Laryngeal muscles are spared in the dystrophin deficient mdx mouse

Purpose: Duchenne muscular dystrophy (DMD) is caused by the loss of the cytoskeletal protein, dystrophin. The disease leads to severe and progressive skeletal muscle wasting. Interestingly, the disease spares some muscles. The purpose of the study was to determine the effects of dystrophin deficiency on 2 intrinsic laryngeal muscles, the posterior cricoarytenoid and the thyroarytenoid, in the mouse model. Method: Larynges from dystrophin-deficient mdx and normal mice were examined histologically. Results: Results demonstrate that despite the absence of dystrophin in the mdx laryngeal muscles, membrane damage, inflammation, necrosis, and regeneration were not detected in the assays performed. Conclusions: The authors concluded that these muscles are 1 of only a few muscle groups spared in this model of dystrophin deficiency. The muscles may count on intrinsic and adaptive protective mechanisms to cope with the absence of dystrophin. Identifying these protective mechanisms may improve DMD management. The study also highlights the unique aspects of the selected laryngeal skeletal muscles and their dissimilarity to limb skeletal muscle.