Figure 1
PDL induces islet formation and β cell proliferation in adult mouse pancreas. Eight-week-old male Balb-c mice, underwent PDL or Sham surgery. (a) PDL and Sham tail total β cell volume (mm3) and (b) number of β cell clusters in the indicated diameter (μm) categories (n=3; *P<0.05, **P<0.01, ***P<0.001, ns: P>0.05, PDL versus Sham tail). (c) Panels show the total tissue volume (gray) and insulin+ volumes (red) detected by OPT microscopy in tail regions of Sham or PDL operated pancreases. The total islet volume increased after PDL to 2.0 × 109±3.5 × 108 μm3 (compared with Sham tail 1.1 × 109±2.8 × 108 μm3; n=3; P=0.056). The total number of insulin+ islets significantly increased from 1000±184 in Sham to 1539±77 in PDL tails (n=3; P<0.05). This increase could be attributed to a significant increase in small islets (<106 μm3) (711±107 islets in Sham versus 1082±25 islets in PDL; n=3; P<0.05). (d,e) β cell proliferation was determined in ligated PDL tail, unligated PDL head or Sham tail pancreas, at 7 and 14 days post-PDL by immunofluorescence staining (d) for insulin and Ki67 (n=5–14) or (e) for insulin, Nkx6.1 and Ki67 (n=3) (***P<0.001, ns: P>0.05, versus Sham tail or PDL head by two-way ANOVA). (f) 5-iodo-2′-deoxyuridine (IdU, 1 mg/ml) was i.p. injected precisely at 8 and 4 h before sacrifice at the indicated time points following PDL. The percentage of IdU-labeled β cells was determined by immunostaining for insulin and IdU (n=3, *P<0.05, **P<0.01 versus Sham tail by two-way ANOVA). 1800±200 β cells were counted per tissue sample. See also Supplementary Figure S4A
