ObjectiveTo explore the potential mechanisms of action of the modified Duhuo Jisheng Mixture （JDJM） in treating synovial lesions in knee osteoarthritis （KOA）. MethodsA total of 43 male New Zealand white rabbits were randomly allocated into a blank group （n=8） and a model group （n=35）. The KOA model was induced by immobilizing the right hind limb with a high-molecular resin plaster bandage， with a modeling period of 6 weeks， resulting in successful modeling in 32 rabbits. These rabbits were then randomly allocated to the model group， celecoxib group， JDJM group and JDJM+740Y-P group， each consisting of 8 rabbits. The celecoxib group received celecoxib via gavage at a single dose of 0.009 3 g·kg^-1， while the JDJM was administered a single dose of 6.8 mL·kg^-1 （4.515 2 g·kg^-1） of the herbal preparation via gavage. The phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin （PI3K/Akt/mTOR） pathway activator + JDJM group received 4.515 2 g·kg^-1 of the herbal preparation via gavage along with an auricular vein injection of 0.15 μmol·kg^-1 740Y-P. For a period of 6 weeks， the remaining groups received an equal volume of physiological saline via gavage daily. After the medication period， the knee joint pain threshold and circumference were measured， and hematoxylin-eosin （HE） staining was performed to assess the pathological changes in the synovial tissues. Enzyme-linked immunosorbent assay （ELISA） measured the levels of interleukin-1β （IL-1β）， interleukin-6 （IL-18） and tumor necrosis factor-α （TNF-α） in the joint fluid. Real-time fluorescence quantitative polymerase chain reaction （Real-time PCR） was used to assess the mRNA expression of PI3K， Akt， mTOR， NOD-like receptor protein 3 （NLRP3）， cysteine-requiring aspartate protease-1 （Caspase-1） and gasdermin D （GSDMD） in the synovial tissues. Immunohistochemical （IHC） assay was performed to assess the protein expression of NLRP3， Caspase-1 and GSDMD. Western blot was carried out to analyze the protein expression of p-PI3K/PI3K， p-Akt/Akt， p-mTOR/mTOR， NLRP3， Caspase-1 and GSDMD. ResultsCompared to the blank group， the model group showed a significant increase in knee joint circumference and decrease in pain threshold， the synovial tissue pathology score was higher （P<0.05）， and the levels of IL-1β， IL-18， and TNF-α in the joint fluid significantly increased （P<0.01）. PI3K， Akt， mTOR phosphorylation as well as mRNA and protein expression increased （P<0.01）， while the mRNA and protein expression levels of NLRP3， Caspase-1 and GSDMD also significantly increased （P<0.01）. Compared to the model group， the celecoxib and JDJM groups exhibited a significant reduction in knee joint circumference and increase in pain threshold， the synovial tissue pathology score was lower （P<0.05）， and the levels of IL-1β， IL-18， and TNF-α in the joint fluid decreased （P<0.01）. The mRNA and protein expression of p-PI3K， p-Akt， p-mTOR， NLRP3， Caspase-1 and GSDMD were reduced （P<0.01）. Compared to the JDJM group， the JDJM+740Y-P group showed a decrease in the improvement of synovial lesions， an increase in knee joint circumference， and a decrease in pain threshold. The synovial tissue pathology score was lower （P<0.05）， and the levels of IL-1β， IL-18， and TNF-α in the joint fluid were higher （P<0.01）. The mRNA and protein expression of p-PI3K/PI3K， p-Akt/Akt， p-mTOR/mTOR， NLRP3， Caspase-1 and GSDMD increased （P<0.01）. ConclusionJDJM is effective in treating KOA. Its mechanism may involve modulating the PI3K/Akt/mTOR pathway in synovial tissues， inhibiting pyroptosis， reducing inflammatory factor release， and protecting bony structures.

Objective To explore the value of MR T2 mapping imaging in evaluation of the effection of Zhitong-Jiangu recipes in treatment of cartilage injury in osteoarthritis.Methods The models of osteoarthritis in the knee of New Zealand white rabbits were made with intra-articular injection of papain.Totally 48 New Zealand white rabbits were randomly divided into normal control group,model control group,glucosamine hydrochloride treatment group and Zhitong-Jiangu recipes treatment group.MR T2 mapping was performed on the knee and the content of MMP-1 in articular cartilage was analyzed with immunohistochemistry 4 weeks after treatment.The differences of T2 value and MMP-1 content of articular cartilage among the four groups were compared.The correlation among the different intervention methods,MMP-1 content of articular cartilage and the T2 value of articular cartilage were analyzed.Results T2 value of articular cartilage in the model control group was significantly higher than that in the other three groups (all P＜0.01),and there was no significant difference of T2 value among the other three groups.The MMP-1 content of articular cartilage in glucosamine hydrochloride treatment group and Zhitong-Jiangu recipes treatment group was lower than that in model control group (both P＜0.05),and was higher than that in normal control group (both P＜0.05).There was no significant difference between the two groups.The relationship between MMP-1 content and T2 value of articular cartilage was nonlinear.With the increase of MMP-1 content,T2 value first increased slowly and then increased rapidly (P＜0.05).Conclusion MR T2 mapping imaging is helpful to evaluating the efficacy of Zhitong-Jiangu recipes in treatment of cartilage injury in osteoarthritis in rabbit models.The relationship between MMP-1 content and T2 value of articular cartilage may be nonlinear.