Delcanho R E, Kim Y J, Clark G T
UCLA School of Dentistry, Diagnostic Sciences and Orofacial Pain 90095-1668, USA.
Arch Oral Biol. 1996 Jun;41(6):585-96. doi: 10.1016/0003-9969(96)00009-x.
Although mechanisms underlying chronic muscle pain are poorly understood, one prevalent theory is that it is due, in part, to localized hypoxia. The purpose of this study was to evaluate this theory using non-invasive near-infra-red spectroscopy that monitors relative changes in intramuscular haemoglobin (Hb) concentration and oxygen saturation levels. Data were collected for the human masseter muscle during and following three isometric 30-s trials at 50% maximum voluntary contraction. Ten females, with a history of chronic muscle pain in the jaw, and eight matched healthy females without muscle pain (controls) participated. Results showed that, upon initiation of masseter muscle contraction, there was a rapid reduction in the intramuscular Hb concentration concomitant with a reduction in oxygen saturation levels. After cessation of the contraction, the Hb concentration increased rapidly and then fell toward the baseline. Significant differences in the recovery profile for oxygen saturation were found between the first trial and the following two trials for both the muscle pain- and control group. Looking at the first trial only, and adjusting for covariates of height, weight and bite-force in the analysis, revealed a marginally significant postcontraction difference between the two groups with a lower level of oxygen saturation during recovery in the group with chronic muscle pain. Significant group differences were found in Hb concentrations without any significant trial effect. It is likely that the well-known changes in intramuscular blood flow that occur during and after contraction in human muscles are reflected in these altered relative Hb concentrations. The group with chronic muscle pain showed a clearly reduced magnitude of the Hb concentration change in the postcontraction recovery period. The results support the concept that patients with chronic muscle pain have a slower intramuscular reperfusion during the recovery phase after sustained isometric contractions.
尽管慢性肌肉疼痛的潜在机制尚不清楚，但一种普遍的理论认为，它部分是由局部缺氧引起的。本研究的目的是使用无创近红外光谱法评估这一理论，该方法可监测肌肉内血红蛋白（Hb）浓度和氧饱和度水平的相对变化。在50%最大自主收缩状态下进行三次30秒等长试验期间及之后，收集了人类咬肌的数据。十名有下颌慢性肌肉疼痛病史的女性和八名匹配的无肌肉疼痛的健康女性（对照组）参与了研究。结果显示，咬肌收缩开始时，肌肉内Hb浓度迅速降低，同时氧饱和度水平也降低。收缩停止后，Hb浓度迅速升高，然后降至基线。在第一次试验与后两次试验之间，肌肉疼痛组和对照组的氧饱和度恢复曲线均存在显著差异。仅观察第一次试验，并在分析中对身高、体重和咬合力等协变量进行调整后发现，两组在收缩后存在边缘显著差异，慢性肌肉疼痛组在恢复过程中的氧饱和度水平较低。在Hb浓度方面发现了显著的组间差异，但没有任何显著的试验效应。人类肌肉收缩期间和之后发生的肌肉内血流的众所周知的变化，很可能反映在这些相对Hb浓度的改变中。慢性肌肉疼痛组在收缩后恢复期的Hb浓度变化幅度明显减小。结果支持了这样一种观点，即慢性肌肉疼痛患者在持续等长收缩后的恢复阶段，肌肉内再灌注较慢。
