Satellite cells and utrophin are not directly correlated with the degree of skeletal muscle damage in mdx mice

• Published in: American Journal of Physiology: Cell Physiology Vol. 289; no. 1; pp. C42 - C48
• Main Authors: Yamane, Akira, Akutsu, Satonari, Diekwisch, Thomas G. H, Matsuda, Ryoichi
• Format: Journal Article
• Language: English
• Published: United States 01.07.2005
• Subjects: Animals; Cadherins - genetics; Homeodomain Proteins - genetics; Immunohistochemistry; Mice; Mice, Inbred C57BL; Mice, Inbred mdx; Muscle, Skeletal - metabolism; Muscle, Skeletal - pathology; Muscular Dystrophy, Animal - metabolism; Muscular Dystrophy, Animal - pathology; Muscular Dystrophy, Duchenne - metabolism; Muscular Dystrophy, Duchenne - pathology; PAX7 Transcription Factor; Polymerase Chain Reaction; RNA, Messenger - metabolism; Satellite Cells, Perineuronal - pathology; Utrophin - genetics; Utrophin - metabolism
• ISSN: 0363-6143; 1522-1563
• DOI: 10.1152/ajpcell.00577.2004

1 Department of Pharmacology and 2 High Technology Research Center, Tsurumi University School of Dental Medicine, Yokohama, Japan; 3 Brodie Laboratory for Craniofacial Genetics, Department of Orthodontics, University of Illinois College of Dentistry, Chicago, Illinois; and 4 Department of Biology, The University of Tokyo, Tokyo, Japan Submitted 29 November 2004 ; accepted in final form 3 February 2005 To determine whether muscle satellite cells and utrophin are correlated with the degree of damage in mdx skeletal muscles, we measured the area of the degenerative region as an indicator of myofiber degeneration in the masseter, gastrocnemius, soleus, and diaphragm muscles of mdx mice. Furthermore, we analyzed the expression levels of the paired box homeotic gene 7 ( pax7 ), m-cadherin (the makers of muscle satellite cells), and utrophin mRNA. We also investigated the immunolocalization of m-cadherin and utrophin proteins in the muscles of normal C57BL/10J (B10) and mdx mice. The expression level of pax7 mRNA and the percentage of m-cadherin-positive cells among the total number of cell nuclei in the muscle tissues in all four muscles studied were greater in the mdx mice than in the B10 mice. However, there was no significant correlation between muscle damage and expression level for pax7 mRNA ( R = –0.140), nor was there a correlation between muscle damage and the percentage of satellite cells among the total number of cell nuclei ( R = –0.411) in the mdx mice. The expression level of utrophin mRNA and the intensity of immunostaining for utrophin in all four muscles studied were greater in the mdx mice than in the B10 mice. However, there also was not a significant correlation between muscle damage and expression level of utrophin mRNA ( R = 0.231) in the mdx mice, although upregulated utrophin was incorporated into the sarcolemma. These results suggest that satellite cells and utrophin are not directly correlated with the degree of skeletal muscle damage in mdx mice. dystrophy; pax7 ; m-cadherin; dystrophin-related proteins Address for reprint requests and other correspondence: A. Yamane, Dept. of Pharmacology, Tsurumi Univ. School of Dental Medicine, 2-1-3 Tsurumi, Tsurumi-ku, Yokohama 230-8501, Japan (e-mail: yamane-a{at}tsurumi-u.ac.jp )