Mercer R R, Crapo J D
Department of Medicine, Duke University Medical Center, Durham, North Carolina 27710.
J Appl Physiol (1985). 1992 Apr;72(4):1473-9. doi: 10.1152/jappl.1992.72.4.1473.
Ultrastructural changes in lung parenchymal elastic fibers were studied morphometrically 1, 4, and 12 wk after a single 12-unit dose of pancreatic elastase and in a saline-instilled control group. The mean linear intercept of the parenchymal air spaces was increased in the 1-, 4-, and 12-wk post-elastase instillation groups compared with age-matched controls. The volume of alveolar connective tissue fibers predominantly composed of elastin (elastic fibers) was decreased by 35% 1 wk after the instillation of elastase but returned to control levels by 4 wk. Although the total volume of elastic fibers was normal 12 wk after instillation of elastase, the volume of elastic fibers in alveolar entrance rings remained significantly reduced. In serial sections of elastic fibers, numerous gaps or separations in the normally continuous band of elastic fibers that encircle each alveolus were identified 1 wk after elastase instillation. There were 169 +/- 8 (SE), 62 +/- 32, and 12 +/- 6 gaps per millimeter of alveolar entrance ring circumference at 1, 4, and 12 wk, respectively, in the elastase-treated groups. The number of gaps at 12 wk was equivalent to two gaps or discontinuities in the elastic fibers of every alveolar entrance ring. No gaps or separations in elastic fibers were detected at 1, 4, or 12 wk in the control groups. These defects occur in concordance with the progression of air space enlargement and presumably contribute to the progression of air space enlargement that occurs after the elastin content of the tissue has returned to normal.
在单次给予12单位剂量的胰腺弹性蛋白酶后1周、4周和12周，以及在生理盐水注入的对照组中，对肺实质弹性纤维的超微结构变化进行了形态计量学研究。与年龄匹配的对照组相比，弹性蛋白酶注入后1周、4周和12周的肺实质气腔平均线性截距增加。主要由弹性蛋白组成的肺泡结缔组织纤维（弹性纤维）的体积在弹性蛋白酶注入后1周减少了35%，但在4周时恢复到对照水平。尽管弹性蛋白酶注入后12周弹性纤维的总体积正常，但肺泡入口环处的弹性纤维体积仍显著减少。在弹性纤维的连续切片中，弹性蛋白酶注入后1周，在环绕每个肺泡的正常连续弹性纤维带中发现了许多间隙或分离。弹性蛋白酶处理组在1周、4周和12周时，每毫米肺泡入口环周长的间隙数分别为169±8（标准误）、62±32和12±6。12周时的间隙数相当于每个肺泡入口环弹性纤维中的两个间隙或不连续处。对照组在1周、4周或12周时未检测到弹性纤维的间隙或分离。这些缺陷与气腔扩大的进展一致，并且可能促成了在组织弹性蛋白含量恢复正常后发生的气腔扩大的进展。
