SITE-DEPENDENT PATHOLOGICAL DIFFERENCES IN SMOOTH MUSCLES AND SKELETAL-MUSCLES OF THE ADULT MDX MOUSE

This study presents a survey of the morphometric characteristics, the regeneration rate, and the extent of muscle dystrophy in several smoot h and skeletal muscles from adult mdx mice, an animal model of the Duc henne muscular dystrophy (DMD). Smooth muscles from adult mdx mice sho wed neither cell necrosis nor fibrosis. As compared to control C57 mic e, the thickness of the mdx smooth muscle was normal in the vascular a nd urogenital layers but significantly reduced in the digestive layers , a finding relevant to clinical reports of gastrointestinal dilatatio n in DMD patients, and suggesting that gastrointestinal dysfunctions s hould be systemically searched for in DMD patients. Adult mdx skeletal muscles, however, presented different patterns of muscle suffering: e ither absent (esophagus); very mild (trunk and limb muscles); or sever e (diaphragm). In these three conditions we studied the fiber diameter s, the nuclei locations, and the regeneration rate. From this comparat ive study, it seems that severe dystrophy occurs in muscle tissues sho wing large fiber diameter and peripheral location of the nuclei. We sh owed that this combination occurs in the mouse diaphragm which is thus a realistic model for human DMD muscles. (C) 1995 John Wiley & Sons, Inc.