Purpose: To evaluate the toxicity of trypan blue on retinal cells in vitro.
Methods: Human retinal pigment epithelial cells (ARPE-19) and rat neurosensory retinal cells (R28) were grown in tissue culture and treated with four different concentrations of trypan blue (0.1%, 0.05%, 0.025%, and 0.0125%), in combination with surgical light exposure (0, 5, or 10 minutes). Cell viability, mitochondrial function, and DNA synthesis were measured by trypan blue dye-exclusion assay, mitochondrial dehydrogenase assay, and tritiated [3H] thymidine incorporation, respectively.
Results: ARPE-19 and R28 cells exposed to trypan blue with or without illumination did not show any significant decrease, either in cell viability by the dye-exclusion assay or in [3H] thymidine incorporation. R28 cells exposed to 0.1% trypan blue with and without light showed a significant reduction of mitochondrial dehydrogenase activity (P <0.05). ARPE-19 cells exposed to trypan blue, with or without light, did not show any significant decrease in mitochondrial dehydrogenase activity.
Conclusions: This study suggests that rat neurosensory retina (R28) cells are more sensitive than human RPE (ARPE-19) cells to trypan blue. ARPE-19 cells showed no evidence of toxicity with any of the three assays, but R28 cells showed evidence of toxicity with the mitochondrial dehydrogenase assay at the higher doses and light-exposure times studied. Clinical studies must be conducted to determine the safety and efficacy of staining of the inner limiting membrane with trypan blue.