Mintz Ellen L, Passipieri Juliana A, Lovell Daniel Y, Christ George J
Department of Pathology, University of Virginia.
Department of Biomedical Engineering, University of Virginia.
J Vis Exp. 2016 Oct 7(116):54487. doi: 10.3791/54487.
Despite the regenerative capacity of skeletal muscle, permanent functional and/or cosmetic deficits (e.g., volumetric muscle loss (VML) resulting from traumatic injury, disease and various congenital, genetic and acquired conditions are quite common. Tissue engineering and regenerative medicine technologies have enormous potential to provide a therapeutic solution. However, utilization of biologically relevant animal models in combination with longitudinal assessments of pertinent functional measures are critical to the development of improved regenerative therapeutics for treatment of VML-like injuries. In that regard, a commercial muscle lever system can be used to measure length, tension, force and velocity parameters in skeletal muscle. We used this system, in conjunction with a high power, bi-phase stimulator, to measure in vivo force production in response to activation of the anterior crural compartment of the rat hindlimb. We have previously used this equipment to assess the functional impact of VML injury on the tibialis anterior (TA) muscle, as well as the extent of functional recovery following treatment of the injured TA muscle with our tissue engineered muscle repair (TEMR) technology. For such studies, the left foot of an anaesthetized rat is securely anchored to a footplate linked to a servomotor, and the common peroneal nerve is stimulated by two percutaneous needle electrodes to elicit muscle contraction and dorsiflexion of the foot. The peroneal nerve stimulation-induced muscle contraction is measured over a range of stimulation frequencies (1-200 Hz), to ensure an eventual plateau in force production that allows for an accurate determination of peak tetanic force. In addition to evaluation of the extent of VML injury as well as the degree of functional recovery following treatment, this methodology can be easily applied to study diverse aspects of muscle physiology and pathophysiology. Such an approach should assist with the more rational development of improved therapeutics for muscle repair and regeneration.
尽管骨骼肌具有再生能力，但永久性的功能和/或外观缺陷（例如，由创伤性损伤、疾病以及各种先天性、遗传性和后天性疾病导致的肌肉体积损失（VML））却相当常见。组织工程和再生医学技术具有提供治疗方案的巨大潜力。然而，利用具有生物学相关性的动物模型并结合对相关功能指标的纵向评估，对于开发用于治疗VML样损伤的改良再生疗法至关重要。在这方面，一种商用肌肉杠杆系统可用于测量骨骼肌的长度、张力、力量和速度参数。我们使用该系统，并结合高功率双相刺激器，来测量大鼠后肢前腿部隔室激活后体内产生的力量。我们之前已使用该设备评估VML损伤对胫前肌（TA）的功能影响，以及用我们的组织工程肌肉修复（TEMR）技术治疗受伤的TA肌肉后的功能恢复程度。对于此类研究，将麻醉大鼠的左脚牢固地固定在与伺服电机相连的脚板上，通过两根经皮针电极刺激腓总神经，以引发肌肉收缩和足部背屈。在一系列刺激频率（1 - 200 Hz）下测量腓总神经刺激诱导的肌肉收缩，以确保力量产生最终达到平稳状态，从而能够准确测定强直收缩峰值力。除了评估VML损伤的程度以及治疗后的功能恢复程度外，该方法还可轻松应用于研究肌肉生理学和病理生理学的各个方面。这种方法应有助于更合理地开发用于肌肉修复和再生的改良疗法。
