1
|
Bailey SJ, Gandra PG, Jones AM, Hogan MC, Nogueira L. Incubation with sodium nitrite attenuates fatigue development in intact single mouse fibres at physiological P O 2 . J Physiol 2019; 597:5429-5443. [PMID: 31541562 DOI: 10.1113/jp278494] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 09/20/2019] [Indexed: 12/22/2022] Open
Abstract
KEY POINTS Dietary nitrate supplementation increases plasma nitrite concentration, which provides an oxygen-independent source of nitric oxide and can delay skeletal muscle fatigue. Nitrate supplementation has been shown to increase myofibre calcium release and force production in mouse skeletal muscle during contractions at a supra-physiological oxygen tension, but it is unclear whether nitrite exposure can delay fatigue development and improve myofibre calcium handling at a near-physiological oxygen tension. Single mouse muscle fibres acutely treated with nitrite had a lower force and cytosolic calcium concentration during single non-fatiguing contractions at a near-physiological oxygen tension. Nitrite treatment delayed fatigue development during repeated fatiguing isometric contractions at near-physiological, but not at supra-physiological, oxygen tension in combination with better maintenance of myofilament calcium sensitivity and sarcoplasmic reticulum calcium pumping. These findings improve understanding of the mechanisms by which increased skeletal muscle nitrite exposure might be ergogenic and imply that this is related to improved calcium handling. ABSTRACT Dietary nitrate (NO3 - ) supplementation, which increases plasma nitrite (NO2 - ) concentration, has been reported to attenuate skeletal muscle fatigue development. Sarcoplasmic reticulum (SR) calcium (Ca2+ ) release is enhanced in isolated single skeletal muscle fibres following NO3 - supplementation or NO2 - incubation at a supra-physiological P O 2 but it is unclear whether NO2 - incubation can alter Ca2+ handling and fatigue development at a near-physiological P O 2 . We hypothesised that NO2 - treatment would improve Ca2+ handling and delay fatigue at a physiological P O 2 in intact single mouse skeletal muscle fibres. Each muscle fibre was perfused with Tyrode solution pre-equilibrated with either 20% ( P O 2 ∼150 Torr) or 2% O2 ( P O 2 = 15.6 Torr) in the absence and presence of 100 µM NaNO2 . At supra-physiological P O 2 (i.e. 20% O2 ), time to fatigue was lowered by 34% with NaNO2 (control: 257 ± 94 vs. NaNO2 : 159 ± 46 s, Cohen's d = 1.63, P < 0.05), but extended by 21% with NaNO2 at 2% O2 (control: 308 ± 217 vs. NaNO2 : 368 ± 242 s, d = 1.14, P < 0.01). During the fatiguing contraction protocol completed with NaNO2 at 2% O2 , peak cytosolic Ca2+ concentration ([Ca2+ ]c ) was not different (P > 0.05) but [Ca2+ ]c accumulation between contractions was lower, concomitant with a greater SR Ca2+ pumping rate (P < 0.05) compared to the control condition. These results demonstrate that increased exposure to NO2 - blunts fatigue development at near-physiological, but not at supra-physiological, P O 2 through enhancing SR Ca2+ pumping rate in single skeletal muscle fibres. These findings extend our understanding of the mechanisms by which increased NO2 - exposure can mitigate skeletal muscle fatigue development.
Collapse
Affiliation(s)
- Stephen J Bailey
- Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK.,School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK
| | - Paulo G Gandra
- Section of Physiology; Division of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of California, San Diego, CA, USA.,Department of Biochemistry and Tissue Biology, Institute of Biology, University of Campinas (Unicamp), Campinas, Brazil
| | - Andrew M Jones
- Sport and Health Sciences, College of Life and Environmental Sciences, University of Exeter, Exeter, UK
| | - Michael C Hogan
- Section of Physiology; Division of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of California, San Diego, CA, USA
| | - Leonardo Nogueira
- Section of Physiology; Division of Pulmonary, Critical Care & Sleep Medicine, Department of Medicine, University of California, San Diego, CA, USA.,Instituto de Bioquímica Médica Leopoldo de Meis (Medical Biochemistry Institute Leopoldo de Meis), Federal University of Rio de Janeiro, Rio de Janeiro, Brazil
| |
Collapse
|
2
|
de Lima Portella R, Lynn Bickta J, Shiva S. Nitrite Confers Preconditioning and Cytoprotection After Ischemia/Reperfusion Injury Through the Modulation of Mitochondrial Function. Antioxid Redox Signal 2015; 23:307-27. [PMID: 26094636 DOI: 10.1089/ars.2015.6260] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
SIGNIFICANCE Nitrite is now recognized as an intrinsic signaling molecule that mediates a number of biological processes. One of the most reproducible effects of nitrite is its ability to mediate cytoprotection after ischemia/reperfusion (I/R). This robust phenomenon has been reproduced by a number of investigators in varying animal models focusing on different target organs. Furthermore, nitrite's cytoprotective versatility is highlighted by its ability to mediate delayed preconditioning and remote conditioning in addition to acute protection. RECENT ADVANCES In the last 10 years, significant progress has been made in elucidating the mechanisms underlying nitrite-mediated ischemic tolerance. CRITICAL ISSUES The mitochondrion, which is essential to both the progression of I/R injury and the protection afforded by preconditioning, has emerged as a major subcellular target for nitrite. This review will outline the role of the mitochondrion in I/R injury and preconditioning, review the accumulated preclinical studies demonstrating nitrite-mediated cytoprotection, and finally focus on the known interactions of nitrite with mitochondria and their role in the mechanism of nitrite-mediated ischemic tolerance. FUTURE DIRECTIONS These studies set the stage for current clinical trials testing the efficacy of nitrite to prevent warm and cold I/R injury.
Collapse
Affiliation(s)
- Rafael de Lima Portella
- 1 Vascular Medicine Institute, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania
| | - Janelle Lynn Bickta
- 1 Vascular Medicine Institute, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania.,2 Department of Bioengineering, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania
| | - Sruti Shiva
- 1 Vascular Medicine Institute, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania.,3 Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania.,4 Center for Metabolism and Mitochondrial Medicine, University of Pittsburgh School of Medicine , Pittsburgh, Pennsylvania
| |
Collapse
|