Beta cell loss in diabetic RIP-REST mice occurs through apoptosis.

<p><i>A</i>. Nuclear PCNA (green) and insulin (red) staining show same level of proliferating beta cells (arrows) in both wild type (WT, left panel) and diabetic RIP-REST mice (right panel) at P2. Blue staining is the DAPI labeling of nuclei. Scale bar, 50 μm. <i>B</i>. Representative images of nuclear TUNEL (green) and insulin (red) staining showing apoptotic nuclei of beta cells in sections of P2 diabetic RIP-REST mice. No apoptotic beta cells were detected in wild type animals (not shown). Blue staining is the DAPI labeling of nuclei. Scale bar, 25 μm. C. Quantification of apoptotic nuclei in non-infected INS-1E cells (NI) and INS-1E cells transfected with a control (Ad-GFP) or REST-expressing adenovirus (Ad-REST) at different multiplicity of infection (MOI) as indicated, and treated 24 h with a mix of cytokines (black bars) or not (white bars). Results are mean ± SD of six independent experiments. *<i>P</i><0.05 versus respective controls in treated or untreated conditions. # <i>P</i><0.05 versus MOI 2 of Ad-REST infection.