The Research Of Expression Relationship Between HMGB1and NF-κB In Rabbit Intervertebral Disc Degeneration

Objective:To investigate expression of High Mobility Protein Group Box-1and Nucleus factor-Kappa B in the end-plate of degenerative intervertebral disc and its significance.Methods:Japanese White Rabbit was chosen to be the laboratory animal as model to create intervertebral disc degeneration (IDD). The annulus fibrosus of models were damaged with needle of limited the type and depth; the animals were divided into anterior4weeks,8weeks,12weeks and24weeks group. L2-3, L3-4, L4-5segment was selected to undergo surgical intervention. The rabbits were killed at4weeks,8weeks,12weeks,24weeks after making model, intactly removed the affected discs as the experimental group, and L1-2L5-6that were non-affected as control group; HE staining of tissue sections was used to verify the disc degeneration from the view of histological. The standard of Thompson disc degeneration pathological grade was chosen to assess the degree of disc degeneration. HMGB1and NF-kB were detected by immunohistochemical double staining method for qualitative analysis in the degeneration of intervertebral disc tissue.Results.1. Results of tissue sections with HE staining showed that:in the control group, cartilage end plate structure was normal. Those in four weeks'intervention intradiscal group were seen that annulus fibrosus structural was disorder and cartilage endplate at the cellular level was unclear and disorganized; the nucleus pulposus of8weeks age group was shrinkage, annulus was fissures, calcification layer of cartilage endplate was thicken, the number of cells was reduced. Disc of 12weeks of age group was obviously degenerative, cartilage endplate calcification layer was significantly thicker,ossification,structural disorder, cartilage lacuna was disappear, and nucleus pulposus which was adjacent cartilage endplate was significantly degeneration and fibrosis. The disc degeneration of24weeks group were more pronounced, the nucleus pulposus and annulus were fissured, wide range of the cartilage endplate were hardened, and a large number of vertebral osteophyte were formation.2. The result of pathologic grade of Thompson disc degeneration:Ⅰ level mainly in the control group, Ⅱ level mainly was seen in4weeks group model,8weeks group model was Ⅲ level degeneration,12weeks group model was majority of Ⅳ grade degeneration and24weeks group model was seen in Ⅴ grade degeneration.3. Results of immunohistochemical double staining of HMGB1and NF-κB:Both had a small amount of expression in rabbit intervertebral disc endplate of the normal group; At4weeks of the model, the disc immunohistochemical double staining sections can be seen expression of HMGB1and NF-κB in a lot of cells, cell that single factor expresses was rarely seen, the matrix surrounding cells can also be seen expression of HMGB1. At the late stage of model (8weeks,12weeks,24weeks), the cells expression HMGB1and NF-κB alone were increased, the cells NF-κB expressed were decreased, while the cells HMGB1expressed were increased in the nucleus, cytoplasm and extracellular cells of co-expression were rare. Cells that HMGB1and NF-κB expression separately could be seen in the local area.Conclusion:1. The method of annulus layer acupuncture anteriorly could successfully induce the degeneration of corresponding segments of the intervertebral disc in rabbit and the degree of degeneration gradually increased with time.2. HMGB1may increase the expression of NF-κB via RAGE and TOLL-like receptors by the paracrine-like and/or autocrine-like form in the cartilage endplate of rabbit degenerative disc, 3. The reason that the expression of NP-kB in intervertebral disc degeneration reduced in late stage is related to the negative feedback regulation, the possible reason is that many inflammatory factors increased and lead to negative feedback regulation; the regulatory role of TLR2and TLR4and RAGE receptor is to be confirmed.