Omija fruit extract improves endurance and energy metabolism by upregulating PGC-1α expression in the skeletal muscle of exercised rats.

This study was conducted to examine the effects of omija fruit extract on the endurance and energy metabolism of rats trained under a progressive loaded exercise program. Thirty male Sprague-Dawley rats (6 weeks old) were divided into three groups according to exercise and experimental diets for 6 weeks: the sedentary control (SC) group (n=10), the exercise control (EC) group (n=10), and the exercise group supplemented with 0.6% w/w omija extract (OM; n=10). The omija supplement significantly extended the running endurance time compared with the EC group. The soleus muscle weight was significantly higher in the OM group compared with the EC group and the plasma lactate and ammonia levels were significantly lower in the OM group than in the EC group. Plasma glucose, free fatty acid, and gastrocnemius muscle glycogen concentrations were also significantly lower in the OM group compared with the EC group. The lactate dehydrogenase activity was significantly higher in the gastrocnemius muscle of the OM group compared with the EC group. Expression of the peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) mRNA in the gastrocnemius muscle and soleus muscle were significantly elevated in the OM group and the soleus muscle peroxisome proliferator-activated receptor α (PPARα), carnitine palmitoyltransferase 1b (CPT1b), and ß-hydroxyacyl coenzyme A dehydrogenase (ß-HAD) mRNA expressions showed the same tendency. Taken together, these results show that supplementation of omija fruit extract enhances endurance and energy metabolism by upregulating the PGC-1α expression in the skeletal muscle.