FIGURE 7.

The role of caspase activation in nitric oxide-induced γH2AX formation. A, isolated rat islets (150 islets/condition) were treated for 24 h with cytokines (10 units/ml IL-1 and 150 units/ml IFN-γ) or for 2 h with camptothecin (25 μm). Islets were dispersed and centrifuged onto slides, and the localization of γH2AX (red) formation in insulin-containing cells (green) was determined by immunofluorescent microscopy. Images were captured using a ×60 objective and ×2 field zoom. B, INS 832/13 cells were treated for the indicated times with 1 mm DEA/NO and harvested, and cleaved caspase-3, γH2AX, and GAPDH were detected by Western blot analysis. C, INS 832/13 cells were pretreated for 1 h with or without caspase inhibitor 1 (10 μm). DEA/NO (1 mm) or camptothecin (25 μm) were added, and the cells were cultured for the indicated times. Dimethyl sulfoxide (DMSO) was used as a vehicle control. Cells were harvested, and cleaved caspase 3, γH2AX, and GAPDH levels were determined by Western blot analysis, with GAPDH serving as a protein loading control. Results are representative of three independent experiments.