Deschenes Michael R, Rackley Max, Fernandez Sophie, Heidebrecht Megan, Hamilton Kate, Paez Hector G, Paez Christopher R, Alway Stephen E
Department of Kinesiology and Health Sciences, College of William & Mary, Williamsburg, USA.
Program in Neuroscience, College of William & Mary, Williamsburg, USA.
Synapse. 2025 Jul;79(4):e70022. doi: 10.1002/syn.70022.
Neuromuscular diseases and damage affect many people of all ages and are responsible for an exorbitant medical cost, more than $200 million annually. Accordingly, finding an appropriate model to investigate potential curative interventions is necessary. One currently used involves the application of toxic agents on skeletal muscle followed by mitochondrial transplant therapy. A question regarding this model is whether such toxins impact not only muscle tissue but also the neuromuscular junctions (NMJs) responsible for exciting the muscle tissue. This question was addressed here by forming four experimental groups of C57BL/six mice (10-14 per group) that were 8-12 weeks of age: 1) controls whose muscles had not been injured or treated, 2) muscles taken from mice that were injured and then treated with mitochondrial supplement, 3) muscles that had not been injured but were still treated with mitochondria, and 4) muscles that were injured and received no mitochondrial treatment. Several pre- and postsynaptic features of NMJs were subject to immunofluorescent staining procedures before having morphological features assessed with confocal microscopy. Results revealed that only postsynaptic acetylcholine (ACh) receptors showed any significant (p < 0.05) between-group differences, including decreased area size and perimeter length around ACh receptor clusters in injured NMJs. However, presynaptic nerve terminal branching was not different (p > 0.05) among treatment groups, and structural features were not different between groups with the exception of dispersion of postsynaptic receptors. Overall, these results suggest that skeletal muscles damaged with toxin accurately mimic what occurs during toxin-induced damage and post-injury recovery and can be used as a faithful model of occurrences during damage to NMJs as a result of muscle damage along with recovery from that insult.
神经肌肉疾病和损伤影响着各个年龄段的许多人，并导致了高昂的医疗费用，每年超过2亿美元。因此，找到一个合适的模型来研究潜在的治疗干预措施是必要的。目前使用的一种方法是在骨骼肌上应用有毒物质，然后进行线粒体移植治疗。关于这个模型的一个问题是，这些毒素是否不仅会影响肌肉组织，还会影响负责刺激肌肉组织的神经肌肉接头（NMJ）。本文通过将8-12周龄的C57BL/6小鼠（每组10-14只）分为四个实验组来解决这个问题：1）肌肉未受伤或未接受治疗的对照组；2）取自受伤后接受线粒体补充治疗的小鼠的肌肉；3）未受伤但仍接受线粒体治疗的肌肉；4）受伤且未接受线粒体治疗的肌肉。在通过共聚焦显微镜评估形态学特征之前，对NMJ的几个突触前和突触后特征进行免疫荧光染色程序。结果显示，只有突触后乙酰胆碱（ACh）受体在组间存在任何显著差异（p<0.05），包括受伤NMJ中ACh受体簇周围的面积大小和周长长度减小。然而，突触前神经末梢分支在各治疗组之间没有差异（p>0.05），除了突触后受体的分散外，各组的结构特征也没有差异。总体而言，这些结果表明，用毒素损伤的骨骼肌准确模拟了毒素诱导损伤和损伤后恢复过程中发生的情况，并且可以用作肌肉损伤导致NMJ损伤以及从该损伤中恢复过程中发生情况的可靠模型。
