Fig. 4. Increase of acinar cell apoptosis and ductal proliferation in orpk mice after birth (P4). TUNEL staining showed an increase of apoptotic cells in pancreas of orpk mice (B) when compared with wild-type mice (A). Inset in B shows that no apoptotic cells could be detected in islets (outlined) in orpk mice. Proliferation is increased in dilated ducts of orpk mice, as shown by Ki-67 staining (C,D). Note that the number of proliferating cells in orpk mice in dilated ducts (outlined in white) is higher than in non-dilated ducts (outlined in yellow). Quantification of apoptotic cells, measured as number of cells positive for TUNEL staining per field of view (E; blue, wild type, n=5; red orpk, n=5), showed an increase of cell apoptosis in orpk mice. Proliferation indexes of pancreatic cells are given as number of Ki-67-positive cells per mucin-positive, insulin-positive or amylase-positive cells (F; wild type, n=5; orpk, n=5). Wild-type numbers for apoptosis and proliferation were set to `1' to facilitate comparison (E,F). Errors bars are shown as ±s.e.m.