Figure 4.

Basal and adaptive β-cell regeneration capacity in WT and PARP-1^−/− mice. Representative sections of pancreatic sections immunostained with antibodies against insulin (green) and BrdU (red) and counterstained with DAPI (blue) before (A) and after (B) STZ (n = 4–5). (C) Proportion of BrdU-positive β cells of young and old mice before and after STZ injection. Values were averaged from 5 slides for each mouse, with 4–5 mice in each group.**p < 0.01 versus old WT mice. Yellow arrows = insulin and BrdU copositive cells; white arrows = BrdU-labeled and non–insulin-labeled cells. Bar = 50 μm.