| 1. Creating animal model of intervertebral disc degeneration (IDD):30 Japanese White Rabbit were used in this study, each rabbit's discs at L3-4,L4-5,L5-6 were chose for model group, and the discs at L1-2,L2-3,L6-7 from the same rabbit for self-control group. And the method of damaging annulus fibrosus with needle of defined gauge and depth was used to establish animal model of rabbit intervertebral disc degeneration. The rabbits were respectively taken for x-ray and MRI examination in postoperative 4 weeks,8 weeks,12 weeks, then the rabbits were killed for disc samples at different time point, the morphology and micro-structure changes of samples were observed through visual study and tissue slice, and the establishment of disc degeneration model was assessed.2. Detecting the proteins of NF-κB and COX-2:The expressions of nuclear factorκB and Cyclooxygenase-2 in degenerated and controlled discs were detected through immunohistochemisty, and the expression of nuclear factorκB in Cartilage endplate were detected through western blotting.3. Statistic analysis:The immunohistochemisty tissue slices of NF-κB and COX-2 were analysed with Image pro plus6.0 soft ware, and the bands of NF-κB from western blotting were analysed with Quantity one soft ware. Then, the acquired data was analysed with SPSS 11.5 system.1. Compared with the control groups, the loss of disc height, calcification of end-plate, syndesmophyte formation of adjacent vertebrae bottom margin were detected by X-ray in 8 weeks and 12 weeks after opretion in model groups, and these changes were observed obviously in 12 weeks after operation. The decrease of water content and low signal intensity in experimental nucleus pulposus were revealed on T2-weighted MRI in 8 weeks and 12 weeks after opretion in model groups, and the low signal intensity was apparently in 12 weeks. Arranging disorder of annulus fibrosus, cell decrease and loss of water in nucleus pulposus were discovered in tissue slice, and these alterations became more serious from 4 weeks to 12 weeks after opration.2. The immunohistochemisty of samples showed NF-κB expressed in the cells of Cartilage endplate and nucleus pulposus of both control and model groups'discs, and COX-2 expressed in cells of Cartilage endplate. Moreover, the expressions of NF-κB and COX-2 in model groups are higher than control groups in postoperative 4 weeks and 8 weeks, and the expressions in postoperative 4 weeks is the highest, as the aggravated degeneration, their expressions have a downward trend.3. Western blotting showed NF-κB expressed in end-plate of both control and model groups'discs. Moreover, the expression of NF-κB in model groups are higher than control groups in postoperative 4 weeks and 8 weeks, and the expression in postoperative 4 weeks is the highest, as the aggravated degeneration, its expression has a downward trend. 1. The method of stabbing the disc annulus fibrosus could establish the animal model of intervertebral disc degeneration successfully.2. In the early phase of intervertebral disc degeneration, NF-κB may up-regulate the expressions of many inflammatory cytokines and activate apoptosis program in disc cells, which cause disc of inflammation and cell apoptosis, and then aggravate disc degeneration.3. In the early phase of intervertebral disc degeneration, COX-2 may take part in the inflammation of disc by upregulating the expression of PGE2 in the intervertebral disc cells and cause disc degeneration, or may upregulate the expression of VEGF which induces the formation of new blood vessels in discs after injury, and participate in the repair process of discs.4. The signal way of NF-κB may up-regulate the expression of COX-2 in disc cells, but the up-regulation expression of COX-2 by NF-κB needs other cytocines to participate, and the pure activation of NF-κB cannot lead to the expression of COX-2.
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