Abstract:

【Objective】 A study was conducted to investigate the protective effects of purified whey protein isolate (WPI) peptides P4 on lung fibroblasts cell MRC-5 caused by the damage of H2O2 and its protective mechanism. 【Method】 Oxidative damage was induced by H2O2, and cell viability was measured by the 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) assay. The influence of WPI peptides P4 on H2O2-induced MRC-5 injury was assessed by measuring the superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) activities and the malondialdehyde (MDA) content. The change of cell morphology was observed by scanning transmission electron microscopy. 【Result】 The results demonstrated that MRC-5 cells were damaged by incubation with 1 mmol?L-1 H2O2 for 24 h, and the viability of MRC-5 cells reduced to 22.47%. The addition of WPI peptides P4 (4, 20, and 100 μg?mL-1) into the MRC-5 cell suspensions prior to the exposure to 1 mmol?L-1 of H2O2 resulted in a greater survival rate of the cells. In particular, the cell viability reached 44.77% after treating with 100 μg?mL-1 WPI peptides P4. Moreover, at elevated concentrations, WPI peptides P4 exhibited increased repairing capability for injured MRC-5 as well as increased protection of SOD, CAT and GSH-PX while reducing MDA formation. Scanning transmission electron microscopy also showed that WPI peptides P4 had the protection on MRC-5. 【Conclusion】 The purified WPI peptides P4 possess protective effects on MRC-5 cell injuries induced by H2O2, and this may be related to the antioxidative activity of WPI peptides.

Key words: whey protein isolate (WPI) peptides, antioxidant capacity, human lung fibroblast, H2O2, protection