Objective:To discuss the repairment effect of intra-articular injection of adipose derived stem cells(ADSCs)on articular cartilage destruction in the temporomandibular joint osteoarthritis(TMJOA)model rabbits,and to clarify the possible mechanism.Methods:Twenty-seven rabbits were randomly divided into control group,model group,and ADSCs group.The ADSCs of the rabbits were extracted and cultured.The rabbit TMJOA model was prepared by monosodium-iodoacetate(MIA)injection technique.The temporomandibular joint cavity of the TMJOA model rabbits in ADSCs group was given two continuous intra-articular injections of 1.0×106 mL-1 ADSCs,while the rabbits in control and model group were given sequivalent volume of saline into the temporomandibular joint cavity.After 8 weeks,Micro-CT scan was performed on the temporomandibular joints of the rabbits in various groups;the bone volume fraction(BV/TV),bone surface area/bone volume(BS/BV),trabecular thickness(Tb.Th),trabecular separation(Tb.Sp),and trabecular number(Tb.N)of condyles tissue of the rabbits in various groups were analyzed;HE staining was used to observe the pathomorphology of condyles tissue of the rabbits in various groups;immunohistochemistry was used to detect the localization and expression levels of SRY-related high mobility group box gene 9(SOX9),matrix metalloproteinase-13(MMP-13),and vascular endothelial growth factor(VEGF)proteins in condyles tissue of the rabbits in various groups;Western blotting method was used to detect the expression levels of SOX9,MMP-13,and VEGF proteins in condyles tissue of the rabbits in various groups.Results:The micro-CT scan results showed that compared with control group,the BV/TV,Tb.Th,and Tb.N of condyles tissue of the rabbits in model group were significantly decreased(P<0.05),while the BS/BV and Tb.Sp were significantly increased(P<0.05);compared with model group,the BV/TV,Tb.Th,and Tb.N in condyles tissue of the rabbits in ADSCs group were significantly increased(P<0.05),and the BS/BV and Tb.Sp were significantly decreased(P<0.05).The HE staining results showed that the condylar cartilage surface of the rabbits in control group was smooth with clear layers and intact structure;compared with control group,the surface of condyles tissue of the rabbits in model group was irregular with thickened hypertrophic layer and areas of cell depletion and clustering;compared with model group,the pathological damage of condyles tissue of the rabbits in ADSCs group was significantly decreased.The immunohistochemical staining results showed that compared with control group and ADSCs group,the number of brown granule in condyles tissue of the rabbits in model group was increased,mainly concentrated in the hypertrophic layer,especially in the bone cartilage junction site and the expression levels of SOX9,MMP-13,and VEGF proteins in condyles tissue of the rabbits in model group were significantly increased(P<0.05);compared with model group,the number of brown granule in condyles tissue of the rabbits in ADSCs group was significantly decreased,and the expression levels of SOX9,MMP-13,and VEGF proteins were significantly decreased(P<0.05).The Western blotting results showed that compared with control group,the expression levels of SOX9,MMP-13,and VEGF proteins in condyles tissue of the rabbits in model group were significantly increased(P<0.05);compared with model group,the expression levels of SOX9,MMP-13,and VEGF proteins in condyles tissue of the rabbits in ADSCs group were significantly decreased(P<0.05).Conclusion:Intra-articular injection of ADSCs can effectively repair the cartilage destruction in TMJOA,alleviate the cartilage injury,and mitigate the progression of osteoarthritis.