Abstract
Introduction: :
F. Yano, C. Yabuta, and M. AzumaSenju Pharmaceutical Co., Ltd. Kobe, Japan.
Purpose: :
Treatment of epithelial wounds in corneal disorders is a major clinical problem. A number of growth factors including EGF have been tested, but the results have not been fully acceptable. Galectins are a member of the lectin family and recognize β-galactoside residues on glycoconjugates in the extracellular matrix (ECM). Galectin-3 is a known mediator of cell-matrix interactions and is expressed in human cornea. Galectin-3 knockout mice show significantly slower healing of corneal wounds compared to wild type mice. These observations suggest that exogenous galectin-3 may be a candidate for therapy of corneal wounds. The purpose of the present experiment was to test if recombinant galectin-3 facilitates wound healing in cultured rat cornea. The mechanism of action for galectin-3 was also investigated.
Methods: :
An abraded, 3.5 mm diameter area in the central corneal epithelium of anesthetized rats was produced with a trephine and router. Enucleated corneas were then incubated for 16 hours with or without recombinant galectin-3. The defect area was measured with digital microscope after staining with 5 % fluorescein sodium. For the cell adhesion assay, dissociated corneal epithelial cells from rat were cultured for 24 hours with or without recombinant galectin-3 on plates coated with collagen type IV or laminin. Attached cells were counted after fixing and staining with 1% crystal violet. Binding of galectin-3 to ECM in vitro was tested using a biotin label transfer method.
Results: :
Recombinant galectin-3 significantly accelerated wound healing in the corneal epithelial layer 16 hours after incubation. Galectin-3 also significantly promoted adhesion of cultured corneal epithelial cells. Galectin-3 bound to collagen IV and laminin, which was almost completely inhibited by β-lactose. This suggested the involvement of a carbohydrate recognition site in corneal wound healing.
Conclusions: :
Galectin-3 may facilitate corneal wound healing by promoting cell migration due to recognition of components in extracellular matrix, such as collagen IV and laminin. Since this mechanism for promoting wound healing is different from that of growth factors, galectin-3 is a possible candidate drug for clinical trial involving treatment of corneal disorders.
Keywords: cornea: epithelium • wound healing • drug toxicity/drug effects