Figure 3.

β cell apoptosis and proliferation rates of islets embedded within fibroblast populated collagen gel. Mouse islets were embedded within IDO-expressing or control scaffolds or cultivated in regular petri dishes as described in the Materials and Methods. On days 1, 7, and 14 of coculture, islets were harvested and subjected to insulin/cleaved caspase-3 dual immunofluorescence staining and MTT assay. The four upper panels show insulin (red)/cleaved caspase-3 (green) dual immunofluorescence staining in islets cultured in petri dishes (A), embedded within either acellular gel (B), control fibroblast gel (C), or IDO fibroblast gel (D) for 14 days. (E and F) show β cell apoptosis and islets proliferation rates in islets embedded in IDO-expressing (solid triangles) or control fibroblast (open triangles) populated or acellular (solid circles) collagen gel matrices and islets cultured in petri dishes using regular two-dimensional culture method (solid diamonds- dotted line) on days 1, 7, and 14 post-coculture. Islet proliferation rates are reported as the percentage of the optical densities of MTT assay at each time point adjusted to those of day 1. * denotes significant difference in apoptosis and proliferation rates on day 14 compared to day 1 (n = 3, P < 0.001). White arrows show representative islet cells stained for both insulin and cleaved capase-3. Scale bar = 50 μm.