Application of topical Mitomycin C in different doses and different periods on rabbit eyes: Evaluation of the effects on intraocular pressure and related histopathological changes

Purpose: To evaluate the effects of topical mitomycin C on intraocular pressure and related histopathological changes in the rabbit eyes with various doses and application periods.Materials-Methods: Thirty five albino rabbits were used in the study. The rabbits were investigated in seven different groups including 10 eyes of 5 rabbits in each group. Six cycles of mitomycin C were applied in Group 1,2 and 3 and 12 cycles in Group 4,5 and 6 as 0,2, 0,4, 0,8 mg/ml respectively. Group 0 was accepted as a control group and topical saline solution was used instead of mitomycin C. The intraocular pressure of the rabbits was measured monthly with Tonopen XL. At the end of the mitomycin C application cycles, all rabbits were sacrificed with intracardiac ketamine and enucleated for histopathological evaluation.Results: The intraocular pressures were significantly lower in all groups 4,5 and especially in group 6 compared to others in which high dose with long duration was used (p< 0,001). The examinations of all groups with light and electron microscopy revealed various histopathological changes of cornea epithelium, endothelium and ciliary body in different grades with relation to dose and application periods.Conclusions: Topical mitomycin C had intraocular pressure lowering effect and was found to be toxic on cornea and ciliary body of rabbit eyes depending on application period and significantly on dosage. This study will be helpful to define the optimal dosage of topical mitomycin C application with minimal toxic effects.Keywords: Topical mitomycin C, ciliary body, cornea, intraocular pressure, toxicity.