Fig. 2.

Characterization of leaky gut model with advanced features mimicking IBD condition. Confocal z-stack images of co-cultures representing a tight (day 12; upper panel) or sub-confluent epithelium (day 7; lower panel) stained for cell nuclei (DAPI; blue) and cytoskeleton (AF488-phalloidin; green) (A). Top or side view images are shown in separated or overlaid fluorescence channels (merge) and leaky regions are indicated by white arrows (axis unit = μm). Measurement of epithelial barrier function monitored by TEER over time (intact barrier with 300 Ω*cm²); (n = 6–15; N = 4) (B). Confluency measurements of leaky gut model by area calculation of cell-free regions compared to tight epithelium (100% confluency) with ≥2 positions of ten leaky models from 6 independent preparations (n = 21; N = 6) (C). Barrier function decrease of tight barrier model after LPS inflammation (10 μg/mL) compared to unstimulated control. TEER represented as percentage, normalized to the initial TEER value (*denotes p < 0.05 according to Student's test); (n = 9; N = 3) (D). Comparison of cytokine release after LPS stimulation for tight barrier and leaky gut model monitoring the secretion of interleukin 8 (IL-8) (E) and tumor necrosis factor alpha (TNF-α) (F) to the apical (AP) and basolateral (BL) compartment (** p < 0.01 and **** p < 0.0001 according to ANOVA); (n = 6; N = 2). (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)