FITC Dextran Permeability Assay

4 kDa FITC dextran (Sigma Aldrich, St. Louis, MO) permeability assay was performed as previously described (26). Briefly, mice were fasted for 4 h and then gavaged with an 80 mg/kg dose of FITC dextran. 4 h later, mice were bled to obtain serum and a FITC dextran standard curve (20 to 0.3125 μg/ml) was prepared by diluting the stock solution with PBS. The standard and serum samples from naïve and DSS treated mice were transferred to black bottom 96 well plates and fluorescence was read at 525 nm on a Perkin Elmer Wallace Microplate Reader (GMI, Ramsey, MN). A linear curve was fitted to the standard and used to quantify serum FITC dextran levels.