenase with indomethacin (Indo; 5 microm) nor blockade of endothelial nitric oxide synthase with N(G)-nitro-L-arginine methyl ester (L-NAME; 300 microm) eliminated this ACh- or flow-induced vasodilatation. The depressed vasodilatory response to SNP caused by vascular occlusion was reversed with training. These data indicate that exercise training improves endothelium-mediated vasodilatory capacity of hindlimb collateral arteries, apparently by enhanced production of the putative endothelium-derived hyperpolarizing factor(s). If these findings were applicable to patients with PAI, they could contribute to an improved collateral vessel function and enhance exercise tolerance during routine physical activity.
运动训练被认为是改善外周动脉功能不全（PAI）患者功能能力和生活质量的有效手段。然而，运动训练引起的侧支血管内的特定生理适应性仍有待明确界定。本研究的目的是确定运动训练对分离的外周侧支血管血管舒缩功能的影响。我们假设，每天进行跑步机运动可改善因股动脉结扎而导致的大鼠侧支血管舒张能力受损的情况。股动脉结扎后，动物要么保持静止，要么每天进行运动训练，持续 3 周。然后，将后肢侧支动脉分离、插管并通过静水压力库加压至血管内压力 45 或 120 cmH2O。静止动物的未闭塞对侧血管作为正常对照。乙酰胆碱（ACh；1×10(9)-1×10(5)m）和硝普钠（SNP；1×10(9)-1×10(4)m）诱导的血管舒张反应、对苯肾上腺素（PE；1×10(9)-1×10(4)m）的收缩反应以及血流诱导的血管舒张反应。内皮介导的血管舒张反应对 ACh（P < 0.02）或血流（P < 0.001）的反应在训练大鼠的侧支血管中明显更大。环氧化酶抑制剂吲哚美辛（Indo；5 µm）或内皮一氧化氮合酶抑制剂 N(G)-硝基-L-精氨酸甲酯（L-NAME；300 µm）均不能消除 ACh 或血流诱导的血管舒张。血管闭塞引起的 SNP 舒张反应的抑制作用在训练后得到逆转。这些数据表明，运动训练可改善后肢侧支血管的内皮介导的血管舒张能力，显然是通过增强潜在的内皮衍生超极化因子的产生。如果这些发现适用于 PAI 患者，它们可能有助于改善侧支血管功能并增强日常体力活动中的运动耐量。
