| Purpose:In this study,the model rats of myofascial pain syndrome(MPS)established by percussion combined with centrifugation were taken as the research object.The improvement effect of acupuncture on Myofascial Trigger Point(MTr P)of MPS rats was observed,and the influence of acupuncture on inflammatory factors was analyzed.Then,the regulatory mechanism of acupuncture on central pain sensitization related factors was further discussed from the perspective of related nerve cells and biological factors in spinal dorsal horn The experimental basis was provided for the treatment of MPS in bed.Material and method:32 healthy male SD rats(SPF grade,7-week-old,weight 220-250g)were randomly divided into control group,model group,Myofascial Trigger Point(MTr P)group and Yanglingquan group.The rats in the model group,MTr P group and the Yanglingquan group were used to prepare the chronic MPS model by percussion combined with centrifugal exercise.The specific methods were as follows: on the first day of each week,the rats were weighed one by one,anesthetized intraperitoneally with 10% chloral hydrate(3ml / kg),and hit the left lower limb medial femoral muscle once with a self-made beating machine.On the second day of the experiment,the rats were kept at the speed of 16 m / min on the-16 ° electric running platform The rest 3-7 days,all the rats were fed normally without intervention.The above process lasted for 8 weeks repeatedly,which was the dry expectation;after 4 weeks,without any intervention,it was the recovery period.After the establishment of the model,the rats in the MTr P group were treated with 0.35 mm * 40 mm filiform needle,and inducing local convulsion reaction with the method of lifting,inserting and twisting,connect the electroacupuncture instrument,apply the density wave with the frequency of 2-20 hz,the current intensity is suitable for the slight tremor of the left lower limb of the rat,keep the needle for 15 min,once a day,for 7 consecutive days;the rats in the Yanglingquan group needled the Yanglingquan point of the left lower limb,and The rats in the control group and model group were grabbed and fixed in the same way at the same time and place without any treatment.This study was divided into two parts:Thesis 1: Establishment of myofascial pain syndrome model and the study of acupuncture effect in ratsBehavioral and hot plate methods were used to detect the latent period of rat’s heat contraction foot;electromyography was used to detect the spontaneous potential and activity frequency of left lower limb medial femoris muscle;pathomorphology was used to observe the morphological changes of muscle fibers in left lower limb medial femoris muscle.Thesis 2: The effect of acupuncture at MTr Ps on pain sensitization of MPS ratsThe expression of IL-1β and TNF-α in serum of rats was detected by Enzyme-linked Immunosorbent Assay(ELISA),and the activation markers of astrocytes in spinal dorsal horn of rats were detected by Immunohistochemistry The gene and protein expressions of nerve growth factor(NGF)and brain-derived nerve growth factor(BDNF)in spinal cord were detected by Real-Time PCR and Western blot.Results:Thesis 1:1.The changes of the latent period of thermal constriction foot in the left lower extremity of rats in each group At the end of modeling,the rats in the control group did not have abnormal gait,spontaneous leg lifting and foot licking behaviors,and the latency of heat shrinkable foot did not change significantly.Compared with the control group,the rats in the model group,MTr Ps group and the Yanglingquan group occasionally limped,and the latency of heat shrinkable foot decreased significantly(P<0.05).Compared with the model group,the rats in MTr Ps group and Yanglingquan group had gait and hot foot contraction There was no significant difference in incubation period(P>0.05).After the treatment,compared with the control group,the rats in the model group occasionally limped,the rats in MTr Ps group and Yanglingquan group walked normally,but the latent period of left leg heat contraction foot in three groups decreased significantly(P<0.05).Compared with the model group,the latent period of left leg heat contraction foot in the two groups increased significantly(P<0.05),and compared with Yanglingquan group,the latent period of claw increased significantly(P<0.05).2.Changes of spontaneous potential and activity frequency of rats in each group The results of EMG showed that the EMG in the control group was like a straight line without abnormal spontaneous potential under the resting state,which proved that there was no trigger point in the medial femoral muscle of the left lower limb of the rats in the control group.Compared with the control group,the model group had a series of background potential with high frequency,low amplitude and peak potential with relatively high amplitude,which lasted for more than 30 s,but not more than 10 mins,indicating that the left lower limb of the rats in the control group had no abnormal spontaneous potential.Compared with the control group,the spontaneous potential activity frequency was statistically significant(P<0.05).Compared with the model group,the spontaneous power generation activity of both MTr Ps group and the Yanglingquan group was sporadic,and the frequency was significantly reduced,and the abnormal spontaneous power generation activity of two rats in MTr Ps group disappeared,indicating that the trigger point was inactivated.3.Pathomorphological changes of left lower limb medial femoris in each group The observation under optical microscope showed that the muscle cells in the transverse section of the control group showed regular polygon,uniform size,close,orderly and regular arrangement,with multiple nuclei at the edge of each cell,and the nuclei were located under the muscular membrane;the muscle