Whitehead Nicholas P, Pham Catherine, Gervasio Othon L, Allen David G
Bosch Institute, School of Medical Sciences, University of Sydney F13, Sydney, NSW 2006, Australia.
J Physiol. 2008 Apr 1;586(7):2003-14. doi: 10.1113/jphysiol.2007.148338. Epub 2008 Feb 7.
Duchenne muscular dystrophy (DMD) is a severe degenerative muscle disease caused by a mutation in the gene encoding dystrophin, a protein linking the cytoskeleton to the extracellular matrix. In this study we investigated whether the antioxidant N-acetylcysteine (NAC) provided protection against dystrophic muscle damage in the mdx mouse, an animal model of DMD. In isolated mdx muscles, NAC prevented the increased membrane permeability and reduced the force deficit associated with stretch-induced muscle damage. Three-week-old mdx mice were treated with NAC in the drinking water for 6 weeks. Dihydroethidium staining showed that NAC treatment reduced the concentration of reactive oxygen species (ROS) in mdx muscles. This was accompanied by a significant decrease in centrally nucleated fibres in muscles from NAC-treated mdx mice. Immunoblotting showed that NAC treatment decreased the nuclear protein expression of NF-kappaB, a transcription factor involved in pro-inflammatory cytokine expression. Finally, we show that NAC treatment reduced caveolin-3 protein levels and increased the sarcolemmal expression of beta-dystroglycan and the dystrophin homologue, utrophin. Taken together, our findings suggest that ROS play an important role in the dystrophic pathogenesis, both in terms of activating damage pathways and in regulating the expression of some dystrophin-associated membrane proteins. These results offer the prospect that antioxidants such as NAC could have therapeutic potential for DMD patients.
杜兴氏肌营养不良症（DMD）是一种严重的退行性肌肉疾病，由编码肌营养不良蛋白的基因突变引起，肌营养不良蛋白是一种将细胞骨架与细胞外基质连接起来的蛋白质。在本研究中，我们调查了抗氧化剂N-乙酰半胱氨酸（NAC）是否能保护mdx小鼠（DMD的动物模型）的营养不良性肌肉损伤。在分离的mdx肌肉中，NAC可防止膜通透性增加，并减少与拉伸诱导的肌肉损伤相关的力量缺陷。给三周龄的mdx小鼠饮用含NAC的水6周。二氢乙锭染色显示，NAC处理降低了mdx肌肉中活性氧（ROS）的浓度。这伴随着NAC处理的mdx小鼠肌肉中中央核纤维的显著减少。免疫印迹显示，NAC处理降低了NF-κB的核蛋白表达，NF-κB是一种参与促炎细胞因子表达的转录因子。最后，我们发现NAC处理降低了小窝蛋白-3的蛋白水平，并增加了β-肌营养不良聚糖和肌营养不良蛋白同系物抗肌萎缩蛋白的肌膜表达。综上所述，我们的研究结果表明，ROS在营养不良发病机制中起着重要作用，无论是在激活损伤途径方面，还是在调节一些与肌营养不良蛋白相关的膜蛋白表达方面。这些结果为NAC等抗氧化剂对DMD患者具有治疗潜力提供了前景。
