Peripheral blood leucocyte functional responses to acute eccentric exercise in humans are influenced by systemic stress, but not by exercise-induced muscle damage

Abstract

The effects of comparable lower-limb eccentric exercise that induces high (bench-stepping; STEP) and low (repeated eccentric muscle action; ECC) systemic stress on neutrophil and monocyte phagocytic and respiratory burst activity, and activation antigen (CD11b, CD66b, CD64) expression, were compared in recreationally active subjects (20–37 years old). Leucocyte responses were determined before and 4, 24, 48 and 72h after exercise using whole-blood flow cytometry. Serum creatine kinase (CK) activity and perceived muscle soreness [delayed-onset muscle soreness (DOMS)] were assessed at the same time points up to 96 h; as a control, measurements were taken during 5 days of rest. DOMS in quadriceps and contralateral triceps surae peaked 24–72h after STEP (P<0.05) and 48–72h after ECC (P<0.05), whereas serum CK activity (mean±S.E.M.) was only higher than baseline after ECC (15123±3488 at 96h compared with 115±29 units·l-1 pre-exercise; P<0.01). The total leucocyte count increased from (5.4±0.4)×109·l-1 and (5.7±0.5)×109·l-1 at baseline to (7.6±0.5)×109·l-1 and (7.0±0.5)×109·l-1 at 4h after STEP and ECC respectively; this was largely attributable to changes in the neutrophil count (P<0.05). The proportion of neutrophils undergoing phagocytosis and respiratory burst was unchanged 4h after ECC and STEP, which, given the increase in neutrophil count after exercise, would suggest an overall improvement in systemic neutrophil microbicidal potential. The intensity of neutrophil (P = 0.01) and monocyte (P<0.05) phagocytosis and neutrophil respiratory burst responses (P<0.05) was only increased 24h after STEP, whereas no changes in these measures were observed after ECC. Activation antigen expression was unchanged in all groups. These findings suggest that systemic stress evoked during an acute bout of eccentric exercise has a greater influence on subsequent leucocyte functional responses than the degree of muscle damage induced.

Acute Exercise Modulates BDNF and pro-BDNF Protein Content in Immune Cells

“…Cytokines are believed to play important roles in the inflammatory responses to muscle damage and subsequent regeneration (27). Therefore, the profile of such inflammatory mediators (particularly of IL-6) might be different between the concentric exercise performed in this study and an eccentric exercise where muscle inflammation is much more severe (34). Moreover, as recently underlined by Croft et al (9), the increase in cytokine concentrations induced by acute exercise is attenuated by previous exercise training, and therefore, the good fitness status of the subjects investigated in the present study might have been responsible for the blunted response observed.…”

Effects of resistance exercise and protein ingestion on blood leukocytes and platelets in young and older men

“…The mechanisms behind the delayed increase of neutrophils (design I) are not known in detail, but may include possibly increased levels of hormones and cytokines during and shortly after exercise, i.e., interleukin 6 that stimulates the bone marrow release of leukocytes (Jagels and Hugli 1992;Yamada et al 2002). Muscle damage could also play a role in the production of cytokines and the leukocytosis after exercise (Paulsen et al 2005), but the cardiovascular stress may be more important when the degree of muscle damage is limited (Saxton et al 2003).…”

“…Intensive exercise causes rapid, transient changes in the number of white cells (leukocytes) in the circulation Paulsen et al 2005). The blood leukocyte response may be biphasic, comprising an acute increase immediately after exercise and delayed increase some hours later (Gabriel and Kindermann 1997;Saxton et al 2003;Paulsen et al 2005). The acute increase in blood leukocytes has been shown to occur after traditional resistance exercise (RE) workout in many studies (Nieman et al 1995;Kraemer et al 1996;Simonson 2001;Natale et al 2003;Ramel et al 2003;Risoy et al 2003;Simonson and Jackson 2004;Mayhew et al 2005;McFarlin et al 2005).…”

The inflammatory response: friend or enemy for muscle injury?: Figure 1

“…Saxton et al 15 showed that the total leucocyte count was increased within four hours of repeated eccentric contraction and bench stepping exercise, but had returned to pre-exercise levels 24 hours later. This increase in total leucocyte count was attributed to changes in the numbers of circulating neutrophils.…”