Increased oxidative stress in dystrophin deficient (mdx) mice masticatory muscles

Background: It has been suggested that increased oxidative stress and the glutathione antioxidant system play an important role in the pathogenesis of Duchenne muscular dystrophy. However, there is still a lack of data about the oxidative status in dystrophic masticatory muscles. Methods: In the masticatory muscles of the mouse model of Duchenne muscular dystrophy (mdx and controls; 100 days old, n = 8-10 each group) we examined the GSH and GSSG content (glutathione reduced/oxidized form) and the level of lipid peroxidation (LPO) as measured by the thiobarbituric acid-reaction. Results: In the mdx mice masticatory muscles we found increased oxidative stress as compared to the controls. The GSH values in mdx muscles were decreased (mean +/- SEM; masseter 339.8 +/- 37.6 mu g/g vs. 523.1 +/- 36.1 mu/g, temporal 304.1 +/- 49.6 mu g/g vs.512.6 +/- 60.6 mu g/g, tongue muscle 243.3 +/- 28.8 mu g/g vs. 474.9 +/- 40.1 mu g/g; Fig. 1) as compared to normal mice. The GSH/GSSG ratio in mdx mice was consequently decreased. No significant differences in GSSG content and LPO levels were found between mdx and control mice. Conclusions: The results imply that oxidative stress is present in all three studied mdx mouse masticatory muscles. (C) 2010 Elsevier GmbH. All rights reserved.