Voluntary training in mice and submandibular lymphocyte response to acute exercise.
BACKGROUND
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.


OBJECTIVE
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Boudreau
Jeanette
J
Department of Health Studies and Gerontology, Faculty of Applied Health Sciences, University of Waterloo, Waterloo, Ontario, CANADA.
Quadrilatero
Joe
J
Hoffman-Goetz
Laurie
L
D000818:Animals; D001522:Behavior, Animal; D002470:Cell Survival / Q000502:physiology; D005260:Female; D008198:Lymph Nodes / Q000502:physiology*; D008214:Lymphocytes / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009061:Mouth Mucosa; D010805:Physical Conditioning, Animal / Q000502:physiology*; D010807:Physical Endurance / Q000502:physiology; D012307:Risk Factors; D013363:Submandibular Gland / Q000503:physiopathology*; D013997:Time Factors