Fujikawa L S, Foster C S, Gipson I K, Colvin R B
J Cell Biol. 1984 Jan;98(1):128-38. doi: 10.1083/jcb.98.1.128.
The nature of the substrate that supports epithelial migration in vivo is of interest, particularly with respect to mechanisms of wound healing. Immunofluorescence and electron microscopy were used to search for common substrate components in prototype rabbit corneal wounds: epithelial scrape wounds, in which the corneal or conjunctival epithelium migrated over the denuded lamina densa of the corneal basement membrane (CBM), and superficial keratectomy, in which the corneal epithelium migrated over a bare stroma without CBM. The corneal epithelium moved rapidly over the CBM or stroma to cover the defect within 2-3 d, whereas the conjunctival epithelium required 1-2 wk. In all wounds, fibronectin and fibrin/fibrinogen were deposited onto the bare surface within 8 h after wounding and persisted under the migrating epithelium until migration was complete. Bullous pemphigoid antigen (BPA), a normal component of the CBM, was removed with the epithelium upon scrape wounding and reappeared in the CBM after migration was completed. In contrast, the conjunctival epithelium had a continuous subepithelial band of BPA out to the migrating tip. Laminin, also a normal component of the CBM, was not removed in the scrape wounds, indicating that the region of least resistance to shear stress was between the BPA and laminin layers. Laminin was removed by superficial keratectomy and was not detectable under the leading edge of the migrating cells. Laminin and BPA were restored in the CBM by 2-4 wk. Type IV collagen could not be detected in normal CBM, but was conspicuously present in conjunctival basement membrane and in blood vessels. Focal bands of type IV collagen did appear in the newly synthesized CBM 2-4 wk after keratectomy. These results argue that BPA, laminin, and type IV collagen are not essential for the migration of corneal epithelium during wound healing and support the hypothesis that fibronectin and fibrin/fibrinogen are the common, perhaps the essential, components of the provisional matrix that serves as a substrate until the permanent attachment components are regenerated.
支持上皮细胞在体内迁移的底物的性质备受关注，尤其是在伤口愈合机制方面。免疫荧光和电子显微镜技术被用于探寻兔角膜典型伤口中的常见底物成分：上皮刮伤伤口，其中角膜或结膜上皮细胞在角膜基底膜（CBM）裸露的致密层上迁移；以及浅层角膜切除术伤口，其中角膜上皮细胞在没有CBM的裸露基质上迁移。角膜上皮细胞在2 - 3天内迅速在CBM或基质上移动以覆盖缺损，而结膜上皮细胞则需要1 - 2周。在所有伤口中，纤连蛋白和纤维蛋白/纤维蛋白原在受伤后8小时内沉积在裸露表面，并在迁移的上皮细胞下方持续存在直至迁移完成。大疱性类天疱疮抗原（BPA）是CBM的正常成分，在刮伤伤口时随上皮细胞被移除，并在迁移完成后重新出现在CBM中。相比之下，结膜上皮细胞有一条连续的上皮下BPA带延伸至迁移尖端。层粘连蛋白也是CBM的正常成分，在刮伤伤口中未被移除，这表明对剪切应力抵抗力最小的区域位于BPA和层粘连蛋白层之间。层粘连蛋白在浅层角膜切除术中被移除，在迁移细胞的前沿下方无法检测到。层粘连蛋白和BPA在2 - 4周后在CBM中恢复。在正常CBM中无法检测到IV型胶原，但在结膜基底膜和血管中明显存在。IV型胶原的局灶性条带在角膜切除术后2 - 4周出现在新合成的CBM中。这些结果表明，BPA、层粘连蛋白和IV型胶原在伤口愈合过程中对于角膜上皮细胞的迁移并非必不可少，并支持这样一种假说，即纤连蛋白和纤维蛋白/纤维蛋白原是临时基质的常见成分，也许是必不可少的成分，在永久附着成分再生之前作为底物发挥作用。
