Expression of bone-resorbing cytokines according to aerobic exercise intensities |
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Abstract |
The purpose of this study was to elucidate changes in bone-resorbing cytokines according to aerobic exercise intensities. Nine male participants (aged 24.4 ± 2.7 yrs) underwent exhaustive maximal exercise testing with a cycle ergometer for determination of ventilation thresholds (VT), which were used as aerobic exercise intensities. The exercise was loaded at levels of 70%, 80%, 90%, and 100% VT intensity, and all exercise trials were equally maintained constantly at 300 kcal of expenditure. The expressions of TNF-α and IL-6 mRNA from PBMC and the concentrations of TNF-α and IL-6 in the serum were measured before and immediately after excise and then during recovery 90 min after each trial. Although serum TNF-α concentration was significantly lower immediately after excise compared to before the trial (p=.02), there were no significant differences by intensity or any interaction effects, and there was also no significant difference in mRNA expression by any time or any intensity (p>.05). The expression of IL-6 mRNA and serum IL-6 concentration, however, showed a tendency to increase immediately after exercise and had a tendency to decrease or be maintained at 90 minutes after exercise following exercise intensities of 80% 90%, and 100% VT, respectively. On the other hand, TNF-α mRNA expression showed a significant positive correlation with IL-6 mRNA expression as well as serum TNF-α concentration (p<.01), and there was also a significant relationship between serum TNF-α and serum IL-6 concentrations (p<.01). These results suggest that serum TNF-α has a tendency to decrease immediately after aerobic exercise, whereas IL-6 showed a tendency to increase immediately after exercise and was dependent on exercise intensity. Also indicated was a strong relationship between the expression of cytokine mRNA from PBMC and the release of cytokines in the blood. |
Key Words:
aerobic exercise, bone-resorbing cytokines, TNF-α, IL-6, mRNA, PBMC |
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