Study on the mechanism of action of different synovial cell-derived inflammatory exosomes on chondrocytes after lipopolysaccharide intervention / 安徽医科大学学报

Objective To observe the effect of different synovial cell secretions on chondrocytes after LPS-induced inflammation,and to explore the mechanism of two synovial cell secretions causing cartilage damage in the progres-sion of KOA disease.Methods Two kinds of synovial cells were co-cultured at 1∶4 and LPS-induced inflamma-tion.The supernatant and exocrine were extracted,and then the normal and LPS-induced inflammation were extrac-ted.The human cartilage tissue obtained during the operation was isolated and cultured into chondrocytes,which were divided into five groups:the first group was added with FLS secretion,the second group was added with nor-mal FLS secretion,the third group was added with secretion after co-culture of two kinds of synovial cells,the fourth group was added with inflammatory MLS secretion,and the fifth group was added with inflammatory FLS se-cretion.CCK-8 was used to detect the viability of chondrocytes in each group.TNF-α,IL-1β,IL-6 level in the su-pernatant of chondrocytes in each group was detected by ELISA.The protein expression of TLR4,NF-κB,IkK,IκB,ADAMTS5 in chondrocytes of each group was detected by Western blot method.Results CCK-8 showed that the activity of chondrocytes in the three groups of inflammatory secretions decreased compared with the secretions from normal synovial cells(P＜0.05);ELISA showed TNF-α,IL-1 β,IL-6 level in the supernatant of group Ⅲ,Ⅳ and V was higher than that of group Ⅰ and Ⅱ(P＜0.05),TNF-α,IL-1 β,IL-6 level in group Ⅲ was higher than that in group Ⅳ but lower than that in group Ⅴ(P＜0.05).Western blot showed the protein expression of TLR4,NF-κB,IkK,IκB,ADAMTS5 in chondrocytes of group Ⅲ,Ⅳ and Ⅴ was higher than that in group Ⅰ and Ⅱ(P＜0.05),the protein expression of TLR4,NF-κB,IkK,IκB,ADAMTS5 in group Ⅲ was higher than that in group Ⅳbut lower than that in group Ⅴ(P＜0.05).Conclusion Two kinds of synovial cell-derived secretions after LPS-induced inflammation can regulate cartilage TLRs/NF-κB signal pathway,causing cartilage inflammation.The in-flammatory effect of MLS secretion is stronger than that of FLS secretion,but the inflammatory effect of MLS secre-tion under two co-cultures is weaker than that of MLS secretion alone.

Effect of modified citrus pectin on glycolysis of rabbit articular chondrocytes / 国际生物医学工程杂志

Objective:To investigate the effect of modified citrus pectin (MCP) on the glucose metabolism of rabbit articular chondrocytes.Methods:The third generation (P3) rabbit knee chondrocytes were extracted and cultured with 0 μg/ml (MCP0, control group) and 500 μg/ml of MCP (MCP500) for 3 days. Chondrocytes (P2-P7)were cultured continuously, and each generation of chondrocytes was treated with MCP0 and MCP500 medium for 3 days. Chondrocytes were treated with interleukin-1β (IL-1β) for 1 day and then treated with MCP0 and MCP500 medium for 3 days, respectively. Chondrocytes were treated with 2-deoxy-glucose (2DG) for 1 day and then treated with MCP0 and MCP500 medium for 3 days, respectively. After three days of culture, the proliferation of chondrocytes was calculated by CCK-8. Glucose uptake activity and lactate production of chondrocytes were measured by glucose and lactate detection kits. The synthesis of type Ⅱ collagen (COL2A1) in sequential chondrocytes was investigated by immunofluorescence staining. The gene expression of COL2A1, proteoglycan ( ACAN), SOX9, hypoxia-inducible factor-1α ( HIF-1α), glucose transporter-1 ( Glut-1), pyruvate kinase M2 ( PKM2), lactate dehydrogenase-A ( LDHA) and glucose transporter-1 ( Glut-3) were further detected by RT-qPCR. Results:Compared with the control group, MCP treatment could increase the glucose uptake activity and lactate production of chondrocytes, and enhance the gene expression ability of HIF-1α, Glut-1, PKM2 and ACAN. Besides, MCP treatment could stimulate chondrocyte proliferation, maintain chondrocyte phenotype, increase lactate production, and upregulate the expression of COL2A1, ACAN, SOX9, HIF-1α, Glut-1, PKM2 and LDHA. After the treatment with IL-1β, MCP treatment could increase glucose uptake activity and upregulate the expression of COL2A1, ACAN, HIF-1α and Glut-1. After treatment with 2DG, MCP treatment could increase glucose uptake activity and upregulate the expression of SOX9, HIF-1α, PKM2 and Glut-3 genes. Conclusions:MCP can enhance the glucose uptake capacity of chondrocytes and increase the level of chondrocyte glycolytic metabolism.

