Effects of tranilast on cultured rabbit corneal keratocytes and corneal haze after photorefractive keratectomy

Purpose: In vitro and in vivo studies were performed to elucidate the effects of tranilast on cellular proliferation and collagen synthesis. Methods: Subculturing was carried out using keratocytes from rabbits that underwent photorefractive keratectomy (PRK) and developed corneal haze, and keratocytes from normal rabbit cornea. Results: Tranilast suppressed proliferation in cultured keratocytes from the corneal haze region at doses of 30 and 300 mu mol/L and collagen synthesis at doses of 3, 30, and 300 mu mol/L. Normal corneal cultures showed suppression of keratocyte proliferation and collagen synthesis only at a high dose of tranilast (300 mu mol/L). Betamethasone suppressed proliferation of keratocytes in both haze and normal cornea at a dose of 10 mu mol/L, as well as collagen synthesis at respective doses of 1 and 10 mu mol/L. Diclofenac sodium suppressed collagen synthesis of keratocytes in haze cornea at a high dose of 100 mu mol/L, and in keratocytes in normal cornea, at doses of 10 and 100 mu mol/L. In an in vivo study, either 0.5% tranilast, 0.1% betamethasone phosphate eye drops, or a tranilast base solution (control) was instilled four times daily to rabbits that had undergone PRK. Weekly evaluation of the inhibitory effect of these drugs on the development of haze was performed 2 weeks after surgery. Tranilast suppressed haze 6-13 weeks after PRK, but betamethasone phosphate showed no effect. Conclusion: These results indicate that tranilast is potentially effective for inhibiting the corneal haze that occurs after PRK. (C) 1999 Japanese Ophthalmological Society.