tranilast and Corneal-Opacity

To determine whether topical tranilast might reduce corneal haze through suppression of transforming growth factor (TGF)-beta1 synthesis in keratocyte after photorefractive keratectomy.. Department of Ophthalmology, Korea University College of Medicine, Seoul, Republic of Korea.. Photorefractive keratectomy was performed on 48 eyes of 28 white rabbits and 24 eyes in a tranilast group were treated with tranilast solution, and the other 24 eyes in control group were treated with saline after laser ablation. The grades of corneal haze at 1, 2, 4, and 8 weeks after surgery were evaluated in 10 eyes of each group for comparison. Immunohistochemistry was performed on 10 eyes of each group, and Western blot analysis was done on 4 eyes of each group for studying TGF-beta1 expression at postoperative day 7.. There was no statistically significant difference in corneal haze between 2 groups from week 1 to week 4 after surgery, but a significant difference was found at week 8 after photorefractive keratectomy (P=.02). The mean number of keratocytes that expressed TGF-beta1 in the tranilast group was 58.3 (+/-17.2), which showed significant difference, compared with that of the control group, 104.5 (+/-23.0) (P<.01). Western blot analysis also revealed that the amount of TGF-beta1 in tranilast group was slightly less than the control group.. Topical tranilast could reduce corneal haze by suppressing TGF-beta1 expression in keratocytes after photorefractive keratectomy.

Topics: Administration, Topical; Animals; Anti-Allergic Agents; Blotting, Western; Cornea; Corneal Opacity; Fibroblasts; Immunoenzyme Techniques; Lasers, Excimer; Ophthalmic Solutions; ortho-Aminobenzoates; Photorefractive Keratectomy; Rabbits; Transforming Growth Factor beta; Transforming Growth Factor beta1

Tranilast (trade name Rizaben), an anti-allergic drug with anti-inflammatory effects, is thought to inhibit synthesis of extracellular matrix of fibroblasts through the suppression of TGF-beta. We evaluated the effect of topical tranilast on the subepithelial haze that developed after excimer laser keratectomy and its effect was compared with that of betamethasone eye drops. Excimer laser keratectomy (phototherapeutic keratectomy mode) was performed with the Nidek EC-5000 excimer laser on 16 rabbit corneas (eight rabbits). From the second postoperative day, topical 2% tranilast was instilled in the right eye and the control solution in the left eye, four times daily. Until the fourth week after the operation, we measured the densitometric values of scattered light intensity of the subepithelial haze with an anterior ocular analyzer, EAS-1000 (Nidek). At the fifth postoperative week, light and electron microscopy and immunohistochemistry with an antibody to TGF-beta were also performed.. Densitometric values of the subepithelial haze in the corneas treated with 2% tranilast were slightly less than those of the subepithelial haze in the control corneas. However, the values of the subepithelial haze in the betamethasone-treated corneas were significantly less than those in control corneas. Histochemical examinations revealed that topical tranilast had a small effect on the subepithelial haze after excimer laser keratectomy in rabbits.. Topical 0.1% betamethasone can limit the amount of subepithelial haze and tranilast may inhibit development of subepithelial haze by the suppression of TGF-beta.

Topics: Administration, Topical; Animals; Anti-Inflammatory Agents; Anti-Inflammatory Agents, Non-Steroidal; Betamethasone; Cornea; Corneal Opacity; Epithelium; Immunohistochemistry; Lasers, Excimer; Ophthalmic Solutions; ortho-Aminobenzoates; Photorefractive Keratectomy; Rabbits; Transforming Growth Factor beta

Recent studies have reported that tranilast inhibited in vitro the proliferation of keratocytes from corneal subepithelial opacities (haze) and collagen synthesis in cultured corneas after excimer laser photorefractive keratectomy (PRK). In this study 0.5% tranilast eye drops, 0.1% betametazone phosphate eyedrops, and a 0.5% tranilast base solution (control) were administered four times daily to rabbits which had undergone PRK. Weekly evaluation of the inhibitory effect of these drugs on haze began two weeks after surgery according to Fantes' classification. 0.5% tranilast suppressed haze from six weeks to thirteen weeks after PRK (p < 0.05). 0.1% betametazone phosphate showed no effect. These results suggested that 0.5% tranilast had a satisfactory therapeutic effect on haze after PRK.

Topics: Animals; Anti-Allergic Agents; Corneal Opacity; Lasers, Excimer; Male; Ophthalmic Solutions; ortho-Aminobenzoates; Photorefractive Keratectomy; Rabbits; Time Factors