Exercise increases lactoferrin, but decreases lysozyme in salivary granulocytes

Abstract

Introduction: Intracellular lactoferrin (Lac) and lysozyme (Lys) content play an important role in regulating inflammation and promoting host protection. While exercise has demonstrated an increase in Lac and Lys concentration in exocrine solutions, little is known regarding intracellular concentration changes in response to exercise.

Purpose: To quantify intracellular Lac and Lys concentration before and after exercise in salivary CD45⁺CD15⁺ cells.

Methods: 11 males (20.3 ± 0.8 years, 57.2 ± 7.6 mL/kg/min V̇O_2pk, 11.1 ± 3.9% body fat) ran for 45 min at 75% of VO_2pk. 12 mL of stimulated saliva were collected pre and immediately post exercise. Saliva was filtered through a 30-µm filter before analysis of leukocytes (CD45⁺) and granulocytes (CD45⁺CD15⁺) using flow cytometry.

Results: Median fluorescent intensity (MFI) of Lac increased from pre (64,268 ± 46,036 MFI) to post (117,134 ± 88,115 MFI) exercise (p <0.05). Lys MFI decreased with exercise (pre: 16,933 ± 8249; post: 11,616 ± 6875) (p <0.05).

Conclusion: Acute running resulted in an increased Lac concentration which could lead to a decrease in inflammation, adding further evidence of the anti-inflammatory effects of exercise. Conversely, the exercise-associated decrease of intracellular Lys content could be the cause of increased Lys in exocrine solutions.

Keywords: Antimicrobial protein; CD45+CD15+; Immune; Upper respiratory syndrome.