Non-invasive assessment of muscle injury in healthy and dystrophic animals with electrical impedance myography.

Introduction: Dystrophic muscle is particularly susceptible to eccentric contraction-induced injury. We tested the hypothesis that electrical impedance myography (EIM) can detect injury induced by maximal-force lengthening contractions.

Methods: We induced injury in the quadriceps of wild-type (WT) and dystrophic (mdx) mice with eccentric contractions using an established model.

Results: mdx quadriceps had significantly greater losses in peak twitch and tetany compared with losses in WT quadriceps. Injured muscle showed a significant increase in EIM characteristic frequency in both WT (177 ± 7.7%) and mdx (167 ± 7.8%) quadriceps. EIM also revealed decreased extracellular resistance for both WT and mdx quadriceps after injury.

Discussion: Our results show overall agreement between muscle function and EIM measurements of injured muscle, indicating that EIM is a viable tool to assess injury in dystrophic muscle. Muscle Nerve 56: E85-E94, 2017.