| Osteoarthritis is one of the most common diseases of the elderly population, due to the increase in the human lifespan, the incidence of osteoarthritis significantly increased, especially in overweight elderly population. More than50%of the population over60years, performance of osteoarthritis in X-ray. Its common pathological change is sclerosis of subchondral bone, around joint osteophyte formation and chronic synovitis, it decreased the quality of life of patients seriously with pain and dysfunction. Healthy cartilage is a kind of connective tissue without blood vessels, nerves, lymphatic vessels. The articular cartilage nutrition and oxygen supply is mainly through the synovial fluid and subchondral bone. The joint is a kind of physiology in hypoxia environment. Previous studies have shown that the oxygen partial pressure in the synovial fluid is only6.65-7.98Kpa, the oxygen concentration of the surface layer of cartilage is from7%to10%, The hypoxia increased as the depth increased, the deep cartilage oxygen content is only1%. Under normal circumstances, such a hypoxic environment is important to the normal articular cartilage physiological function. Bone arthritis lesions, certain cytokines and proteins such as TNF-a, IL-1of IL-17promote hyperplasia of the synovial fibroblasts, resulting in synovial proliferation. When the synovial tissue proliferation rate exceeds the corresponding angiogenesis rate and blood supply, the intra-articular pressure will further reduce and the intra-articular synovial hypoxia further aggravate. Yudoh k and his colleagues found when osteoarthritis occurs, the oxygen content of the cartilage surface is3%-8%, under conditions of hypoxia aggravated, many types of cells within the PHD-PHD-3significantly increased, thereby contributing to hypoxia inducible factor (hypoxia-inducible factor, HIF-1) increased gene expression.HIF-1is a nuclear transcription factors which regulated the expression of EPO (erythropoietin, EPO) in hypoxia-induced erythrocyte. It is a heterodimer composed of HIF-1α and HIF-1β. HIF-1α is a number of bHLH-PAS protein family. The structure of the HIF-1beta has a additional oxygen-dependent degradation domain, hence HIF-1beta is the characteristic subunits which play regulation effect during hypoxia. During severe articular hypoxia, HIF-la translocate from the cytoplasm to the nucleus, and bind to the DNA of vascular endothelial growth factor (VEGF), increase the expression of VEGF. VEGF is widely recognized as a kind of angiogenesis factors, which lead to endothelial cell proliferation and migration, or stimulate blood vessel growth via cycloxygenase-2(COX-2). When the vascular endothelial growth factor stimulated blood vessel growth, beta nerve growth factor and neuropeptide play to the role of promoting nerve growth, these new nerve grew along the new blood vessel, in the end, join with the new blood vessels and grow into cartilage, mecus and osteophytenis.New blood vessels improve the oxygen supply to the joints, but at the same time increase the Inflammatory infiltration in the joint, and the newborn nerve may aggravate the pain of osteoarthritis.Previous studies for osteoarthritis, mainly concentrated in the cartilage and subchondral bone. In recent years, it was discovered that the chronic synovitis of osteoarthritis played an important role in the pathogenesis. Early osteoarthritis (arthroscopic treatment patients) or late osteoarthritis (joint replacement patients), these patients presented with chronic synovitis. Synovitis occured in synovial cells secrete a variety of pro-inflammatory cytokines and cytokine-mediated downstream factors involved in cartilage damaging effects, IL-1β is one of the most important inflammatory cytokines in this process, It played an important role in the pathogenesis of osteoarthritis, it was mainly secreted from CD14+synovial macrophages, and stimulated cartilage cells and synovial cells to secrete PGE2(prostaglandin E2) and other inflammatory regulation, and further promoted synovial inflammation induced bone resorption. IL-1β was added to the chondrocytes in vitro, the inducible NO synthase (iNOS) was activated and produced a large amount of NO, NO, which is the downstream product of the IL-1β, was the major effector molecule of IL-1β in the cartilage. IL-1β significant influenced by the apoptotic Fas pathway of chondrocytes. IL-1β and TNF-a bound to the cell surface receptors, activated inflammatory signaling pathways, and finally activated nuclear factor kappa B (NF-κB)..The NF-κB is a transcription factor, which is stress-related stimulated, including excessive mechanical stress and ECM degradation products. Once activated, the NF-κB regulated many cytokines, chemokines, adhesion molecules and inflammatory mediators, the expression of MMPs and matrix-degrading enzymes. The activition of MMPs was depended on zinc ions protease superfamily. MMPs widely existed in the connective tissue with a high cracking activity to type Ⅱ collagen and proteoglycans in the cartilage extracellular matrix components. recent studies reported:IL-1beta