Protective effect of whey protein hydrolysates on H2O2-induced PC12 cells oxidative stress via a mitochondria-mediated pathway

• Whey protein hydrolysates (WPHs) contain antioxidant peptides.
• Pretreatment with WPHs could protect PC12 cells against oxidative damage.
• WPHs inhibited oxidative stress by regulating mitochondrial apoptotic pathway.

Whey protein hydrolysates (WPHs) were prepared with pepsin and trypsin. A PC12 cell model was built to observe the protective effect of WPHs against H2O2-induced oxidative stress. The results indicated that WPHs reduced apoptosis by 14% and increased antioxidant enzyme activities. Flow cytometry was used to assess the accumulation of reactive oxygen species (ROS), Ca2+ levels and the mitochondrial membrane potential (MMP). The results showed that WPHs suppressed ROS elevation and Ca2+ levels and stabilised MMP by 16%. The anti-apoptosis/pro-apoptosis proteins Bcl-2/Bax and poly (ADP-ribose) polymerase (PARP) were investigated by Western-blot analysis, which indicated that WPHs increased the expression of Bcl-2 while inhibiting the expression of Bax and the degradation of PARP. WPHs also blocked Caspase-3 activation by 62%. The results demonstrate that WPHs can significantly protect PC12 cells against oxidative stress via a mitochondria-mediated pathway. These findings indicate the potential benefits of WPHs as valuable food antioxidative additives.