Background/aims: To investigate if galectin-3: (1) enhances adhesion of rat corneal epithelial cells onto a collagen IV substrate and (2) promotes wound healing in rat corneal explants.
Methods: Primary cultures of rat corneal epithelial cells were fixed and immunostained with galectin-3 antibody. To test cellular adherence onto plates coated with collagen type IV, isolated corneal epithelial cells from rats were cultured for 24 h with or without recombinant galectin-3. The attached cells were counted after fixing and staining with 0.1% crystal violet. Direct binding of galectin-3 to collagen IV was tested using a biotin label transfer method. To evaluate wound healing, explants with a 3.5-mm diameter wound in the central corneal epithelium from rats were incubated for 16 h with or without recombinant galectin-3. Changes in the size of the wound were measured with a digital microscope after staining with 5% fluorescein sodium.
Results: In rat corneal epithelial cells, galectin-3 was stained throughout the cytoplasm, with increasing density adjacent to the plasma membrane. Exogenous galectin-3, but not epidermal growth factor (EGF), significantly promoted adhesion of corneal epithelial cells onto the collagen IV substrate. Galectin-3 directly bound to collagen IV in vitro. Exogenous galectin-3 significantly enhances wound healing in the corneal explants, which was partially inhibited by β-lactose.
Conclusion: Galectin-3 promotes adhesion of corneal epithelial cells onto collagen IV and enhances wound healing in corneal explants. Since galectin-3 functions in promoting wound healing by a different mechanism than that used by EGF, exogenous galectin-3 may be a candidate drug for enhancing epithelial cell wound healing in disorders of the cornea.