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Abstract #6926 Published in IGR 4-1
Toxic effects of mitomycin-C on cultured ciliary process cells and trabecular meshwork cells
Hong SJ; Wu KY; Wang H; Lai YHJournal of Ocular Pharmacology and Therapeutics 2001; 17: 331-342
Mitomycin-C has recently become an adjunct medication for inhibition of fibroblast proliferation in glaucoma filtering procedures. Prolonged postoperative ocular hypotony has been a frequent complication of trabeculectomy with mitomycin-C. In order to characterize the hypotony mechanism, the authors compared the toxic effects of mitomycin-C on cultured rabbit ciliary process cells and trabecular meshwork cells. The results indicate that mitomycin-C has a more marked effect on ciliary process cells on 3H-thymidine uptake than on trabecular meshwork cells at concentrations ranging from 10-1 to 10-5 mg/ml after three-, five- and 60-minutes' treatment, respectively. The living cells after mitomycin-C treatment were estimated with MTT assay that was converted tetrazolium dye of living cells only into insoluble purple formazan crystals within mitochondria. In the presence of mitomycin-C for three, five, and 60 minutes, the cellular MTT values in ciliary process cells were more decreased than in trabecular meshwork cells. Depolarization of the trabecular meshwork cells with 50 mM KCl led to an increase in intracellular calcium concentration, whereas application of mitomycin-C at 10-3 mg/ml resulted in decrease of KCl-induced intracellular calcium increase. Mitomycin-C (10-3 mg/ml) decreased cAMP concentration in ciliary process cells following three and five minutes of treatment; however, it did not significantly affect the cellular cAMP concentration after only a one-minute exposure. Mitomycin-induced marked ladder pattern of DNA fragmentation was observed in ciliary process tissues after treatment with 10-1 mg/ml of mitomycin-C for three and five minutes. However, the DNA pattern in trabecular meshwork tissues was not obviously affected by mitomycin-C. These findings from the authors' results indicate that mitomycin-induced ocular hypotony may result from damage to both ciliary process and trabecular meshwork tissues.
Dr. S.J. Hong, Department of Pharmacology, Kaohsiung Medical University, Taiwan, ROC. hong6657@ms5.hinet.net
Classification:
12.8.10 Woundhealing antifibrosis (Part of: 12 Surgical treatment > 12.8 Filtering surgery)
