Laboratory of Morphology and Physical Activity (LAMAF), Institute of Biosciences (IB), São Paulo State University (UNESP), Rio Claro, São Paulo, Brazil.
Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil.
Microsc Res Tech. 2024 Aug;87(8):1733-1741. doi: 10.1002/jemt.24549. Epub 2024 Mar 19.
The peripheral nerve injury (PNI) affects the morphology of the whole locomotor apparatus, which can reach the myotendinous junction (MTJ) interface. In the injury condition, the skeletal muscle satellite cells (SC) are triggered, activated, and proliferated to repair their structure, and in the MTJ, the telocytes (TC) are associated to support the interface with the need for remodeling; in that way, these cells can be associated with SC. The study aimed to describe the SC and TC relationship after PNI at the MTJ. Sixteen adult Wistar rats were divided into Control Group (C, n = 8) and PNI Group (PNI, n = 8), PNI was performed by the constriction of the sciatic nerve. The samples were processed for transmission electron microscopy and immunostaining analysis. In the C group was evidenced the arrangement of sarcoplasmic evaginations and invaginations, the support collagen layer with a TC inside it, and an SC through vesicles internally and externally to then. In the PNI group were observed the disarrangement of invaginations and evaginations and sarcomeres degradation at MTJ, as the disposition of telopodes adjacent and in contact to the SC with extracellular vesicles and exosomes in a characterized paracrine activity. These findings can determine a link between the TCs and the SCs at the MTJ remodeling. RESEARCH HIGHLIGHTS: Peripheral nerve injury promotes the myotendinous junction (MTJ) remodeling. The telocytes (TC) and the satellite cells (SC) are present at the myotendinous interface. TC mediated the SC activity at MTJ.
周围神经损伤 (PNI) 会影响整个运动器官的形态，甚至可以到达肌-腱连接 (MTJ) 界面。在损伤状态下，骨骼肌卫星细胞 (SC) 被触发、激活并增殖以修复其结构，而在 MTJ 中，存在着与支持界面重塑相关的长梭形细胞（TC）；通过这种方式，这些细胞可以与 SC 相关联。本研究旨在描述 PNI 后 MTJ 处 SC 和 TC 的关系。将 16 只成年 Wistar 大鼠分为对照组 (C 组，n=8) 和 PNI 组 (PNI 组，n=8)，通过坐骨神经缩窄来建立 PNI 模型。对样本进行透射电子显微镜和免疫染色分析。在 C 组中，观察到了肌浆内陷和外凸的排列，支持胶原层内有一个 TC，以及一个通过囊泡内部和外部延伸的 SC。在 PNI 组中，观察到 MTJ 处的内陷和外凸排列紊乱以及肌节降解，TC 的附属物与 SC 相邻并接触，具有特征性的旁分泌活性，伴有细胞外小泡和外泌体。这些发现可以确定 TC 和 SC 在 MTJ 重塑中的联系。研究亮点：周围神经损伤促进肌-腱连接 (MTJ) 重塑。长梭形细胞 (TC) 和卫星细胞 (SC) 存在于肌-腱连接界面。TC 介导了 MTJ 处的 SC 活性。
