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GMS Current Posters in Otorhinolaryngology - Head and Neck Surgery

German Society of Oto-Rhino-Laryngology, Head and Neck Surgery (DGHNOKHC)

ISSN 1865-1038

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Masticatory muscles show differential expression of MHC-isoforms in mdx-mice

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  • corresponding author Christiane Kunert-Keil - Institut für Pathophysiologie, Karlsburg
  • Alexander Spassov - Department of Onthodontics, Greifswald
  • Silke Lucke - Department of Onthodontics, Greifswald
  • Tomas Gedrange - Department of Onthodontics, Greifswald

GMS Curr Posters Otorhinolaryngol Head Neck Surg 2009;5:Doc41

doi: 10.3205/cpo000445, urn:nbn:de:0183-cpo0004452

Published: April 16, 2009

© 2009 Kunert-Keil et al.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en). You are free: to Share – to copy, distribute and transmit the work, provided the original author and source are credited.

Outline

Abstract

Background: Duchenne Muscular Dystrophy (DMD) and its murine model, mdx, are characterized by Ca2+ induced muscle damage, fibrosis and muscle weakness. Furthermore, DMD patients have distorted dentofacial morphology which could be a result of changed masticatory mechanics due to muscular dysfunction.

Aim: To determine potential changes in masticatory mechanics we searched for morphological abnormalities including nuclei localisation, fibre diameters and collagen expression and examined the expression of myosin heavy chain (MHC)-isoforms in control and mdx mice.

Methods: The mRNA and protein levels of the MHC-isoforms were studied using quantitative RT-PCR, western blot analyses and histochemistry in Musculus masseter, temporalis, soleus and tongue of both mouse strains.

Results: Dystrophin-deficient masticatory muscles contained 11–75% fibres with centralized nuclei, numerous inflammatory foci and an accumulation of collagen except tongue. Furthermore, a significant increased mean fibre diameter was observed all tested mdx muscles. In contrast to soleus muscle the MHC type I isoform was not detectable in masticatory muscle tissues of control and mdx mice. In mdx masticatory muscles and tongue MHC type IIb and IIx were significantly down regulated.

Conclusion: These observations suggest that mdx masticatory muscles are differentially affected by the disease process. However, the observed down regulation of the MHC IIx and IIb isoforms may be responsible for the functional misbalance of masticatory muscles in DMD and could be causing morphological changes which are observed in this disorder.