Mechanical and Aerospace Engineering, the University of Texas at Arlington, Arlington, 76010, USA.
Sci Rep. 2017 Jul 13;7(1):5323. doi: 10.1038/s41598-017-05790-3.
The purpose of this study is to conduct modeling and simulation to understand the effect of shock-induced mechanical loading, in the form of cavitation bubble collapse, on damage to the brain's perineuronal nets (PNNs). It is known that high-energy implosion due to cavitation collapse is responsible for corrosion or surface damage in many mechanical devices. In this case, cavitation refers to the bubble created by pressure drop. The presence of a similar damage mechanism in biophysical systems has long being suspected but not well-explored. In this paper, we use reactive molecular dynamics (MD) to simulate the scenario of a shock wave induced cavitation collapse within the perineuronal net (PNN), which is the near-neuron domain of a brain's extracellular matrix (ECM). Our model is focused on the damage in hyaluronan (HA), which is the main structural component of PNN. We have investigated the roles of cavitation bubble location, shockwave intensity and the size of a cavitation bubble on the structural evolution of PNN. Simulation results show that the localized supersonic water hammer created by an asymmetrical bubble collapse may break the hyaluronan. As such, the current study advances current knowledge and understanding of the connection between PNN damage and neurodegenerative disorders.
本研究旨在进行建模和模拟，以了解冲击波引起的机械加载（以空化气泡溃陷的形式）对脑周细胞网络（PNNs）损伤的影响。众所周知，由于空化溃陷引起的高能内爆是许多机械装置腐蚀或表面损伤的原因。在这种情况下，空化是指由压降产生的气泡。类似的损伤机制在生物物理系统中已经存在很长时间，但尚未得到充分探索。在本文中，我们使用反应分子动力学（MD）模拟了在周细胞网络（PNN）内诱导的冲击波空化溃陷的情景，PNN 是大脑细胞外基质（ECM）的近神经元域。我们的模型集中在透明质酸（HA）的损伤上，HA 是 PNN 的主要结构成分。我们研究了空化气泡位置、冲击波强度和空化气泡大小对 PNN 结构演化的影响。模拟结果表明，由不对称气泡溃陷产生的局部超声速水锤可能会破坏透明质酸。因此，本研究推进了目前关于 PNN 损伤与神经退行性疾病之间联系的知识和理解。
