Fucoidan enhances intestinal barrier function by upregulating the expression of claudin-1

Figure 3 Fucoidan prevented H₂O₂-induced increases in paracellular permeability. First, 0.5 mg/mL 4-kDa FITC-labeled dextrans (FD4) were added into the apical well and cultured for 6 h with or without H₂O₂ (500 μmol/L) and/or fucoidan (2.5 mg/mL). After 6 h of incubation, the basal medium was collected, and the fluorescence was measured as fluxed-FD4. H₂O₂-induced FD4 flux was considered 100%. The data are expressed as the means ± SEM of 5 independent experiments. ^bP < 0.01 (Student’s t test).