| Background dataThe lumber disc hernia(LDH) is the leading disease in the spine surgery. Intervertebral disc degeneration(IVDD) is the main pathological reason. the dehydration of the gel-like nucleus pulposus, progressive fibrosis of the annulus fibrosus has been presented in the aging.Nucleus pulposus and annulus fibrosus gradually disappearing boundaries of the original definition. In fact, almost 80% of adults will encounter some form of back pain in their lifetimes. The degeneration of the disc is the leading cause of back pain. But its exact pathogenesis has not yet clearly.Past studies have shown that Genetic factors,biomechanics and biochemistry elements are relevant with IVDD。Recently, the fundamental research of disc degeneration has been focused on immunology and genetic aspects,the immunological research of Matrix metalloproteinase investigated that the disorder of synthesis and degradation of the matrix caused by MMPS is one of the reasons for the loss of the disc biomechanics, the expression of Hypoxia-inducible factor-1α(HIF-1α) have been detected in the herniated disc of the human beings in current report. HIF-1αcould be another impact factor on the reabsorption and the generation of the disc cells. No paper about the correlation between HIF-1αand MMP-2, the mechanism of the two factor involved in the process of disc degeneration, has been published. We performed the comparison of the expression of the HIF-la and MMP-2 in both normal and degenerated disc to reveal the disc degeneration further.ObjectiveTo investigate the expression of the HIF-la and MMP-2 in the disc with different degree of degeneration and to evaluate the significance and the correlation of the two factors in the process of the degeneration。Materials and MethodsAll the materials were drawn from the spinal surgery departments of the third affiliated hospitaof the Southern Medical University during jan,2008 to june,2009.Experimental group contained 45 cases diagnosed as LDH,Male 33 cases, female 12cases. The mean age is 31.5 years old(range from 20 to 40), the course of the disease range form 3 months to 10years;L4/L5 disc herniation in 23 cases, L5/S1 disc herniation 20 cases, L4/L5, L5/S1 disc herniation in 2 cases. Nucleus pulposus inside the annulus fibrosis were removed as main materials. Based on preoperative MRI imaging, the degenerated nucleus pulposus has been divided into 3 groups. Group A:Disc signal intensity slightly reduced, Group B:Disc signal intensity moderate reduced; Group C: Disc signal intensity disappeared. Control group included 12cases,male 10 cases, female 2 cases, The mean age is 31.5 years old(range from 20 to 40).The normal nucleus pulposus which was removed during the anterior decompression was obtained from young patients with spinal fracture. T2 weighted imaging presented disc uniform high signal intensity on preoperative MRI imaging.All samples were rinsed thoroughly in 0.9%NaCl to remove blood right after the surgical Procedure, and soaped in 4% formalin within 3 min.After fixed for 24 hours, samples were embedded in paraffin wax, then sectioned to 5 um thick slices.Immunostaining method was used to detect the expression level of HIF-1αand MMP2.Since HIF-1αand MMP2 are located in the cytoplasm,the presence of these proteins is correlated with brown grains in the cytosol when observed under microseope. The cell counting was performed under the microscope by two Pathologist.10 fields were randomly selected and the number of cells was counted.protein expression level was showed as the percentage of positive staining cells. All the data were analyzed by SPSS 13.0 software package for the significance test and the correlation analysis. The P value was set at 0.05.ResultThe result of the immunohistochemical test showed HIF-1αand MMP-2 were sited at the cytoplasm, the positive result of the cartilage cell displayed the Brown yellow or brown granules in the cytoplasm, the coloring of the nucleolus is light blue. The expression of HIF-1α,MMP-2 in the experimental group is significant higher than the control group (P<0.05),meanwhile, the expression in the disc with different degree of degeneration varied (P<0.05) it is significant difference.r=0.959, the expression of the HIF-1αand MMP-2 in the degeneration of the intervertebral disc was positively correlated.ConclusionsHIF-1αand MMP-2 are both important impact factors involved in the degeneration of the human beings lumber disc. The expression of the HIF-1αand MMP-2 in the degeneration of the disc was positively correlated. With the coordinating of MMP-2HIF-1αcould be a regulated element of MMP-2 to promote the intervertebral disc degeneration.
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