Tea polyphenols alleviated endothelial hyperpermeability induced by angiotensin Ⅱ

  Objective   To observe the effects of tea polyphenols on endothelial cell hyperpermeability induced by Ang Ⅱ and search for the mechanism of tea polyphenols on down-stream redox signal mediated by Ang Ⅱ receptor typeⅠ(AT1).

  Methods   The intracellular superoxide anion production in BACECs challenged with AngⅡ(1 mg/L)was measured by quantitative nitroblue tetrazolium(NBT)assay and the extracellular hydrogen peroxide concentration was determined after the cells were pre-incubated with GTP or BTP(0.4 mg/L)for 24 h.In cultured monolayer BCA ECs, permeable FITC- dextran(2.5μmol/L)was measured to evaluate the effects of tea polyphenols on the changes of AngⅡ-induced endothelial permeability.

  Results   Both green tea and black tea polyphenols diminished the intracellular superoxide anion induced by Ang Ⅱ(P < 0.05), and alleviated the intercellular permeability induced by Ang Ⅱ(P < 0.05).The similar permeability decrease induced by Ang Ⅱ was also obtained using either NADPH oxidase inhibitor DPI or antioxidant VE pretreatment.

  Conclusion   Tea polyphenols alleviated Ang Ⅱ-induced hyperpermeability-mainly via decreasing the ROS production.