Sieving characteristics of cytokine- and peroxide-induced epithelial barrier leak: Inhibition by berberine

Figure 4 The effect of tumor necrosis factor-α + interferon-γ + interleukin-1β on transepithelial flux of ¹⁴C-D-mannitol, ³H-lactulose, and ¹⁴C-polyethylene glycol across CACO-2 cell layers. Twenty-one day post-confluent CACO-2 cell layers on Millipore PCF filters were refed in control medium or medium containing the combination of 200 ng/mL tumor necrosis factor-α, 150 ng/mL interferon-γ, and 50 ng/mL interleukin-1β (apical and basal-lateral compartments) 48 h prior to radiotracer flux studies. These studies were performed using 0.1 mmol/L, 0.1 μCi/mL ¹⁴C-D-mannitol; 0.1 mmol/L, 0.25 μCi/mL ³H-lactulose; and 0.1 mmol/L, 0.3 μCi/mL ¹⁴C-polyethylene glycol as described in Materials and Methods. Data represent the percent of control flux rate normalized across 2 experiments, and is expressed as the mean ± SE of 8 cell layers per condition for the mannitol flux and 4 cell layers per condition for both the lactulose and polyethylene glycol fluxes. NS indicates non significance. ^bP < 0.001 vs control (Student’s t test, one-tailed).