Hilman Melanie C, Mourkioti Foteini, Das Suradip, Cullen D Kacy
Center for Brain Injury & Repair, Department of Neurosurgery, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA.
Center for Neurotrauma, Neurodegeneration & Restoration, Corporal Michael J. Crescenz Veterans Affairs Medical Center, Philadelphia, Pennsylvania, USA.
Biotechnol J. 2025 Jun;20(6):e70047. doi: 10.1002/biot.70047.
While it is understood that muscle tissue generates contractile forces, it is less appreciated that muscle dynamically responds to applied forces during development. We previously fabricated tissue engineered muscle comprised of skeletal myocytes in co-culture with spinal motor neurons on aligned nanofiber poly-caprolactone scaffolding, demonstrating that innervation elicited more robust myofibers and formation of neuromuscular junctions. The current study utilized custom mechanobioreactors to apply tensile elongation to this engineered muscle platform to explore the effects of exogenous forces and scaffold topology on innervated versus non-innervated myocytes. Nanofiber scaffold alignment played a significant role in myocyte thickness, width, and fusion under both innervated and non-innervated conditions. A combination of tensile loading and nanofiber alignment increased myocyte fusion, suggesting these parameters work together to expedite and enhance myofiber formation and maturation. Overall, this multi-faceted paradigm, featuring biomechanical loading, substrate topology, and innervation, mimics key features of the developmental microenvironment experienced by myocytes in vivo. These findings may facilitate more sophisticated studies on muscle development, function, and responses to trauma while also elucidating principles to support the fabrication of engineered muscle to repair major muscle defects.
虽然人们都知道肌肉组织会产生收缩力，但肌肉在发育过程中对施加的力做出动态反应这一点却较少受到重视。我们之前构建了一种组织工程化肌肉，它由骨骼肌细胞与脊髓运动神经元在排列的纳米纤维聚己内酯支架上共培养而成，这表明神经支配能引发更强壮的肌纤维以及神经肌肉接头的形成。当前的研究利用定制的机械生物反应器对这个工程化肌肉平台施加拉伸伸长，以探究外力和支架拓扑结构对有神经支配和无神经支配的肌细胞的影响。在有神经支配和无神经支配的条件下，纳米纤维支架的排列对肌细胞的厚度、宽度和融合都起到了重要作用。拉伸加载和纳米纤维排列的组合增加了肌细胞融合，这表明这些参数共同作用以加速和增强肌纤维的形成与成熟。总体而言，这种多方面的模式，包括生物力学加载、底物拓扑结构和神经支配，模拟了体内肌细胞所经历的发育微环境的关键特征。这些发现可能有助于开展更复杂的关于肌肉发育、功能以及对创伤反应的研究，同时也阐明了支持构建工程化肌肉以修复主要肌肉缺陷的原理。
