treatment influences the AJC ultrastructural characteristics of Caco-2 cells. Caco-2 cells were grown on Transwell filters until they achieved confluence, treated with 1 μM PGE2 and processed for electron microscopy analysis. Representative images of thin sections of control cells (A) shows an intact AJC between two neighbor cells, however cells treated with PGE2 for 15 (B), 30 (C) and 60 (D) show alterations in the AJC region, mainly at the adherent junction area. Note that the TJ (Arrowheads) apparently remain unaltered. Bar: 2.5 μm. TJs: Tight Junctions.