[The cytotoxic effect of topical mitomycin C on the ciliary body in rabbits]

We evaluated the cytotoxic effects of mitomycin C (MMC) in rabbit eyes. A sponge soaked with MMC was placed on the bared sclera after conjunctival incision. We used four concentrations of MMC in distilled water: 0%, 0.04%, 0.1%, and 0.4%. MMC was applied to one eye only, with the fellow eye serving as control. The eyes were studied for intraocular pressure (IOP) and by fluorophotometry at 3, 7, 14, and 28 days of treatment. Eyes treated with 0.04% and 0.4% MMC were studied histologically at 3 and 28 days. All the MMC-treated eyes showed no significant changes regarding IOP (56 eyes) or fluorophotometric features (28 eyes) regarding aqueous humor dynamics and blood-aqueous barrier. Pathologic changes of the ciliary epithelium, including intracellular vacuoles and swelling of mitochondria, were more pronounced in eyes treated with 0.4% MMC than those treated with 0.04%. These changes were more manifest in areas inner to the site of application than in the opposite area. Topical application of 0.04% MMC thus showed no evident toxic effects on the function of the ciliary body and other pathological changes were minor.