Applied Physics Laboratory, Johns Hopkins University, 11100 Johns Hopkins Road, Laurel, MD, 20723, USA.
Department of Mechanical Engineering, Johns Hopkins University, Baltimore, MD, 21218, USA.
Biomech Model Mechanobiol. 2024 Apr;23(2):397-412. doi: 10.1007/s10237-023-01781-8. Epub 2023 Oct 28.
Mouse models are used to better understand brain injury mechanisms in humans, yet there is a limited understanding of biomechanical relevance, beginning with how the murine brain deforms when the head undergoes rapid rotation from blunt impact. This problem makes it difficult to translate some aspects of diffuse axonal injury from mouse to human. To address this gap, we present the two-dimensional strain field of the mouse brain undergoing dynamic rotation in the sagittal plane. Using a high-speed camera with digital image correlation measurements of the exposed mid-sagittal brain surface, we found that pure rotations (no direct impact to the skull) of 100-200 rad/s are capable of producing complex strain fields that evolve over time with respect to rotational acceleration and deceleration. At the highest rotational velocity tested, the largest tensile strains (≥ 21% elongation) in selected regions of the mouse brain approach strain thresholds previously associated with axonal injury in prior work. These findings provide a benchmark to validate the mechanical response in biomechanical computational models predicting diffuse axonal injury, but much work remains in correlating tissue deformation patterns from computational models with underlying neuropathology.
鼠类模型被用于更好地理解人类的脑损伤机制，但对于生物力学相关性的理解还很有限，这从头部受到钝性冲击时鼠脑的变形方式就可以看出来。这个问题使得一些弥漫性轴索损伤的特征难以从鼠类模型转化到人类。为了解决这一差距，我们呈现了在矢状面经历动态旋转的鼠类大脑的二维应变场。我们使用高速摄像机和暴露的中矢状脑表面的数字图像相关测量，发现纯旋转（头骨没有直接撞击）100-200 rad/s 就能产生复杂的应变场，这些应变场随着旋转加速度和减速度的变化而随时间演变。在测试的最高旋转速度下，在鼠类大脑的选定区域中，最大的拉伸应变（≥21%伸长）接近先前与轴索损伤相关的应变阈值。这些发现为验证预测弥漫性轴索损伤的生物力学计算模型中的力学响应提供了基准，但仍有大量工作需要将计算模型中的组织变形模式与潜在的神经病理学相关联。
