| BackgroundDisc degeneration disease usually results in primary low back pain and cervical or lumbar radiculopathy syndrome. In clinical, it is a very commonly disease, which has dramatic effect on people's health. The etiology of disc degeneration is still unclear, but series of research have showed that CEP degeneration may be the major cause of disc degeneration. Presently, the study of CEP degeneration is mostly limited to its morphologic change, however, the investigation of its etiology is too little. At present, it has been found that inflammatary cytokine?NO and apoptosis play an important role on the degeneration of disc and articular cartilage. While, several growth factor such as TGF-β?IGF- I can resist the role of inflammatary cytokine(IL-1β, IL-6, TNF-α), NO and apoptosis, which are easy to destroy the cartilage. The structure and biochemical characteristics of CEP is similar to article cartilage, therefore, it can be deduced that those factors may play the same role on CEP. With the study of those factors' role on disc degeneration, the relationship to them is expected to know and the main factor is expected to be clear. By using the growth factors, the progress of CEP degeneration tried to be retarded or prevented in order to provide newly methods to the treatment of disc degeneration.Objective(1) To explore the structure and biochemical changes of CEP in the induced degeneration by injuring the intervertebral stability of the lumbar spine. (2) To evaluate the role of different factors on the chondrocytes of CEP so as to define the interaction of those factors by the culture of chondrocytes in vitro. (3) To investigate the effect of retardment or prevention of growthfactors on CEP degeneration by applying growth factors to CEP and chondrocytes.Methods(1) 36 New Zealand rabbits were divided into experimental group and control group randomly. The experimental group model of lumbar CEP degeneration in rabbits was established by resection of all lumbar supraspinous and interspinous ligaments, excision of parts of zygapophysial joints and detachment of the posterior paravertebral muscles from lumbar vertebraes. The control group model was incised only the skin. All of the rabbits examined 12w?24w and 36w after operation by X-ray, scanning electron microscope, histopathologic study, the detection of content of NO and the activity of NOS, the content of IL-1, IL-6 and TNF-a, the detection of content of proteoglycan and the release of collagen.(2) The chondrocytes were isolated and harvested from the CEP of 8 porcines, The growth curve was drawn by MTT chromatometry. The biological phenomena was observed by light microscope and HE staining. Their biological characteristics were identified by toluidine blue and safranine O staining for proteoglycan and immunocytochemistry for type II collagen. After using sodium nitroprusside (2mmol/L) , IL-lp(10ng/ml), IL-6(50ng/ml), TNF-a(50ng/ml) and H2O2(200mol/l) respectively to stimulate chondrocytes, the content of IL-1?IL-6?TNF-a was measured by radioimmunoassay. The apoptosis was observed by PI or AO fluorescent staining and DNA fragment gel electrophoresis. The content of NO and the activity of NOS were measured by Griess reaction method. The proteoglycan synthesis was assessed by incorporation of radiolabelled sodium sulphate Na235SO4. The incorporation of 3H-proline was used to detect synthesis of collagen.(3) According to different time, the CEPs were achieved from the above animals after death. And then, the tissues were cultured with the growth factor such as TGF-1?IGF- I and TGF-1?with IGF- I . TGF- 1 or IGF-I was also applied to the chondrocytes of CEP. Then, with using the previous methods, the activity of NOS, the content of NO, the content of IL-1, IL-6, TNF-a and proteoglycan and the release of collagen were detected.Results(1) With the elapse of time, the CEP of experimental group had more serious calcification than that of the control group. The collagen fibers became thin and breakdo...
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