Curcumin Enhances Performance Recovery After Exerciseinduced Muscle Damage

Abstract

Unaccustomed exercise with a large eccentric component produces the greatest muscle fiber damage, inflammation, delayed-onset muscle soreness (DOMS) and functional deficits. Curcumin (extract of the Indian spice, turmeric) has potent anti-inflammatory activity in a variety of inflammation models, but has not been evaluated with respect to exercise-induced muscle damage. It is possible that the anti-inflammatory activity of curcumin could hasten recovery of performance due to an attenuation of the primary and especially secondary inflammation associated with delayed regeneration of muscle fibers, soreness, and CNS fatigue. PURPOSE 1) to develop a mouse model of performance recovery following exercise-induced muscle damage and 2) to determine the effects of curcumin on performance recovery in this model. METHODS In EXP 1, treadmill run times to fatigue (36m/min, 8% grade) were performed at 24, 48, 72 & 96 h after an uphill (UP) or downhill (DWN) run in male mice. DWN running was 150 min starting at 16m/min, −5% grade with increments every 5 min to 22m/min, −14% grade. UP running was the same, but grade was increased from 5% to 14%. Separate groups of mice were sacrificed at 24, 48 and 96 h after UP and DWN for collection of blood, muscle (soleus), and selected brain regions. Creatine kinase (CK) was measured in blood and inflammatory cytokines (IL-1β, IL-6, and TNF-α) were measured in muscle and brain. Exp 2 evaluated the effect of curcumin on performance recovery at 48 and 72 h after UP and DWN. Mice were fed curcumin (10 mg) once daily in a highly palatable food pellet (410 mg; bacon flavor) for 3 d prior to UP or DWN running. RESULTS In EXP 1, treadmill run time to fatigue was suppressed in DWN vs Up by over 50% for up to 72 h following the initial run. DWN was also associated with an increase in plasma CK at 24 and 48 h, and inflammatory cytokines in muscle (IL-6 & IL-1β) and brain (IL-1β only in cortex & cerebellum) at 24h. In EXP 2, curcumin feedings attenuated the reduction in run time to fatigue at 48 and 72 h in DWN, with no effect in UP. CONCLUSIONS In this model, recovery of endurance capacity takes up to 72 h following downhill running, which is associated with an increase in plasma CK, and muscle and brain inflammatory cytokines. Ingestion of Curcumin (anti-inflammatory herbal supplement) for 3 d prior to muscle-damaging exercise hastens recovery of endurance performance, but the extent to which this is due to a reduction in the inflammatory response (in muscle and/or CNS) awaits further research. Funded by the DOD, Natick Soldier Center, Grant # DAAD 16-02-C-0015.