posted on 2023-06-09, 13:12authored byAlex J Wadley, Adrian Holliday, Rhys MorganRhys Morgan, Kate J Heesom, Sarah Aldred, Derek M Peters, Allain A Bueno, Steven J Coles
This study investigated immunophenotypic differences in intracellular thiol redox state of peripheral blood mononuclear cells (PBMCs) isolated from trained (TR, n=9, mean {plus minus} SD: age 28 {plus minus} 5 years; BMI 23.2 {plus minus} 2.6 kg·m; VO 56.9 {plus minus} 6.1 ml·kg·min) and recreationally active (RA, n=11, mean {plus minus} SD: age 27 {plus minus} 6 years; BMI 24.2 {plus minus} 3.7 kg·m; VO 45.1 {plus minus} 6.4 ml·kg·min) participants before and after a maximal aerobic exercise tolerance test. Blood samples were taken before (PRE), during (sample acquired at 70% HRmax), immediately (POST+0) and 15 minutes post-exercise (POST+15). PBMCs were isolated and reduced thiol analysis (fluorescein-5 maleimide (F5M)) by immunophenotype (CD3+, CD4+ and CD8) was performed using flow cytometry. A significant increase in cellular F5M fluorescence was observed in CD3+ T-cells at POST+0, with changes driven to a greater extent by CD8 T-cells (fold change in both groups CD4: +2.3, CD8: +2.8; p<0.05). Further analysis revealed a population of highly reduced CD8 T-cells (CD8T-reduced) that significantly increased from PRE to POST+0 in RA participants only (RA: +272 cell/µL, p<0.05). To further understand these results, CD8T-reduced and CD8T-reduced- cells were analysed for immunophenotype in response to the same exercise protocol (n=6, mean {plus minus} SD: age 24 {plus minus} 5 years; BMI 25.7 {plus minus} 4.1 kg·m; VO 41.33 {plus minus} 7.63 ml·kg·min). CD8T-reduced had significantly less lymphoid homing potential (CCR7) POST+0 compared to PRE. This study is the first to demonstrate that lymphocyte populations become more reductive in response to acute exercise.