背景:推拿按法干预肌筋膜触发点疼痛疗效明确,但是不同力量按法的作用需要深入研究. 目的:观察不同力量推拿按法对肌筋膜疼痛大鼠触发点的影响. 方法:将60只SPF级雄性SD大鼠随机分为不参与造模的空白组10只和参与触发点造模的大鼠50只.以定期钝性击打结合离心运动法在大鼠左侧大腿内侧肌建立慢性触发点模型,将造模成功的40只大鼠随机分为模型组、轻按组、中按组和重按组,每组10只.空白组、模型组大鼠不予干预,轻按组、中按组和重按组以自制按法刺激器,分别以轻力量(0.3 kg)、中力量(0.5 kg)和重力量(0.7 kg)对触发点局部进行干预,7.5 min/次,隔天1次,共计7次.在干预前后分别以电生理仪、软组织张力测定仪和机械痛阈测定仪检测触发点局部肌电图、软组织张力和机械痛阈值.干预结束后,空白组大鼠取左侧大腿内侧肌组织,其余组大鼠取触发点组织,以苏木精-伊红染色观察病理形态,ELISA法检测环氧化酶2、前列腺素E2和缓激肽水平. 结果与结论:①与空白组比较,模型组机械痛阈值降低,软组织张力升高,自发电活动振幅频率升高,病理形态学明显改变,环氧化酶2、前列腺素E2和缓激肽水平增加(P<0.05);②与模型组比较,中按组和重按组机械痛阈值升高,软组织张力降低,肌电图频率和振幅降低,环氧化酶2、前列腺素E2和缓激肽水平降低(P<0.05),病理形态学恢复明显;轻按组以上指标无明显变化(P>0.05);③与中按组比较,重按组上述指标改善作用更明显(P<0.05).结果表明:对触发点疼痛,按压力度可能为中至重度才能有治疗效果.
BACKGROUND:Pressing massage applied to myofascial trigger points(MTrPs)has shown clear effect in relieving pain.However,further research is needed to investigate the effects of different levels of pressure applied during the massage. OBJECTIVE:To investigate the different strength of pressing on MTrPs in rats with chronic pain. METHODS:Sixty SPF-rated male Sprague-Dawley rats were randomly divided into a blank group of 10 rats not involved in MTrPs modeling and 50 rats involved in modeling.The MTrPs model was established in the left medial thigh muscle of rats by blunt strikes combined with centrifugal exercise and 40 rats that met the evaluation criteria after modeling were randomly divided into model group,light press group,medium press group and heavy press group,with 10 rats in each group.The rats in the blank group and the model group were not intervened,while the rats in the light press group,the medium press group and the heavy press group were intervened with a homemade press stimulator with light force(0.3 kg),medium force(0.5 kg)and heavy force(0.7 kg)to MTrPs.The intervention time was 7.5 minutes per session,with one session every other day,totaling seven sessions.Electromyogram,soft tissue tension and mechanical pain threshold were detected by electrophysiological instruments,soft tissue tension tester,and pressure painmeter,respectively.After the intervention,in the blank group,muscle tissue was taken from the inside of the left thigh,while in the other groups,MTrPs tissue was taken.The pathological morphology was observed by hematoxylin-eosin staining,while enzyme-linked immunosorbent assay(ELISA)was used to detect the levels of cyclooxygenase-2,prostaglandin E2 and bradykinin. RESULTS AND CONCLUSION:Compared with the blank group,the model group had lower mechanical pain thresholds,higher soft tissue tone,higher amplitude frequency of spontaneous electrical activity,significant pathomorphological changes,and increased levels of cyclooxygenase-2,prostaglandin E2 and bradykinin(P<0.05).Compared with the model group,the medium press group and the heavy press group showed increased mechanical pain thresholds,decreased soft tissue tension,decreased spontaneous potential frequency amplitude,and decreased levels of cyclooxygenase-2,prostaglandin E2 and bradykinin(P<0.05),and significant recovery on pathomorphological changes.No significant changes in the above indicators were observed in the light press group(P>0.05).Compared with the medium press group,the heavy press group showed better improvement in the above indicators(P<0.05).To conclude,moderate to heavy pressing is often required to alleviate MTrPs pain.