Early changes of lung function and structure in an elastase model of emphysema -: a hyperpolarized 3He MRI study
Early changes of lung function and structure in an elastase model of emphysema -: a hyperpolarized 3He MRI study
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DOI：
10.1152/japplphysiol.00482.2007
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发表时间：
2008-03-01
影响因子：
3.3
通讯作者：
Rizi, Rahim R.
中科院分区：
文献类型：
--
作者：
Emami, Kiarash;Cadman, Robert V.;Rizi, Rahim R.
用弹性蛋白酶诱发大鼠肺气肿模型，观察了35只SD大鼠轻度（5 U/100 g）和中度（10 U/100 g）肺气肿早期肺功能和结构的变化。在模型诱导后5周和10周，通过超极化He-3 MRI在区域基础上（平面分辨率为3.2 mm）测量肺通气。在成像之后，从取自每个肺叶中心的组织切片测量平均肺泡直径。研究疾病进展期间平均通气分数、平均线性截距和受试者内通气异质性的变化。在10单位组的两个时间点，健康对照组（0.23 +/- 0.04）和肺气肿动物之间的平均通气分数存在显著差异（分别为0.06 +/- 0.02和0.12 +/- 0.05）。直到第10周，健康大鼠（37 +/- 10 μ m）和肺气肿大鼠（5和10单位分别为73 +/- 25和95 +/- 31 μ m）的平均肺泡直径的变化才在统计学上可观察到。功能-结构相关性的评估表明，通气分数的大部分下降发生在前5周，而肺泡直径的扩大主要出现在第5和第10周之间。基于整个肺的通气分数的第20百分位数的阈值度量被用于检测具有置信度的疾病的发作，而不依赖于区域通气测量是否相对于每只大鼠的递送潮气量和估计的功能残气量被标准化。
Early changes of lung function and structure were studied in the presence of an elastase-induced model of emphysema in 35 Sprague-Dawley rats at mild ( 5 U/100 g) and moderate ( 10 U/100 g) severities. Lung ventilation was measured on a regional basis ( at a planar resolution of 3.2 mm) by hyperpolarized He-3 MRI at 5 and 10 wk after model induction. Subsequent to imaging, average alveolar diameter was measured from histological slices taken from the centers of each lobe. Changes of mean fractional ventilation, mean linear intercept, and intrasubject heterogeneity of ventilation were studied during disease progression. Mean fractional ventilation was significantly different between healthy controls ( 0.23 +/- 0.04) and emphysematous animals at both time points in the 10-unit group ( 0.06 +/- 0.02 and 0.12 +/- 0.05, respectively). Changes in average alveolar diameter were not statistically observable until the 10th wk between healthy ( 37 +/- 10 mu m) and emphysematous rats (73 +/- 25 and 95 +/- 31 mu m, for 5 and 10 units, respectively). Assessment of function- structure correlation suggested that the majority of the decline in fractional ventilation occurred in the first 5 wk, while enlargement of alveolar diameters appeared primarily between the 5th and 10th wk. A thresholding metric, based on the 20th percentile of fractional ventilation over the entire lung, was utilized to detect the onset of the disease with confidence, independent of whether the regional ventilation measurements were normalized with respect to the delivered tidal volume and estimated functional residual capacity of each individual rat.