increased the mRNA expression of the MMP-13,3in cartilage cells, inhibited type II collagen and proteoglycan synthesis. IL-1beta also promoted the anabolism of MMP1,3through the degradation of type II collagen, achieve the goal of destruction of articular cartilage. IL-1β upregulated expression of HIF-1α protein, raising the expression of the downstream gene VEGF to promote the proliferation of blood vessels in the synovial tissue, thus contributing to the inflammatory infiltration.In this study, the papain was injected into rabbit knee joint cavity, synovial tissue was cut from the knee after the completion of the modeling. In order to explore the relationship between the expression of IL-1β, HIF-1α, VEGF and OA, ELISA was used to determine the expression of osteoarthritis synovial IL-1β, VEGF and, Western blot was used to detect the expression of HIF-1α in experimental osteoarthritis synovium. HIF-1α expression in synovial tissues of rabbit knee osteoarthritis modelObjective1、The model of osteoarthritis was set up by injection of papain into the rabbit knee joint cavity,.2. At different times after the manufacturing model, observe the rabbit knee joint synovial and cartilage, Surgically harvested synovial tissue and preserved.3、Western blot detected HIF-1α expression in experimental osteoarthritis synovium and explore its significance.Materials and Methods30male New Zealand white rabbit was divided into6groups (experimental group A1, A2, A3; control group B1, B2, B3), each group included five rabbit, or10knees joint. In group A1, A2, A3,1.6%papain were injected into the rabbit model of knee osteoarthritis knee joint cavity seperately at1,4, and7days, control group B1, B2, B3, and physiological saline was injected in the knee joint cavity respectively at1,4, and7days as control.2,4and6weeks after the injection, the group A1B1, A2B2, and A3B3was sacrificed with gas embolism method. The animal knees were opened, and the hyperplasia of knee joint cavity synovial and cartilage degeneration were observed. The knee synovial tissue was harvested, quickly put in liquid nitrogen jar, and eventually into-80℃, after waiting for6weeks, synovial samples were collected, remove synovial tissue from the refrigerator, to join organizations pyrolysis liquid rapidly after grinding into slurry, Western blot detected experimental osteoarthritis synovial membrane of the expression of HIF-1alpha.ResultsIn control group B1, B2, B3, rabbit knee swelling, congestion, transparent synovial fluid, synovial tissue edema, hypertrophy, smooth articular cartilage translucent, pale blue; In group A1, A2, A3, rabbit knee swelling, the congestion significantly synovial fluid pale yellow turbid state A1synovial tissue slightly thickened, rough articular surface of the articular cartilage color gray, presented an early manifestation of osteoarthritis; Group A2synovial obvious thickening of the articular surface of the cartilage color gray,ulceration presented the osteoarthritis mid-performance; the group A3synovial was the thickest, severe adhesion of synovial tissue and femur cartilage defects and, partial cartilage exfoliative subchondral bone exposed, showing a late manifestation of osteoarthritis. Experimental group A1, A2, A3synovial expression of HIF-la, respectively, compared with the control group B1,B2,B3, the A1group> B1group, A2group> B2group, A3> B3group (all P<0.01the); Experimental group A1, A2, A3group synovial HIF-la expression differences were significant, A1<A2group, group A2A3group (P<0.05).ConclusionModeling in different periods, the rabbit knee showed early, middle, late performance of osteoarthritis knee synovial thickening HIF-la factor expression was positively correlated with the degree of knee synovial proliferation, HIF-la of differentially expressed with degenerative osteoarthritis. The research of IL-1β, VEGF expression in the model synovial tissue of rabbit knee osteoarthritisObjective1The model of osteoarthritis was set up by injection of papain into the rabbit knee joint cavity.(HIF-la protein and detection from the same animal model)2, IL-1β, VEGF expression was detected by ELISA in experimental osteoarthritis synovium to explore its significance.Materials and MethodsModeling and detection of HIF-la protein in the knee synovial tissue, adding buffer rapidly at-80℃save spare ground into homogenate packing to be completely Harvested specimens were frozen slide the membranous tissue removed using the ELISA method in experimental osteoarthritis synovial IL-1β expression of VEGF.Results Model group A1, A2, A3synovium in IL-1(3, VEGF expression with the control group B1, B2, B3group, A1Group> B1group, A2Group> B2group A3> B3group (all P<0.01); the model group A1, A2, A3group synovium in IL-1β, VEGF expression differences were significant group A1<A2group group A2A3group (P<0.05).Conclusions:With the progression of osteoarthritis, IL-1β,VEGF three factors expression gradually increased, the different expression of IL-1β and VEGF related to the degree of degenerative osteoarthritis. |
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