Effects of Mitomycin C on Lens: in Vitro Study

ABSTRACT

PURPOSE: Cataract could occur as a complication of mitomycin C (MMC) used to increase the success rate of glaucoma surgery. Thus, the effects of MMC on cellular growth inhibition and apoptosis induction were examined by the culturing lens epithelial cells and the morphologic change in cells when MMC induced apoptosis. METHODS: Cellular morphology was observed after treating the mouse lens epithelial cell line, alpha-TN4, with MMC at different concentrations. Cellular toxicity was measured using LDH. Furthermore, IC50 inhibiting cellular proliferation and IC50 inducing apoptosis were measured. Staining and TUNEL assay were done to define apoptosis. The lens shape was observed under a transmission electron microscope, and electrophoresis was performed investigate the change in protein level when cataract was induced by MMC. RESULTS: The lens epithelial cells were atrophic even at low concentrations of MMC and more severe cellular changes along with reduced survival rate were seen at higher concentrations. According to the results of measuring cellular toxicity using LDH, the amount of LDH increased with increasing concentrations of MMC. The results of staining showed the findings of apoptosis of cells with orange-colored, compressed nuclei at low concentrations of MMC. Also on microscopic observation, the compression of chromosomes and fragmentation of nuclei were seen. Furthermore, the number of the high molecularr 53 KDa protein was increased among lens proteins of fertilized egg. CONCLUSIONS: These results demonstrated that MMC induced apoptosis of lens epithelial cells; the formation of cataract occurred in subcapsular area and the equator region; and denatuation of lens proteins and high molecular weight 53 KDa protein were increased.