| Average life span of the citizen is longer than before because of the development of the economy, medical technology and the standard of living enjoyed by our people.But the problem cause by ageing can hampered the improvement of living standards,therefore,it’s a full of contradictions and urgent problem.It mainly embodied in the increase of prevalence rate of gerontic illness, include spinal degenerative disease,which have a high morbidity rate and disorder people’s life seriously. The local pathological anatomy and pathological physiology changes caused by lumbar degenerative changes not only can lead to disc dysfunction and lumbar spinal canal stenosis, but also may affect the stability of the motion segment and abnormal activity which can also further exacerbate the intervertebral disc degeneration. Intervertebral disc degeneration is the first step of the spinal degeneration. degeneration of intervertebral disc is the premise and basis pathological process of a series of lumbar degenerative disease such as disc herniation, degenerative spondylolisthesis, spinal stenosis and segmental instability.When the pathological changes above occur,spine,nerve root and cauda equian will be compressed,and lead to meropresthesia, muscle weakness and sphincter disturbances. Cervicodynia, lumbodynia or radiating ache in underbody will occur if nerve root is compressed and become inflamed,or stimulation of sinuvertebral nerve ending. At present, it has clearly that process of intervertebral disc degeneration mean water and proteoglycan is reducing, type I collagen is increasing within the nucleus pulposus,it lead to reduction of loading capacity of intervertebral discThe exact mechanism attracted lumbar intervertebral disc degeneration is still inconclusive. The occurrence of lumbar disc degeneration in addition to the traditional mechanical factors, neuro-psychological factors and biochemical factors, but also closely related to immune response. The cytokines and inflammatory mediators had played an increasingly important role in intervertebral disc degeneration.The important role of neovascularization in intervertebral disc degeneration process is inconclusive. Some scholars abroad believed that the angiogenesis was the body trying to repair tissue damage and the spontaneous reaction to delaying the process,because passive diffusion of nutrients from endplate and anulus fibrosus decrease. However,others believed that the disc vascularization caused disc degeneration occurs because matrix-degrading zymogens get activity from blood,and it was the pathological basis of disc degeneration, so it was harmful to the body.Cyclooxygenase-2(COX-2) factor is a multifunctional protein, there are at least two isomerase of cyclooxygenase in mammals:COX-1and COX-2.COX-2is a inducible protein, and it is highly expressed in many malignant tissues, which closely related to tumor angiogenesis,beside,COX-2is a rate-limiting enzyme to catalysts arachidonic acid into prostaglandins material. COX-2has Various ways to regulate tumor angiogenesis process,such as up-regulation of VEGF and bel-2. Metabolite of arachidonic acid such as TXA2and PGE2,which can induce angiogenesis, moreover,COX-2can inhibits endothelial cells apoptosis. The study found that selectively COX-2inhibitors has significant inhibition of gastric cancer angiogenesis.There are no vessel in normal intervertebral disc,but it is very common in degenerative disc. Some studies have shown that factor COX-2expression was significantly higher in degenerative intervertebral disc tissue than in normal disc. So,whether the role of COX-2factor played in the vascularization of intervertebral disc degeneration as well as in the formation of vascular structure in tumor tissue?Hypoxia-inducible factor-1(HIF-1α) is an oxygen-dependent transcriptional activator and can trigger the transcription of downstream genes through a hypoxia response element (HRE) binding. HIF-1α is an important molecule for cells to adapt to the hypoxia. Diffusion of nutrients decrease lead to insufficient supply of nutrients and relatively hypoxic environment in degenerative intervertebral disc. some scholars have confirmed that the expression of HIF-1α was significantly higher than the normal disc by the method of the immunohistochemistry. When the tumor grows rapidly, it will definitely lead to serious local tissue hypoxia and induce the expression of HIF-la. HIF-la is thought be involved in new blood vessel formation in tumors by the following ways:(1)Start-up stage,it up-regulate VEGF and it’s ligand result in increased permeability of the vessel.