| Objective: To investigate the anatomical relationship between the motor endplate,abnormal contractile nodules and abnormal muscle spindles in the myofascial trigger point region through animal experiments,and observe the changes in the morphology and internal ultrastructure of muscle spindles before and after modeling,so as to provide further explanation for the pathological mechanism of the formation of myofascial trigger points.Methods: Thirty-six seven-week-old male SD rats(200-250g)were selected for animal experiments,and 18 were randomly assigned to the experimental group(group M)and 18 to the control group(group C).1.Materials for modeling: Rats in group M were subjected to modeling for two months(blow to the left gastrocnemius muscle every Monday,centrifugal running downhill on Tuesday,once a week)and then rested for one month,while rats in group C were not subjected to intervention.Three months later,clinical palpation and verification of electromyographic signals were used to determine whether the modeling was successful.After modeling,the left gastrocnemius tissue of group M and group C SD rats was frozen and stored.2.Comparison of staining methods of muscle spindle in trigger point tissues: The left gastrocnemius tissue of rats in group M and C was taken,and the staining effect was compared by HE,Masson,acetylcholinesterase combined with silver nitrate staining.3.Relationship between the number of positions of muscle spindle,trigger point cells and motor endplate: After combining all the results,the number of muscle spindles,the maximum equatorial area and the total area of intra spindles in the gastrocnemius tissues of group M and group C were statistically analyzed by acetylcholinesterase and HE staining.The position relationships among muscle spindles,trigger cells and motor endplate were observed under light microscope,and the ultrastructural changes of muscle fibers and muscle spindles were observed by electron microscope.Results: 1.Comparison of muscle spindles staining methods: HE,Masson and acetylcholinesterase combined with silver nitrate staining could not observe the muscle spindles morphology in the skeletal muscle tissue of model group rats,while acetylcholinesterase combined with HE staining could clearly observe the muscle spindles morphology.2.Statistics of muscle spindles morphology: the equatorial area of muscle spindles in the model group was decreased compared with that in the control group,while the intra findus muscle fiber area did not change significantly3.Comparative study on tissue morphology under light microscope: two kinds of nodular cells appeared in muscle fibers of the modeling group,one was directly connected to the motor endplate,and the other was at a certain distance from the motor endplate.Contracture nodules appeared in the motor endplate directly connected with the extrafuscular muscle fibers,and appeared in different tissues several times.4.Comparative study of tissue morphology under electron microscope: structural changes of muscle fibers,mitochondrial degeneration,incomplete inner and outer capsula of muscle spindle,disordered arrangement of intrafusional muscle fibers,and hyperplasia of collagen fibers.Conclusions: 1.ACh E combined with HE staining is suitable for the model of traumatic myofascial trigger point,which can clearly observe the morphological changes of muscle spindle,trigger point cells and motor end plate.2.The morphological structure of trigger point tissue and normal tissue changed significantly,especially the maximum equatorial area of muscle spindle decreased significantly;3.The anatomical relationship among muscle spindle,trigger point cells and motor endplate proved the role of muscle spindle in the pathogenesis of trigger point cells.Trigger point cells were more likely to be generated around the muscle spindle.4.The ultrastructural changes of muscle spindle and trigger point cells under electron microscope,especially the decrease of mitochondria,proved that insufficient energy supply may also occur in the muscle spindle. |
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