| Part one Biomechanical comparison of cervical spines between rabbits and humanObjective: Because of the limits of ethics and medical development,occurrence mechanism of cervical spinal cord whiplash without fracture and dislocation is still not clear till now.Volunteer testing and corpse experiment can't simulate the process of injury,so we should search for an ideal animal model which biomechanical property is similar to that of human.This article is to use sensor technology to analyze ROM and NZ of rabbit cervical spine,and compare them with those of human.We observe similarity and difference between them,and these results could offer help in developing animal models,understanding the injury mechanism and improving protective device in car.Methods: Eight fresh male New Zealand white rabbit cervical spines(C1-T1)had been taken and received CT scans.Then the muscle and soft tissue of each cervical spine were removed,preserving the full ligament.The flexion/extension,axial rotation,and left/right lateral bending were applied continuously on ROM and NZ.The results were compared with the published data of human cervical spine.Results: Rabbit Cobb's angle of C2-7 was 29.8°+0.9°,which was larger than that of human.The facet joints of rabbit cervical spine which was smaller than human was 30°.In flexion,the largest ROM of both human and rabbit occurred in C1-2 segment.In extension,ROM of C1-2 was larger than other segments in both of them.In axial rotation,ROM in C1-2 of human and rabbit were obviously larger than other segments.In lateral bending,ROM was gradually larger from top to bottom but decreased in C6-7 segment.There was no statistical difference(P>0.05)of each segmental ROM and NZ between rabbit and human during different motor patterns.Summary: Biomechanics of rabbit cervical spine is similar to that of human.Rabbit cervical spine might be an ideal animal model for human study.Part two Development and application of cervical spinal cord whiplash injury without dislocation platform for rabbitObjective: A lot of animal experiments are required for the fundamental studies which are related to occurrence mechanism and prevention of cervical spinal cord whiplash injury without dislocation.Because of biomechanical similarity between rabbit and human,easy control and low cost,experimental process is convenient for replication.On account of complex injury course which is affected by different location,gesture and state,different injury condition will lead to different results,so experimental facility is the important premise and basis in research.This study is aimed at development of simple platform which physical parameter can be controlled,thus to realize the whole simulation of cervical spinal cord whiplash injury without dislocation in dynamic condition.Injury movement locus is obtained through motion image analysis technology in rear collision experiment.Severity of injury is discussed based on the experimental results.This study provides new simple facility and analytical method for small animal injury experiment.Methods: Part One: Based on present condition of biomechanics lab,simple devices such as bob,structure and sled for animal fixation,slide rail were developed.We took full advantage of existing equipment to establish a platform for small animal injury.Part Two: Rear collision experiments for rabbit were carried out on the platform.Injury feature were studied through moving image,image exam and pathology.Occurrence mechanism of cervical spinal cord whiplash injury without dislocation had been deeply discussed.Results: Part One: The structures of sled and rail were not damaged in no-load crash and rear collision experiments.Theoretical estimated data of sled agreed with the analysis results of moving image.Part Two: The injury of rabbit occurred mostly in lower cervical spine,especially in C5/7 segment.The injury degree was positively correlated with velocity and accelerated velocity.The initial velocity and/or accelerated velocity was larger,the cervical cord injury was heavier.Summary: The injury platform matched present condition of biomechanical lab very well.Different collision conditions were duplicated using pendulum bob.This platform had been rationally designed.It could stimulate many traffic generation processes such as direct impact,side impact and rear-end collision.This equipment met the requirements of experiments.High speed photography and moving image analysis technology were important in the study.Cervical cord injury of rabbit occurred mostly in lower cervical spine.The injury degree was positively correlated with velocity and accelerated velocity.Part three Significant role of miR-219-5p in spinal cord injury via LRH-1/Wnt/?-Catenin signaling pathway regulationObjective: The present study aimed to investigate the role of mi R-219-5p in spinal cord injury(SCI),and to explore the underlying molecular mechanism.Methods: To perform the present study,SCI rat model and cell model were conducted.qRT-PCR was used to detect the level of miR-219-5p in SCI mice and neurons.Bioinformatics(microRNA.org)was applied to predict the target genes of miR-219-5p and dual luciferase reporter analysis was used to verify our prediction.MTT assay and flow cytometry(FCM)were carried out to determine the cell viability and cell apoptosis of neurons respectively.Additionally,western blot analysis was performed to detect related protein expression.Results: We found mi R-219-5p was highly expressed in SCI mice and neurons.MiR-219-5p directly targets LRH-1.Neuron viability significantly reduced by SCI and was rescued by miR-219-5p inhibitor.Apoptosis of neurons was notably induced by SCI and inhibited by miR-219-5p inhibition.LRH-1/Wnt/?-Catenin signaling pathway was inhibited by SCI and significantly enhanced by miR-219-5p inhibitor.Furthermore,LRH-1 over-expression could eliminate the effects of miR-219-5p inhibitor on SCI.Summary: The data indicated that miR-219-5p inhibitor played a protective role in SCI via regulating LRH-1/Wnt/?-Catenin signaling pathway.Part four Clinical treatment of young and middle-aged cervical spinal cord whiplash injury without dislocationObjective: There was no single standard of clinical treatment for cervical spinal cord whiplash injury without dislocation at present.This injury was common in young and middle-aged people.In order to obtain theoretical basis and effective treatment,our study combined injury condition of spinal cord and imaging examination to discuss clinical treatment strategy and curative effects.Methods: Thirty-eight patients were retrospective analyzed in January 2007 to March 2014,including 30 male,8 female.The range of age was 20 to 59 years and average age was 44.3 years.Different treatment method was chosen on the basis of spinal cord injury condition and imaging exam.Neural classification of American Spinal Cord Injury Association(ASIA)and standard of Japanese Orthopedic Association(JOA)were used to evaluate curative effects.Results: During 38 patients,Type ?(13%)were treated by conservative treatment;Type ?(40%)were treated by posterior open-door extensive laminoplasty;Type ?(26%)were treated by anterior depression and interbody fusion;Type ?(21%)were treated by anterior and posterior operation.Post-operation follow-up were 14 to 32 months,average 22 months.All patients' conditions were improved after treatment.There was no death and serious complication during follow-up.Summary: Choosing effective therapy methods combined with spinal cord injury condition and imaging performance could obtain ideal curative effects.The simple types in our study nearly including all patients will afford reference for future clinical treatments.Conclusions: Biomechanics of rabbit cervical spine is similar to that of human.Rabbit cervical spine might be an ideal animal model for human study.The injury platform matched present condition of biomechanical lab very well.The data indicated that miR-219-5p inhibitor played a protective role in SCI via regulating LRH-1/Wnt/?-Catenin signaling pathway.Choosing effective therapy methods combined with spinal cord injury condition and imaging performance could obtain ideal curative effects. |
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