Ivanics T, Miklós Z, Ruttner Z, Bátkai S, Slaaf D W, Reneman R S, Tóth A, Ligeti L
Second Department of Physiology, Semmelweis University of Medicine, Budapest, Hungary.
Pflugers Arch. 2000 Jun;440(2):302-8. doi: 10.1007/s004240000287.
Accumulation of intracellular free calcium (Ca2+i) may play an essential role in the ischemia/reperfusion injury of skeletal muscle. Although it has been shown that Ca2+i levels significantly increase during ischemia/reperfusion, it is still a matter of debate whether Ca2+i increases during ischemia alone. It was the aim of this study to monitor the in vivo Ca2+i levels in the rat spinotrapezius muscle during ischemia of varying duration and reperfusion, using a ratiometric fluorescence technique, and to investigate the relationship between the postischemic flow patterns and Ca2+i, if any. The muscle was loaded with Indo-1/AM and imaged by a cooled digital camera. Pre- and postischemic tissue perfusion was assessed by means of an analogue camera. Our results show that short-term ischemia (5, 15 and 30 min) and subsequent reperfusion (60 min) does not alter Ca2+i homeostasis and that tissue perfusion promptly recovers after the insult. One or two hours of ischemia resulted in changes in Ca2+i levels, varying from preparation to preparation; increases in some and no changes in others. In these preparations three distinct flow patterns - normal, compromised and no-reflow - could be distinguished during the 60-min reperfusion. Our main conclusion is that in skeletal muscle Ca2+i levels may increase, the increase probably depending on the muscle fiber type exposed.
细胞内游离钙（Ca2+i）的蓄积可能在骨骼肌缺血/再灌注损伤中起关键作用。尽管已有研究表明在缺血/再灌注期间Ca2+i水平显著升高，但单独缺血期间Ca2+i是否升高仍存在争议。本研究的目的是使用比率荧光技术监测大鼠斜方肌在不同时长缺血和再灌注期间的体内Ca2+i水平，并研究缺血后血流模式与Ca2+i之间的关系（若存在）。肌肉用Indo-1/AM负载，并由冷却数码相机成像。缺血前后的组织灌注通过模拟相机评估。我们的结果表明，短期缺血（5、15和30分钟）及随后的再灌注（60分钟）不会改变Ca2+i稳态，且损伤后组织灌注能迅速恢复。一或两小时的缺血导致Ca2+i水平发生变化，不同标本变化各异；一些标本升高，另一些则无变化。在这些标本中，在60分钟的再灌注期间可区分出三种不同的血流模式——正常、受损和无复流。我们的主要结论是，在骨骼肌中Ca2+i水平可能升高，这种升高可能取决于所暴露的肌纤维类型。
