Isolated myofibers from rat skeletal muscle in suspension: Cellular morphology and calcium homeostasis
Isolated myofibers from rat skeletal muscle in suspension: Cellular morphology and calcium homeostasis
复制标题
从悬浮的大鼠骨骼肌中分离出的肌纤维：细胞形态和钙稳态
作者：
J. Zuurveld;J. Veerkamp;P. Wirtz
从大鼠肌肉中制备存活率为80%（形态完整）的肌纤维悬液。用胶原酶处理6小时的屈趾短肌。活纤维肌膜完整，基底层连续。细胞内室表现出正常的肌肉形态。悬浮的肌纤维表现出良好的耐受性对细胞外钙（高达30 mM），但对15 mM EGTA敏感。钙离子载体A23187诱导收缩，在含钙和名义上无钙的Krebs-Ringer培养基中均丧失活力。EGTA阻止了离子载体效应，但一旦钙得到补充，肌肉细胞就会崩溃。在离体骨骼肌细胞中，不能诱导出与灌注心脏一样的钙悖论。这种悬浮细胞系统应提供一个有用的工具，研究代谢参数和肌肉生理之间的关系。细胞外环境可以很容易地操纵，单个骨骼肌纤维的细胞反应可以测量和可视化。
Myofiber suspensions with 80% viability (morphological intactness) were prepared from rat m. flexor digitorum brevis by a 6‐hour collagenase treatment. The viable fibers had intact sarcolemmas and generally showed continuous basal laminae. The intracellular compartments exhibited normal muscular morphology. The suspended myofibers showed good tolerance against extracellular calcium (up to 30 mM), but were susceptible to 15mM EGTA. Calcium ionophore A23187 induced contraction, with loss of viability in both calcium‐containing and nominally calcium‐free Krebs‐Ringer medium. EGTA prevented the ionophore effect, but the muscle cells collapsed as soon as calcium was replenished. A calcium paradox, as observed with perfused heart, could not be induced in isolated skeletal myocytes. This suspended cell system should provide a useful tool for investigating relationships between metabolic parameters and muscle physiology. The extracellular environment can be manipulated easily, and cellular responses of individual skeletal muscle fibers can be measured and visualized.