A trial to evaluate the mechanical anisotropy in human lung ; Aim for elucidating why centrilobular type emphysema occurs predominantly at upper lung

与香烟烟雾相关的小叶中心性肺气肿主要发生在上肺的原因尚不清楚。肺上叶呼吸运动小于肺下叶呼吸运动。我们假设细胞外基质的重建随着呼吸运动的机械负荷范围的不同而变化。根据这一假设，上肺抵抗机械应力的阈值可能低于下肺。在此背景下，我们试图评估人肺的力学各向异性，以明确力学性质在小叶中心型肺气肿发生发展中的作用。通过对片状样品的切割，制备了用于力学测量的狭缝样品。对机械应力的阈值是通过拉伸样品直到其分解来评估的。结果是，上肺的机械拉伸强度低于下肺。这一结果提示机械性能的分布可能有助于小叶中心型肺气肿的发生。

It has not been elucidated why centrilobular emphysema, associated with cigarette smoke, occurs predominantly at upper lung. Respiratory movement in the upper lobe is smaller than that in the lower lung. We hypothesize that reconstruction of extra cellular matrix varies according to range of mechanical load by respiratory movement. Based on this hypothesis the threshold against mechanical stress in the upper lung may be lower than that in the lower lung. In this context we tried to evaluate mechanical anisotropy in human lung to make clear the role of mechanical property in development of centrilobular emphysema.We prepared sheet samples from coronal plate of human lung. Slit samples for mechanical measurements were prepared by cutting the sheet samples. The threshold against mechanical stress was evaluated by stretching the samples until their breakdown.As a result, the mechanical stretching strength in the upper lung was lower than in the lower lung. This result suggests that the distribution of mechanical property may contribute to the development of centrilobular emphysema.