Saboorian AmirAli, Vahidi Bahman
Department of Medical Technology and Tissue Engineering, Faculty of Life Science Engineering, College of Interdisciplinary Science and Technology, University of Tehran, Tehran, Iran.
Phys Eng Sci Med. 2025 Jul 21. doi: 10.1007/s13246-025-01591-5.
Despite various studies on axonal mechanics in recent years, the mechanisms and factors contributing to axonal transport are still not fully understood. In this study, the possible role of action potential (AP) propagation through neurites in axonal transport was explored by utilizing underlying physical principles through numerical simulation. A fluid-structure interaction model was used to simulate the physical behavior of the axon as action potential waves propagate. The axon and its membrane were modeled as a fluid-filled cylinder with elastic walls, where the action potential acts as a moving radial load on the axon. Utilizing computational fluid dynamics simulation and accounting for forces induced by the action potential led to the emergence of an intercellular fluid flow inside the axon, which was subsequently incorporated into current models of axonal transport in the literature. The convective intercellular fluid flow induced by the action potential acts as a mechanism for axonal transport, with velocities ranging from 2 to 17 mm per day, which is consistent with previously reported ranges for the slow axonal transport component. Additionally, by incorporating the effect of convective flow, it was shown that unidirectional transport, coupled with convective transport, can successfully describe the movement of larger cargos against their concentration gradients. The results demonstrated that for the squid giant axon and hippocampal neurites, the displacement pulse propagates almost simultaneously with the AP. Analyzing the interaction between action potential and axonal transport can lead to a better understanding of these phenomena.
尽管近年来对轴突力学进行了各种研究，但对轴突运输的机制和影响因素仍未完全了解。在本研究中，通过数值模拟利用潜在的物理原理，探讨了动作电位（AP）通过神经突传播在轴突运输中的可能作用。使用流固相互作用模型来模拟动作电位波传播时轴突的物理行为。轴突及其膜被建模为一个具有弹性壁的充满流体的圆柱体，其中动作电位作为轴突上的移动径向载荷。利用计算流体动力学模拟并考虑动作电位诱导的力，导致轴突内出现细胞间流体流动，随后将其纳入文献中当前的轴突运输模型。动作电位诱导的对流细胞间流体流动作为轴突运输的一种机制，速度范围为每天2至17毫米，这与先前报道的慢轴突运输成分的范围一致。此外，通过纳入对流流动的影响，结果表明单向运输与对流运输相结合，可以成功描述较大货物逆其浓度梯度的移动。结果表明，对于鱿鱼巨轴突和海马神经突来说，位移脉冲几乎与动作电位同时传播。分析动作电位与轴突运输之间的相互作用可以更好地理解这些现象。
