Figure 2.

PAG reinforces the intestinal barrier in vitro by increasing expression levels of tight junction proteins. (A) Caco-2 monolayers were cultured with or without PAG 400 μg/mL for 13 days, and trans-epithelial electric resistance values of the monolayers were recorded at days 0, 7, and 13 in triplicate; (B,C) Expression levels of tight junction-related proteins in total cell lysate (B), cytoplasmic (soluble) fraction and cytomembrane (insoluble) fraction (C) of Caco-2 monolayers after 48-h incubation with varying concentrations of PAG; (D) 14-day polarized Caco-2 monolayers were incubated with or without 2.5% DSS for 48 h after pre-treatment with PAG 400 μg/mL for 24 h; immunostaining was subsequently performed to visualize expression levels of the ZO-1 protein. Values are presented as mean ± standard deviation (Student t-test was applied for statistical analysis; *, # p < 0.05; ** p < 0.01; ***, ### p < 0.001).