Submandibular lymph nodes (SLN) are important for immune responses to antigens in the eye and oral mucosa. Athletes and exercise participants may be at increased risk of ocular, oral, and upper respiratory tract infections.
This study was conducted to examine the effects of voluntary training on the distribution, number, and apoptotic status of SLN lymphocytes in response to an acute bout of strenuous exercise.
Female C57BL/6 mice were assigned to voluntary wheel-running (WR) exercise (N=20) or were sedentary (N=10) for 16 wk. SLN lymphocytes were examined immediately (EX+Imm) or 24 h (EX+24 h) following strenuous treadmill exercise, or exposure to treadmill conditions without running (NonEX). Intracellular glutathione (GSH), mitochondrial membrane potential (MMP), cell viability (propidium iodide uptake, PI), surface phosphatidylserine (Annexin V), T-lymphocyte (CD3, CD4, CD8), and B-lymphocyte (CD19) phenotype distribution and number were assessed.
The WR mice had a higher number and percent CD8 SLN lymphocytes, higher MMP, and lower Annexin V/PI SLN lymphocytes than controls. Regardless of training status, an acute bout of strenuous exercise decreased the total and phenotype specific (CD3, CD4, CD8) number of cells, MMP, and GSH levels immediately after exercise.
WR in mice improved some aspects of cell viability in SLN lymphocytes compared with controls, but did not prevent the transient cell loss after acute treadmill exercise. Given the depletion in intracellular GSH levels, oxidative stress may account for the decline in SLN lymphocyte numbers following acute exercise. Loss of SLN lymphocytes may have consequences for ocular, oral, and upper respiratory tract health in some exercise participants and athletes during periods of overtraining.
"On the other hand, a single session of acute exercise has been shown to display suppressive effects on SIgA production in saliva (in humans, Bishop and Gleeson, 2009; in rats, Kimura et al., 2008) and on cytokine levels in the upper respiratory pathways (Kohut et al., 2001). Furthermore, there are various reports that moderate exercise training can attenuate the deleterious effects of acute stress (Boudreau et al., 2005; Davidson and Hoffman-Goetz , 2006; Fu et al., 2003; Hoffman-Goetz et al., 2010). There is, however, scarce evidence in the literature about the effects of strenuous exercise on the pIgR-mediated transport and production of SIgA in the small intestine, and even less evidence on the relation between moderate exercise training followed by strenuous exercise in relation to these same parameters. "
[Show abstract][Hide abstract] ABSTRACT: Intestinal homeostasis effectors, secretory IgA (SIgA) and polymeric immunoglobulin receptor (pIgR), have been evaluated in proximal and distal small intestine with moderate-exercise training but not with strenuous exercise or a combination of these two protocols. Therefore, two groups of mice (n=6-8) were submitted to strenuous exercise, one with and one without previous training. The control group had no exercise protocol. Assessment was made of intestinal SIgA and plasma adrenal hormones (by immunoenzymatic assay), alpha-chain and pIgR proteins in intestinal mucosa (by Western blot), lamina propria IgA plasma-cells (by cytofluorometry), mRNA expression (by real-time PCR) for pIgR, alpha- and J-chains in liver and intestinal mucosa, and pro- and anti-inflammatory cytokines in mucosa samples. Compared to other exercise protocols, training plus strenuous exercise elicited: (1) higher levels of SIgA and pIgR in the proximal intestine (probably by hepatobiliary contribution); (2) higher levels of SIgA in the distal segment; (3) lower mRNA expression of some SIgA- and most pro-inflammatory pIgR-producing cytokines. SIgA and pIgR in both segments were derived from an existing pool of their corresponding producing cells. The apparent decreased translation of mRNA transcripts underlies lower levels of SIgA and pIgR in distal than proximal small intestine. There was no significant difference in the relatively high adrenal hormone levels found in both exercised groups. Further study is required about the effects of training plus strenuous exercise on pool-derived SIgA levels and mRNA expression of pro-inflammatory pIgR-producing cytokines. These results could have important implications for intestinal disorders involving inflammation and infection.
"Upregulation of glutathione concentration in T lymphocytes occurs in older C57BL/6 mice presumably to combat the effects of free radical accumulation (Kim and Nel 2005). In our present study, the intracellular concentration of glutathione was higher in all groups of older mice compared with earlier results obtained with younger mice (Boudreau et al. 2005). Whether the lack of SLN lymphocyte response to the oxidant stress of exercise in older mice reflects the onset of age-related changes in signal transduction pathways remains to be determined experimentally. "
[Show abstract][Hide abstract] ABSTRACT: Submandibular lymph nodes (SLN) are crucial for immune surveillance of the anterior ocular chamber and upper respiratory tract; little is known about how training and exercise affect SLN lymphocytes. The intent of this study was to describe the impact of long term freewheel running followed by acute strenuous exercise on SLN lymphocytes in mice. Female C57BL/6 mice were assigned to running wheels or remained sedentary for 8 months, and further randomized to treadmill exercise and sacrifice immediately, treadmill exercise and sacrifice 24 h after exercise cessation, or no treadmill exposure. SLN lymphocytes were isolated and analyzed for CD3, CD4, CD8, and CD19 cell surface markers, phosphatidylserine externalization as a marker of apoptosis, and intracellular glutathione as a marker of oxidative stress. Compared with running wheel mice, older sedentary mice had a lower percent of T cells and higher percent of B cells (p < 0.05). Although intracellular glutathione did not differ between groups, running mice had a lower percent of Annexin V(+) SLN lymphocytes 24 h after treadmill exercise. Further research will be needed to determine if voluntary exercise translates into improved anterior ocular and upper respiratory tract health.
Canadian Journal of Physiology and Pharmacology 05/2006; 84(5):565-72. DOI:10.1139/y06-011 · 1.77 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: There is substantial evidence that physical inactivity is an important risk factor for a number of chronic diseases, including cancer. As consequences of physical inactivity on cancer risk and treatment efficacy surface, there is increasing interest in determining the benefits of a physically active lifestyle and of exercise as a component of that lifestyle. In the cancer research field, the spectrum of research activities includes pre-clinical studies and clinical and population-based interventions; of these approaches, pre-clinical experiments combining animal cancer models with physical activity (PA) have been underutilized. Clarifying the amounts and types of PA that inhibit carcinogenesis is best done in animals, where mechanistic inquiry and biomarker evaluation of the protected state can be carried out in a more favorable environment than in clinical populations. The expertise required to integrate models for investigating PA with those used to study carcinogenesis is not trivial, but mastery of these models is likely to result in highly translatable pre-clinical findings that advance this important field of investigation. This brief review and analysis is intended to focus attention on the issues and opportunities associated with the pre-clinical investigations of PA and cancer.
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