| The chewing action of the upper and lower teeth or the contact between the upper and lower teeth is called occlusal.The occlusal contact during chewing is constantly changing.Under the guidance of the occlusal,the chewing movements of the upper and lower jaws produce the effects of grinding,squeezing,and mashing on the food in the oral cavity.In this process,the periodonceptors(prioceptive sensation)are responsible for collecting signals related to the thickness and hardness of foods,as well as the signals related to the size and direction of tooth pressure.The vesicle glutamate in the olfactory sensory nerve endings Vesicular glutamate transporters(VGLUTs)transmit stimulation signals through the trigeminal mesencephalic nucleus(Vme)periphery to the Vme neuronal cell body,and then through the axon process to transmit signals to the trigeminal motor nucleus(trigeminal).Partial motor nuclei of motor nucleus,Vmo).The motor nuclei issue axon terminals to the chewing muscles,pull the mandible,and drive the entire dentition to complete the chewing process.In this process,VGLUTs play an important role and are divided into three subtypes: I,II,and III(VGLUT1,VGLUT2,and VGLUT3).Among them,VGLUT1 and VGLUT2 as the specific markers of glutamatergic axon terminals are mainly distributed in the axon terminals of glutamatergic neurons.The trigeminal motor nucleus(Vmo)acts as an important motor nucleus in the trigeminal system and can be divided into the dorsolateral nucleus(Mo5DL)and the ventromedial nucleus(Mo5VM).VGLUT1 is mainly distributed in the dorsolateral part of the trigeminal motor nucleus(Vmo),and VGLUT2 is distributed in the entire trigeminal motor nucleus(Vmo).Masticatory muscles are the main muscles of the exercise jaw and play an integral role in daily language exchange,diet chewing and so on.Masticatory muscles can be divided into two groups of opposing muscles: masseter muscle,diaphragm muscle,wing muscles,digastric muscles,contraction of the lower abdomen when raising the jaw,it is called the closed muscle group;digastric anterior abdomen,mandibular hyoid muscle The focus point of the geniohyoid muscle is mainly in the sacral region.When contracting,the lower jaw can be lowered,so it is called opening muscle group.The extra-pterygoid muscle assists other masticatory muscles to complete movements such as anterior extension of the jaw and lateral jaw.It has not been clearly defined as an open or closed muscle for many years.The trigeminal motor nucleus(Vmo)located on the inner side of the pons is composed of several subnuclei,which can be divided into two parts: the dorsolateral nucleus and the ventromedial nucleus.The axon terminals of the dorsal lateral nucleus motor neurons dominate the closed muscle and the axons of the ventromedial nucleus motor axons ultimately dominate the ventral muscles.Reversed standard muscles of diaphragmatic muscles such as diaphragm,masseters,and pterygoid muscles showed that neuronal markers were distributed in certain areas of the dorsolateral nucleus;The results showed that neuronal markers were distributed in certain regions of the ventromedial nucleus.However,due to the special anatomical position,the distribution of neurons that govern the outer muscles of the exoskeleton is currently inconclusive.The exoskeleton muscle is the core content of this study.Therefore,it is the key to this research to find out which nuclear group the axon terminals that control the outer muscles of the exoskeleton are originated from.The temporomandibular joint is one of the most complex joints in the human body.Under the traction of the masticatory muscles including the exoskeleton muscles,it exercises complex functions such as language,chewing,swallowing,and expression,which are indispensable in daily life.However,the more complex the structure is,the more prone to problems.In the common oral and maxillofacial disorders,TMJA is a chronic disease that has not yet been overcome.It will not only seriously affect the patient’s speech,chewing and other functions,but also cause abnormal jaw bone.Shape affects the appearance,so that the patient’s physical and mental health suffer double harm.For a long time,medical workers have been exhausting their efforts to adopt various methods for the treatment of TMJA.However,they have had little success.The treatment process has been laborious and time-consuming.It has both increased the economic burden on patients and has not achieved the desired therapeutic effect.The recurrence rate remains high.The main reason for the current situation is that the pathogenesis of TMJA is not yet clear.Many factors such as tumor,trauma,and infection can cause TMJA.Among them,trauma is the most common pathogenic factor.TMJA caused by trauma is called Traumatic TMJA.Only by truly clarifying the cause of the disease,can clinical symptomatic treatment be found and find the right treatment.Therefore,the exploration of the pathogenesis of TMJA has been a hotspot and difficulty in the field of oral and maxillofacial research in recent years.In this study group,the traumatic temporomandibular joint rigidity model was successfully established in sheep with unilateral temporomandibular joint(TMJ)combined injury.The general observation,imaging observation,histological observation and other methods were used to study the pathophysiology of the exoskeleton.Distraction osteogenesis plays an important role in traumatic TMJA.But how does the temporomandibular joint(TMJ)injury contribute to the outer pterus muscles and how does it cause traumatic TMJA? Its molecular mechanism has not yet been clarified.In this study,SD rats will be used as experimental animals.Based on the existing studies,a rat model of temporomandibular joint complex injury will be established to further study the anatomy of the projection pathway of the trigeminal motor nucleus-exoplanelanis muscle.The relationship