Department of Orthodontics, Carl Gustav Carus Campus Technische Universitaet, Dresden, Germany.
Department of Anaesthesiology and Intensive Care Medicine, Carl Gustav Carus Campus, Technische Universitaet, Dresden, Germany.
J Physiol Pharmacol. 2017 Apr;68(2):181-189.
Progressive muscle wasting, frequently associated with inflammation, muscle fibre degeneration and fibrosis, is a characteristic of DMD (Duchenne muscular dystrophy). Its most common used animal model, the mdx mouse, however can overcome muscle degeneration by regeneration processes and is for this reason not suitable to answer all scientific questions. The aim of this study was to evaluate the ability of botulinum toxin A (BTX-A) in breaking down muscle regeneration in mdx mice. For this purpose, the right masseter muscle of 100 days old mdx and healthy mice was paralyzed by a single specific intramuscular injection of BTX-A. After 21 days, right and left masseter and temporal muscles as well as tongue muscle were carefully dissected, and gene and protein expression of caveolin-1, caveolin-3 and vascular endothelial growth factor (VEGF) were determined using quantitative RT-PCR and Western blot technique. Statistics were performed using Student's t-test and Mann Whitney U-test (significance level: P ≤ 0.05). After BTX-A injection, in both mice strains and for all three studied genes, no significant differences in mRNA amount could be detected between treated and untreated masseter muscles. A significant increase in caveolin-1, caveolin-3 and VEGF mRNA expression could only be found in the right temporal muscle of control mice compared to the left side. All three investigated proteins were more frequent to be found in dystrophic masseter muscle samples compared to the corresponding control samples, whereas significant decreased caveolin-3 protein levels could only be detected in the treated masseter versus untreated masseter muscle of controls. In contrast to previous conclusions, with this study it was not possible to prove a BTX-A-induced dystrophic phenotype in control animals, in which only the known decreases of caveolin-3 protein expression could be verified due to denervation. At the same time, however, gene and protein expression in dystrophic mice was not changed after BTX-A injection.
进行性肌肉萎缩，常伴有炎症、肌纤维变性和纤维化，是 DMD（杜氏肌营养不良症）的特征。然而，其最常用的动物模型 mdx 小鼠可以通过再生过程克服肌肉退化，因此不适合回答所有科学问题。本研究旨在评估肉毒杆菌毒素 A（BTX-A）在破坏 mdx 小鼠肌肉再生中的能力。为此，通过单次特定的肌肉内注射 BTX-A 使 100 天大的 mdx 小鼠和健康小鼠的右侧咬肌瘫痪。21 天后，仔细解剖右侧和左侧咬肌、颞肌和舌肌，并使用定量 RT-PCR 和 Western blot 技术测定 caveolin-1、caveolin-3 和血管内皮生长因子（VEGF）的基因和蛋白表达。使用 Student's t-test 和 Mann Whitney U-test 进行统计学分析（显著性水平：P ≤ 0.05）。BTX-A 注射后，在两种小鼠品系和所有三种研究基因中，处理和未处理的咬肌之间的 mRNA 量没有显著差异。仅在对照小鼠的右侧颞肌中，与左侧相比，caveolin-1、caveolin-3 和 VEGF mRNA 表达显著增加。所有三种研究的蛋白质在营养不良的咬肌样本中比相应的对照样本更频繁地被发现，而仅在对照的处理咬肌与未处理咬肌相比，caveolin-3 蛋白水平显著降低。与之前的结论相反，本研究未能证明 BTX-A 诱导的对照动物的营养不良表型，在对照动物中，由于去神经支配，仅证实了 caveolin-3 蛋白表达的已知减少。同时，然而，BTX-A 注射后，营养不良小鼠的基因和蛋白表达没有改变。
