平滑肌层增生对气道管壁内应力分布影响的数值模拟研究

Numerical Simulation of the Effect of Smooth Muscle Layer on the Stress Distribution in the Airway Wall

许多慢性呼吸道疾病都伴随着气道管壁组织重塑,其中平滑肌肥大和增生直接影响气道的力学特性,进而因为气道内应力的分布不均,导致内壁出现局部应力刺激增加等现象。本研究基于气道的解剖结构,将其简化成为具有内壁、平滑肌层和外膜等三层结构的中空管状结构,构建具有层结构的气道有限元模型,并用来分析在生理和病理情况下平滑肌增生对气道力学行为的影响。结果表明,在气道外膜层出现应力最小值;平滑肌层增厚和局部平滑肌的增生都会导致气道平滑肌层受到的应力值增加,同时在增生面积相同的情况下,平滑肌层的应力值随增生的数目增加而增加;平滑肌层增生的分布对气道力学性能有较大的影响,增生越集中,气道所受到的应力值越大。

Many chronic respiratory diseases are associated with airway remodeling. It is well known hyperplasia and hypertrophy of smooth muscle directly affect the mechanical properties of the airway. This can cause uneven distribution of stress in the airway,leading to local stress stimulation increase in the inner layer. In present work,we built a finite element model which simplified the anatomical structure of airway into a three-layers structure： inner wall,smooth muscle layer and the adventitia layer. This model was further used to analyze the mechanical properties variation of airway smooth muscle layer under physiological and pathological situations. It was observed that the minimum stress occurr in the adventitia layer. While smooth muscle layer thickening and local smooth muscle hyperplasia can lead to the stress increase of airway smooth muscle layer. With the same hyperplasia area,the stress of the smooth muscle layer increase along with the increasing numbers of hyperplasia. In addition,the distribution of hyperplasia in smooth muscle layer has a great influence on airway mechanical properties,the more concentrated the hyperplasia is,the greater the stress value of airway ever receive.