Grape Seed Extracts Improve Mitochondrial Function in Muscle
The aim of this study was to determine the effect of chronic dietary supplementation of a grape seed proanthocyanidin extract (GSPE) at a dose of 35 mg/kg body weight on energy metabolism and mitochondrial function in skeletal muscle of Zucker obese rats. Three groups of ten animals each were used: lean Fa/fa Lean Group (LG) rats, a control fa/fa Obese Group (OG) of rats and an obese supplemented fa/fa Proanthocyanidins Obese Group (POG) of rats, which were supplemented with a dose of 35 mg GSPE/kg of body weight/day during the 68 days of experimentation. Skeletal muscle energy metabolism was evaluated by determining enzyme activities, key metabolic gene expression, and the immunoblotting of oxidative phosphorylation complexes. Mitochondrial function was analysed by high-resolution respirometry using both a glycosidic and a lipid substrate. In muscle, chronic GSPE administration decreased citrate synthase activity, the amount of oxidative phosphorylation complexes I and II, and Nrf1 gene expression, without any effects on the mitochondrial oxidative capacity. This situation was associated with lower reactive oxygen species (ROS) generation. Additionally, GSPE administration enhanced the ability to oxidise pyruvate, and it also increased the activity of enzymes involved in oxidative phosphorylation including cytochrome c oxidase. There is strong evidence to suggest that GSPE administration stimulates mitochondrial function in skeletal muscle specifically by increasing the capacity to oxidise pyruvate and contributes to reduced muscle ROS generation in obese Zucker rats.
Arola L, Pajuelo D, Fernandez-Iglesias A, Díaz S, Quesada H, Arola-Arnal A, Blade C, Salvadó J. Improvement of mitochondrial function in muscle of genetically obese rats after chronic supplementation with proanthocyanidins. Agric Food Chem. 2011 July