| Background:In the present study,it is important to find a model that can be used as an alternative to human research,because of the difficulty of obtaining fresh human specimens.Rabbits are commonly used in animal experiments on cervical disease,and less research study the anatomy of rabbit cervical spine.Animal models have been used widely to study the consequences of spinal cord injury,degenerative diseases,and biomechanics of the spine.Comparative studies have investigated resemblances and distinctions between various species.However,a perceptible anatomic comparison of non-human primate,rabbit,and human cervical spines using micro-computed tomography(CT)has not been reported.Purpose of the study:1.The rabbits were randomly divided into two groups of different degree of injury,and the MRI and the histological findings of different degree of injury were studied.2.The objective of this study is to compare the fundamental structural similarities and differences in cervical spines of non-human primate,rabbit and human.Research methods:1.Establishment of rabbit cervical spinal cord hemi-contusion modelThe 22 adult male New Zealand white rabbits were randomly divided into severe injury group(N=9),moderate group(N=9)and sham group(N=4).Before surgery,MRI scanning and measuring the relevant parameters is needed.Using the electromagnetic servo material testing machine to contuse on the left side of the spinal cord with high-speed.Strike displacement is 2.8 mm and 2.0 mm,respectively.Sham operation group is without contusion.Twenty-four hours after injury,MRIs of two groups were performed.After scanning,all animals were perfused and analyzed by histological observation.2.Anatomical study of rabbit,non-human primate and human cervical spineCervical spines were collected from male non-human primate(n=4)and New-Zealand rabbit(n=4)and were scanned using micro-computed tomography,and 3 dimensions(3D)were reconstructed to measure the spinal anatomy,including the width and depth of the vertebra(Vw;Vd),vertebral body(VBw;VBd),and spinal canal(SCw;SCd),as well as the vertebral body and intervertebral disc heights(VBh;IVDh).Normalized measurements of non-human primate and rabbit were also computed to compared with corresponding measurements of the human in the cervical spine.Research result:1.Establishment of rabbit cervical spinal cord hemi-contusion modelThe severity of severe injury was significantly greater than that of moderate injury.MRI of 24 hours after injury showed that the signal of left side of spinal cord at C5 segment changes more significantly in severe injury group than that in the moderate injury group.Severe damage to the spinal cord tissue HE staining piece of tissue damage range,and the center cross-sectional area of hemorrhage in severe injury group was 0.039±0.006 mm2,which was more significantly than that was 0.012±0.006 mm2 in the moderate group(P<0.05).2.Anatomical study of rabbit,non-human primate and human cervical spineThe vertebral dimensions of the non-human primate spine were similar across spinal levels as that in humans while dimensions of rabbit spine vary more between spinal levels than in humans.Overall,non-human primate vertebrae are similar to human vertebrae,except the shape of spinal canal.Rabbit vertebrae are more slender than human vertebrae,but the intervertebral disc height to vertebral body height ratios(IVDh/VBh)are very similar in both species in the cervical vertebra.Analysis conclusion:1.This study successfully established a rabbit model of cervical spinal cord contusion hemi,with varying degrees of spinal cord injury in a striking force,and the MRIs and histology in different groups showed significant differences.2.The similar cervical spinal morphology in the non-human primates and humans supports that the non-human primate cervical spine is more suitable human substitutions than rabbit cervical spine.Furthermore,the function of spinal structure is also need to be considered when choosing the experimental animal models. |
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