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

Figure 4 Fucoidan promoted intestinal epithelial barrier function via direct upregulation of tight junction proteins in intestinal epithelial cells Polarized Caco-2 cell monolayers injured by H₂O₂ (500 μmol/L) for 24 h with or without pretreatment of fucoidan (2. 5 mg/mL) 30 min prior to H₂O₂ administration. The expression of tight junction proteins, including claudin-1, claudin-2, and occludin, was examined using reverse-transcription polymerase chain reaction. The data shown are representative and are from 1 of the 3 independent experiments.