Inhibitory Effect of Radiation on the Transdifferentiation of Lens Epithelial Cells into Fibroblasts

ABSTRACT

PURPOSE: We estimated the effectiveness of radiation on transdifferentiation of the lens epithelial cells into fibroblast. METHODS: The morphologic changes and number of fibroblasts were determined using a phase contrast microscope. The proliferation of lens epithelial cells was analyzed by PCNA and BrdU assay in the control group and in the experimental groups exposed to 500, 1000 or 2000 rad of X-ray on the 7th day of culture. Expression of type IV collagen was estimated by Western blot and apoptosis was investigated using TUNEL assay. RESULTS: The number of fibroblast transdifferentiated from lens epithelial cell was 300+/-1.58 in control group, and 240+/-1.58, 231.75+/-4.1E, and 213.50+/-0.22 in the group exposed to 500 (experimental group I), 1000 (experimental group II), and 2000 rad (experimental group III), respectively, on the 7th day of culture (radiation was decreased in a dose-dependent manner). The index of PCNA and count of BrdU labeling cells were 56+/-1.58% and 27.6+/-4.6 in control group; 26+/-1.56% and 18.4+/-8.5 in experimental group I; 24+/-1.60% and 17.2+/-4.2 in experimental group II; 16+/-1.58% and 8.6+/-2.4 in experimental group III, respectively. These results indicated that proliferation of lens epithelial cells was inhibited by radiation in a dose-dependant manner. The Western blot showed that the expression of collagen decreased in experimental groups I and II and markedly decreased in experimental group III, compared with control group. TUNEL showed no differences between the control and experimental groups I and II but showed increased apoptosis in experimental group III. CONCLUSIONS: Radiation may inhibit the transdifferentiation of lens epithelial cells into fibroblasts. It would be practicable that radiation suppresses proliferation of lens epithelial cells in posterior capsular opacity.