Hunt Emily R, Confides Amy L, Abshire Sarah M, Dupont-Versteegden Esther E, Butterfield Timothy A
Department of Rehabilitation Sciences, Center for Muscle Biology, University of Kentucky, Lexington, Kentucky.
Physiol Rep. 2019 Sep;7(17):e14200. doi: 10.14814/phy2.14200.
Massage is a widely accepted manual therapy used to modulate the inflammatory response of muscle and restore function, but prolonged compression of muscle potentially causes overt injury and damage to muscle fibers. Therefore, a balance exists between the positive effects of massage and the induction of mechanical damage and injury. In addition, skeletal muscle of aged individuals displays increased stiffness, and therefore, the response to massage is likely different compared with young. We hypothesized that the aged skeletal muscle exhibits increased sarcolemmal permeability when subjected to massage compared with young skeletal muscle. Male Brown Norway/F344 rats, 10 and 30 months of age, were each divided into control, non-massaged (n = 8) and massaged (n = 8) groups. The right gastrocnemius muscle received one bout of cyclic compressive loading for 30 min at 4.5 N as a massage-mimetic. Muscles were dissected and frozen 24 h after massage. Alterations in sarcolemma permeability were quantified by measuring the level of intracellular IgG within the muscle fibers. Immunohistochemistry was performed to determine IgG inside fibers and Pax7+ cell number as an indicator of stem cell abundance. Average IgG intensity was not different between control and massaged animals at either age. However, a significant shift to the right of the density histogram indicated that massaged animals had more fibers with higher IgG intensity than control at 10 months. In addition, Pax7+ cell number was significantly elevated in massaged muscles compared with control at both ages. One bout of massage did not induce overt muscle injury, but facilitated membrane permeability, which was associated with an increase in satellite cell number. Data suggest that the load applied here, which was previously shown to induce immunomodulatory changes, does not induce overt muscle injury in young and old muscles but may result in muscle remodeling. Funded by NIH grant AG042699 and AT009268.
按摩是一种被广泛接受的手动疗法，用于调节肌肉的炎症反应并恢复功能，但对肌肉的长时间压迫可能会导致明显的损伤和肌纤维破坏。因此，按摩的积极效果与机械损伤的诱导之间存在平衡。此外，老年个体的骨骼肌僵硬程度增加，因此，与年轻人相比，其对按摩的反应可能不同。我们假设，与年轻骨骼肌相比，老年骨骼肌在接受按摩时肌膜通透性会增加。将10个月和30个月大的雄性棕色挪威/ F344大鼠各分为对照组、未按摩组（n = 8）和按摩组（n = 8）。右腓肠肌接受一次4.5 N的循环压缩负荷30分钟，作为模拟按摩。按摩24小时后解剖并冷冻肌肉。通过测量肌纤维内细胞内IgG的水平来量化肌膜通透性的变化。进行免疫组织化学以确定纤维内的IgG和Pax7 +细胞数量，作为干细胞丰度的指标。在两个年龄段，对照组和按摩组动物的平均IgG强度没有差异。然而，密度直方图显著右移表明，10个月大时，按摩组动物中IgG强度较高的纤维比对照组更多。此外，在两个年龄段，按摩组肌肉中的Pax7 +细胞数量均显著高于对照组。一次按摩并未引起明显的肌肉损伤，但促进了膜通透性，这与卫星细胞数量的增加有关。数据表明，此处施加的负荷先前已显示可诱导免疫调节变化，不会在年轻和老年肌肉中引起明显的肌肉损伤，但可能导致肌肉重塑。由美国国立卫生研究院（NIH）资助，资助号为AG042699和AT009268。
