| Background and Objective:Chronic cervical spinal cord compression can be caused by CSM, OPLL, tumor or tuberculosis. Because the spinal cord receives long-time outside compression, it arouses functional and organic changes. The patients can show obstacle in sense and movement. Because specimen of spinal cord is difficult to obtain, the pathophysiology change of the disease is still not fairly clear. The purpose of the experiment is to build an animal model. By self-made compression device displacing normal cervical posterior anatomic structure, the rats can catch chronic spinal cord compression by bending and stretching the cervical spine. The activity score gradually reduces and spinal cord ischemia gets harder with the increase of time testing by TTC staining, which it demonstrates that the model made is successful. Last, observe the pathological character of nerve cells in different time by pathological section technology,and pay more analysis on the meaning of apoptosis which exists in self-fixing and self-renewal of nerve cells. Thus, from basis experiment, we search pathological mechanism, postpone or interrupt the further impairment of spinal cord, improve the patient's life quality, lessen the pain of patients, and seek a new cure thread.Methods:28 healthy mice were randomly divided into 14 of experimental group,14 of control group. The postanesthetic mice in experimental group are taken posterior median neck incision, every laminae discussion and separation along posterior median line, C5-C6 processus spinalis, lmina of vertebra and ligamentum flavum removal. Self-made compression equipment is fixed on the vacancy by its two wings, then we suture and close the wound, and the device is kept in the mice body. In control group, the device is firstly fixed in rice, then immediately taken out, and the wound is closed. When the rice are awake after operation, they can act freely in the cage. Observe the activity and urine and stool of the rice everyday, and take x-ray test of cervical spine once per week.6 weeks after operation, the movement and sensation of all rice are scored by CBS to value the functional state of spinal cord.1 of experimental group and 1 of control group are selected to take TTC staining after injecting overdose anesthesia to observe the blood transportation change of the spinal cord.6 of experimental group and 6 of control group are selected for injecting 4% paraformaldehyde to fix the texture, and the changed shape of spinal cord for compression can be observed and compared experimental group with control group. By pathology specimen staining technology, HE, TUNEL and immunahistochemisy staining can be done, and we also can calculate apoptosis rate of cells in spinal cord, and compare with the two groups. The rest of 14 mice do the same after 12 week's compression. We compare apoptosis rate of cells in spinal cord between 6 week's compression and 12 week's compression, and analyze the mechanism of cell apoptosis by the result of immunahistochemisy staining. For further control, we otherwise take 2 normal mice, one for TTC staining, the other for pathological section staining.Rusults:1. the combine behavioral score:The score of 6 week's or 12 week's compression group is clearly lower than that of control group. The score of 12 week's compression group is clearly lower than that of 6 week's compression group.2. TTC staining to observe the state of spinal cord ischemia:The normal mouse section of spinal cord has good blood move. That of mouse by 6 week's compression shows sporadic whitening area in white matter of compression side. That of mouse by 12 week's compression shows mass whitening area in compression side.3. The shape of spinal cord after paraformaldehyde fixing:That of 6 week's compression group shows that the compression area appears a latent nick. That of 12 week's compression group shows swelling in compression area and the shape of spinal cord is irregular,losing the former arc contour.4. HE staining of spinal cord specimen:In control group,there is no clearly abnormality. That of 6 week's experimental group shows blood vessel inflammation in compression area, obviously seen in white matter and grey matter junctional zone; rarefaction in white matter showing irregular demyelination; cytopenia,atrophy nissl body vanishing of nerve cells in grey matter. That of 12 week's compression group shows mass inflammation cellular proliferation around blood vessel in compression area, mass irregular demyelination in white matter; the gap around nerve cells and neuroglial cells in grey matter enlarges,with stress force defect,nerve cell highly swelling, eating nerve cell phenomenon and gliocyte hyperplasia significance.5. TUNEL stained to compare apoptosis rate:The apoptosis cells gliocyte in 6 week's compression group mainly exists in white matter and grey matter junctional zone of compression side, the major part of which is gliocyte. The amount of that in 12 week's compression group is much more than that of 6 week's. We can see not only gliacytes apoptosis, but also mass nerve cells apoptosis.6.. TNF immunohistochemisty staining:TNF receptor asassociated factor-1 antibody mediated immunohistochemisty staining in 6 week's compression group exists partly nerve cell colouring. That in 12 week's compression group exists different extent of deep colouring in nerve cell and gliocyte.Conclusion:1. The acute spinal cord change doesn't take place in mice of all compression group. The behavioristic score descends and spinal cord ischemia area gradually increases showing by TTC staining, both parallel to the compression time, which accord with the condition of chronic spinal cord compression animal model, showing that the model is made successfully.2. HE staining shows that blood vessel inflammation in white matter and grey matter junctional zone of compression area, which turns more and more serious with the increasing compression time. The result corresponds with that of TTC staining. Otherwise, we also see eating nerve cell phenomenon in grey matter of spinal cord.3. By TUNEL staining, it proves that the area of blood vessel inflammation in HE staining exists cell apoptosis, the amount of which is positively relevant to the compression time. What is eaten in eating nerve cell phenomenon in HE staining is apoptotic nerve cells, which explains why the animal behavioristics score descends.4. Immunohistochemisty staining shows that TNF participates cells apoptotic process. We can demonstrate that TNF takes a series of complicated mechanism to make apoptosis, to a certain degree, self -death style of spinal cord, and self-protection style of cells.
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