Latvala T, Päällysaho T, Tervo K, Tervo T
Department of Ophthalmology, University of Helsinki, Finland.
Acta Ophthalmol Scand. 1996 Feb;74(1):21-5. doi: 10.1111/j.1600-0420.1996.tb00675.x.
Integrin complex alpha 6 beta 4 is a component of the hemidesmosome. In the unwounded cornea both the integrin subunits face the laminin-containing basement membrane, but the alpha 6 subunit is also located between the basal cells. While the migrating epithelium is known to be without hemidesmosomes, we investigated the distribution of alpha 6 beta 4 during epithelial healing. Epithelial abrasion 7.5 mm in diameter was mechanically created. The rabbits were killed 1-24 h or 2, 3, or 7 days later. Monoclonal antibodies against alpha 6, beta 4, and laminin A were used to detect their distributions by immunohistochemistry. Positive immunostaining for laminin A on the surface of the unepithelialized stroma indicated that basement membrane was intact after the epithelial abrasion. Three hours after corneal wounding, alpha 6, was detectable around the entire cell up to the leading edge of the migrating epithelium. In the peripheral wound, alpha 6, was also prominently present around the basal and suprabasal cells with only the superficial cell layers being negative. The beta 4 subunit showed a dissimilar distribution; it was not detectable subjacent to the leading edge. After 1 h the immunoreaction for the beta 4 subunit had faded 15 - 20 microns peripheral to the wound margin. Thereafter the subepithelial band was segmentally reassembled, starting from the periphery and progressing toward the central area of the wound. One week after epithelial wounding, immunolabeling for both integrin subunits was indistinguishable from that of the control cornea. Our results indicate that in addition to the beta 4 in the rabbit cornea, the alpha 6 subunit is also complex with another beta subunit during the epithelial healing phase. The results also suggest that basal cells 15 - 20 microns peripheral to the wound margin disassemble their HDs prior to the migration process.
整合素复合体α6β4是半桥粒的一个组成部分。在未受伤的角膜中，整合素亚基均面向含层粘连蛋白的基底膜，但α6亚基也位于基底细胞之间。虽然已知迁移的上皮细胞没有半桥粒，但我们研究了上皮愈合过程中α6β4的分布情况。通过机械方法造成直径7.5毫米的上皮擦伤。在1 - 24小时或2、3或7天后处死兔子。使用针对α6、β4和层粘连蛋白A的单克隆抗体，通过免疫组织化学检测它们的分布。未上皮化基质表面层粘连蛋白A的阳性免疫染色表明上皮擦伤后基底膜完整。角膜受伤3小时后，在迁移上皮的前沿直至整个细胞周围均可检测到α6。在周边伤口，α6在基底细胞和基底上细胞周围也显著存在，仅表层细胞层为阴性。β4亚基显示出不同的分布；在前沿下方无法检测到。1小时后，β4亚基的免疫反应在伤口边缘外周15 - 20微米处消失。此后，上皮下带从周边开始分段重新组装，并向伤口中心区域推进。上皮受伤一周后，两种整合素亚基的免疫标记与对照角膜无异。我们的结果表明，在兔角膜上皮愈合阶段，除了β4外，α6亚基还与另一个β亚基形成复合体。结果还表明，伤口边缘外周15 - 20微米处的基底细胞在迁移过程之前会分解其半桥粒。
