Figure 4

Detection of apoptosis. (a) Apoptosis was quantified by FACS analysis after staining with Annexin V and PI at the end of the experiment (day 14) (islets were incubated with trypsin to obtain dispersed cells). Viable cells were Annexin V−/PI− (III), early apoptotic cells were Annexin V+/PI− (IV), late apoptotic cells were Annexin V+/PI+ (II) and necrotic cells were Annexin V−/PI+ (I). Representative examples are shown in b. (c) We also performed PI/FDA staining for determination of cell viability in normal and STZ-induced pancreatic islets cocultured with rBM-MSCs and calculated as described in Methods. STZ induced a significant decrease in the viability rates in islets compared with untreated islets (10%±2.8, 60%±2.81, respectively). Coculture with rBM-MSCs induced a significant increase in viability rates in STZ-induced islets (72.5%±4.01; P<0.001). (mean±S.D., n=3 each, ^**P<0.01, ^***P<0.001)