title: High Intensity Interval Training (HIIT) Induces Specific Changes in Respiration and Electron Leakage in the Mitochondria of Different Rat Skeletal Muscles.
abstract: High intensity interval training (HIIT) is characterized by vigorous exercise with short rest intervals. Hydrogen peroxide (H2O2) plays a key role in muscle adaptation. This study aimed to evaluate whether HIIT promotes similar H2O2 formation via O2 consumption (electron leakage) in three skeletal muscles with different twitch characteristics. Rats were assigned to two groups: sedentary (n=10) and HIIT (n=10, swimming training). We collected the tibialis anterior (TA-fast), gastrocnemius (GAST-fast/slow) and soleus (SOL-slow) muscles. The fibers were analyzed for mitochondrial respiration, H2O2 production and citrate synthase (CS) activity. A multi-substrate (glycerol phosphate (G3P), pyruvate, malate, glutamate and succinate) approach was used to analyze the mitochondria in permeabilized fibers. Compared to the control group, oxygen flow coupled to ATP synthesis, complex I and complex II was higher in the TA of the HIIT group by 1.5-, 3.0- and 2.7-fold, respectively. In contrast, oxygen consumed by mitochondrial glycerol phosphate dehydrogenase (mGPdH) was 30% lower. Surprisingly, the oxygen flow coupled to ATP synthesis was 42% lower after HIIT in the SOL. Moreover, oxygen flow coupled to ATP synthesis and complex II was higher by 1.4- and 2.7-fold in the GAST of the HIIT group. After HIIT, CS activity increased 1.3-fold in the TA, and H2O2 production was 1.3-fold higher in the TA at sites containing mGPdH. No significant differences in H2O2 production were detected in the SOL. Surprisingly, HIIT increased H2O2 production in the GAST via complex II, phosphorylation, oligomycin and antimycin by 1.6-, 1.8-, 2.2-, and 2.2-fold, respectively. Electron leakage was 3.3-fold higher in the TA with G3P and 1.8-fold higher in the GAST with multiple substrates. Unexpectedly, the HIIT protocol induced different respiration and electron leakage responses in different types of muscle.
authors.affiliation: Laboratory of Bioenergetics and Mitochondrial Physiology-Institute of Medical Biochemistry Leopoldo de Meis-Federal University of Rio de Janeiro, UFRJ, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Dionizio
authors.initials: D
authors.lastname: Ramos-Filho
authors.affiliation: Laboratory of Bioenergetics and Mitochondrial Physiology-Institute of Medical Biochemistry Leopoldo de Meis-Federal University of Rio de Janeiro, UFRJ, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Chicaybam
authors.affiliation: Laboratory of Bioenergetics and Mitochondrial Physiology-Institute of Medical Biochemistry Leopoldo de Meis-Federal University of Rio de Janeiro, UFRJ, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Eduardo
authors.initials: E
authors.lastname: de-Souza-Ferreira
authors.affiliation: Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro UFRJ, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Camila
authors.initials: C
authors.lastname: Guerra Martinez
authors.affiliation: Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro UFRJ, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Eleonora
authors.initials: E
authors.lastname: Kurtenbach
authors.affiliation: Institute of Physical Education and Sports-State University of Rio de Janeiro, UERJ, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Gustavo
authors.initials: G
authors.lastname: Casimiro-Lopes
authors.affiliation: Laboratory of Bioenergetics and Mitochondrial Physiology-Institute of Medical Biochemistry Leopoldo de Meis-Federal University of Rio de Janeiro, UFRJ, Rio de Janeiro, Rio de Janeiro, Brazil.
authors.forename: Antonio
authors.initials: A
authors.lastname: Galina
mesh_terms: D000818:Animals; D001835:Body Weight; D019069:Cell Respiration; D002950:Citrate (si)-Synthase / Q000378:metabolism; D004579:Electron Transport; D004734:Energy Metabolism; D006861:Hydrogen Peroxide / Q000378:metabolism; D050152:Intra-Abdominal Fat; D008297:Male; D008931:Mitochondria, Muscle / Q000378:metabolism*; D018482:Muscle, Skeletal / Q000502:physiology*; D009929:Organ Size; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D010742:Phospholipid Ethers / Q000378:metabolism; D010805:Physical Conditioning, Animal; D051381:Rats
chemical_list: D010742:Phospholipid Ethers; D006861:Hydrogen Peroxide; D002950:Citrate (si)-Synthase