Abstract
Purpose::
Laminin-5 (α3, ß3, γ2 chains) is a major component of corneal basement membrane and has a crucial role in corneal epithelial adhesion and migration. In our previous study, we revealed that soluble-Laminin-5 promoted corneal epithelial cells adhesion in vitro (Exp Eye Res 2000, 71: 69-79). Furthermore, we also revealed that the expression of Laminin-5 in corneal epithelial cells reduced under high glucose condition (Cornea 2006, 25: 61-67). However, the information of the effect of topical use of soluble Laminin-5 promoting corneal epithelial migration in vivo is unknown. Therefore, we investigated the effect of topical soluble Laminin-5 on corneal epithelial defect in rabbit model.
Methods::
Japanese White rabbits (Japan, SLC, Shizuoka), weighing about 2-3kg, were used. Corneal epithelial defect was induced by n-Heptanol injection. About 3mm diameter erosion was treated with topical use of 20µg/ml soluble Laminin-5 (4 times daily) or PBS. After the treatment for 3 or 4 days, rabbits were killed by intravenous injection of sodium pentobarbital. The eyes were enucleated and fixed in acetone/glutaraldehyde solution for histological examination using electron microscope.
Results::
Initially we investigated the effects of topical use of soluble Laminin-5 on corneal epithelial defect in rabbit model. Topical use of Laminin-5 strongly promoted cell migration compared to that of PBS. Histological analysis showed, in Laminin-5 treated groups, that the structure of epithelium already showed normal architecture in 3 days after the ablation. On the other hand, in PBS treated groups, the epithelium was very thin and immature structures. Many hemidesmosomes were recognized in the interface between basal cells and underlying stroma in Laminin-5 treated groups. On the other hand, a few numbers of hemidesmosomes were recognized in that of PBS treated groups.
Conclusions::
In the future, soluble Laminin-5 could be a useful drug for the prevention of recurrent corneal erosion and prolonged corneal epithelial defects in diabetic keratopathy.
Keywords: cell adhesions/cell junctions • cornea: basic science • wound healing