Trypan blue induces apoptosis in human retinal pigment epithelial cells

PURPOSE: To examine whether trypan blue dye induces apoptosis in human retinal pigment epithelium cells. DESIGN: Laboratory investigation. METHODS: Pure cultures of human retinal pigment epithelium cells were isolated. The cells were incubated with different concentrations of trypan blue (0.5%, 0.10%, and 0.05%) for either 5 or 30 minutes. The rate of retinal pigment epithelium cell apoptosis was assessed with Annexin V-PE staining and flow cytometry. RESULTS: Trypan blue induced a statistically significant amount of apoptosis in retinal pigment epithelium cells at all the concentrations (0.5%, 0.10%, and 0.05%) (P <.05). The increase in incubation time (from 5 to 30 minutes) led to an increase in the number of apoptotic retinal pigment epithelium cells. CONCLUSION: The incubation of retinal pigment epithelium cells with trypan blue increased the number of apoptotic retinal pigment epithelium cells in vitro. Our results suggest that decisions regarding the intravitreal application of trypan blue dye need to be made with caution.