between the nucleus muscles of the exosuis muscles and the outer pterygoid muscle and the excitability changes of the trigeminal motor nucleus-external muscle projection pathway after complex injury of the temporomandibular joint are explored.The specific content contains the following three parts:Experiment 1: To establish rat model of temporomandibular joint complex injuryOBJECTIVE: To establish a unilateral temporomandibular joint composite injury model by composite injury of the unilateral condylar process,articular disc and glenoid fossa in SD rats.Methods: Ten six-week-old SD rats were used as experimental animals.The maximum active opening was measured and recorded before surgery.All experimental animals were operated on the right temporomandibular joint to simulate condylar fractures,removal of the articular discs,joint capsules,and the creation of a "10" shaped lesion on the glenoid fossa.The left normal temporomandibular joint was used as a control.At the 6th and 12 th week after operation,the maximum active opening measurement and the living Micro-CT scan were performed on the experimental animals that had not yet died.The maximum opening degree,the size and shape of the condylar changes,and the joint space in the joint complex were observed before and after operation.And the change of upper and lower articular surface.RESULTS: Compared with preoperative,the opening degrees of the experimental animals that survived 6 weeks and 12 weeks after surgery were all reduced to different degrees,with statistical differences(P<0.001).The experimental joint complex was significantly damaged,and the glenoid and condylar bone surface was rough and uneven with calcified images.Compared with the normal left condyle,the condylar malformation of the experimental side was enlarged and the width of the condylar neck was significantly larger than that of the left normal condyle.A small amount of discontinuous new bone formation was seen in the joint space of the experimental side(P<0.001).Conclusion: The rat model of complex temporomandibular joint injury was initially established successfully.Experiment 2: Study on the Projection Pathway of Trigeminal Motor Nucleus-Pterygium in Rats Before and After Combined Damage of Temporomandibular JointOBJECTIVE: To find the neuron projections between the trigeminal motor nucleus and the exoskeleton in the process of traumatic temporomandibular joint stiffness(TMJA)by back-marking the pterygopalatine muscles of the temporomandibular joint before and after composite injury.relationship.METHODS: Six SD rats were used as experimental animals and randomly divided into two groups.The experimental group established a left temporomandibular joint composite injury rat model according to the experimental method.The control group rats did not undergo any treatment of the temporomandibular joint.Two groups of Sprague-Dawley rat left lateral wing muscles were injected with retrograde neurotracer-Fluorogold(FG).One week after injection,the animals were perfused and the brains were harvested.After fixation,Shen sugar and frozen sections were obtained.Fluorescence microscopy and confocal microscopy were performed on the specimens to observe the labeling and localization of FG retrograde neurons in Vmo.RESULTS: Under a fluorescence microscope,SD rats injected with FG in the exotemporal muscle of the experimental group and control group were observed in the entire trigeminal motor nucleus,including the dorsolateral portion of the dorsal closed muscle and the ventral medial portion of the dominant opening muscle.To FG reverse standard neurons.Immunofluorescence double-labeling under confocal microscopy revealed that the central apical terminal of most of the FG-labeled Vmo neurons was also positive for Neu N immunoreactivity,and that the cell bodies and dendrites of nearly all FG and Neu N-labeled neurons were in close contact.Conclusion: Before and after temporomandibular joint composite injury,the extra-pterygoid muscles are regulated by the trigeminal motor nucleus(Vmo)and participate in both open and closed movementsExperiment 3: Role of Trigeminal Motor Nucleus-Exteruclear Muscular Projection Pathway in the Treatment of Complex Injury of the Temporomandibular JointOBJECTIVE: To determine the type I vesicular glutamate glutamate transporter(VGLUT1)and the extra-apical muscle acetylcholinesterase in the trigeminal motor nucleus(Vmo)of the outer muscles of SD rats that are subjected to combined injury of the temporomandibular joint.Analysis of the expression status of(ACh E)to clarify the excitatory effects of trigeminal motor nucleus(Vmo)neurons on exotrophic muscle neurons.METHODS: Twenty SD rats were used as experimental animals and randomly divided into 4 groups with 5 rats in each group.Group 1 was a blank control group.Groups 2,3,and 4 were operated on the left temporomandibular joint composite wound model.The left trigeminal motor nucleus and extra-pterygoid muscle were harvested at 1 week,2 weeks,and 4 weeks,respectively,and protein levels of VGLUT1 and ACh E were analyzed by Western blot.Results: The concentrations of VGLUT1 in the trigeminal motor nucleus of groups 2,3 and 4 were 1.20±0.38mg/ml,1.37±0.62mg/ml,and 1.46±0.69mg/ml,respectively,which were significantly more than that of the first group 1.00mg/ml.The level of acetylcholinesterase(ACh E)in exoplanets of groups 2,3,and 4 was increased(P<0.001).The concentrations of ACh E were 1.09±0.10 mg/ml,1.30±0.10 mg/ml,and 1.30 ±0.21 mg/ml,respectively.The second and third groups were significantly higher than the first group at 1.00 mg/ml(P<0.001).Conclusion: After the temporomandibular joint composite injury occurs,the excitability of the trigeminal motor nucleus(Vmo)and the exoskeleton of the exoskeleton muscle are enhanced,and both of them have a positive correlation with time. |
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