Zonulin elisa kit

For quantitative assessment of the plasma levels of zonulin, a commercial enzyme-linked immunosorbent assay, Zonulin ELISA Kit, (MyBiosource, San Diego, CA) was used according to the manufacturer’s instructions.

Colonic permeability was assessed by measuring FITC-dextran (4 kDa) flow in Ussing chambers with an exchange surface of 0.07 cm² (Harvard Apparatus, Holliston, United States). FITC-dextran (5 mg/ml) was placed in the mucosal side. After 3 h at 37 °C, medium from the serosal side was removed and stored at −80 °C. The fluorescence level of FITC-dextran (excitation at 485 nm, emission at 535 nm) was measured in 96- well black plate with spectrometer Chameleon V (Hidex, Turku, Finland). Values were converted to concentration (mg/mL) using a standard curve.
As serum Zonulin, (identified as prehaptoglobin-2) is one of the few known physiological mediators of paracellular intestinal permeability, its concentration was assessed46 (link). Serum zonulin concentrations were measured by Zonulin ELISA kit (MyBiosource, San Diego, CA) according to the manufacturer’s instructions.