Influence of physical exercise on β-amyloid, α-synuclein and tau accumulation: an in vitro model of oxidative stress in human red blood cells

A common pathological feature of neurodegenerative disorders (NDs), such as Alzheimer's (AD) and Parkinson's (PD) diseases, is the accumulation and misfolding of specific proteins, primarily alpha-synuclein (alpha-syn), beta-amyloid(I-42) (A beta) and tau, in brain and in peripheral tissues too. Oxidative stress has been proved to be involved in NDs at various levels and, in particular, in such protein alterations, on the contrary physical activity is emerging as a counteracting factor in NDs. In the present work, the content of A beta, alpha-syn and tau in red blood cells (RBCs) derived from ten endurance athletes (ATHL) and ten sedentary volunteers (SED) were compared before and after in vitro oxidative stress treatment. Total A beta, alpha-syn and tau were quantified in RBCs (isolated from the subjects) by immunoenzymatic assays. Oxidative stress was induced by in vitro H2O2 administration to RBCs. H2O2 treatment was confirmed to significantly enhance ROS accumulation in RBCs. Total A beta content in RBCs was lower in the ATHL subgroup with respect to the SED one. In the SED subgroup, but not in the ATHL one, total A beta levels were increased by oxidative stress. Total alpha-syn content was lower in the ATHL subgroup with respect to the SED one and alpha-syn levels were increased by oxidative stress in both subgroups, with the percentage of increase higher in SED. Total tau content was comparable in both ATHL and SED and it was not affected by oxidative stress. Our data confirm previous findings evidencing that both oxidative stress and sedentary style contribute to aberrant folding and accumulation of NDs-related proteins, pointing to the importance of both anti-oxidant therapies and exercising in the prevention and treating of such diseases.