Figure 1.

Effects of poly IC and IFN-γ on islet cell DNA integrity. Rat islets (100 per 400 μl of complete CMRL-1066) (a) or FACS-purified β-cells (50,000 per 400 μl of complete CMRL-1066) (c) were treated for 24 hours with 50 μg/ml of poly IC, or rat islets (b) and FACS-purified β-cells (d) were treated with the indicated concentrations of poly IC, rat IFN-γ, and NMMA. The islets and β-cells were isolated and DNA damage was analyzed by TUNEL staining (green fluorescence) as described in Materials and Methods. Insulin-containing cells were identified using a guinea pig anti-human insulin and CY3-conjugated donkey anti-guinea pig secondary antibodies (a). The arrows indicate TUNEL-positive β-cells (c). The percentage of TUNEL-positive cells was determined in a double-blind manner. Results are representative of three independent experiments (a and c) or the average ± SEM of three independent experiments (b and d).