Influence of Endogenous Cardiac Glycosides, Digoxin, and Marinobufagenin in the Physiology of Epithelial Cells

Figure 3

Involvement of Na-K-ATPase in the effect of marinobufagenin and digoxin on Gap Junctional Intercellular Communication (GJIC) and transepithelial electrical resistance (TER). (a) Representative images of cells stained with Lucifer Yellow, obtained after injection of a single cell, in mononolayers of MDCK-R cells, either untreated (CTRL) or treated with marinobufagenin (MBGN) 100 nM or digoxin (DGX) 10 nM during 1 hour before injections. (b) Bar chart showing the corresponding average ± SE number of cells stained in each trial. A paired comparison (t-student) of treatment versus its control produced no significant difference for neither ECS. (c) Representative images of immunofluorescence assays obtained on monolayers of MDCK-R, either untreated (control) or treated with digoxin or marinobufagenin 100 nM for 48 hours. Sampled were incubated with anti-claudin-4, and their expression is revealed by streptavidin FITC (green); samples were counterstained with DAPI to reveal the presence of nuclei (blue). (d) Bar chart comparing the average ± SE value of TER obtained from 9 repeats of 3 independent experiments from control and treated MDCK-R monolayers at distinct times after addition of treatment, either marinobufagenin (MBGN) 10 nM or digoxin (DGX) 100 nM. Multiple comparison statistical test (Kruskal–Wallis one-way analysis of variance on ranks) does not indicate a statistically significant difference of any treatment in any of the times in which TER was measured.

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