Division of Neurology, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town,, South Africa.
Division of Exercise Science and Sports Medicine, Department of Human Biology, University of Cape Town, Newlands, South Africa.
Muscle Nerve. 2020 Aug;62(2):284-288. doi: 10.1002/mus.26904. Epub 2020 Jun 5.
The mechanism by which weakness develops in idiopathic inflammatory myopathies (IIMs) is still unclear. In this study we investigated the maximum force of single muscle fibers from patients with IIMs.
Permeabilized single muscle fibers from patients with IIMs and healthy controls were subjected to contractility measurements. Maximum force and specific force production (maximum force normalized to fiber size) and fiber type were determined for each isolated fiber.
A total of 178 fibers were studied from five patients with IIMs and 95 fibers from four controls. Specific force production was significantly lower in the IIM group for all fiber types.
The findings from this exploratory study suggest that weakness in IIMs may, in part, be caused by dysfunction of the contractile apparatus. These findings provide a basis for further studies into the mechanisms underlying weakness in IIMs.
特发性炎性肌病（IIM）中出现无力的机制仍不清楚。本研究中我们检测了特发性炎性肌病患者的单条肌纤维的最大力。
对特发性炎性肌病患者和健康对照者的经通透处理的单条肌纤维进行收缩力测量。对每条分离纤维测定最大力和比力（最大力除以纤维大小）及纤维类型。
共研究了 5 例特发性炎性肌病患者的 178 条纤维和 4 例对照者的 95 条纤维。所有纤维类型中，特发性炎性肌病组的比力产生均显著降低。
该探索性研究的结果提示，特发性炎性肌病中的无力可能部分由收缩装置的功能障碍所致。这些发现为进一步研究特发性炎性肌病中无力的机制提供了基础。
