Prolonged exercise does not cause lymphocyte DNA damage or increased apoptosis in well-trained endurance athletes

Abstract

Recent research has demonstrated that lymphocyte apoptosis sensitivity appears to be related to training status and exercise intensity. This work investigated the effect of prolonged, submaximal treadmill running on percentage (%) apoptosis, % necrosis and DNA strand breaks in lymphocytes and related these to changes in total lymphocyte and blood cortisol concentrations in well-trained runners. Venous blood samples (n = 14) were taken immediately before (PRE), immediately after (IPE) and 3 h after (3PE) 2.5 h of treadmill running at 75% of VO2 max from eight well-trained male endurance athletes (age 34.2 +/- 2.44 years) and analysed for cellular content and serum cortisol concentrations. Lymphocytes were isolated from whole blood and % apoptotic and necrotic cell were detected by flow cytometry using Annexin V-FITC and propidium iodide uptake. DNA strand breaks were measured by single-cell gel electrophoresis. Despite a significant (P < 0.001) exercise-induced increase in mean serum cortisol concentrations and reduction in lymphocyte counts, the mean % Annexin-V positive cells (13.3 +/- 6.78 in PRE, 11.3 +/- 5.51 in IPE and 12.8 +/- 6.75 in 3PE samples) were not significantly different at the three time-points (P > 0.05). Mean DNA strand breaks in the lymphocytes also did not change significantly (P > 0.05) rising from 25.7 +/- 2.16 to 26.9 +/- 1.89 and 27.1 +/- 1.38 microm in IPE and 3PE samples, respectively. The exercise-induced changes in total blood lymphocyte counts and cortisol concentrations did not result in a significant change in % apoptotic lymphocytes or DNA strand breaks in the endurance-trained athletes during this prolonged, submaximal exercise.

Warfighter Sustainability: Maximizing Human Performance in Hostile Environments

“…In contrast, Peters et al [2006] found no significant increases in DNA migration as a measure of damage at 3 h post-exercise following 2.5-h exercise trials. Moreover, Mars et al [1998] described significant increases in both DNA strand breaks and apoptotic cells in untrained subjects, immediately after incremental exercise protocol to exhaustion, but not 24 and 48 hours after exercise.…”

“…This is supported by the fact that in endurance-trained individuals, the Type I fibers are more noticeable because of abundant mitochondrial density compared with the Type II fibers [Coyle 1995]. Thus, trained athletes or individuals who are regularly involved in endurance training may have an enhanced adaptive response, which results in a protective effect against oxidative stress [Radak et al 2003] and attenuates the extent of apoptosis (e.g., DNA fragmentation and caspases activity) [Peters et al 2006]. However, whether or not DNA damage directly results from oxidative damage, or whether it is derived from a part of the process of apoptosis remains elusive [Mars et al 1998].…”

Spermatogenesis Process Following Chronic Swimming and Standing in Cold, Warm and Lukewarm Water

“…Apoptosis is a programmed cell death process that takes places in different cells during both embryonic and adult life (23). Exercise can either cause (24), inhibit (25) or have no effect on apoptosis of different cell types (26). The probable mechanisms responsible for exercise -induced apoptosis include: increased glucocorticoid hormone, intracellular calcium concentration and reactive oxygen species (27).…”

The Current State of Exercise-Induced Lymphocyte Apoptosis

“…However, as more researchers began to investigate the ability of exercise to serve as a stimulus to induce apoptosis in lymphocytes, some authors began to question these findings, particularly in terms of its role in the post-exercise decrease in immune cell volume, termed lymphocytopenia [6,7]. In fact, two opposing views began to form: that exercise is capable of inducing lymphocyte apoptosis and does contribute to lymphocytopenia; and that exercise does not induce apoptosis and therefore plays no role in the decrease in circulating lymphocyte concentration observed following exercise.…”