Effects of synthetic Inhibitor of Metalloproteinase and Cyclosporin A on Corneal Haze and Collagen Synthesis after Excimer Laser Photorefractive Keratectomy in Rabbits

ABSTRACT

Photorefractive keratectomy(PRK) was performed on 60 rabbit eyes, and synthetic inhibitor of metalloproteinase(SIMP) and cyclosporin A(CsA) was topically administered and their effects on coreneal haze were evaluated. They were randeomized to one of four groups group A received topical SIMP, group B received topical CsA, group C received both SIMP and CsA, and group D received vehicles. At one, two, four, and six weeks after surgery, slit lamp examination was performed, and haze gradings were recorded. Light microscopy, together with immunohistochemistry using antibodies against collagen types III, IV, and VI were performed in corneas from all groups. Slit lamp examination and light microscopy revealed that SIMP significantly reduced corneal haze after PRK and subepithelial deposition of newly synthesized extracellular matrix, but CsA did not. By immunohistochemistry, deposition of types III and IV collagen was noted in ablated area of all groups. Positive staining for type III collagen was less frequent in groups treated with SIMP than in groups not treated with SIMP. In conclusion, SIMP significantly reduced the synthesis of type III collagen in treated area as well as corneal haze after excimer laser PRK in rabbits.