Walker D C, Behzad A R, Chu F
University of British Columbia, Pulmonary Research Laboratory, St. Paul's Hospital, Vancouver, Canada.
Microvasc Res. 1995 Nov;50(3):397-416. doi: 10.1006/mvre.1995.1067.
The purpose of this study was to determine whether or not there are preexisting holes in the endothelial and epithelial basal laminae of alveolar walls and to determine the path taken by neutrophils as they migrate from the capillaries to the airspace of the alveoli during inflammation. Using transmission electron microscopy and serial thin sections of normal rabbit and mouse lung, we have demonstrated the presence of slit-like holes in the capillary basal laminae and round holes in the basal laminae of type 2 pneumocytes. The slits in the capillary basal laminae were observed at the intersection of the thick and thin walls where endothelium, pericytes, and fibroblasts make close contact. The round holes in the type 2 cell basal laminae were observed at sites of close contact with fibroblasts. Neutrophils were observed to migrate through these slits and holes during streptococcal pneumonia in rabbit lungs. We conclude that during inflammation in the lung, migrating neutrophils displace pericytes and fibroblasts from the slits in the capillary basal lamina and then crawl through these slits into the alveolar interstitium. We postulate that neutrophils find their way to type 2 pneumocytes by following interstitial fibroblasts. We believe that neutrophils displace fibroblasts from their close contacts with the type 2 cells and then crawl through the holes in the basal lamina into the basal lateral space of the type 2 cells. From there, neutrophils migrate into the alveolar airspace.
本研究的目的是确定肺泡壁的内皮和上皮基膜中是否预先存在孔洞，并确定中性粒细胞在炎症过程中从毛细血管迁移至肺泡气腔所采取的路径。通过使用透射电子显微镜和正常兔及小鼠肺的连续薄片，我们证实了毛细血管基膜中存在缝隙状孔洞，以及Ⅱ型肺细胞基膜中存在圆形孔洞。毛细血管基膜中的缝隙在厚壁与薄壁的交汇处被观察到，此处内皮细胞、周细胞和成纤维细胞紧密接触。Ⅱ型细胞基膜中的圆形孔洞在与成纤维细胞紧密接触的部位被观察到。在兔肺链球菌肺炎期间，观察到中性粒细胞通过这些缝隙和孔洞迁移。我们得出结论，在肺部炎症期间，迁移的中性粒细胞将周细胞和成纤维细胞从毛细血管基膜的缝隙中挤开，然后通过这些缝隙爬入肺泡间质。我们推测中性粒细胞通过跟随间质成纤维细胞找到通往Ⅱ型肺细胞的路径。我们认为中性粒细胞将成纤维细胞从其与Ⅱ型细胞的紧密接触中挤开，然后通过基膜中的孔洞爬入Ⅱ型细胞的基外侧间隙。从那里，中性粒细胞迁移到肺泡气腔。
