Skinned single fibers from normal and dystrophin-deficient dogs incur comparable stretch-induced force deficits

Intact dystrophin‐deficient canine muscles were previously shown to incur greater‐than‐normal stretch‐induced force deficits. Here we tested the hypothesis that maximally activated detergent‐treated (skinned) single fibers from normal and dystrophin‐deficient dogs would incur comparable force deficits after stretch. Skinned cranial sartorius (CS) fibers from dystrophin‐deficient and normal dogs were calcium‐activated (pCa 4.5) and rapidly stretched. A single 30% stretch induced force deficits of 27.07 ± 3.9% and 29.7 ± 4.8% in dystrophin‐deficient (n = 22) and normal (n = 18) fibers, respectively. Our data support the hypothesis that maximally activated skinned single fibers from normal and dystrophin‐deficient dogs incur comparable force deficits after stretch. Our findings suggest that knowledge of the extent of stretch‐induced force deficits following repeated stretch‐activations in the GRMD dog may be useful to assess future therapeutic interventions aimed at replacing dystrophin in the sarcolemmal membrane. Muscle Nerve, 2005