Differences in strength-duration curves of electrical diagnosis by physiotherapists between DJ-1 homozygous knockout and wild-type mice: a randomized controlled pilot trial

[Purpose] Strength-duration (SD) curves are used in electrical diagnosis by physiotherapists to confirm muscle degeneration. However, the usefulness of SD curves in comparing muscle degeneration in DJ-1 homozygous knockout (DJ-1(−/−)) and wild-type mice (DJ-1(+/+)) is not yet fully understood. The electrical properties of the gastrocnemius muscles of DJ-1(−/−) and DJ-1(+/+) mice were compared in the current study. [Subjects and Methods] The electrode of an electrical stimulator was applied to the gastrocnemius muscle to measure the rheobase until the response of contractive muscle to electrical stimulation became visible in mice. [Results] The rheobase of DJ-1(−/−) mice showed a significant increase in a time-dependent manner, compared to that of DJ-1(+/+) mice. [Conclusion] These results demonstrate that the DJ-1 protein may be implicated in the regulation of neuromuscular activity of gastrocnemius muscles of mice.