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Qian Z, Ping L, Xuelin Z. Re‑examining the mechanism of eccentric exercise‑induced skeletal muscle damage from the role of the third filament, titin (Review). Biomed Rep 2024; 20:14. [PMID: 38124762 PMCID: PMC10731162 DOI: 10.3892/br.2023.1703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Accepted: 10/23/2023] [Indexed: 12/23/2023] Open
Abstract
Intense and unaccustomed eccentric exercise has been extensively studied for its ability to induce muscle damage. However, the underlying mechanism of this phenomenon still requires further clarification. This knowledge gap arises from the need for explanation of the eccentric contraction through the sliding filament theory. The two-filament sarcomere model, which is consisted of thin and thick filaments, forms the basis of the sliding filament theory. The mechanisms of concentric and isometric contractions at the cellular and molecular levels are effectively described by this model. However, when relying solely on the cross-bridge swing, the sliding filament theory fails to account for specific observations, such as the stability of the descending limb of the force-length relationship curve. Recent evidence indicated that titin and the extracellular matrix (ECM) may play a protective role by interacting with the thick and thin filaments. During an eccentric contraction, titin serves as a third filament in the sarcomere, which helps regulate changes in passive force. The two-filament sarcomere model has limitations in explaining eccentric contraction, thus this compensates for those shortcomings. The present review explored the potential of replacing the two-filament sarcomere model with a three-filament sarcomere model, incorporating thin filaments, thick filaments and titin. This revised model offers a more comprehensive explanation of eccentric contraction phenomena. Furthermore, the sliding filament theory was investigated in the context of the three-filament sarcomere model. The double-layer protection mechanism, which involves increased titin stiffness and the ECM during eccentric contraction was explored. This mechanism may enhance lateral force transmission between muscle fibers and the ECM, resulting in sarcolemma and ECM shear deformation. These findings provided insight into the mechanism of eccentric exercise-induced skeletal muscle damage. Considering the three-filament sarcomere model and the double-layer protection mechanism, the present review offered a more logical and comprehensive understanding of the mechanism behind eccentric exercise-induced muscle damage.
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Affiliation(s)
- Zhao Qian
- College of Physical Education, Qufu Normal University, Jining, Shandong 273165, P.R. China
| | - Liu Ping
- College of Physical Education, Qufu Normal University, Jining, Shandong 273165, P.R. China
| | - Zhang Xuelin
- College of Physical Education, Qufu Normal University, Jining, Shandong 273165, P.R. China
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Gottschalk F, Eiken O, Elia A, Gennser M. Eccentric exercise 24 h prior to hypobaric decompression increases decompression strain. Eur J Appl Physiol 2023; 123:2001-2011. [PMID: 37140728 PMCID: PMC10460726 DOI: 10.1007/s00421-023-05214-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2022] [Accepted: 04/26/2023] [Indexed: 05/05/2023]
Abstract
PURPOSE Animal studies have shown that recent musculoskeletal injuries increase the risk of decompression sickness (DCS). However, to date no similar experimental study has been performed in humans. The aim was to investigate if exercise-induced muscle damage (EIMD)-as provoked by eccentric work and characterized by reduced strength and delayed-onset muscle soreness (DOMS)-leads to increased formation of venous gas emboli (VGE) during subsequent hypobaric exposure. METHODS Each subject (n = 13) was on two occasions exposed to a simulated altitude of 24,000 ft for 90 min, whilst breathing oxygen. Twenty-four hours prior to one of the altitude exposures, each subject performed 15 min of eccentric arm-crank exercise. Markers of EIMD were reduction in isometric m. biceps brachii strength and DOMS as assessed on the Borg CR10 pain scale. The presence of VGE was measured in the right cardiac ventricle using ultrasound, with measurements performed at rest and after three leg kicks and three arm flexions. The degree of VGE was evaluated using the six-graded Eftedal-Brubakk scale and the Kisman integrated severity score (KISS). RESULTS Eccentric exercise induced DOMS (median 6.5), reduced the biceps brachii strength (from 230 ± 62 N to 151 ± 8.8 N) and increased the mean KISS at 24,000 ft, both at rest (from 1.2 ± 2.3 to 6.9 ± 9.2, p = 0.01) and after arm flexions (from 3.8 ± 6.2 to 15.5 ± 17.3, p = 0.029). CONCLUSION EIMD, induced by eccentric work, provokes release of VGE in response to acute decompression.
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Affiliation(s)
- Frode Gottschalk
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden.
