Dataset for: The impact of a short term high fat diet on mitochondrial respiration, reactive oxygen species production and dynamics in oxidative and glycolytic skeletal muscles of young rats

Background: Multiple aspects of mitochondrial function and dynamics remain poorly studied in the skeletal muscle of pediatric models in response to a short-term high fat diet (HFD). The present study investigated the impact of a short-term HFD on mitochondrial function and dynamics in the oxidative soleus (SOL) and glycolytic extensor digitorum longus (EDL) muscles in young rats. Methods: Young male Wistar rats were submitted to either HFD or normal chow (NCD) diets for 14 days. Permeabilized myofibers from SOL and EDL were prepared to assess, mitochondrial respiration and ROS production. The expression and content of protein involved in mitochondrial metabolism and dynamics (fusion/fission) were also quantified. Results: While no effects of HFD was observed on mitochondrial respiration when classical complex I and II substrates were used, both SOL and EDL of Rats submitted to a HFD displayed higher basal and ADP-stimulated respiration rates when Malate + Palmitoyl-L-carnitine were used as substrates. HFD did not alter ROS production and markers of mitochondrial content. The expression of CPT1b was significantly increased in SOL and EDL of HFD rats. Although the expression of UCP3 was increased in SOL and EDL muscles from HFD rats, uncoupling was not altered. In SOL of HFD rats, the transcript levels of Mfn2 and Fis1 were significantly upregulated. The expression and content of proteins regulating mitochondrial dynamics was not modulated by HFD in the EDL. Finally, DRP1 protein content was increased by over 4-fold in the SOL of HFD rats. Conclusions: Exposing young animals to short-term HFD results in an increase capacity of skeletal muscle mitochondria to oxidize fatty acids, without altering ROS production, coupling efficiency and mitochondrial content. Our results also highlight that the impact of HFD on mitochondrial dynamics appears to be muscle specific.