Research On The Mechanism Of Non-communication Cervical Syringomyelia Associated With Thoracic Scoliosis

ObjectiveOn established non-communicating cervical syringomyelia induced by Kaolin and associated with scoliosis rabbit model, Further research the change of blood-spinal cord barrier around to syringomyelia which influence of the formation and change of syringomyelia; And the relationship between syringyelia and scoliosis occurrence and development.Methods34Japanese white rabbits were chosen for experimental object, and underwent dural sac exposure after C7laminectomy. After that, fine needle had been punctured into medullae spinalis and25%Kaolin60ul had been injected. Animals were divided into four groups, included Kaolin group, physiological saline group,shamed-operation group and normal group for control design,each group has15rabbit. Experimental observation time for12weeks (the death animal established in time), at each point which after operation3d,2w,4w,6w,8w,12w, Tarlov score for evaluated limb motion; Magnetic resonance imaging (MRI) scanning on cervical and thoracic spine,observation syringomyelia; Some animals were chosen to gain continuous shaft bits slice of the cervical spinal cord with hematoxylin-eosin (HE) staining and light microscopy was employed to observe. Histopathologic study of syringomyelia validation; anterior-posterior radiographies of spine for Cobb's angle measurement were performed on all animals; In3d,2w,4w,6w,8w, when the animals12w selected by ear margin veins push note Horseradish peroxidase (HRP) after the perfusion materials, neck period of syringomyelia and slice materials, two amino LianBenAn (3,3'diaminobenzidine, DAB) show color, light-microscopy HRP reaction products;12W with scanning electron microscopy each group animal neck period of the spinal cord, observe each animal syringomyelia section of the change of the ultrastructure of the spinal cord.ResultsContinuous observation on the rabbit of kaolin group model, syringomyelia in the4w,6w,8w,12w most experienced rabbits who were observed, there were2,9,18and23animals each time, the diameters of syringomyelia were increased gradually. The syringomyelia section for a slice of spinal cord shaft, pure-Iraq sappanwood red (HE) dyeing observed by syringomyelia formation by inflammation adhesion and central canal obstruction could be induced the central tube expanding; Moreover, there were4,11and17animals detected scoliosis at6weeks,8weeks and12weeks by x-ray, respectively, with average Cobb angle of18.57°±3.83°(13°-26°);22.63°±9.67°(12°-38°)and36.42°±14.12°(19°-73°). All thoracic curves were associated with cervical syringomyelia and progressed gradually. There are no syringomyelia or scoliosis observed in the control group. The kaolin groups can be observed HRP reaction products in the thoracic segments of the central at3d and2w.The kaolin group syringomyelia section, HRP reaction products observed gathered at syringomyelia within and ependymal around, kaolin group did not happen syringomyelia section, physiological saline group, shamed-operation group and normal group were not observed the central tube and ependymal HRP reaction products around the gathered together, and HRP product main gathered at the ependymal around intermitting position. Physiological saline group,shamed-operation group and normal group of animals for scanning electron microscope (sem) in the neck spinal cord anterior,poster and side horn is not have obvious change;Syringomyelia not associated with scoliosis empty section by electron visible to the spinal cord anterior and poster nerve cells edema, nucleoli and nuclear membrane, blurred; The side spine in the cytoplasm of mitochondria swelling and crest, fuzzy fault; Endoplasmic reticulum swelling, expansion; Austenite, destruction, the particles on the surface to reduce; Nerve neuraxial myelin lamellar structure loose solution, fracture, a mild demyelinated change, two side do not have obvious difference;Syringomyelia associated scoliosis animal empty section by electron spinal cord anterior and poster observed, nerve cells severe swelling, disintegration and nucleoli and nuclear membrane, damage disappeared, two side do not have obvious difference; The side spine mitochondria crest structure disappear, serious swelling crumbling; Endoplasmic reticulum damage, the structure is not clear cytoplasm and solid cable, confuse, austenite; Nerve neuraxial arranging disorderly, in severe demyelinated change, local form plasma lake. Syringomyelia on both sides of the structure change does not symmetrical, convex side changes on a concave.Conclusion1.Established the rabbit model of non-communicating cervical syringomyelia associated with thoracic scoliosis, induced by Kaolin injected into medullary substance of C7corresponding spinal cord. The animal model was closed to clinical features, established by simple proceeding, Repeatability strong, scoliosis occurrence time is short and validated by maturity iconographic techniques. It provided an idea Modeling method for further research involving syringomyelia associated scoliosis.2.Syringomyelia around blood spinal cord microcirculation changed, extracellular fluid into the organization gap, this may be spinal cord is empty and increasing the formation of one of important mechanism.3.The increase of the syringomyelia further aggravating the empty section of the asymmetry of the spinal cord damage change, But despite the spinal cord ultrastructure of the asymmetry of the phenomenon of change, and it may not cause bilateral imbalance of the vertebral muscle loss caused by nerve scoliosis, should have the participation of other pathological mechanism.