Figure 4. Apoptosis visualized by TUNEL. TUNEL staining of ARPE-19 cells incubated in the presence of cytochrome C (cyC) with (middle panels) or without (upper panels) exposure to taurine also showed that significantly fewer cells were undergoing cyC-induced apoptosis in the presence of taurine. Octanol had a similar effect to taurine in blocking the spread of cell death induced by cyC (lower panels). Scale bars represent 50 μm.