Defined Electrical Stimulation Emphasizing Excitability for the Development and Testing of Engineered Skeletal Muscle
Defined Electrical Stimulation Emphasizing Excitability for the Development and Testing of Engineered Skeletal Muscle
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DOI：
10.1089/ten.tec.2011.0364
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发表时间：
2012-05-01
影响因子：
3
通讯作者：
Baar, Keith
中科院分区：
文献类型：
--
作者：
Khodabukus, Alastair;Baar, Keith
电刺激是骨骼肌成熟所必需的，也是一种非破坏性监测肌肉发育的方法。然而，错误的刺激参数可能导致损害肌肉发育/再生的电化学损伤。本研究的目的是确定电脉冲的哪个方面，特别是脉冲幅度或脉冲宽度，对工程肌肉功能有害，以及随后工程肌肉如何对持续24小时的电刺激作出反应。以大于6倍基强度的脉冲幅度进行急性刺激导致半弛豫时间增加2.4倍（32.3 +/- 0.49 ms对77.4 +/- 4.35 ms; p < 0.05）和疲劳性增加1.59倍（38.2% +/- 3.61%对60.6% +/- 4.52%; p < 0.05）。当脉冲能量通过延长脉冲宽度而增加时，没有观察到负面影响，这表明电化学损伤是由于处于或高于6倍基强度的电场。在大于0.5 V/mm的电场下连续刺激24 h，始终导致力增加2.5倍（0.30 +/- 0.04 kN/m（2）vs. 0.67 +/- 0.06 kN/m（2）; p < 0.05）。这种力量增加的40%依赖于雷帕霉素（RAP）复合物1（mTORC 1）的哺乳动物靶标，由于RAP阻止了这部分的兵力增加，（CON = 0.30 +/- 0.04 kN/m（2）至0.67 +/- 0.06 kN/m（2），RAP = 0.21 +/- 0.01 kN/m（2）至0.37 +/- 0.04 kN/m（2）; p < 0.05）。由于肌球蛋白重链没有增加，在刺激的24小时内剩余的力增加可能是由于细胞骨架重排。这些数据表明，电化学损伤发生在肌肉中的电压场大于6倍的基强度，因此，最佳的肌肉刺激应使用较低的电场（2至4倍的基强度）。
Electrical stimulation is required for the maturation of skeletal muscle and as a way to nondestructively monitor muscle development. However, the wrong stimulation parameters can result in electrochemical damage that impairs muscle development/regeneration. The goal of the current study was to determine what aspect of an electrical impulse, specifically the pulse amplitude or pulse width, was detrimental to engineered muscle function and subsequently how engineered muscle responded to continuous electrical stimulation for 24 h. Acute stimulation at a pulse amplitude greater than six-times rheobase resulted in a 2.4-fold increase in the half-relaxation time (32.3 +/- 0.49 ms vs. 77.4 +/- 4.35 ms; p < 0.05) and a 1.59-fold increase in fatigability (38.2% +/- 3.61% vs. 60.6% +/- 4.52%; p < 0.05). No negative effects were observed when the pulse energy was increased by lengthening the pulse width, indicating electrochemical damage was due to electric fields at or above six-times rheobase. Continuous stimulation for 24 h at electric fields greater than 0.5 V/mm consistently resulted in similar to 2.5-fold increase in force (0.30 +/- 0.04 kN/m(2) vs. 0.67 +/- 0.06 kN/m(2); p < 0.05). Forty per cent of this increase in force was dependent on the mammalian target of rapamycin (RAP) complex 1 (mTORC1), as RAP prevented this portion of the increase in force (CON = 0.30 +/- 0.04 kN/m(2) to 0.67 +/- 0.06 kN/m(2) compared with RAP = 0.21 +/- 0.01 kN/m(2) to 0.37 +/- 0.04 kN/m(2); p < 0.05). Since there was no increase in myosin heavy chain, the remaining increase in force over the 24 h of stimulation is likely due to cytoskeletal rearrangement. These data indicate that electrochemical damage occurs in muscle at a voltage field greater than six-times rheobase and therefore optimal muscle stimulation should be performed using lower electric fields (two-to four-times rheobase).