Retinotoxicity of Intravitreal Mitomycin C

Shin, Jae Pil; Hong, Sung Pyo; Kim, Sang Ha

Abstract

Mitomycin C(MMC), an antineoplastic drug, is a potent inhibitor of cell mitosis, and the intravitreal application of MMC can be a useful treatment for proliferative vitreoretinopathy by inhibiting intraocular cellular proliferation. We investigated the retinal toxicity of an intravitreal injection of MMC in the pigmented rabbits electroretinographically and histologically. Pigmented rabbits received various dosages of intravitreal MMC(1.0, 2.0, 3.0, 4.0, 10.0 microgram) at a constant volume of 0.1ml. Eltroretinographic data were obtained on 1, 3, 5, 7, days after injection and compared with preinjection ERG data. On 14 days after injection, we evaluated the retinel toxicity of MMC histologically. A dosage of 1.0 microgram MMC resulted in no demonstrable retinal toxicity by electroretinographical and histological studies. A toxic dose of MMC(2.0, 3.0, 4.0, 10.0 microgram) suppressed the b-wave and that of oscillatory potentials were not affected. This fact may suggest that a toxic dose of intravitreal MMC have caused destructive retinopathy. On the light microscopic examination, the outer layer of the retina was most sensitive to the toxic effect of MMC, and higher than 2.0 microgram dosage of MMC affected all layers of the retina.