Histological changes in masticatory muscles of mdx mice

Spassov, Alexander; Gredes, Tomasz; Gedrange, Tomasz; Lucke, Silke; Pavlovic, Dragan; Kunert-Keil, Christiane

doi:10.1016/j.archoralbio.2010.02.005

« Previous Next »Archives of Oral Biology
Volume 55, Issue 4 , Pages 318-324, April 2010

Histological changes in masticatory muscles of mdx mice

Alexander Spassov
- Department of Orthodontics, Faculty of Medicine, University of Greifswald, Rotgerber Str. 8, 17475 Greifswald, Germany
- Corresponding author. Tel.: +49 3834 867119; fax: +49 3834 867113.
Tomasz Gredes
- Department of Orthodontics, Faculty of Medicine, University of Greifswald, Rotgerber Str. 8, 17475 Greifswald, Germany
Tomasz Gedrange
- Department of Orthodontics, Faculty of Medicine, University of Greifswald, Rotgerber Str. 8, 17475 Greifswald, Germany
Silke Lucke
- Department of Orthodontics, Faculty of Medicine, University of Greifswald, Rotgerber Str. 8, 17475 Greifswald, Germany
Dragan Pavlovic
- Department of Anaesthesiology and Intensive Care Medicine, Faculty of Medicine, University of Greifswald, Friedrich-Loeffler Str. 23c, 17475 Greifswald, Germany
Christiane Kunert-Keil
- Department of Orthodontics, Faculty of Medicine, University of Greifswald, Rotgerber Str. 8, 17475 Greifswald, Germany
- Institute of Pathophysiology, Faculty of Medicine, University of Greifswald, Greifswalder Str. 11C, 17495 Karlsburg, Germany

Accepted 6 February 2010.

Abstract

Objective

Duchenne muscular dystrophy (DMD) patients have distorted dentofacial morphology that could be a result of changed force balance of masticatory muscles due to unequal dystrophic changes in various masticatory muscles. Skeletal muscles of DMD patients and those of murine model of DMD – mdx mice – are both characterized by Ca²⁺ induced muscle damage, muscle weakness and characteristic histological changes. Therefore, to determine the pathological changes in this animal model of DMD, we examined the masticatory muscles of the mdx mice for histological abnormalities including nuclei localization, fibre diameters, and collagen expression.

Design

Muscle sections from masseter (MAS), temporal (TEM), tongue (TON) and soleus (SOL) of mdx and control normal mice were stained with hemalaun/eosin or with Sirius Red and morphometrically analysed. Levels of collagen staining in normal and mdx muscles were measured using image analysis and the mean optical density (mod) was determined.

Results

Dystrophin deficient masticatory muscles contained 11–75% fibres with centralised nuclei. In mdx mice an increased mean fibre diameter was observed as compared to the age-matched control muscles (control vs. mdx; MAS: 33.44±0.49μm vs. 37.76±0.68μm, p<0.005; TEM: 32.93±0.4μm vs. 42.93±0.68μm, p<0.005; SOL: 33.15±0.29μm vs. 40.62±0.55μm, p<0.005; TON: 13.44±0.68μm vs. 15.63±0.18μm, p<0.005). Increased expression of collagen was found in MAS (mod control vs. mdx: 1.34 vs. 3.99, p<0.005), TEM (mod control vs. mdx: 3.11 vs. 4.73, p<0.01) and SOL (mod control vs. mdx: 2.36 vs. 3.49, p<0.01).

Conclusion

Our findings revealed that mdx masticatory muscles are unequally affected by the disease process. The masticatory muscles of the mdx mice could present a useful model for further investigating the influence of dystrophin deficiency on muscles function.

Keywords: Mdx mice, Muscular dystrophy, DMD, Histopathology, Masticatory muscles