Effects of an oral supplementation of omega‐3 polyunsaturated fatty acids on the muscle mass, function, and metabolism under hypoxia

Chronic obstructive pulmonary disease (COPD) is associated with patientˈs muscle mass loss and exercise intolerance. An oral supplementation with omega‐3 polyunsaturated fatty acids has been shown to increase exercise capacity in COPD patients. To understand the underlying mechanisms, we studied the effect of docosahexaenoic acid (DHA) oral administration on the muscle function of animals chronically exposed to hypoxia (FiO 2 12%) for 3 weeks. Endurance time increased by 210 % in animals under Hypoxia+DHA compared to animals under Hypoxia alone. DHA supplementation preserves the soleus and plantaris muscle masses under Hypoxia despite a similar decrease in total body weight compared to Hypoxia. Oxygen consumption by muscle fibers from soleus using complex I substrate is similar in DHA+Hypoxia and in control (Normoxia) groups but lower in Hypoxia group. This effect of DHA is not seen in white gastrocnemius muscle fibers. Maximal activities and expression levels of respiratory chain complexes are differently affected by Hypoxia and Hypoxia+DHA conditions, suggesting that mitochondria are sensitive to DHA supplementation. These alterations could contribute to the greater exercise tolerance and the muscle mass preservation reported that could justify the use of DHA in patients with muscle mass loss. Further studies are necessary to characterize the action mechanism of DHA on hypoxia‐induced alterations.