角膜上皮细胞的基底上层是小分子被动转运和白细胞迁移的主要屏障部位。
The suprabasal layer of corneal epithelial cells represents the major barrier site to the passive movement of small molecules and trafficking leukocytes.
作者信息
Sosnová-Netuková Magdaléna, Kuchynka Pavel, Forrester John V
机构信息
Department of Ophthalmology, University of Aberdeen, AB25 2ZD, Aberdeen, Scotland, United Kingdom.
出版信息
Br J Ophthalmol. 2007 Mar;91(3):372-8. doi: 10.1136/bjo.2006.097188. Epub 2006 Oct 4.
AIMS
To investigate the site of barrier function to the passive diffusion of a small molecule (phalloidin) in the corneal epithelium in the mouse.
METHODS
Penetration of phalloidin (molecular weight 1115 daltons) into the cornea was evaluated by studying fluorescent binding of phalloidin to actin in tissue sections, in whole mount preparations, and in the fixed intact globe by confocal microscopy. In addition, the location of tight junction proteins in the individual layers of the corneal epithelium was determined by immunohistochemistry.
RESULTS
Phalloidin staining of corneal sections was positive in all corneal layers in tissue sections and in all layers of the corneal epithelium except the suprabasal layer in excised fixed whole mounts of the cornea. However, when phalloidin staining was attempted in intact fixed globes, before excision of the cornea for whole mount preparation, only the most superficial layer of cells was stained indicating that phalloidin could not penetrate the tissue beyond the suprabasal epithelial layer. Detergent (Triton X-100) treatment of the excised cornea and the intact fixed globe, allowed penetration of phalloidin into the suprabasal epithelial layer. Tight junction proteins occludin, ZO-1 and claudin were present in most layers of the cornea but while ZO-1 and occludin were distributed in a typical pericellular pattern, claudin seemed to be particularly prominent in the suprabasal layer and appeared only as a discontinuous punctate pericellular pattern in the superficial layer. Intraepithelial leukocytes were detected in the superficial epithelium and the basal epithelium but not in the suprabasal epithelium.
CONCLUSION
The suprabasal epithelium cell layer appears to represent the main barrier site to the passage of small molecules and cells in the mouse cornea and this property may be attributable to prominent claudin expression in this layer.
目的
研究小鼠角膜上皮中对小分子（鬼笔环肽）被动扩散起屏障作用的部位。
方法
通过共聚焦显微镜研究鬼笔环肽（分子量1115道尔顿）与组织切片、整装标本以及固定完整眼球中肌动蛋白的荧光结合，评估鬼笔环肽进入角膜的情况。此外，通过免疫组织化学确定紧密连接蛋白在角膜上皮各层中的位置。
结果
在组织切片的所有角膜层以及切除并固定的角膜整装标本中除基底上层之外的角膜上皮各层中，角膜切片的鬼笔环肽染色均为阳性。然而，在完整固定眼球上尝试进行鬼笔环肽染色（在切除角膜用于整装标本制备之前）时，仅最表层细胞被染色，这表明鬼笔环肽无法穿透基底上层上皮层之外的组织。对切除的角膜和完整固定眼球用去污剂（曲拉通X - 100）处理后，鬼笔环肽能够穿透进入基底上层上皮层。紧密连接蛋白闭合蛋白、ZO - 1和claudin存在于角膜的大多数层中，但ZO - 1和闭合蛋白以典型的细胞周围模式分布，而claudin似乎在基底上层特别突出，在表层仅呈现为不连续的点状细胞周围模式。在上皮浅层和基底上皮层中检测到上皮内白细胞，但在基底上层上皮中未检测到。
结论
基底上层上皮细胞层似乎是小鼠角膜中小分子和细胞通过的主要屏障部位，这一特性可能归因于该层中claudin的显著表达。
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