Garlick J A, Parks W C, Welgus H G, Taichman L B
Department of Oral Biology and Pathology, School of Dental Medicine, State University of New York at Stony Brook 11794-8702, USA.
J Dent Res. 1996 Mar;75(3):912-8. doi: 10.1177/00220345960750030801.
Re-epithelialization involves interactions between keratinocytes and the extracellular matrix upon which these cells move. It is hypothesized that keratinocytes are activated when wounded, and the resultant phenotypic change directs re-epithelialization. We have adapted organotypic cultures, in which oral gingival keratinocytes are fully differentiated, to study re-epithelialization following wounding. To elucidate keratinocyte behavior and phenotype during re-epithelialization, we have investigated this process in the presence and absence of the growth factor TGF-beta 1 and have monitored expression of MMP-1 (Type I collagenase) mRNA by in situ hybridization. In addition, we have followed proliferation and migration of wound keratinocytes by genetically marking these cells with a retroviral vector and by measuring their proliferative index. We found that keratinocytes grown without TGF-beta 1 were hyperproliferative in response to wounding, and re-epithelialization was complete by 24 h. However, 2.5 ng/mL TGF-beta 1 induced a transient delay in re-epithelialization, a reduction in proliferation, and fewer clusters of genetically marked cells. Keratinocytes expressed MMP-1 mRNA only when they covered the wounded surface, suggesting that the cells acquire a collagenolytic phenotype during re-epithelialization and that contact with different ECM components may modulate keratinocyte expression of MMP-1. We conclude that the phenotype of oral keratinocytes is altered during re-epithelialization in vitro and that this process is modulated by TGF-beta 1. Re-epithelialization occurs as keratinocytes are activated to move over the wound bed. Understanding the phenotype of wounded keratinocytes may facilitate treatment of chronic oral wounds and periodontal disease.
再上皮化涉及角质形成细胞与这些细胞赖以移动的细胞外基质之间的相互作用。据推测，角质形成细胞在受伤时被激活，由此产生的表型变化引导再上皮化。我们采用了器官型培养（其中口腔牙龈角质形成细胞已完全分化）来研究受伤后的再上皮化过程。为了阐明再上皮化过程中角质形成细胞的行为和表型，我们在有和没有生长因子转化生长因子-β1（TGF-β1）的情况下研究了这一过程，并通过原位杂交监测了基质金属蛋白酶-1（I型胶原酶）mRNA的表达。此外，我们通过用逆转录病毒载体对伤口角质形成细胞进行基因标记并测量其增殖指数，追踪了这些细胞的增殖和迁移。我们发现，在没有TGF-β1的情况下培养的角质形成细胞在受伤后会过度增殖，24小时内再上皮化完成。然而，2.5 ng/mL的TGF-β1会导致再上皮化出现短暂延迟、增殖减少以及基因标记细胞簇减少。角质形成细胞仅在覆盖受伤表面时才表达MMP-1 mRNA，这表明细胞在再上皮化过程中获得了胶原溶解表型，并且与不同的细胞外基质成分接触可能会调节角质形成细胞MMP-1的表达。我们得出结论，体外再上皮化过程中口腔角质形成细胞的表型会发生改变，并且这一过程受到TGF-β1的调节。再上皮化发生在角质形成细胞被激活并在伤口床上移动时。了解受伤角质形成细胞的表型可能有助于慢性口腔伤口和牙周疾病的治疗。
