Related Experiment Video
Updated: May 18, 2026
Myo-mechanical Analysis of Isolated Skeletal Muscle
Published on: February 22, 2011
Muscle function in a canine model of X-linked myotubular myopathy
Robert W Grange1, Jon Doering, Erin Mitchell
1Department of Human Nutrition, Foods and Exercise, College of Agriculture & Life Sciences, Virginia Polytechnic and State University, Blacksburg, Virginia, USA 24060.
Introduction:
We established a colony of dogs that harbor an X-linked MTM1 missense mutation.Muscle from affected male dogs exhibits reduction and altered localization of the MTM1 gene product, myotubularin, and provides a model analogous to X-linked myotubular myopathy (XLMTM).
Methods:
We studied hindlimb muscle function in age-matched canine XLMTM genotypes between ages 9 and 18 weeks.
Results:
By the end of the study, affected dogs produce only ∼15% of the torque generated by normals or carriers (0.023 ± 0.005 vs. 0.152 ± 0.007 and 0.154 ± 0.003 N-m/kg body mass, respectively, P < 0.05) and are too weak to stand unassisted. At this age, XLMTM dogs also demonstrate an abnormally low twitch:tetanus ratio, a right-shifted torque-frequency relationship and an increase in torque during repetitive stimulation (P < 0.05).
Conclusions:
We hypothesize that muscle weakness results from impaired excitation-contraction (E-C) coupling. Interventions that improve E-C coupling might be translated from the XLMTM dog model to patients.
