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 effec ts of tranilast on cellular proliferation and collagen synthesis. Methods: Subculturing was carried out using keratocytes from rabbits that u nderwent photorefractive keratectomy (PRK) and developed corneal haze, and keratocytes from normal rabbit cornea. Results: Tranilast suppressed proliferation in cultured keratocytes from th e corneal haze region at doses of 30 and 300 mu mol/L and collagen synthesi s at doses of 3, 30, and 300 mu mol/L. Normal corneal cultures showed suppr ession of keratocyte proliferation and collagen synthesis only at a high do se of tranilast (300 mu mol/L). Betamethasone suppressed proliferation of k eratocytes 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 hi gh dose of 100 mu mol/L, and in keratocytes in normal cornea, at doses of 1 0 and 100 mu mol/L. In an in vivo study, either 0.5% tranilast, 0.1% betame thasone phosphate eye drops, or a tranilast base solution (control) was ins tilled four times daily to rabbits that had undergone PRK. Weekly evaluatio n of the inhibitory effect of these drugs on the development of haze was pe rformed 2 weeks after surgery. Tranilast suppressed haze 6-13 weeks after P RK, 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 Op hthalmological Society.