Aoyagi N, Masuzawa H, Sano K, Kihira M, Kobayashi S
No To Shinkei. 1982 May;34(5):509-16.
It is important to have information about physical property of the brain in order to elucidate both the physical changes of the morbid brain and the physical mechanism of the traumatic brain injury. Under the hypothesis that reaction of the active brain to the dynamic load can be compared to the Maxwell-Voigt three dimensional model, elastic property of the brain was obtained as the Young's modulus (E: 10(-2) Kgf/cm2) of which error was less than 10%, and viscous property of the brain as the Viscous modulus (eta: 10(-2) Kgf.sec/cm2). And it was confirmed that the reactive pressure of the brain to dynamic load came from the surface to about 15 mm depth of the brain. In this report, experiments were done on the alive normal brains, the edematous ones nd necrotic ones which were produced by the cold injury (dry ice-aceton) in dogs (9.0--16.0 Kg). In the normal brain, E = 3.24 +/- 0.25, eta = 1.10 +/- 0.37 and these moduli were also stable when the physical conditions of the brain were stable. Under the dehydration by 20% mannitol, E increased in its value (p less than 0.01). But under the hydration by 5% glucose, E did not change at all. In the edematous brain, E = 3.28 +/- 0.44, eta = 1.74 +/- 0.06 and E of the edematous brain was almost same as that of normal ones, but under the dehydration, E of the edematous brain decreased (p less than 0.10), on the other hand it increased in its value under the hydration (p less than 0.05). In the necrotic brain, E = 1.60 +/- 0.14, eta = 0.82 +/- 0.28. Both moduli were of lower values and moreover they did not change its values at all under dehydration and hydration. As Young's modulus is the elastic index of the brain, the converse (1/E) should be compliance of the brain, that is to say, buffer effect of the brain. As for the compliance, the necrotic brain has maximum buffer effect and the over-hydrated edematous brain and the dehydrated normal ones have minimum buffer effect. From analysing the changes of the viscous moduli, it became clear that the viscous moduli took quite different functions in alive brains and in fatal ones, and it was suspected that the alive brain might not be so simple in its viscoelastic property.
为了阐明病态大脑的物理变化以及创伤性脑损伤的物理机制，了解大脑的物理特性非常重要。在活跃大脑对动态负荷的反应可与麦克斯韦 - 沃伊特三维模型相比较的假设下，获得了大脑的弹性特性，即杨氏模量（E：10^(-2) Kgf/cm²），其误差小于10%，以及大脑的粘性特性，即粘性模量（η：10^(-2) Kgf·sec/cm²）。并且证实了大脑对动态负荷的反应压力从大脑表面延伸至约15毫米深度处。在本报告中，对犬（9.0 - 16.0千克）中通过冷损伤（干冰 - 丙酮）产生的正常活脑、水肿脑和坏死脑进行了实验。在正常脑中，E = 3.24 ± 0.25，η = 1.10 ± 0.37，并且当大脑的物理条件稳定时，这些模量也稳定。在20%甘露醇脱水情况下，E值增加（p < 0.01）。但在5%葡萄糖水化情况下，E根本没有变化。在水肿脑中，E = 3.28 ± 0.44，η = 1.74 ± 0.06，水肿脑的E与正常脑的几乎相同，但在脱水时，水肿脑的E降低（p < 0.10），另一方面在水化时其值增加（p < 0.05）。在坏死脑中，E = 1.60 ± 0.14，η = 0.82 ± 0.28。两个模量的值都较低，而且在脱水和水化时它们的值根本没有变化。由于杨氏模量是大脑的弹性指标，其倒数（1/E）应是大脑的顺应性，也就是说，是大脑的缓冲效应。至于顺应性，坏死脑具有最大缓冲效应，过度水化的水肿脑和脱水的正常脑具有最小缓冲效应。通过分析粘性模量的变化，很明显粘性模量在活脑和死亡大脑中发挥着截然不同的作用，并且怀疑活脑的粘弹性特性可能并非如此简单。
