Institute of Sports Medicine Copenhagen, Department of Orthopedic Surgery M, Bispebjerg Hospital, Building 8, Nielsine Nielsens vej 11, 2400 Copenhagen NV, Denmark.
Xlab, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark.
Cells. 2020 Apr 6;9(4):893. doi: 10.3390/cells9040893.
The decline in muscle mass and function with age is partly caused by a loss of muscle fibres through denervation. The purpose of this study was to investigate the potential of exercise to influence molecular targets involved in neuromuscular junction (NMJ) stability in healthy elderly individuals. Participants from two studies (one group of 12 young and 12 elderly females and another group of 25 elderly males) performed a unilateral bout of resistance exercise. Muscle biopsies were collected at 4.5 h and up to 7 days post exercise for tissue analysis and cell culture. Molecular targets related to denervation and NMJ stability were analysed by immunohistochemistry and real-time reverse transcription polymerase chain reaction. In addition to a greater presence of denervated fibres, the muscle samples and cultured myotubes from the elderly individuals displayed altered gene expression levels of acetylcholine receptor (AChR) subunits. A single bout of exercise induced general changes in AChR subunit gene expression within the biopsy sampling timeframe, suggesting a sustained plasticity of the NMJ in elderly individuals. These data support the role of exercise in maintaining NMJ stability, even in elderly inactive individuals. Furthermore, the cell culture findings suggest that the transcriptional capacity of satellite cells for AChR subunit genes is negatively affected by ageing.
随着年龄的增长，肌肉质量和功能的下降部分是由于神经支配丧失导致肌肉纤维的损失。本研究旨在探讨运动对健康老年人神经肌肉接点（NMJ）稳定性相关分子靶点的潜在影响。来自两项研究的参与者（一组 12 名年轻女性和 12 名老年女性，另一组 25 名老年男性）进行了单侧抗阻运动。运动后 4.5 小时至 7 天采集肌肉活检，进行组织分析和细胞培养。通过免疫组织化学和实时逆转录聚合酶链反应分析与失神经和 NMJ 稳定性相关的分子靶点。除了存在更多失神经纤维外，老年人的肌肉样本和培养的肌管显示乙酰胆碱受体（AChR）亚基的基因表达水平发生改变。单次运动在活检采样时间内引起 AChR 亚基基因表达的普遍变化，表明老年人的 NMJ 具有持续的可塑性。这些数据支持运动在维持 NMJ 稳定性中的作用，即使在不活跃的老年人中也是如此。此外，细胞培养结果表明，卫星细胞的 AChR 亚基基因转录能力受到衰老的负面影响。
