Abstract
Purpose: :
Dry eye is characterized by a decreased tear production; abnormalities in the tear film profiles for lipid, protein and mucin; corneal epitheliopathy; and poor corneal wound healing. Poor wound healing is caused by decreased cell migration over an epithelial defect. Migration involves complex interactions between migrating cells and the extracellular matrix (ECM). The galectin family member galectin-3 (Gal-3) contains a carbohydrate recognition domain that binds to ECMs such as laminin and collagen. Corneal wound healing vanished in Gal-3-/- mice, and recombinant Gal-3 accelerated corneal epithelial wound healing in an organ culture model. The purpose of the present experiment was to investigate if topical administration of Gal-3 facilitates corneal epithelial wound healing in a live rat model of dry eye.
Methods: :
Dry eye was produced by surgical removal of the lacrimal glands in anesthetized rats. After treating the central cornea with n-heptanol, a 3 mm diameter portion of epithelium was scraped off with a dull scalpel blade. Recombinant Gal-3 was topically administrated 8 times per day. The volume of tear fluid was measured by holding a phenol red-impregnated cotton thread onto the lateral canthus for 20 seconds. Corneas were stained with 1 % sodium fluorescein, and corneal wound healing was quantified by digital image analysis. Laminin-5 in the basement membrane of the corneas was determined by immunohistochemistry.
Results: :
Three days after removal of the lacrimal grand, tear fluid volume decreased to ~ 40% of normal. Wound healing in the abraded corneas was delayed, and topical administration of Gal-3 significantly facilitated epithelial wound healing. Laminin-5 was detected in corneas with abraded epithelium, suggesting that the basement membrane remained.
Conclusions: :
Exogenous Gal-3 may have enhanced corneal wound healing by mediating the binding between migrating epithelial cells and laminin on the corneal basement membrane. Gal-3 may be a candidate drug to enhance epithelial cell wound healing in patients with dry eye.
Keywords: cornea: tears/tear film/dry eye • wound healing • lacrimal gland