| Objective: Cervical Spondylotic Myelopathy is commonly caused by disc herniation,calcification of posterior longitudinal ligaments,ossification of yellow ligaments,tumor and spinal deformities.The exact pathophysiological mechanism of cervical spondylotic myelopathy remains to be elucidated.Because specimen of spinal cord is difficult to obtain,therefore,the establishment of an animal model simulating human pathogenesis of cervical disease is the basis of studies of cervical myelopathy.Way to build the existing animal models,such as screws into law,the presence of a controlled balloon or balloon compression method resulted in a higher rate of infection due to repeated operations and mortality and increased compression strength of nonlinear problems,reducing its stability,science and practicality;and expansion of physical laws,due to the implant material expansion rate,which often resemble sub-acute model of oppression models.This study was designed on the basis of the existing modeling,build better simulate chronic disease animal model of cervical spinal cord compression.By microscopic observation of pathological changes in spinal cord tissue revealed cervical myelopathy possible mechanism for the treatment of cervical myelopathy and explore new ideas.Materials and Methods:(1)10 healthy rats were randomly divided into five experimental group and control group 5.Preoperative two groups of animals with modified Rivlin ramp test,evaluate the functional status of the spinal cord.Two groups of animals were anesthetized at the level of C5 to C7 in turn cut the skin,subcutaneous tissue and muscle to expose the C5 to C7 laminectomy,incision bleeding,cut interlaminar the yellow ligament,exposing the dura and nerve dissection hard ridge separating the child care lamina membrane surrounding tissue.In the experimental group of rats placed in a polyvinyl alcohol hydrogel between rats and lamina dura of C5-C6.Hemostatic layer by layer suture muscle,fascia,subcutaneous tissue and skin.Awake after surgery rats in a cage free.Observe the behavior of rats and the two will be the case every day.Again after three weeks in the two groups of animals with modified Rivlin ramp test,parallel MRI.The experimental and control rats were sacrificed after cervical spinal cord of narcotic direct specimen HE staining histological changes in spinal cord tissue.(2)BBB score showed that the two groups of rats similar preoperative behavioral science capability,BBB score was no significant difference.Motor function in rats that direct pressure group decreased rapidly during the first week after surgery,continues to slowly decrease after two weeks;the first week of the film wrapped group score more moderate decline,oppression with time,BBB scores continued to decline.TUNEL assay apoptosis results in spinal cord tissue showed that the two groups can be seen specimens positive apoptotic cells were shown,but the number of direct pressure group specimens positive apoptotic cells was significantly less than the film set of specimens wrapped apoptotic cells number.Western Blot protein electrophoresis results are visible film wrapped group Caspase-3 protein expression levels of apoptosis compared with more direct pressure groups.Results:(1)Experimental and control groups of rats before surgery improved Rivlin ramp test similar to the average of the tilt angle,spinal surgery showed two groups of rats were no significant differences in functional status.Rivlin modified rats in the control group after the third week of the tilt angle of the swash plate test average of 70.00 °,the average tilt angle of the experimental group was 36.17 °(P <0.05),the experimental group after spinal cord of rats was significantly worse functional status in the control group.MRI T2-weighted image shows signal enhancement of local or wider area than the experimental group clearly shows the structure of the damaged area of spinal cord disorders,diffuse lesion signal anomalies like ill-defined;subdural effusion dorsal see local exudation high signal.Gross pathologic examination showed cervical spinal cord tissue of rats in the experimental group than in the control group was significantly damaged,visible blood vessels distorted,subdural bleeding points;HE staining in the control group of rat spinal cord tissue swelling deformation,there demyelination,glial cell proliferation,swelling of the nerve cells in the gray matter damage such disintegration performance.(2)BBB score showed that the two groups of rats similar preoperative behavioral science capability,BBB score was no significant difference.Motor function in rats that direct pressure group decreased rapidly during the first week after surgery,continues to slowly decrease after two weeks;the first week of the film wrapped group score more moderate decline,oppression with time,BBB scores continued to decline.TUNEL assay apoptosis results in spinal cord tissue showed that the two groups can be seen specimens positive apoptotic cells were shown,but the number of direct pressure group specimens positive apoptotic cells was significantly less than the film set of specimens wrapped apoptotic cells number.Western Blot protein electrophoresis results are visible film wrapped group Caspase-3 protein expression levels of apoptosis compared with more direct pressure groups.Conclusion: Polyvinyl alcohol hydrogel implants are an ideal method of establishing an animal model of spinal cord compression.Postoperative improvement Rivlin ramp tests and magnetic resonance imaging,pathology detection can be clearly detected in experimental animals compressive spinal cord injury.By implanting the film wrapped polyvinyl alcohol hydrogel can slow down the process of cervical spinal cord compression,better simulate cervical myelopathy of chronic disease process.By observing direct compression group and spinal cord wrap film,different variations of apoptosis protein slice of apoptotic cells,suggesting that apoptosis may be a cause of cervical spinal cord disease. |
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