Expression of extracellular matrix ligands and receptors in the muscular tissue and draining lymph nodes of mdx dystrophic mice

The mdx mouse, an animal model of Duchenne muscular dystrophy, develops an X-linked recessive inflammatory myopathy. During onset of disease and heigh t of myonecrosis, mdx mice also display important changes in the microenvir onment of lymphoid tissues, Draining lymph nodes showed reduced cellularity and atrophy accompanied by intense immunolabeling for fibronectin, laminin , and type-IV collagen. Following clinical amelioration of dystrophy, mdx m ice showed enhanced cellularity and a consistent increase in the absolute n umbers of CD4(+) and CD8(+) cells expressing alpha 4(high) and alpha 5(high ) extracellular matrix receptors, Furthermore, infiltrating cells in the pr oximity of myonecrosis expressed alpha 4, alpha 5, and alpha 6 integrin cha ins during both height of myonecrosis and muscular tissue regeneration. Suc h results indicate that during distinct phases of muscular dystrophy, alter ed expression of extracellular matrix ligands and receptors may be influenc ing myonecrosis by promoting adhesion and migration of mononuclear cells in to the altered skeletal muscle and toward local draining lymphoid tissue. ( C) 1999 Academic Press.