Hoffe Brendan, Kang Gia, Thomson Hannah, Banton Rohan, Piehler Thuvan, Petel Oren E, Holahan Matthew R
Departement of Neuroscience, Carleton University, Ottawa, Ontario, Canada.
Department of Mechanical and Aerospace Engineering, Carleton University, Ottawa, Ontario, Canada.
PLoS One. 2025 Feb 24;20(2):e0318932. doi: 10.1371/journal.pone.0318932. eCollection 2025.
Brain tissue as a material presents unique properties with a multitude of cell types and densities, varying degrees of axonal fiber diameters and blood vessels. These neural components are contained within a very viscous environment that upon impact, can result in a variety of tensile, compressive and rotational forces. The depths of the sulcus appear to be particularly vulnerable to biomechanical forces following an impact. The movement and subsequent forces loaded on to the brain have been shown to produce a variety of biomechanical responses that impair neurophysiological functioning at the cellular level. We recently reported a decrease in microtubule associated protein 2 (MAP2) within the depths of the porcine sulcus in an ex vivo model, along with elevated tensile strain in this region within 1 hour after impact. In the current work, using the same impact model, we explored whether changes in spine morphology and density occurred within the same timeframe following impact. The Golgi-Cox method was used to visualize dendritic spine morphology. Cortical pyramidal neurons within the depths and the arms of the sulcus were reconstructed. One hour after impact, there was a change in the distribution of spine type resulting in an increased proportion of mushroom-type spines compared to nonimpacted tissue. The increased proportion of mushroom-type spines was proportional to tensile strain measurements in the apical dendrites. These results demonstrate the sensitivity of dendritic spine morphology to tensile strain within the porcine cortex and suggest a state of hyperexcitability during the hyperacute phase following an impact.
脑组织作为一种材料，具有独特的特性，包含多种细胞类型和密度、不同程度的轴突纤维直径以及血管。这些神经成分存在于一个非常粘稠的环境中，受到撞击时，会产生各种拉伸、压缩和旋转力。脑沟深度在受到撞击后似乎特别容易受到生物力学力的影响。已表明作用于大脑的运动及随后的力会产生各种生物力学反应，这些反应会在细胞水平上损害神经生理功能。我们最近在一个体外模型中报告了猪脑沟深度内微管相关蛋白2（MAP2）的减少，以及撞击后1小时内该区域拉伸应变的升高。在当前的研究中，我们使用相同的撞击模型，探讨了撞击后在同一时间范围内脊柱形态和密度是否发生变化。采用高尔基-考克斯法来观察树突棘形态。对脑沟深度和脑沟臂内的皮质锥体神经元进行了重建。撞击后1小时，脊柱类型的分布发生了变化，与未受撞击的组织相比，蘑菇型脊柱的比例增加。蘑菇型脊柱比例的增加与顶端树突中的拉伸应变测量值成正比。这些结果证明了猪皮质内树突棘形态对拉伸应变的敏感性，并表明撞击后超急性期存在过度兴奋状态。
