Purpose: Macrophage accumulation in response to decreasing myonuclei may be the major mechanism underlying immobilization-induced muscle fibrosis in muscle contracture, an intervention strategy suppressing these lesions is necessary. Therefore, this research investigated the effect of belt electrode-skeletal muscle electrical stimulation (B-SES), a new electrical stimulation device, to the macrophage accumulation via myonuclei decrease in immobilization-induced muscle fibrosis. Materials and Methods: 18 Wistar male rats were divided into the control group, immobilization group (with plaster cast fixation to immobilize the soleus muscles in a shortened position for 2 weeks), and B-SES group (with muscle contractile exercise through B-SES during the immobilization period). B-SES stimulation was performed at a frequency of 50 Hz and an intensity of 4.7 mA, muscle contractile exercise by B-SES was applied to the lower limb muscles for 20 minutes/session (twice a day) for 2 weeks (6 times/week). The bilateral soleus muscles were used for histological, immunohistochemical, biochemical, and molecular biological analyses. Results: The number of myonuclei was significantly higher in the B-SES group than in the immobilization group, and there was no significant difference between the B-SES and control groups. The cross-sectional area of type I and II myofibers in the immobilization and B-SES groups was significantly lower than that in the control group, and the cross-sectional area of type I myofibers in the B-SES group was higher than that in the immobilization group. However, Atrogin-1 and MuRF-1 mRNA expression in the immobilization and B-SES groups was significantly higher than those in the control group. Additionally, the number of macrophages, IL-1β, TGF-β1, and α-SMA mRNA expression, and hydroxyproline expression was significantly lower in the control and B-SES groups than those in the immobilization group. Conclusion: This research surmised that muscle contractile exercise through B-SES prevented immobilization-induced muscle fibrosis, and this alteration suppressed the development of muscle contracture.

中文翻译：

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腰带电极-骨骼肌电刺激对固定性肌纤维化的影响

目的：响应于减少的肌核，巨噬细胞蓄积可能是固定化诱导肌肉挛缩引起的肌肉纤维化的主要机制，因此有必要采取抑制这些病变的干预策略。因此，本研究调查了一种新型的电刺激设备-皮带电极-骨骼肌电刺激（B-SES）对通过肌核减少固定化引起的肌纤维化对巨噬细胞积累的影响。材料与方法：将18只Wistar雄性大鼠分为对照组，固定组（用石膏石膏固定以使比目鱼肌在较短的位置固定2周）和B-SES组（通过B-SES进行肌肉收缩运动）在固定期间）。B-SES刺激的频率为50 Hz，强度为4。7 mA，通过B-SES对下肢肌肉进行肌肉收缩运动，每次20分钟（一天两次），持续2周（6次/周）。双侧比目鱼肌用于组织学，免疫组织化学，生化和分子生物学分析。结果：B-SES组肌核细胞数量明显高于固定组，B-SES组与对照组无明显差异。固定组和B-SES组的I型和II型肌纤维的截面积明显低于对照组，B-SES组的I型肌纤维的截面积高于对照组。固定组。然而，固定组和B-SES组中Atrogin-1和MuRF-1 mRNA的表达显着高于对照组。另外，在对照组和B-SES组中，巨噬细胞，IL-1β，TGF-β1和α-SMAmRNA表达以及羟脯氨酸表达的数量显着低于固定组。结论：本研究推测通过B-SES进行的肌肉收缩运动可预防固定化所致的肌肉纤维化，并且这种改变抑制了肌肉挛缩的发展。