Exercise does not increase salivary lymphocytes, monocytes, or granulocytes, but does increase salivary lysozyme

ABSTRACT

An increase in salivary leukocytes may contribute to the exercise-induced increase in salivary antimicrobial proteins (AMPs). However, exercise-induced changes in salivary leukocytes have not been studied. The purpose of the study was to describe salivary leukocyte changes with exercise. Participants (n = 11, 20.3 ± 0.8 years, 57.2 ± 7.6 ml kg⁻¹ min⁻¹ peak oxygen uptake ((VO) ̇₂peak), 11.1 ± 3.9% body fat) ran for 45 min at 75% of VO_2peak. Stimulated saliva (12 mL) was collected pre- and immediately post exercise. Saliva was filtered through a 30 µm filter before analysis of leukocytes (CD45⁺), granulocytes (CD45⁺CD15⁺), monocytes (CD45⁺CD14⁺), T-cells (CD45⁺CD3⁺), and B-cells (CD45⁺CD20⁺) using flow cytometry. Saliva was analysed for Lysozyme (Lys) using ELISA. Exercise did not alter any leukocyte subset. The major constituent of leukocytes pre-exercise were granulocytes (57.9 ± 30.3% compared with monocytes: 5.1 ± 2.7%, T-cells: 17.1 ± 8.9%, B-cells: 12.1 ± 10.2%) (P < 0.05). In a subset of n = 6, Lys secretion rate increased after exercise (pre: 5,170 ± 5,215 ng/min; post: 7,639 ± 4,140 ng/min) (P < 0.05). Exercise does not result in increased granulocytes, but does increase Lys. Further, these data suggest that an increase in salivary leukocytes is not needed to increase Lys.

KEYWORDS:

• Antimicrobial protein
• leukocyte fluctuation
• upper respiratory syndrome

Acknowledgements

We are grateful to Dave Draper, PhD for his technical support with the flow cytometry design and analysis.

Disclosure statement

No potential conflict of interest was reported by the authors. The authors alone are responsible for the writing and content of this paper.

Additional information

Funding

No author has financial interest or benefit in the results presented in this study.