- Department of Neuroscience, Experimental Traumatology, KI Karolinska Institutet, Stockholm, Sweden.
| | - Ola Eiken
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Antonis Elia
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
| | - Mikael Gennser
- Division of Environmental Physiology, Swedish Aerospace Physiology Center, KTH Royal Institute of Technology, Stockholm, Sweden
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Bjørnsen T, Wernbom M, Paulsen G, Markworth JF, Berntsen S, D'Souza RF, Cameron-Smith D, Raastad T. High-frequency blood flow-restricted resistance exercise results in acute and prolonged cellular stress more pronounced in type I than in type II fibers. J Appl Physiol (1985) 2021; 131:643-660. [PMID: 33955259 DOI: 10.1152/japplphysiol.00115.2020] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Myocellular stress with high-frequency blood flow-restricted resistance exercise (BFRRE) was investigated by measures of heat shock protein (HSP) responses, glycogen content, and inflammatory markers. Thirteen participants [age: 24 ± 2 yr (means ± SD), 9 males] completed two 5-day blocks of seven BFRRE sessions, separated by 10 days. Four sets of unilateral knee extensions to failure at 20% of one-repetition maximum (1RM) were performed. Muscle samples obtained before, 1 h after the first session in the first and second block (acute 1 and acute 2), after three sessions (day 4), during the "rest week," and at 3 (post 3) and 10 days postintervention (post 10) were analyzed for HSP70, αB-crystallin, glycogen [periodic acid-Schiff (PAS) staining], mRNAs, miRNAs, and CD68+ (macrophages) and CD66b+ (neutrophils) cell numbers. αB-crystallin translocated from the cytosolic to the cytoskeletal fraction after acute 1 and acute 2 (P < 0.05) and immunostaining revealed larger responses in type I than in type II fibers (acute 1, 225 ± 184% vs. 92 ± 81%, respectively, P = 0.001). HSP70 was increased in the cytoskeletal fraction at day 4 and post 3, and immunostaining intensities were more elevated in type I than in type II fibers at day 4 (206 ± 84% vs. 72 ± 112%, respectively, P <0.001), during the rest week (98 ± 66% vs. 42 ± 79%, P < 0.001), and at post 3 (115 ± 82% vs. 28 ± 78%, P = 0.003). Glycogen content was reduced in both fiber types, but most pronounced in type I, which did not recover until the rest week (-15% to 29%, P ≤ 0.001). Intramuscular macrophage numbers were increased by ∼65% postintervention, but no changes were observed in muscle neutrophils. We conclude that high-frequency BFRRE with sets performed till failure stresses both fiber types, with type I fibers being most affected.NEW & NOTEWORTHY BFRRE has been reported to preferentially stress type I muscle fibers, as evidenced by HSP responses. We extend these findings by showing that the HSP responses occur in both fiber types but more so in type I fibers and that they can still be induced after a short-term training period. Furthermore, the reductions in glycogen content of type I fibers after strenuous frequent BFRRE in unaccustomed subjects can be prolonged (≥5 days), probably due to microdamage.
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Affiliation(s)
- Thomas Bjørnsen
- Department of Sport Science and Physical Education, Faculty of Health and Sport Sciences, University of Agder, Kristiansand, Norway.,Norwegian Olympic Federation, Oslo, Norway
| | - Mathias Wernbom
- Department of Health and Rehabilitation, Institute of Neuroscience and Physiology, Sahlgrenska Academy, University of Gothenburg, Göteborg, Sweden.,The Rydberg Laboratory for Applied Sciences, Halmstad University, Halmstad, Sweden.,Department of Food and Nutrition, and Sport Science, Center for Health and Performance, University of Gothenburg, Göteborg, Sweden
| | - Gøran Paulsen
- Norwegian Olympic Federation, Oslo, Norway.,Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
| | | | - Sveinung Berntsen
- Department of Sport Science and Physical Education, Faculty of Health and Sport Sciences, University of Agder, Kristiansand, Norway
| | - Randall F D'Souza
- Liggins Institute, University of Auckland, Auckland, New Zealand.,Discipline of Nutrition, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
| | - David Cameron-Smith
- Liggins Institute, University of Auckland, Auckland, New Zealand.,Singapore Institute for Clinical Sciences, Agency for Science, Technology, and Research, Singapore.,Human Potential Translational Research Programme, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Truls Raastad
- Department of Physical Performance, Norwegian School of Sport Sciences, Oslo, Norway
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Jørgensen A, Ekdahl A, Havnes MB, Eftedal I. Eccentric exercise 48 h prior to simulated diving has no effect on vascular bubble formation in rats. Eur J Appl Physiol 2014; 115:597-605. [PMID: 25394809 DOI: 10.1007/s00421-014-3046-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2014] [Accepted: 11/05/2014] [Indexed: 12/01/2022]
Abstract
PURPOSE Decompression sickness (DCS) caused by vascular bubble formation is a major risk when diving. Prior studies have shown that physical exercise has a significant impact in both reducing and increasing bubble formation. There is limited knowledge about the mechanisms, but there are indications that exercise-induced muscle injury prior to diving may cause increased bubble formation. The purpose of this study was to investigate the role of exercise-induced muscle injury as a possible mechanism of bubble formation during diving. METHODS Muscle injury was induced by exposing female Sprague-Dawley rats (n = 30) to a single bout of eccentric exercise, 100 min intermittent, downhill (-16°) treadmill running. Forty-eight hours later, the animals were exposed to a 50-min simulated saturation dive (709 kPa) in a pressure chamber, when the degree of muscle injury and inflammation would be the most pronounced. Bubble formation after the dive was observed by ultrasonic imaging for 4 h. RESULTS No difference in bubble loads was found between the groups at any time despite evident muscle injury. Maximum bubble loads (bubbles cm(-2) heart cycle(-1)) were not different, exercise: 1.6 ± 3.5 SD vs control: 2.2 ± 4.1 SD, P = 0.90, n = 15 in each group. CONCLUSIONS Eccentric exercise performed 48 h prior to diving causes skeletal muscle injury but does not increase the amount of vascular bubbles in rats. The prevailing recommendation is that physical activity prior to diving is a risk factor of DCS. However, present and previous studies implicate that pre-dive physical activity does not increase the DCS risk.
