基于H反射通路探究大鼠慢性肌筋膜疼痛触发点的发病机制

STUDIES ON THE PATHOPHYSIOLOGY OF CHRONIC MYOFASCIAL TRIGGER POINTS BY THE H-REFLEX PATHWAY IN INJURY MODEL OF RATS

目的:基于H反射探究大鼠慢性肌筋膜疼痛触发点(myofascial trigger points,MTrPs)的发病机制。方法:16只7周龄雄性SD大鼠随机分为实验组和对照组,实验组采取对腓肠肌定点钝性打击结合离心运动的模式进行连续8周造模。造模结束后两组均正常饲养4周。12周结束后,检测MTrPs造模成功指标(即紧张带、局部抽搐反应和自发肌电活动),并在此基础上进行H反射的诱发实验,采集引发H波的阈值、Mmax、Hmax、M波和H波潜伏期、Hmax/Mmax等。结果:与非MTrPs相比,MTrPs处诱发的H反射Mmax(4.28±1.27 mV)较低,Hmax(1.01±0.34 mV)较高,H波潜伏期(4.60±0.89 ms)较短,Hmax/Mmax比值(0.21±0.19)较大(P<0.05)。结论:H反射与慢性MTrPs形成的病理生理机制有关,MTrPs大鼠脊髓中枢可能存在高度致敏,Iα类传入神经兴奋性较高,肌梭敏感性可能也较高。

Objective：To investigate the pathophysiology of chronic myofascial trigger points （MTrPs） in rats based on the characteristics of H-reflex.Methods：Sixteen male SD rats （7 weeks old） were randomly divided into experimental group and control group. Rat model of chronic MTrPs was established by striking on fascia muscles and eccentric exercise, once per week, for continuous 8 weeks. Then those rats were reared normally and took rest for 4 weeks. At the end of the 12th week, those rats were examined for locating MTrPs with pal-pable taut band, the local twitch response and spontaneous electrical activity. Subsequently, the H-reflex was induced by the gastrocnemius, collecting the threshold to evoke H-reflex, the latency of M wave and H wave, Mmax, Hmax, and Hmax/Mmax.Results：Compared with non-MTrPs, a lower Mmax （4.28± 1.27 mV）, higher Hmax （1.01±0.34 mV） and Hmax/Mmax （0.21±0.19）, and a shorter latency （4.60±0.89 ms） of H wave were found at MTrPs in comparison with non-MTrPs, and the difference between groups had statistical significance （P 〈 0.05）.Conclusion：The H-reflex pathway is involved in the pathophysiology of MTrPs. For MTrPs rats, It seems to be highly sensitized in the spinal cord, muscle spindle and Iα afferent never fibers.