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. 2010 Feb 18;298(5):G625–G633. doi: 10.1152/ajpgi.00350.2009

Fig. 5.

Fig. 5.

Effect of zinc deprivation on the epithelial barrier of Caco-2 cells. Caco-2 cells were cultured on inserts and treated with N,N,N′,N′-tetrakis (2-pyridylmethyl) ethylenediamine (TPEN) at 2, 3, and 4 μM or 4 μM TPEN plus 100 μM zinc for 24 h. A: distribution of tight-junction proteins were examined by detected by immunofluorescence microscopy. Scale bar = 25 μM. B: protein levels of tight-junction proteins were determined by immunoblotting analysis. Immunoblot bands were quantified by densitometry analysis, and the ratio to GAPDH was calculated by setting the value of controls as 1. C: epithelial barrier function was assessed by measuring TEER and FD-4 permeability. D: effect of NAC on TPEN-induced epithelial barrier disruption. Caco-2 cells were treated with 3 μM TPEN with or without 2 mM NAC pretreatment. Results are means ± SD (n = 4 in B, n = 8 in C and D). Significant differences (P < 0.05, ANOVA) are identified by different letters, a-e. T, TPEN.