THE EFFECT OF HYALURONIC-ACID ON CORNEAL EPITHELIAL-CELL PROLIFERATION

Purpose. The authors investigated the mechanisms by which hyaluronic a cid (HA) promotes corneal epithelial wound healing. The effect of HA o n epithelial cell proliferation was examined in comparison with that o f epidermal growth factor (EGF) and fibronectin (FN). Methods. A penet rating linear incision (6-mm long) was made in the center of rabbit co rneas. Immediately after wounding, the corneas were excised and cultur ed in TCM199 medium alone or medium containing HA (molecular weight, 8 60,000 Daltons; 100, 400, or 1000 mug/ml), EGF (25, 100, or 250 ng/ml) , or FN (100 or 250 mug/ml) for 15 hr at 37-degrees-C. The corneas wer e then labeled with tritiated thymidine (10 muCi/ml) and subjected to autoradiography. Results. In the corneas cultured with HA at concentra tions of 400 and 1000 mug/ml, the number of epithelial cells incorpora ting tritiated thymidine was significantly higher than that in the con trol corneas. In the corneas cultured with EGF at all concentrations, it was also higher than that of the control. FN did not affect cell pr oliferation. Conclusions. HA stimulates corneal epithelial cell prolif eration. This stimulating effect of HA on epithelial cell proliferatio n might partly explain its effect in promoting corneal epithelial woun d healing.