不同部位按法对慢性疼痛激痛点大鼠模型的影响

Effects of different site pressing on local myofascial trigger points in chronic pain model rats

目的 观察局部按法、对侧按法和远端按法刺激对慢性疼痛激痛点大鼠模型局部的影响。方法 将SPF级雄性SD大鼠随意分为空白组10只和造模组50只,以钝性击打结合离心运动法在大鼠左侧大腿内侧肌建立激痛点模型,造模成功后,符合评价标准大鼠随机数字表法分为模型组、局部按法组、对侧按法组和远端按法组,每组10只。空白组、模型组不予干预,其余各组分别以自制按法刺激器干预14 d,局部按法组以按法刺激激痛点局部,对侧按法组以按法刺激激痛点对侧肢体,远端按法组以按法刺激激痛点同侧“太溪”区域。以电生理仪器记录激痛点局部肌电图,以软组织张力测定器检测激痛点软组织张力,以压痛测试仪检测激痛点机械痛阈值。干预结束后取左侧大腿内侧肌或激痛点组织,HE染色观察病理形态,免疫组化和酶联免疫吸附测定检测P物质和降钙素基因相关肽(CGRP)含量。结果 与空白组相比较,模型组机械痛阈值降低,软组织张力升高,自发电活动明显,形态学有明显改变,P物质和CGRP含量增加(P<0.05);与模型组相比较,局部按法组、对侧按法组和远端按法组机械痛阈值提高,软组织张力、自发电位频率和振幅、P物质和CGRP含量降低(P<0.05),其中,局部按法组变化幅度最大(P<0.05)且对形态学改善作用明显,对侧按法组对肌电图、CGRP和P物质的改善作用优于远端按法组(P<0.05)。结论 局部按法、对侧肢体按法和远端“太溪”按法刺激均可以缓解激痛点疼痛,降低软组织张力和自发电活动,可能与抑制P物质和CGRP的高表达有关;激痛点局部按法的作用最佳,对侧按法次之,最后是远端“太溪”区域按法。

Objective We aimed to investigate the differences in the effects of local pressing,contralateral pressing,and distal pressing stimulation on the local myofascial trigger points(MTrPs)in chronic pain model rats.Methods SPF-grade male Sprague-Dawley rats were randomly divided into the blank group(n=10)and the MTrPs group(n=50)in which the MTrPs model was established.The MTrPs model was established in the left medial thigh muscle of rats by blunt strikes combined with centrifugal exercise.Rats that met the evaluation criteria after modeling were randomly divided into the model group,the local pressing group,the contralateral pressing group,and the distal pressing group(n=10).Rats in the blank group and the model group did not undergo intervention,and the remaining groups were treated with homemade pressing stimulators for 14 days.The rats in the local pressing group,the contralateral pressing group,and the distal pressing group were subjected to pressing stimulation at their respective sites.Specifically,they received pressing stimulation locally on the MTrPs,on the contralateral limb of the MTrPs site,and at the ipsilateral KI3 area of the MTrPs,respectively.The electromyogram(EMG)was recorded and soft tissue tension and the mechanical pain threshold were detected by electrophysiological instruments,a soft tissue tension tester,and a pressure painmeter,respectively.At the end of the intervention,tissues from the left medial thigh muscle or MTrPs were taken to observe the pathological morphology using HE staining.In addition,SP and CGRP contents were measured using immunohistochemistry and ELISA.Results Compared with the blank group,the model group had a lower mechanical pain threshold,higher soft tissue tension,obvious spontaneous electrical activity,significant pathological changes,and increased SP and CGRP levels(P<0.05).Compared with the model group,the local pressing group,the contralateral pressing group,and the distal pressing group showed an increased mechanical pain threshold and decreased soft tissue tension,a lower spontaneous potential frequency amplitude,and lower SP and CGRP levels(P<0.05),with the local pressing group showing the greatest improvement(P<0.05)and significant recovery on morphological analysis.The contralateral pressing group showed a better improvement in EMG,CGRP,and SP than the distal pressing group(P<0.05).Conclusion Local pressing,contralateral limb pressing,and distal pressing at KI3 can relieve the pain of MTrPs,reduce soft tissue tension,and decrease spontaneous electrical activity,possibly by reducing the expression of SP and CGRP.Local pressing on MTrPs showed the best efficacy,followed by contralateral pressing and then distal pressing at KI3.