大鼠肌筋膜疼痛触发点自发肌电现象和病理组织学研究

目的:观察局部损伤后肌筋膜疼痛触发点动物模型的自发肌电和触发点肌纤维的病理结构改变。方法:32只雄性SD大鼠(7周龄)随机分成4组,每组8只。A组对照组,不进行干预;B、C、D组为实验组,采取打击结合离心运动进行干预,每周1次,不同组采取的干预持续时间不同,B组干预4周,C组干预8周后饲养2周,D组干预8周后饲养4周。实验共12周。分别在不同时间检查大鼠受累肌的紧张带和局部抽搐反应,采用肌电仪观察自发肌电现象,然后解剖取材,检查触发点肌肉组织学改变,并与对照组进行比较。结果:A组各项检查均为阴性。其它3组与A组比较:(1)紧张带:B组未发现紧张带,阳性率为0;C组阳性率为100%(8/8,P<0.01),D组阳性率为75%(6/8,P<0.01);(2)局部抽搐反应:B组阳性率为37.5%(3/8,P<0.05),C组阳性率87.5%(7/8,P<0.01),D组阳性率为75%(6/8,P<0.01);(3)自发肌电图:B组阳性率为12.5%(1/8,P>0.05);C组阳性率100%(8/8,P<0.01),D组阳性率87.5%(7/8,P<0.01)。组织学观察显示:A组和B组均未发现挛缩肌纤维,C组和D组发现挛缩肌纤维。结论:采取打击结合离心运动干预1个月虽激活了大鼠触发点,但不足以形成慢性肌筋膜触发点疼痛综合征,而2个月的干预可形成稳定可靠的肌筋膜触发点疼痛综合征。

Spontaneous Myoelectric Phenomenon and Histopathology of Myofascial Trigger Points in Rats

Objective We attempted to observe the spontaneous myoelectric phenomenon and histopathology of myofascial trigger points.Methods Thirty two male mice were equally divided into control group(A),and experimental groups B、C and D.Medial vastus muscle of rat was stroked in combination with eccentric exercise once a week in groups B for 4 weeks,in group C for 8 weeks with 2 weeks rest,and in group D for 8 weeks with 4 weeks rest.The responsive taut band,spontaneous EMG,and local tic of rats were checked.Histology of the trigger points was observed as well.Results Comparing with group A:(1)the positive rate of responsive taut band was 0%,100%(8/8,P<0.01),and 75%(6/8,P<0.01)in groups B,C,and D,respectively;(2)the positive rate of local tic was 37.5%(3/8,P<0.05),87.5%(7/8,P<0.01),and 75%(6/8,P<0.01)in groups B,C,and D,respectively;(3)the positive rate of spontaneous EMG was 12.5%(1/8,P>0.05),100%(8/8,P<0.01),and 87.5%(7/8,P<0.01)in groups B,C,and D,respectively.The contracture of muscle fiber was found in group C and D,except in group B.Conclusion 1-week striking plus eccentric exercise can cause the development of myofascial trigger point,but is not enough to induce the myofascial pain syndrome.