Reilly 2013 J Exp Biol

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Reilly BD, Hickey AJ, Cramp RL, Franklin CE (2013) Decreased hydrogen peroxide production and mitochondrial respiration in skeletal muscle but not cardiac muscle of the green-striped burrowing frog, a natural model of muscle disuse. J Exp Biol 217:1087-93.

» PMID: 24311816 Open Access

Reilly BD, Hickey AJ, Cramp RL, Franklin CE (2013) J Exp Biol

Abstract: Suppression of disuse-induced muscle atrophy has been associated with altered mitochondrial reactive oxygen species (ROS) production in mammals. However, despite extended hindlimb immobility aestivating animals exhibit little skeletal muscle atrophy compared with artificially-immobilised mammalian models. Therefore, we studied mitochondrial respiration and ROS (H2O2) production in permeabilised muscle fibres of the green-striped burrowing frog, Cyclorana alboguttata. Mitochondrial respiration within saponin-permeabilised skeletal and cardiac muscle fibres was measured concurrently with ROS production using high-resolution respirometry coupled to custom-made fluorometers. After four months of aestivation, C. alboguttata had significantly depressed whole body metabolism by approximately 70% relative to control (active) frogs, and mitochondrial respiration in saponin-permeabilised skeletal muscle fibres decreased by almost 50% both in the absence of ADP and during oxidative phosphorylation. Mitochondrial ROS production showed up to an 88% depression in aestivating skeletal muscle when malate, succinate and pyruvate were present at concentrations likely reflecting those in vivo. The percentage ROS released per O2 molecule consumed was also approximately 94 % less at these concentrations indicating an intrinsic difference in ROS production capacities during aestivation. We also examined mitochondrial respiration and ROS production in permeabilised cardiac muscle fibres and found that aestivating frogs maintained respiratory flux and ROS production at control levels. These results show that aestivating C. alboguttata has the capacity to independently regulate mitochondrial function in skeletal and cardiac muscles. Furthermore, this work indicates that ROS production can be suppressed in the disused skeletal muscle of aestivating frogs, which may in turn protect against potential oxidative damage and preserve skeletal muscle structure during aestivation and following arousal.

Keywords: Cyclorana alboguttata; Mitochondria; Muscle atrophy; Oxidative stress; Reactive oxygen species; Skeletal muscle, Amplex Red

O2k-Network Lab: NZ Auckland Hickey AJ

Correction

An Oroboros Oxygraph-2k was used in this publication, whereas the Anton Paar/Oroboros Oxygraph was the first-generation instrument for high-resolution respirometry, which was replaced by the Oxygraph-2k in 2002.


Labels: MiParea: Respiration, Comparative MiP;environmental MiP 

Stress:Oxidative stress;RONS  Organism: Amphibians  Tissue;cell: Heart, Skeletal muscle  Preparation: Permeabilized tissue 


Coupling state: LEAK, OXPHOS  Pathway: NS, ROX  HRR: Oxygraph-2k, TIP2k, O2k-Fluorometer 

AmR