fibers in the longitudinal section were closely arranged,regular,uniform in thickness,and most of the nuclei were distributed under the muscular membrane.In the model group,a number of enlarged,round and deeply stained muscle cells were seen in the transverse section,and relatively small round or oval muscle cells were found around the enlarged muscle cells,and inflammatory cell infiltration and nuclear migration were found in different degrees,and the nuclei were mostly moved to the inner or central part of the cells;in the longitudinal section,muscle fibers with unequal thickness and disordered arrangement were found,and large contracture nodules were found Area of adhesions,accompanied by a large number of inflammatory cell infiltration.The transverse section of the rats in the group of MTr Ps and Yanglingquan showed that the morphology of muscle cells was almost normal.The round or oval muscle cells were occasionally seen in the group of Yanglingquan,and the phenomenon of nuclear migration was more obvious than that in the group of MTr Ps.The longitudinal section showed that the muscle fibers in the group of MTr Ps and Yanglingquan recovered gradually,with slight atrophy,degeneration and inflammatory cell infiltration,and the morphology of muscle fibers in the group of MTr Ps was more similar to that in the normal group.Thesis 2:1.Changes of IL-1β and TNF-α expression in serum of rats in each group Compared with the control group,the expression of IL-1β and TNF-α in the serum of the model group,MTr Ps group and the Yanglingquan group increased significantly(P<0.05).Compared with the model group,the expression of IL-1β and TNF-α in the serum of MTr Ps group and the Yanglingquan group decreased significantly(P<0.05).Compared with MTr Ps group,the expression of IL-1β and TNF-α in the serum of the Yanglingquan group increased significantly(P<0.05).The expression of TNF-α increased significantly(P<0.05).2.Expression of GFAP immunoreactive cells in spinal dorsal horn of rats in each group In the control group,there were scattered GFAP positive neurons in the dorsal horn of the spinal cord,with small protrusions,unclear morphology and light staining.The cells were like spiders and distributed in a scattered way,with a small number.Compared with the control group,the positive cells in the model group were obviously dense,and the cytoplasm,cell body and protrusion fibers were brown,with deeper staining,larger cell body and morphological changes compared with the control group Compared with the model group,the expression of GFAP positive cells in MTr Ps group and Yanglingquan group decreased slightly,and the staining in MTr Ps group and Yanglingquan group was slightly shallow,and the comparison between MTr Ps and Yanglingquan group was closer to normal.3.Expression of OX-42 immunoreactive cells in spinal dorsal horn of rats in each group No OX-42 positive cells were found in the dorsal horn of the spinal cord in the control group.The number of positive cells in the model group was significantly denser,the staining was significantly deeper than that in the control group,the cell body became larger,the protuberance shortened,and the cells changed from branching to amoeba like shape.The OX-42 positive cells in MTr Ps group and Yanglingquan group were denser and stained deeper than that in the control group,but less than that in the model group;compared with Yanglingquan group,OX-42 positive cells in MTr Ps group were slightly sparse and stained slightly shallowly.4.Changes of NGF and BDNF gene expression in spinal cord of rats in each group Compared with the control group,the expression of NGF and BDNF gene in the spinal cord of rats in the model group,MTr Ps group and the Yanglingquan group increased significantly(P<0.05).Compared with the model group,the expression of NGF and BDNF gene in the spinal cord of rats in MTr Ps group and the Yanglingquan group decreased significantly(P<0.05).Compared with MTr Ps group,the expression of NGF and BDNF gene in the Yanglingquan group decreased significantly(P<0.05)The difference was statistically significant(P<0.05).5.Changes of NGF and BDNF protein expression in spinal cord of rats in each group Compared with the control group,the expression of NGF and BDNF protein in the spinal cord of rats in the model group,MTr Ps group and the Yanglingquan group increased significantly(P<0.05).Compared with the model group,the expression of NGF and BDNF protein in the spinal cord of rats in MTr Ps group and the Yanglingquan group decreased significantly(P<0.05).Compared with MTr Ps group,the expression of NGF and BDNF protein in the Yanglingquan group increased significantly(P<0.05).Conclusion:1.The model of MPS can be successfully reproduced by blunt percussion combined with centrifugal contraction.2.The MTrP was the core of diagnosis and treatment of MPS.Acupuncture at MTrPs could effectively improve MPS by increasing the threshold of thermal pain sensitivity,reducing the abnormal spontaneous potential of local muscles where MTr Ps were located,and restoring the morphology of muscle cells.3.Acupuncture at MTr Ps could reduce the synthesis and release of the inflammatory factors IL-1β and TNF-α,on the one hand,it could reduce the inflammatory reaction in the area of MTr Ps of MPS rats,directly reduce the pain sensitization degree of peripheral receptors.On the other hand,it could weaken the pain signal intensity,reduce the release of neurotransmitters,inhibit the activation of glial cells,so as to reduce the central sensitization reaction.4.Acupuncture at MTr Ps could reduce the expression of NGF and BDNF,form the mutual inhibition with neurotransmitters and glial cells,so as to reduce the degree of central nervous system pain sensitization,and improve the pain threshold to improve MPS. |
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