Tight junction architecture in the mHepR1 epithelial cell monolayer.

<p><i>a)</i> Note the continuous ZO-1 bands between mHepR1 cells in normal, untreated cell medium DMEM (left column). In contrast, 60 s plasma-treated DMEM stored for 1 d induces large openings between cell margins (arrow, right above), indicating a break of tight junctions. Plasma-treated DMEM (60 s) stored for 7 d induces an irregular cytoplasmic distribution of the ZO-1 proteins (arrow, right below). (AxioObserver.Z1, Carl Zeiss, bars = 5, 10 µm). <i>b)</i> The plasma treatment time of 120 s of the DMEM and storage of 7 d induces not only a retraction of the ZO-1 protein into the cytoplasm but also a nearly complete loss of the cell-cell contacts (arrow), while normal cells show a strong bonding (arrowhead). Note the long-lasting argon plasma effect of cell medium on structural organisation of cells. (AxioObserver.Z1, bar = 50 µm, the windows indicate the areas of the magnified view below).