Differential responses of serum and salivary interleukin-6 to acute strenuous exercise

Abstract

Physical exercise is associated with elevation of serum levels of interleukin-6 (IL-6) because of its production in the muscles. The use of IL-6 measurements in saliva has been proposed in the field of immunopathology, mainly involving salivary gland disease. We evaluated the responses of serum and salivary IL-6 in two different groups of athletes submitted to different types of controlled strenuous exercise (spinning activity and maximal isokinetic test). Serum and salivary samples for IL-6 measurements, and serum samples for lactate and myoglobin determination before and after exercise, were obtained. Salivary IL-6 was measured by ELISA after dilution experiments and compared with results obtained by immunoradiometric assay. Spinning activity elicited significant increases in all the variables, and no correlation was found among the respective variations. A significant response to the isokinetic exercise was observed for serum IL-6, lactate and myoglobin only; no correlation was found between serum and salivary IL-6. Our study demonstrated that serum and salivary IL-6 responses to exercise are dissociated, possibly in relation to the lack of relationships between the systemic/muscular and the salivary routes of IL-6 production. Analytical issues that concern IL-6 measurement in saliva deserve attention, notably regarding the collection method used to absorb saliva. Concomitant monitoring of serum markers of inflammation, muscle metabolism and damage can provide information about muscle function properties and adaptations to physical effort in different types of athletes.

The detection and measurement of interleukin-6 in venous and capillary blood samples, and in sweat collected at rest and during exercise

“…Attempts have been made to detect cytokines in a variety of other body fluids using non-invasive methods including saliva (Cox et al 2008;Minetto et al 2005;Minetto et al 2007) and sweat (Cizza et al 2008;Marques-Deak et al 2006) with varying degrees of success. Saliva has been shown to be a poor medium for cytokine measurement, as there is no correlation between IL-6 concentrations in blood versus saliva either at rest (Cox et al 2008) or following strenuous exercise (Minetto et al 2005).…”

“…Saliva has been shown to be a poor medium for cytokine measurement, as there is no correlation between IL-6 concentrations in blood versus saliva either at rest (Cox et al 2008) or following strenuous exercise (Minetto et al 2005). However, sweat may present a more promising conduit for non-invasive measurement of systemic IL-6.…”

Alterations in peak torque occur without hematological changes after muscle fatigue

“…However, the values in this study were similar to other 30 . Additionally, the increase of lymphocytes is controlled by catecholamine concentration, particularly in activities of short duration 31 .…”

Influência do exercício físico agudo realizado até a exaustão sobre o número de leucócitos, linfócitos e citocinas circulantes

“…O aumento no tráfico de linfócitos é tipicamente controlado pelas concentrações de catecolaminas, especialmente em atividades de curta duração 5,6 . As reduções observadas no número de linfócitos circulantes sofrem influências do cortisol, particularmente em exercícios de duração mais prolongada 7,8 .…”