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Affiliation(s)
- Arve Jørgensen
- Department of Diagnostic Imaging, St. Olavs University Hospital, Post Box 3250, 7006, Trondheim, Norway,
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Madden D, Barak O, Thom SR, Yang M, Bhopale VM, Ljubkovic M, Dujic Z. The impact of predive exercise on repetitive SCUBA diving. Clin Physiol Funct Imaging 2014; 36:197-205. [DOI: 10.1111/cpf.12213] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2014] [Accepted: 10/13/2014] [Indexed: 11/28/2022]
Affiliation(s)
- Dennis Madden
- Department of Physiology; University of Split School of Medicine; Split Croatia
| | - Otto Barak
- Department of Physiology; Faculty of Medicine; University of Novi Sad; Novi Sad Serbia
| | - Stephen R. Thom
- Department of Emergency Medicine; University of Maryland; Baltimore MD USA
| | - Ming Yang
- Department of Emergency Medicine; University of Maryland; Baltimore MD USA
| | - Veena M. Bhopale
- Department of Emergency Medicine; University of Maryland; Baltimore MD USA
| | - Marko Ljubkovic
- Department of Physiology; University of Split School of Medicine; Split Croatia
| | - Zeljko Dujic
- Department of Physiology; University of Split School of Medicine; Split Croatia
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Cumming KT, Paulsen G, Wernbom M, Ugelstad I, Raastad T. Acute response and subcellular movement of HSP27, αB-crystallin and HSP70 in human skeletal muscle after blood-flow-restricted low-load resistance exercise. Acta Physiol (Oxf) 2014; 211:634-46. [PMID: 24762334 DOI: 10.1111/apha.12305] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Revised: 03/12/2014] [Accepted: 04/17/2014] [Indexed: 12/14/2022]
Abstract
AIM Heat-shock proteins (HSP) are important chaperones for stressed and damaged proteins. Low-load blood-flow-restricted resistance exercise (BFRE) is generally believed not to induce significant muscle damage, but is hitherto unverified with intracellular markers. Consequently, the aim of this study was to investigate the HSP response after BFRE in human skeletal muscle. METHODS Nine healthy volunteers performed five sets to failure of unilateral knee extension at 30% of 1RM with partial blood-flow restriction. The contralateral leg performed the same work with free blood flow. Muscle biopsies were collected before exercise, 1, 24 and 48 h after exercise and analysed for HSP27, αB-crystallin, HSP70, desmin, glycogen content and myosin heavy chain by immunohistochemistry, ELISA and western blotting. RESULTS One hour after exercise, HSP27 and αB-crystallin levels were reduced in the cytosolic and increased in the cytoskeletal fraction in the BFRE leg. HSP70 showed a delayed response and was increased over 48 h in the BFRE leg. Immunohistochemical analyses showed higher staining intensity of HSP70 in type 1 fibres in the BFRE leg at 24 and 48 h post-exercise. PAS staining showed decreased glycogen levels after BFRE, and interestingly, glycogen was still depleted 48 h after exercise in the same fibres displaying high HSP70 staining (type 1 fibres). CONCLUSION Translocation of HSP27 and αB-crystallin from cytosol to cytoskeletal structures indicates that cytoskeletal proteins are stressed during BFRE. However, overt signs of myofibrillar disruptions were not observed. Interestingly, the stress response was more pronounced in type 1 than in type 2 fibres and coincided with low glycogen levels.
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Affiliation(s)
- K. T. Cumming
- Department of Physical Performance; Norwegian School of Sport Sciences; Oslo Norway
| | - G. Paulsen
- Department of Physical Performance; Norwegian School of Sport Sciences; Oslo Norway
| | - M. Wernbom
- Department of Physical Performance; Norwegian School of Sport Sciences; Oslo Norway
- Lundberg Laboratory for Human Muscle Function and Movement Analysis; Department of Orthopedics; The Sahlgrenska Academy at University of Gothenburg; Gothenburg Sweden
| | - I. Ugelstad
- Department of Physical Performance; Norwegian School of Sport Sciences; Oslo Norway
| | - T. Raastad
- Department of Physical Performance; Norwegian School of Sport Sciences; Oslo Norway
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