Relationship Between Myofascial Trigger Points And Sarcoplasmic Reticulum Calcium Homeostasis

Objective:Myofascial Trigger Points?MTrPs?are excessive stress points in skeletal muscle,which occur along with touchable hypersensitive nodules in the taut muscle band.When these nodules are stimulated mechanically,local pain and referred pain can be induced together with motor dysfunction and autonomic nervous phenomena.There are many studies on the pathogenesis of myofascial trigger points,among which the comprehensive hypothesis proposed by Simons et al is widely accepted.The formation of myofascial trigger points may involve the homeostasis imbalance of calcium ions in the sarcoplasmic reticulum.Therefore,by exploring Ca²⁺homeostasis related channel proteins in the sarcoplasmic reticulum(Control of Ca²⁺inflow:voltage gated L-type calcium channel;Control of Ca²⁺recovery:calcium pump of sarcoplasmic reticulum)and changes of calcium ions in sarcoplasmic reticulum,clarify the formation mechanism of myofascial trigger points,further clarify the reasons for the disappearance of myofascial trigger points by dry needling,and provide a reasonable basis for clinical dry needling treatment of myofascial trigger points.Methods:40 male SD rats with an average weight of 220-250g were selected,and were raised in separate cages.They were randomly divided into normal control group?CG group?,model group?MG group?,dry needling trigger points group?DG group?and dry needling non-trigger points group?NG group?,with 10 rats in each group.The CG group was fed normally.Rats in the MG group,DG group and NG group were selected as the modeling objects of the chronic myofascial trigger point model.Blunt percussion of gastrocnemius muscle in the left hind limb of the rats was performed on the first day of each week.On the second day,centrifugal exercise intervention was conducted on the running platform?on the electric animal running platform with a tilt angle of-16°,the rats were trained to run downhill continuously,with the speed gradually increased to 16m/min,and keep 90min each time.Sound,wood sticks or electric stimulation could be used to drive the rats to ensure good exercise effect?.The remaining 5 days,rats were fed normally,and the intervention was repeated for 8 weeks.After entering the convalescence period,all the rats were raised normally for 4 weeks without any experimental intervention,and the overall modeling period was 12 weeks.At the end of 12 weeks,the successful formation's indicators of myofascial trigger point in rat modeling were detected?The internationally recognized myofascial trigger point was characterized by taut band,local twitch response,and spontaneous electromyographic activity?.On this basis,dry needling intervention was performed on the DG group and the NG group once a week for 4 weeks.After the intervention,observe the changes of EMG.Record the number of nodules,grasping force of hind limb,voltage gated L-type calcium channel,calcium pump of sarcoplasmic reticulum and calcium ion concentration.Results:The number of trigger point nodules increased in myofascial trigger point model rats,and decreased relatively after dry needling intervention.The grip of rats in the MG group decreased significantly.After 4 weeks of dry needling intervention,the grip of rats in the DG group was significantly higher than that in the MG group,and the grip in the NG group was higher than that in the MG group,but lower than that in the DG group,and the difference was statistically significant.Compared with the CG group,the sarcoplasmic reticulum calcium concentration in the MG group decreased to 32.5%.The sarcoplasmic reticulum calcium concentration in the DG group was higher than that in the MG group and the NG group.The calcium concentration of sarcoplasmic reticulum in the NG group was higher than that in the MG group,but lower than that in the DG group.Compared with the CG group,the content of voltage gated L-type calcium channel in the MG group was significantly higher,and the content of voltage gated L-type calcium channel in the DG group was lower than that in the model group and the NG group.The content of voltage gated L-type calcium channel in the NG group was lower than that in the MG group,but higher than that in the DG group.The content of sarcoplasmic reticulum calcium pump in the MG group was significantly lower than that in the CG group,and the content of sarcoplasmic reticulum calcium pump in the DG group was higher than that in the MG group and the NG group.The content of sarcoplasmic reticulum calcium pump in the NG group was higher than that in the MG group,but lower than that in the DG group.Conclusion:The Ca²⁺concentration in the sarcoplasmic reticulum of the rats at the myofascial trigger point was significantly reduced,and the contents of VGCC and SERCA were abnormal,indicating that there was a homeostasis imbalance of calcium ions in the sarcoplasmic reticulum at the myofascial trigger point.Dry needling intervention can affect the content of voltage gated L-type calcium channel and calcium pump of muscle reticulum in skeletal muscle,and promote the recovery of calcium ion homeostasis at the myofascial trigger point in skeletal muscle of rats.Compared with non-trigger point dry needling,precise dry needling of myofascial trigger point technique has better therapeutic effect.