Shah Jay P, Phillips Terry M, Danoff Jerome V, Gerber Lynn H
Rehabilitation Medicine Department, Clinical Research Center, NIH, Bethesda, MD 20814, USA.
J Appl Physiol (1985). 2005 Nov;99(5):1977-84. doi: 10.1152/japplphysiol.00419.2005. Epub 2005 Jul 21.
Myofascial pain associated with myofascial trigger points (MTrPs) is a common cause of nonarticular musculoskeletal pain. Although the presence of MTrPs can be determined by soft tissue palpation, little is known about the mechanisms and biochemical milieu associated with persistent muscle pain. A microanalytical system was developed to measure the in vivo biochemical milieu of muscle in near real time at the subnanogram level of concentration. The system includes a microdialysis needle capable of continuously collecting extremely small samples (approximately 0.5 microl) of physiological saline after exposure to the internal tissue milieu across a 105-microm-thick semi-permeable membrane. This membrane is positioned 200 microm from the tip of the needle and permits solutes of <75 kDa to diffuse across it. Three subjects were selected from each of three groups (total 9 subjects): normal (no neck pain, no MTrP); latent (no neck pain, MTrP present); active (neck pain, MTrP present). The microdialysis needle was inserted in a standardized location in the upper trapezius muscle. Due to the extremely small sample size collected by the microdialysis system, an established microanalytical laboratory, employing immunoaffinity capillary electrophoresis and capillary electrochromatography, performed analysis of selected analytes. Concentrations of protons, bradykinin, calcitonin gene-related peptide, substance P, tumor necrosis factor-alpha, interleukin-1beta, serotonin, and norepinephrine were found to be significantly higher in the active group than either of the other two groups (P < 0.01). pH was significantly lower in the active group than the other two groups (P < 0.03). In conclusion, the described microanalytical technique enables continuous sampling of extremely small quantities of substances directly from soft tissue, with minimal system perturbation and without harmful effects on subjects. The measured levels of analytes can be used to distinguish clinically distinct groups.
与肌筋膜触发点（MTrP）相关的肌筋膜疼痛是非关节性肌肉骨骼疼痛的常见原因。尽管MTrP的存在可通过软组织触诊来确定，但对于与持续性肌肉疼痛相关的机制和生化环境知之甚少。开发了一种微分析系统，用于在体内以接近实时的方式，在亚纳克浓度水平测量肌肉的生化环境。该系统包括一根微透析针，在暴露于内部组织环境后，能够通过105微米厚的半透膜连续收集极少量（约0.5微升）的生理盐水样本。该膜位于距针尖200微米处，允许分子量小于75 kDa的溶质扩散通过。从三组中每组选取三名受试者（共9名受试者）：正常组（无颈部疼痛，无MTrP）；潜伏组（无颈部疼痛，存在MTrP）；活跃组（颈部疼痛，存在MTrP）。将微透析针插入斜方肌上部的标准化位置。由于微透析系统收集的样本量极小，由一个采用免疫亲和毛细管电泳和毛细管电色谱技术的成熟微分析实验室对选定的分析物进行分析。发现活跃组中的质子、缓激肽、降钙素基因相关肽、P物质、肿瘤坏死因子-α、白细胞介素-1β、血清素和去甲肾上腺素的浓度显著高于其他两组（P < 0.01）。活跃组的pH值显著低于其他两组（P < 0.03）。总之，所描述的微分析技术能够直接从软组织连续采集极少量的物质，对系统的干扰最小，且对受试者无有害影响。所测量的分析物水平可用于区分临床上不同的组。
