The Experiment About Pathological Changes And The Effect Of Cytokine In Subchondral Bone Remodeling During TMJOA

Objective: We establish rabbit model of TMJOA,to observe the pathologicalchange of articular cartilage and subchondral bone during the process of TMJOA. Todetect the expression change of Col Ⅱ,MMP9,sox9and CD44in subchondral bone.To study the role of subchondral bone with OA-like changes.Methods: Twelve New Zealand White Rabbit at5months of age wererandomly divided into experimental groups (Exp) and control groups, In theexperimental group was divided into4weeks,6weeks,8weeks group, a total ofthree groups, each group of three; control group, three. The collagenase-inducedTMJOA model was established. Respectively, experimental animals were sacrificedat the end of the4th,6th,and8th week after the beginning of the experiment. HE andAB-PAS staining were used for histological assessment. Usingimmunohistochemistry to detect the protein levels of Col Ⅱ,MMP9,sox9and CD44in subchondral bone.Results: Histological observation showed that the control of condylar cartilagesurface smooth, level clear; The cartilage cells were distributed evenly in the wholecartilage. Compared with the control group, the experimental group showedosteoarthritis pathological changes, eg: Cartilage fiber layer continuous destruction,cartilage level disorder, osteochondral boundary is not clear, the subchondraltrabecular bone morphology change. Immunohistochemical staining showed:4weeks after the beginning of the induction, the protein levels of Col II insubchondral bone were higher than control group.（P<0.05）,6weeks after thebeginning of the induction, the protein levels of sox9in subchondral bone wassignificantly increased（P<0.05）,8weeks after the induction, the protein levels ofMMP9and CD44in subchondral bone was significant increased（P<0.05）.At the same time, the protein levels of sox9in subchondral bone was further increased（P<0.05）.However the protein levels of Col II was significantly reduced.Conclusion:1. The histopathological changes in Collagenase-Induced Osteoarthritis RabbitModel were consistent with human TMJOA early pathological changes.2.In the early stage of OA, Col Ⅱ, CD44, MMP9, Sox9in subchondral bonemight play an important biological role during the development of OA and thecondylar cartilage restoring after articular cartilage degradation.