Skeletal muscle fibers in dystrophin‐deficient mice express intercellular adhesion molecule‐1 (1102.12)

Abstract

Duchenne muscular dystrophy (DMD) is an X‐linked inherited disease resulting from the absence of the cytoskeletal protein dystrophin in skeletal and cardiac muscle cells. Without dystrophin, skeletal muscles incur repeated cycles of damage and regeneration. In a murine model of DM (i.e. mdx mice), myeloid cells (neutrophils and macrophages) contribute to the onset and progression of DMD. The objective of this investigation was to determine if intercellular adhesion molecule‐1 (ICAM‐1), a protein of the inflammatory response, is expressed by myofibers in mdx mice. We hypothesize that the expression of ICAM‐1 by myofibers in dystrophin‐deficient muscle serves as a mechanism by which myeloid cells exacerbate the muscle pathology. Western blot revealed increased expression of ICAM‐1 in mdx compared to control wild‐type mice. We found ICAM‐1 expressed on the membrane of necrotic, injured, and regenerating myofibers of mdx mice via immunolabeling. Myofibers of control wild‐type mice did not express ICAM‐1. These observations may indicate that skeletal muscle fiber expression of ICAM‐1 serves as a mechanism by which neutrophils and macrophages attach to skeletal muscle and exacerbate the myopathy in the mdx mice.