| 1. |
- Charifi, N., et al.
(författare)
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Enhancement of microvessel tortuosity in the vastus lateralis muscle of old men in response to endurance training
- 2004
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Ingår i: Journal of Physiology. - : Wiley. - 0022-3751 .- 1469-7793. ; 554:Pt 2, s. 559-569
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Tidskriftsartikel (refereegranskat)abstract
- Muscle microvascularization is usually quantified in transverse sections, in absolute terms (capillaries around fibres, CAF, or capillary-to-fibre ratio, C/F) or as CAF related to fibre area (CAF/area, CAFA). The capillary-to-fibre perimeter exchange ratio (CFPE) has been introduced in order to assess the role of the capillary-to-fibre interface in resistance to O(2) diffusion. The ratio between the length of capillaries in contact with fibres and fibre perimeter (LC/PF) has also been used as an index for capillary tortuosity. The possibility of change in capillary tortuosity with endurance training was not considered in previous studies. Consequently, this study investigated the effect of 14 weeks of endurance training on muscle microvascularization, including microvessel tortuosity, in 11 elderly men (8th decade). Microvessels were analysed using the CD31 antibody. Together with the significant increase in peak oxygen exchange and citrate synthase activity, there was a significant increase in C/F. While CFPE and CAFA remained unchanged, an important finding was the clear increase in LC/PF (56%; P < 0.001) for a same sarcomere length. We also found a strong correlation between oxidative enzyme activity and LC/PF both before and after training. These results indicate that endurance training induces significant remodelling in the microvessel network in elderly men and that an increase in the degree of microvessel tortuosity would be an important mechanism of adaptation to endurance training.
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| 2. |
- Larsson, Britt, et al.
(författare)
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Blood supply and oxidative metabolism in muscle biopsies of female cleaners with and without myalgia
- 2004
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Ingår i: The Clinical Journal of Pain. - : Ovid Technologies (Wolters Kluwer Health). - 0749-8047 .- 1536-5409. ; 20:6, s. 440-446
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Pathomechanisms of work-related myalgia are poorly understood. Myalgia is thought to be caused by excitation of nociceptors present in the muscular tissue but not in the muscle fiber itself. Muscle contraction in combination with hypoxia is known to excite nociceptors. Morphologic analysis can contribute to the knowledge of the excitation of nociceptors. This study thoroughly examines the morphology of the trapezius muscle's capillary supply and signs of disturbed oxidative metabolism to understand their role in work-related myalgia. METHODS: Surgical trapezius muscle biopsies were obtained from 25 female cleaners with long-standing work-related myalgia, 25 female cleaners without trapezius myalgia, and 21 healthy teachers. Enzyme and immunohistochemical stainings were performed to highlight fibers with aberrant intermyofibrillar patterns, indicating a disturbed oxidative metabolism (also known as moth-eaten fibers) and a disturbed capillary supply of different fibers. RESULTS: A significantly lower number of capillaries per fiber area in cleaners suffering from myalgia compared with cleaners without trapezius myalgia was found. Moth-eaten fibers were found in the 3 groups, but these fibers were significantly more prevalent in the groups of cleaners than in the healthy teacher group. CONCLUSION: This work indicates that the capillary supply of trapezius is affected in work-related trapezius myalgia. More studies are needed to understand possible mechanisms that would explain the occurrence of moth-eaten fibers.
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