Rabbit corneal epithelial wound repair: tight junction reformation

Abstract

Previous studies have shown that the corneal epithelium will close a limbus to limbus scrape wound in four to five days, but requires 10 days to become firmly attached to the stroma. In order to determine if the restoration of the corneal epithelial barrier follows a similar sequence, we have used freeze-fracture to study tight junction reformation in a rabbit epithelial wound model. Dutch-belted rabbit corneal epithelium was removed with a limbus to limbus scrape wound and sampled from 0 to 30 days post-wounding. A minimum of 3 animals from each time point were processed for electron microscopy and freeze-fracture. Freeze-fracture showed that the cells at the wound margin had a reduction in the number of intramembrane particles on their apical surface. In areas adjacent to the wound edge, fragments of tight junctions were first observed on two days post-wounding specimens. The junctions became progressively more complex in the area behind the wound edge until wound closure at four days when the junctions were also present in the central region of the cornea. The maturation of the junctions continued and at five days after surgery they resembled control junctions. This sequence suggests that the the establishment of morphologically mature tight junctions may be necessary before the corneal epithelium can firmly reattach to the stroma.

Characteristics of Reconstituted Tight Junctions After Corneal Epithelial Wounds and Ultrastructure Alterations of Corneas in Type 2 Diabetic Rats

“…According to previous studies, TJs have been detected in the corneal epithelium and most prominently in the superficial cell layer. 34 Occludin, which is expressed in the superficial epithelium cell layers of the cornea, is a protein expressed in TJs.…”

Secretory Response of Mast Cells Contained in Monodispersed Human Choroidal Preparations

“…Mast cells were positively identi fied by staining with toluidine blue (0.5%). Pellets were also prepared for electron microscopy according to methods previously described [13]. These preparations were stained with uranyl acetate (0.5%/ 30 min) and lead citrate (2.7%/80 s) using an automated system (LKB Ultrostainer), washed, and viewed using a Zeiss CEM-902 electron microscope.…”

Expression and localisation of claudin-1,-2,-3,-4,-5,-7 and-10 proteins in the normal canine mammary gland

“…The first claudin gene (CLDN 1) was identified in a screen for murine proteins that interacted with the known integral TJ protein, occludin (Furuse et al, 1998). Epithelial TJs are dynamic structures and subject to modulation during epithelial tissue remodelling (Peralta Soler et al, 1996), wound repair (McCartney and Cantu-Crouch, 1992), inflammation (Madara et al, 1992) and transformation into tumours (Mullin, 1997). The association of abnormal TJ function and epithelial tumour development has been suggested by earlier human studies showing alterations in the TJ structures of epithelial cancers (Martinez-Palomo, 1970).…”