(2) Progressing stage,it up-regulate MMPs,and promote VEGF to induce vascular endothelial cell proliferation and migration,with the help of angiopoietin, form a new vessels sprout.(3) Forming stage,with the help of VEGF, angiopoietin and integrin,a single vessels sprout form vascular lumen,and anastomosis into vascular network with some small blood vessels near.(4) Modeling stage, with the help of plateletderivedgrowthfactor, angiopoietin, form a intact vascular wall. So,does HIF-1α in the degenerative intervertebral disc promote the formation of blood vessels by similar ways?ObjectiveCOX-2and HIF-la is highly expressed in many malignant tumor tissues,and they are closely related to the neovascularization.Some scholars thought neovascularization in intervertebral disc is an important factor of degeneration. The expression of COX-2and HIF-1α have even been confirmed in the human intervertebral disc.However, combineing measurement of COX-2and HIF-1α is still haven’t performed in previous Studies.Therefore, combineing measurement of COX-2and HIF-1α,and exploreing the expression correlation of these two factors in degenerative intervertebral disc tissue and the correlation with the neovascularization in degenerative intervertebral disc are the objective of this study. Methods20rats of3months old were divided into experiment group and control group randomly.The10rats of experiment group were excised spinous process, articular process, supraspinal ligament, interspinal ligaments and erector spinae surgically,then were kept separately.The rats of control group without operation,and were kept in the same condition as experiment group.12weeks later,all rats were sacrificed,intervertebral discs of L4/5were obtained,and then were sliced to H&E stained pathological sections. The intervertebral discs of normal and degenerative were compared microscopically. The degenerative intervertebral discs were sliced to immunohistochemistry stained pathological sections. We detected the expression of COX-2, HIF-la and capillaries in degenerative intervertebral discs. Correlationship of COX-2and HIF-1α was described by using linear correlation analysis,also,the correlationship of COX-2, HIF-la and MVD was described by using multiple linear regression analysis.Result1. All rats is survived before the trial period expires.2. Optical microscopy resultsAfter the normal nucleus pulposus tissue sections of control group stained by HE dyed, we can see that the thickness of collagen fibers are uniform and arranged parallel to each other. And we could even see a small amount types of chondrocytes under the optical microscopy. But in the experiment group, the collagen fibers of intervertebral disc were disarrangement with significant hyperplasia. Hyaline degeneration and large number of honeycomb-like, vesicle-like cavities and cracks can be seen in nucleus pulposus matrix.3. Immunohistochemical resultsThe immunohistochemical dyed revealed that the expression of COX-2and HIF-la in the normal disc were both too weak to be observed, but they significantly increased in the degenerated nucleus pulposus. The positive expression of COX-2can be observed in most of the cytoplasm,and there are new formation of blood vessels.The positive expression of HIF-1α in degenerated intervertebral disc can be observed in most of the cytoplasm or nucleus. The microvessel density(MVD)was determined by immunohistochemical SP method using a monoclonal antibody to CD34, positive expression of endothelial cells are brown microscopically.4. Statistical resultsAll data was analyzed with SPSS statistical software.The expression of COX-2and HIF-1α in degenerative intervertebral disc tissue had a significant positive correlation by the linear correlation analysis (P=0.027, r=0.690). The expression of COX-2and HIF-1α in degenerative intervertebral disc tissue had a significant correlation with MVD by multiple linear regression analysis (P=0.00057).Multiple correlation coefficient (R2=0.875), standardized partial regression coefficient of COX-2is0.496, standardized partial regression coefficient of HIF-la is0.517.Conclusions1. The expression of COX-2factor and HIF-la factor in the rats’degenerated nucleus pulposus tissue significantly increased.2. There was a positive correlation between the expression of COX-2factor and HIF-1α factor in rats’degenerated nucleus pulposus tissue.3. There was a positive correlation between the expression of MVD and HIF-la factor in rats’degenerated nucleus pulposus tissue.4. There was a positive correlation between the expression of MVD and COX-2factor in rats’degenerated nucleus pulposus tissue. |
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