Hyaluronan, CD44 and fibronectin in rabbit corneal epithelial wound healing

Changes in hyaluronan (HA) concentration and stainability were investigated in the rabbit cornea after wounds made by exposure to n-heptanol. The HA concentration in the cornea increased gradually until day 14 after wounding, and then decreased. The HA concentration returned to the normal level 56 days after wounding. In the normal control cornea, HA staining was observed in the epithelium and stroma. The intensity of HA staining in the epithelium and stroma increased until day 3 after wounding, when the epithelium had completely covered the defect. At day 28, when the thickness of the corneal epithelium returned to the normal level, the intensity of HA staining in the epithelium also decreased. However, staining in the stroma was still strong. HA staining in the stroma decreased by day 56 after wounding. In parallel experiments, the immunostaining for CD44, an HA receptor, and fibronectin (FN) was carried out in the same model. The immunostaining in the epithelium of both CD44 and FN was synchronistic with the HA staining during the early stages after wounding. These events suggest that HA, CD44 and FN cooperatively play important roles in corneal epithelial wound healing.