Evaluation of exercise-induced changes in concentrations of C-reactive protein and serum biochemical values in sled dogs completing a long-distance endurance race.

OBJECTIVE

To determine whether long-distance endurance exercise in sled dogs causes increases in serum concentrations of C-reactive protein (CRP) and whether such increases are correlated with other markers of the exercise-induced acute-phase response.

ANIMALS

25 sled dogs.

PROCEDURES

Serum was obtained from 25 sled dogs approximately 48 hours before and immediately after completing a race of 557 km. Serum was analyzed to determine concentrations of CRP and interleukin (IL)-6, and serum biochemical analysis (and iron homeostasis analysis) also was performed.

RESULTS

CRP concentrations increased significantly from a mean±SD concentration of 22.4±16.3 microg/mL before racing to a mean of 263.3±103.8 microg/mL immediately after racing Serum IL-6 concentrations were unchanged; however, there was a modest but significant correlation (r=0.50) between the increase in CRP concentration and an overall decrease in serum albumin concentration, which suggested an inverse relationship between hepatic synthesis of the 2 proteins. Differences in CRP concentrations among teams of dogs revealed that concentrations before racing may be influenced by previous episodes of exercise. Serum iron concentration had only a mild decrease, which may have been attributable to iron-rich diets consumed by the dogs.

CONCLUSIONS AND CLINICAL RELEVANCE

CRP concentrations may serve as a potential marker for exercise-induced inflammation. The exact amount of exercise required to induce such a response is unknown, but dogs apparently have a more robust acute-phase response than do humans. Clinical evaluation of CRP concentrations must account for physical activity when those concentrations are used as a potential marker for systemic inflammation.