Abstract
Abstract: :
Purpose: To investigate the effect of indocyanine green(ICG) dye on cultured retinal pigment epithelial(RPE) cells. Methods: After the cultured porcine RPE cells were exposed to ICG, the morphological change, toxicity and effects on cell proliferation were evaluated. For morphological and toxic studies, confluent RPE cells were exposed to balanced salt solution(BSS), 0.1%, 0.5% and 1.0% concentration of ICG for 30 seconds, 1 minute, 5 minutes and 10 minutes and were evaluated by phase-contrast microscopy, light microscopy, electron microscopy, mitochondrial dehydrogenase assay at the time point of 3 days, 1 week, 2 weeks and 4 weeks after ICG exposure. For cell proliferation study, proliferating RPE cells were exposed to BSS & same concentrations of ICG at the same exposure time and evaluated the number of live cells with MTT colorimetric assay at the time point reaching to confluence in control group. In addition, after confluent RPE cells were exposed to the same concentration of ICG, central cells were removed as in about 2 mm-diameter and evaluated the adjacent cells to occupy the defect using phase-contrast microscope. Results: RPE cells exposed to ICG showed no histologic or ultrastructural change except slight irregularity in cell size and demonstrated no differences in mitochondrial dehydrogenase activity as compared with control groups. ICG did not seem to affect the cellular proliferation, However, in groups exposed to over 0.5% concentration of ICG for over 5 minutes, RPE cells occupying the central defects were mostly transformed to fibroblast-like cells. Conclusions: These results suggest that ICG with concentrations up to 5.0 mg/mL(0.5%) for about one minute exposure time appears to be safe to RPE cells, but loss of RPE cells during macular hole surgery assisted by ICG may influences visual outcomes due to poor differentiation of proliferating cells.
Keywords: retinal pigment epithelium • drug toxicity/drug effects • microscopy: electron microscopy