Fig. 1

Light and transmission electron microscopy features of jejunum epithelial cells obtained by collagenase digestion. a and d. Single and grouped epithelial cells of control (a) and treated animals (d). Note the columnar shape and the typical eosinophilic brush border (arrow). Haematoxylin-Eosin, scale bar: 10 μm. b and e. Epithelial cell strips obtained by digestion of control (b) and treated jejunum tracts (e). The medium power view reveals the single layer of polarized columnar cells that cover the villous surface. The tall nuclei are lined up at the base of the cells while the apical surface is covered by microvilli (arrow). Transmission electron microscopy. Scale bar, 5000 nm. c and f. High power view of the luminal portion of the epithelial cells obtained by digestion of control (c) and treated jejunum tracts (f). Observe the surface of the columnar epithelial cells with the “brush border” consisting of closely packed microvilli. Transmission electron microscopy. Scale bar, 5000 nm