exPKO acinar cells die through oncosis. (A, B) Acinar cells in the exPKO pancreas have numerous TUNEL-positive cells (A, P31 wild-type; B, P22 exPKO). Note that the TUNEL staining pattern strikingly differs between the two genotypes. TUNEL, green; DAPI, blue; background, red. (C, D) Adjacent serial sections (3μ) of the exPKO pancreas (P19). Pale pink (oncotic) acinar cells identified by H&E staining (C) correspond to cells positive for ApoE (D); see arrows as an examples of several cells. ApoE, red; DAPI, blue; background, green. (E, F) The KO pancreas has significant leukocyte infiltration (E, wild-type; F, exPKO, P74). Dark purple acid phosphatase staining indicates infiltrated leukocytes including macrophages (see arrows) in F but not E. The background cellular staining is methylene blue.