Abstract
Inflammation repairs tissues in response to stressors. Aging alters circulating pro- and anti-inflammatory markers through immunosenescence, the gradual decline of immune function, and increased cytokine secretion, contributing to chronic inflammation. Exercise can modulate cytokine levels, producing anti-inflammatory effects. However, how age and sex influence these responses remains unclear. METHODS: We evaluated blood serum levels of proinflammatory (TNF-α, IL-1β, IL-6) and anti-inflammatory (IL-10) cytokines in young and old male and female Fischer 344 rats before and after a moderate treadmill exercise protocol. RESULTS: TNF-α increased in young rats following both sedentary and exercise treatments, but not in old rats, with no sex differences. Exercise increased IL-1β and IL-6 only in young males, while old males showed elevated levels under sedentary condition that were suppressed by exercise. IL-10 increased exclusively in old females after exercise. CONCLUSION: These results indicate that exercise does not uniformly suppress inflammation but modulates cytokine activity in an age- and sex-dependent manner. In young rats, proinflammatory responses may support tissue repair and muscle remodeling, whereas in old rats, the attenuation of these markers, along with IL-10 elevation in females, suggests a shift toward anti-inflammatory adaptations that may counteract chronic inflammation.