Department of Rehabilitation, School of Sport and Health, Nanjing Sport Institute, Jiangsu Province, China.
Department of Sport Medicine and the Center of Rehabilitation, School of Sport Science, Shanghai University of Sport, Shanghai, China.
Acupunct Med. 2020 Apr;38(2):109-116. doi: 10.1136/acupmed-2017-011626. Epub 2020 Jan 16.
To determine how muscle spindles are involved in the pathophysiology of chronic myofascial trigger spots (MTrSs, similar to myofascial trigger points) in a rat injury model according to the characteristics of the Hoffmann reflex (H-reflex) and the anatomical relationship between muscle spindles and MTrSs.
16 male Sprague-Dawley rats (7 weeks old) were randomly divided into experimental and control groups. A blunt strike injury and eccentric exercise were applied to the gastrocnemius muscle of rats in the experimental group once a week for 8 weeks as a MTrS modelling intervention. Subsequently, the rats were reared normally and rested for 4 weeks. At the end of the 12th week, the rats were examined for the presence of MTrSs defined by the detection of a palpable taut band exhibiting both a local twitch response and spontaneous electrical activity. After modelling, evocation of the H-reflex and morphological examination of muscle spindles and MTrSs were conducted.
The threshold (0.35±0.04 mA) of the H-reflex and latency (1.24±0.18 ms) of the M wave recorded at MTrSs were not significantly different to those at non-MTrSs (P>0.05). Compared with non-MTrSs, a lower Mmax (4.28±1.27 mV), higher Hmax (median (IQR) 0.95 (0.80-1.08) mV) and Hmax/Mmax (median (IQR) 0.21 (0.16-0.40)), and shorter H wave latency (4.60±0.89 ms) were recorded at MTrSs (P<0.05). Morphologically, there was a close anatomical relationship between the MTrS cells and the muscle spindles.
Compared with normal muscles, the H-reflex myoelectrical activity was enhanced and some muscle spindles might have been influenced by active MTrSs. Thus, muscle spindles may play an important role in the pathological mechanism underlying myofascial trigger points.
根据 Hoffmann 反射（H 反射）的特征和肌梭与肌筋膜触发点（MTrPs，类似于肌筋膜触发点）之间的解剖关系，确定肌梭在大鼠损伤模型中慢性肌筋膜触发点（MTrPs）的病理生理学中的作用。
将 16 只雄性 Sprague-Dawley 大鼠（7 周龄）随机分为实验组和对照组。实验组每周对大鼠的腓肠肌进行一次钝击伤和离心运动，共 8 周作为 MTrP 建模干预。随后，大鼠正常饲养并休息 4 周。在第 12 周末，通过检测可触及的紧绷带（同时具有局部抽搐反应和自发性电活动）来检查大鼠是否存在 MTrPs。建模后，诱发 H 反射并对肌梭和 MTrPs 进行形态学检查。
在 MTrPs 处记录的 H 反射阈值（0.35±0.04 mA）和 M 波潜伏期（1.24±0.18 ms）与非 MTrPs 处无显著差异（P>0.05）。与非 MTrPs 相比，MTrPs 处的 Mmax（4.28±1.27 mV）较低，Hmax（中位数（IQR）0.95（0.80-1.08）mV）和 Hmax/Mmax（中位数（IQR）0.21（0.16-0.40））较高，H 波潜伏期较短（4.60±0.89 ms）（P<0.05）。形态上，MTrS 细胞与肌梭之间存在密切的解剖关系。
与正常肌肉相比，H 反射的肌电活动增强，一些肌梭可能受到活动 MTrPs 的影响。因此，肌梭可能在肌筋膜触发点的病理机制中起重要作用。
