High hydrostatic pressure pre-treatment of whey proteins enhances whey protein hydrolysate inhibition of oxidative stress and IL-8 secretion in intestinal epithelial cells

Background: High hyperbaric pressure treatment of whey protein isolate (WPI) causes changes in the protein structure that enhances the anti-oxidant and anti-inflammatory effects of WPI. Objective: The aim of this study was to compare the anti-oxidant and anti-inflammatory effects of pressurized whey protein isolate (pWPI) vs. native WPI (nWPI) hydrolysates in Caco-2 cells exposed to hydrogen peroxide (H2O2). Design: Cells were cultured with different concentrations of pWPI or nWPI hydrolysates either 1 h before or 1 h after H2O2. Cell viability, IL-8 secretion, intracellular reactive oxygen species (ROS), and the medium anti-oxidant capacity (FRAP assay) were measured. Results: Prior to and after H2O2 exposure, pWPI and nWPI hydrolysates inhibited IL-8 secretion and ROS generation, and increased FRAP activity in a dose-dependent manner. The maximal inhibition of H2O2-induced IL-8 secretion was greater with 2000 μg mL 1 of pWPI (50%) vs. nWPI (30%) hydrolysates. At the latter concentration, inhibition of H2O2-induced ROS formation reached 76% for pWPI, which was greater than for nWPI hydrolysates (32.5%). Conclusion: These results suggest that WPI hydrolysates can alleviate inflammation and oxidative stress in intestinal cells exposed to oxidative injury, which is further enhanced by hyperbaric pressure pre-treatment of WPI.