Phasic respiratory pharyngeal mechanics by magnetic resonance imaging in lean and obese Zucker rats
Phasic respiratory pharyngeal mechanics by magnetic resonance imaging in lean and obese Zucker rats
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DOI：
10.1164/rccm.200505-705oc
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发表时间：
2006-05-01
影响因子：
24.7
通讯作者：
Kuna, ST
中科院分区：
文献类型：
--
作者：
Brennick, MJ;Pickup, S;Kuna, ST
理由：尽管阻塞性睡眠呼吸暂停与肥胖密切相关，但我们对肥胖如何改变咽的力学特性以及肥胖在睡眠呼吸暂停发病机制中的作用知之甚少。目的：本研究的总体目的是确定肥胖对瘦和肥胖Zucker大鼠咽气道大小和咽壁组织应变的影响。方法：对麻醉、自主呼吸的瘦（n = 9）和肥胖（n = 9） Zucker大鼠进行无创组织标记呼吸门控磁共振成像。使用平面测量、光流和有限元分析，分析在呼气和吸气时获得的吻侧、中端和尾侧咽的气道大小和咽壁组织应变。采用方差分析比较两组患者气道横截面面积、侧、前后气道直径、咽侧壁和咽腹壁组织应变（拉伸、压缩和拉伸方向）的差异（p < 0.05）。测量结果及主要结果：与瘦仔鼠相比，肥胖大鼠在吸气和呼气时咽部气道横截面积减小，吸气时气道面积增加较小，吸气时侧气道扩张减小。肥胖大鼠和瘦大鼠咽壁组织应变无显著差异。结论：这些发现表明，肥胖导致机械异常，减少咽气道大小，并阻止正常气道对咽壁组织应变变化的反应。
Rationale: Although obstructive sleep apnea is strongly associated with obesity, we have little understanding of how obesity may alter the mechanical properties of the pharynx and the role of obesity in the pathogenesis of sleep apnea.Objectives: The overall objective of this study was to determine the effect of obesity on pharyngeal airway size and pharyngeal wall tissue strain in lean and obese Zucker rats.Methods: Respiratory-gated magnetic resonance imaging with non-invasive tissue tagging was performed in anesthetized, spontaneously breathing lean (n = 9) and obese (n = 9) Zucker rats. Images acquired during expiration and inspiration of the rostral, mid-, and caudal pharynx were analyzed for airway size and pharyngeal wall tissue strain, using planimetry, optical flow, and finite element analyses. Differences in cross-sectional airway area, lateral and anteroposterior airway diameters, and tissue strain (stretch, compression, and direction of stretch) in the lateral and ventral pharyngeal walls were compared by analysis of variance (significance at p < 0.05).Measurements and Main Results: Compared with their lean littermates, obese rats had the following significant findings: reduced pharyngeal airway cross-sectional area during inspiration and expiration, smaller increases in airway area during inspiration, and decreased lateral airway dilation during inspiration. Tissue strain in the pharyngeal walls showed no significant differences between obese and lean rats.Conclusions: These findings suggest that obesity results in a mechanical abnormality that decreases pharyngeal airway size and prevents a normal airway response to a given change in pharyngeal wall tissue strain.