High-energy phosphate metabolism in the calf muscle during moderate isotonic exercise under different degrees of cuff compression: A phosphorus 31 magnetic resonance spectroscopy study
High-energy phosphate metabolism in the calf muscle during moderate isotonic exercise under different degrees of cuff compression: A phosphorus 31 magnetic resonance spectroscopy study
复制标题
DOI：
10.1016/j.jvs.2005.04.042
复制
发表时间：
2005-08-01
影响因子：
4.3
通讯作者：
Schocke, MFH
中科院分区：
文献类型：
--
作者：
Greiner, A;Esterhammer, R;Schocke, MFH
背景：本研究的目的是研究在进行性袖带狭窄的情况下，在4.5 W负荷下运动肌肉的磷酸肌酸（PCr）和无机磷酸盐水平以及pH值的变化，通过流量敏感磁共振成像量化袖带压缩引起的流量减少。方法：采用1.5 t全身磁共振扫描仪和运动台，对10名健康男性进行时间分辨率为30秒的连续磷31 （P-31）磁共振波谱检测。与基线比较，统计评估PCr、无机磷酸盐（Pi）和pH的百分比变化。运动方案的特点是恒定的工作负荷水平为4.5 W。缺血条件是通过在大腿上放置一个袖带来实现的。依次施加0、60、90、120和150毫米汞柱。每个增量持续3分钟。接下来的休息时间为10分钟。在肌肉运动开始后，血流量立即显著增加。未发现显著的血液流动的变化只要气动袖口的气压是60到90修女无花果。血流量显著减少后立即观察通货膨胀的袖口120和150毫米汞柱。PCr传递到一个稳定的状态在第一次增量与0毫米汞柱,没有实质性变化增量60,90和120毫米汞柱。PCr水解似乎进步在150 - min Hg增量。pH值在运动开始时进入平台水平，并在增加150 mm Hg时显著增加。pH值在增加到120 mm Hg时变为稳定状态，没有明显变化。图150 mm Hg时pH值逐渐下降。150毫米汞柱升高结束时的PCr水平与血流量的减少呈显著和中度相关。结论：我们的研究表明，持续肌肉运动时的缺血情况可以通过PCr和Pi动力学以及pH变化来明确表征。运动肌群的血流量减少程度与PCr水平之间的相关性是使用P-31磁共振波谱评估动脉狭窄对跛行者肌肉功能影响的第一个关键。运动肌群由狭窄的动脉供应。
Background: The purpose of this study was to investigate phosphocreatine (PCr) and inorganic phosphate levels as well as pH changes in exercising muscle at a workload of 4.5 W under progressive cuff stenoses, whereby the flow reduction due to cuff compression was quantified by flow-sensitive magnetic resonance imaging.Methods: By using a whole-body 1.5-T magnetic resonance scanner and an exercise bench, serial phosphorus 31 (P-31) magnetic resonance spectroscopy with a time resolution of 30 seconds was performed in 10 healthy men. Percentage changes in PCr, inorganic phosphate (Pi), and pH were statistically evaluated in comparison with baseline. The exercise protocol was characterized by a constant workload level of 4.5 W. Ischemic conditions were achieved by a cuff that was placed at the upper leg. Consecutively, increments of 0, 60, 90, 120, and 150 mm Hg were applied. Each increment lasted for 3 minutes. The following rest period was 10 minutes.Results. Blood flow increased significantly immediately after the onset of muscle exercise. No significant changes in blood flow were detected as long as the air pressure of the pneumatic cuff was 60 to 90 nun Fig. Significant reductions in blood flow were observed immediately after inflation of the cuff to 120 and 150 mm Hg. PCr passed into a steady state during the first increment with 0 mm Hg and showed no substantial changes during the increment with 60, 90, and 120 mm Hg. PCr hydrolysis seemed progressive during the 150-min Hg increment. Pi passed into a plateau level at the onset of exercise and increased significantly at the increment of 150 mm Hg. The pH turned into a steady state with no significant changes during the increments up to 120 nun Fig. At 150 mm Hg, pH decreased progressively. PCr levels at the end of the 150-mm Hg increment correlated significantly and moderately with the reduction in blood flow.Conclusions: Our study shows that the ischemic condition during constant muscle exercise is clearly characterized by PCr and Pi kinetics, as well as by pH changes. The correlation between the degree of blood flow reduction and PCr levels in the exercising muscle groups, which are supplied by the stenosed arteries, is the first essential of using P-31 magnetic resonance spectroscopy in the assessment of the effect of arterial stenoses on muscle function in claudicants.