Bamford J A, Putman C T, Mushahwar V K
Centre for Neuroscience and Department of Biomedical Engineering, Room 503, Heritage Medical Research Centre, University of Alberta, Edmonton, Alberta, Canada.
J Physiol. 2005 Dec 15;569(Pt 3):873-84. doi: 10.1113/jphysiol.2005.094516. Epub 2005 Oct 20.
Intraspinal microstimulation (ISMS), a novel rehabilitative therapy consisting of stimulation through fine, hair-like microwires targeted at the ventral spinal cord, has been proposed for restoring standing and walking following spinal cord injury. This study compared muscle recruitment characteristics of ISMS with those produced by peripheral nerve cuff stimulation (NCS). Thirty-three minutes of either ISMS or NCS at 1, 20 or 50 s(-1) and 1.2 x threshold (T) amplitude depleted glycogen from muscle fibres of vastus lateralis and rectus femoris. ISMS and NCS were also carried out at 20 s(-1) and 3.0T. Muscle serial sections were stained for glycogen and for myosin heavy chain (MHC)-based fibre types using a panel of monoclonal antibodies. The results of this study show that ISMS recruited fatigue-resistant (FR) fibres at 2.9, 1.9, 1.7 and 2.5 times their relative MHC content at 1, 20 and 50 s(-1) 1.2T and 20 s(-1) 3.0T, respectively. In contrast, NCS recruited FR fibres at 1.2, 1.0, 2.1 and 0.0 times their MHC content at 1, 20 and 50 s(-1) 1.2T and 20 s(-1) 3.0T, respectively. The proportion of FR fibres recruited by ISMS and NCS was significantly different in the 20 s(-1) 3.0T condition (P < 0.0001). We also report that force recruitment curves were 4.9-fold less steep (P < 0.019) for ISMS than NCS. The findings of this study provide evidence for the efficacy of ISMS and further our understanding of muscle recruitment properties of this novel rehabilitative therapy.
脊髓内微刺激（ISMS）是一种新型康复疗法，通过极细的毛发状微丝对脊髓腹侧进行刺激，已被提出用于脊髓损伤后恢复站立和行走功能。本研究比较了ISMS与外周神经袖套刺激（NCS）产生的肌肉募集特征。在1、20或50 s⁻¹以及1.2倍阈值（T）幅度下，分别进行33分钟的ISMS或NCS，可使股外侧肌和股直肌肌纤维中的糖原耗尽。ISMS和NCS也在20 s⁻¹和3.0T条件下进行。使用一组单克隆抗体对肌肉连续切片进行糖原和基于肌球蛋白重链（MHC）的纤维类型染色。本研究结果表明，在1、20和50 s⁻¹、1.2T以及20 s⁻¹、3.0T时，ISMS募集的抗疲劳（FR）纤维分别是其相对MHC含量的2.9、1.9、1.7和2.5倍。相比之下，在1、20和50 s⁻¹、1.2T以及20 s⁻¹、3.0T时，NCS募集的FR纤维分别是其MHC含量的1.2、1.0、2.1和0.0倍。在20 s⁻¹、3.0T条件下，ISMS和NCS募集的FR纤维比例存在显著差异（P < 0.0001）。我们还报告称，ISMS的力募集曲线比NCS平缓4.9倍（P < 0.019）。本研究结果为ISMS的有效性提供了证据，并进一步加深了我们对这种新型康复疗法肌肉募集特性的理解。
