Abstract
At the annual Iditarod Race, Alaskan Huskies repeatedly run for up to 8 hours at 16 km/h to complete 1600 km. We previously demonstrated high rates of mitochondrial protein synthesis in Alaskan Huskies, which we suspected allowed rapid remodeling of mitochondrial proteins in response to energetic stress. The purpose of this study was to examine mitochondrial respiration in permeabilized skeletal muscle fibers of Alaskan Huskies in the offseason (Non-raced) and following the 1600 km Iditarod Sled Dog Race (Raced). We hypothesized that compared to Non-raced Huskies, raced Huskies that completed a 1600 km race would have greater mitochondrial respiratory capacities, and improvements in capacities of oxidative phosphorylation (OXPHOS) based on NADH-generating substrates as compared to fatty acids. Using high-resolution respirometry (HRR) we investigated the respiration of permeabilized muscle fibers from Alaskan Huskies. Maximum capacities were 254±26 pmol.s-1.mg-1 for OXPHOS (coupled, P) and 254±37 pmol.s-1.mg-1 for the electron transfer system (ETS; non-coupled, E). After racing respiratory capacities from NADH-linked substrates, but not fat-derived substrates increased. Finally, the OXPHOS to ETS capacity ratio (P/E) increased after racing from 0.90±0.03 to 0.97±0.02. From our previous studies and the current study, we conclude that Alaskan Huskies maintain high mitochondrial protein turnover to facilitate rapid adaptation to environmental extremes and energetic challenges.
Citation: Miller B, Hamilton K, Boushel R, Williamson K, Laner V, Gnaiger E, et al. (2017) Mitochondrial respiration in highly aerobic canines in the non-raced state and after a 1600-km sled dog race. PLoS ONE 12(4):
e0174874.
https://doi.org/10.1371/journal.pone.0174874
Editor: Andrew Philp, University of Birmingham, UNITED KINGDOM
Received: September 25, 2016; Accepted: March 16, 2017; Published: April 26, 2017
Copyright: © 2017 Miller et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Data Availability: The minimal underlying data set necessary for replication of this study is available within the paper and its Supporting Information file.
Funding: EG and VL were supported by the K-Regio project MitoFit. EG is the CEO and author VL an employee of Oroboros Instruments, a commercial entity based in Austria that designed and manufactures the high resolution respirometry instruments used in this study. Through the involvement of these authors, Oroboros Instruments provided salary and travel funds for these authors, as well as several “loaner” instruments that were used in addition to instruments owned by other authors for sample analysis, but did not have any additional role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. The specific roles of these authors are articulated in the ‘author contributions’ section.
Competing interests: Author EG is the CEO and author VL an employee of Oroboros Instruments, a commercial entity based in Austria that designed and manufacturers the high resolution respirometry instruments used in this study. Through the involvement of these authors, Oroboros Instruments provided salary and travel funds for these authors, as well as several “loaner” instruments that were used in addition to instruments owned by other authors for sample analysis. EG and VL also provided published references and instruction (with RB) on the techniques for sample preparation and analysis during initial phases of the study. The specific roles of these authors are articulated in the ‘author contributions’ section. The commercial affiliation of some authors does not alter our adherence to PLOS ONE policies on sharing data and materials.
Description
This study examines mitochondrial respiration in Alaskan Huskies before and after a long-distance race.