Figure 2

β-catenin KO pancreata display extensive loss of exocrine tissue. Hematoxylin and eosin stained paraffin sections were used to compare the histology of wildtype versus β-catenin KO pancreata at one day, one month and two months of age. Compared to one day old wildtype pancreas [A], the absence of acini is readily apparent at low power [D]. At two months of age, compared to wildtype [B, C] the β-catenin KO pancreas is hypoplastic with increased areas of interlobular fibrosis [E]. Under 20× magnification, increased formation of tubular duct-like structures are present suggesting acinar to duct metaplasia (arrows) and inflammatory infiltrate (circled) are evident [F and H]. By two months, low power views demonstrate extensive fibrosis and near complete absence of exocrine pancreatic tissue, likely accounting for the shortened lifespan seen in these animals [E and G]. In several mice aged beyond three months, areas of pancreatic parenchyma histologically resemble liver. Immunostaining for albumin is absent in wildtype pancreas [J], but abundant in normal liver [I] and in β-catenin KO pancreata [K].