Objective: 

In this research, long-term exercise trained (12 weeks/5days/30min) and untrained rats were forced to make exhausting exercise. Immune responses of muscle (IL-6) against the destructive activity of the fast-twitch muscles were compared in two groups.

Methods: 

Both groups were sacrificed just after exhaustion; one day after exahaustion and tree days after exhaustion. The immunoreactivity of the muscles was examined by IL-6 immunohistochemical evaluation in Histology Laboratories of Gazi University Medical Faculty.

Results: 

In both acutely running and exercise-trained rats, IL-6 levels were found to increase significantly compared to controls. However, the strongest IL-6 immunoreactivity emerged in both experimental groups 'one day after exhaustion group', being greater in the acutely run group. Three days after exhaustion, IL-6 levels were found weaker especially in the exercised-trained group.

Conclusions: 

We found that IL-6 immunoreactivity in the rat plantar muscles that exposed to vigorous contractions and destructions mostly exacerbated one day following exhaustion, and lasted about 3 days. This experiment and the other results related with muscle damage after exhausting exercise (that were not shown here), revealed that muscles of the exercise-trained rats were more resistive to this type of destructive muscle contractions than untrained rats. The IL-6 levels that not prominently increased just after the exhaustion but one day after exhaustion make us think that those pro-inflammatory factors might be suppressed by another agent -most probably by cortisol- in the beginning of the muscle damage and increased after the diminishing effects of these agents.