Chen Ying-Ting, Huang Chia-Wei, Huang Fu-Chin, Tseng Shih-Ya, Tseng Sung-Huei
Department of Ophthalmology, College of Medicine, National Cheng Kung University, Tainan, Taiwan.
Mol Vis. 2006 Mar 23;12:196-204.
To determine the anatomic cleavage plane of the corneal epithelial adhesion complex in eyes with traumatic recurrent corneal erosion (RCE).
A loosened sheet of corneal epithelium was obtained from corneal epithelial wounds in eight patients with traumatic RCE, before each patient underwent phototherapeutic keratectomy. Three control groups were employed in the study, including normal corneal epithelial sheets obtained by mechanical separation, normal corneal tissues obtained by partial lamellar keratectomy during pterygial surgery, and corneal tissues from three residual corneoscleral rims of corneas donated for transplantation. Immunofluorescence staining was performed using monoclonal antibodies against integrins beta1 and beta4, laminin 5, and collagen VII to identify abnormalities in specific layers of the adhesion complex.
In both experimental and control specimens, the suprabasal and basal cells stained positive for integrin beta1, and basal cells stained positive for integrin beta4. Similarly, a continuous line along the base of each epithelial sheet and each control specimen stained positive for laminin 5, a major basement membrane component. In contrast, in all controls there was a continuous linear staining pattern along the basement membrane of stain positive for collagen VII, a marker for the presence of fibrils that anchor corneal basement membrane to Bowman's layer, but epithelial sheets from eyes with RCE showed either a discontinuous line stained positive for collagen VII (three out of eight specimens) or no positively stained areas (five out of eight specimens). The results indicated the cleavage plane of RCE was located at collagen VII layer, between basement membrane and Bowman's layer.
This study identified a defect in collagen fibrils that anchor the corneal epithelium basement membrane to Bowman's layer as the cause of corneal epithelial loss in cases of traumatic RCE. As hemidesmosomes do not seem to be impaired, a treatment specific to restore anchoring fibril function might prove helpful.
确定外伤性复发性角膜糜烂（RCE）患者角膜上皮黏附复合体的解剖学分离平面。
在8例外伤性RCE患者接受光治疗性角膜切削术之前，从其角膜上皮伤口获取一片松动的角膜上皮。本研究采用了三个对照组，包括通过机械分离获得的正常角膜上皮片、翼状胬肉手术期间通过部分板层角膜切除术获得的正常角膜组织，以及来自用于移植的捐献角膜的三个剩余角膜巩膜缘组织。使用抗整合素β1和β4、层粘连蛋白5和Ⅶ型胶原的单克隆抗体进行免疫荧光染色，以识别黏附复合体特定层的异常情况。
在实验标本和对照标本中，基底上层和基底细胞的整合素β1染色均呈阳性，基底细胞的整合素β4染色呈阳性。同样，沿着每个上皮片和每个对照标本底部的一条连续线，主要基底膜成分层粘连蛋白5染色呈阳性。相比之下，在所有对照组中，沿着Ⅶ型胶原染色阳性的基底膜有连续的线性染色模式，Ⅶ型胶原是将角膜基底膜锚定到Bowman层的原纤维存在的标志物，但RCE患者眼的上皮片要么显示Ⅶ型胶原染色阳性的不连续线（8个标本中有3个），要么没有阳性染色区域（8个标本中有5个）。结果表明，RCE的分离平面位于基底膜和Bowman层之间的Ⅶ型胶原层。
本研究确定，将角膜上皮基底膜锚定到Bowman层的胶原原纤维缺陷是外伤性RCE病例中角膜上皮缺失的原因。由于半桥粒似乎未受损，恢复锚定原纤维功能的特异性治疗可能会有所帮助。