Tetrandrine attenuates IL-1β-induced injury of human articular chondrocytes in vitro / 基础医学与临床

Objective To investigate the effect of tetrandrine(Tet)on injury of primary human articular chondro-cytes induced by interleukin-1β(IL-1β).Methods Human articular chondrocytes were divided into control group,IL-1β group,hypoxia inducible factor(HIF-1α)inhibitor group[2-methoxyestradiol(2-ME2)group],Tet groups containing low,medium and high concentrations.Each group has six replicated samples.MTT assay was used to de-tect the viability of cells;cell apoptosis was detected by flow cytometry;the level of inflammatory related factors like tumor necrosis factor-α(TNF-α),matrix metalloproteinase 3(MMP-3),inducible nitric oxide synthase(iNOS),cyclooxygenase-2(COX-2)and the activity of antioxidant factors like super oxide dismutase(SOD)and glutathione peroxides(GPx)in cells were detected by ELISA;Western blot was used to detect the expression of HIF-1α and VEGF in cells.Results Compared with the control group,the apoptosis rate,level of TNF-α,MMP-3,iNOS,COX-2 and the protein expression of HIF-1α and VEGF in IL-1β group all increased,the cell survival rate and the activity of SOD and GPx significantly decreased(P＜0.05);compared with IL-1β group,the apoptosis rate,the level of TNF-α,MMP-3,iNOS,COX-2 and the protein expression of HIF-1α and VEGF in 2-ME2 group and Tet groups with low,medium,and high concentration significanthy decreased(P＜0.05).The cell survival rate and the activity of SOD and GPx significantly increased(P＜0.05).Conclusions Tetrandrine attenuates IL-1β-in-duced injury of human articular chondrocytes.

Effects of biological clock gene Bmal1 on the expression of cell cycle-associated genes in chondrocytes / 基础医学与临床

Objective To explore the intrinsic relationship between circadian clock and cell cycle in osteoarthritis(OA)chondrocytes,especially the regulation of cell cycle-related genes by the clock gene Bmal1.Methods The chondroid ATDC5 cells induced by insulin-transfering-selenium(ITS)were divided into control group,OA group and LV-Bmal1 group.The cell viability of each group was detected by CCK8 method.The expression of Bmal1,Per1,Wee1,Cdk1,Ccnb1 and Mmp13 mRNA in each group was detected by RT-qPCR.The expression of BMAL1,PER1,WEE1,CDK1,CCNB1 and MMP13 protein in each group was detected by Western blot.The effects of Bmal1 on different stages of cell cycle and apoptosis was analyzed by flow cytometry.The regulation of Bmal1 on Per1,Wee1,Cdk1,Ccnb1 and Mmp13 and their roles in OA were analyzed.Results Compared with the normal group,the cell viability of the OA group was increased,the relative mRNA expression of Bmal1 and Wee1 in the OA group decreased,and the relative mRNA expression of Per1,Cdk1,Ccnb1 and Mmp13 increased signif-icantly.The cell viability of LV-Bmal1 group decreased,the relative expression of Bmal1 and Wee1 mRNA in-creased,and the relative expression of Per1,Cdk1,Ccnb1 and Mmp13 mRNA decreased(P＜0.05).Correlation analysis showed that Bmal1 was positively correlated with Wee1 and they were negatively correlated with Per1,Cdk1,Ccnb1 or Mmp13.The results of Western blot showed that protein expression in different groups were con-sistent with the trend of PCR.The results of cell cycle and apoptosis showed that compared with the normal group,the S phase and G2/M phase of the OA group were shortened,the proportion of cells decreased significantly,and the proportion of early and late apoptosis increased.The S phase and G2/M phase of the LV-Bmal1 group were prolonged,the proportion of cells was increased,and the proportion of early and late apoptosis was decreased.Conclusions Circadian clock gene Bmal1 in inflammatory chondrocytes might regulate the expression of cell cycle-related genes.

Acupotomy prevents knee osteoarthritis in rats by modulating chondrocyte apoptosis in the mitochondrial pathway / 中国组织工程研究

BACKGROUND:Acupotomy is effective in the treatment of knee osteoarthritis,but its mechanism is not very clear. OBJECTIVE:To observe the effect of acupotomy on the apoptosis of knee chondrocytes in knee osteoarthritis rats based on osteoclast associated receptor(OSCAR)-tumor necrosis factor-associated apoptosis-inducing ligand(TRAIL)-osteoprotetin(OPG)pathway. METHODS:Twenty-seven Sprague-Dawley rats were randomly divided into normal group(n=9),model group(n=9)and acupotomy group(n=9).Rats in the normal group were routinely housed without any treatment.Animal models of knee osteoarthritis were established by knee injection of papain.Acupotomy intervention was performed 1 week after modeling,once a week for a total of three times.Relevant tests were performed at the end of the intervention. RESULTS AND CONCLUSION:The Lequesne MG behavioral scores of rats in the model group were elevated compared with the normal group(P<0.01),while the Lequesne MG behavioral scores of rats in the acupotomy group were decreased comparedwith the model group(P<0.01).Hematoxylin-eosin staining results showed that compared with the normal group,the cartilage surface of the rat's knee joints in the model group was worn and uneven and the chondrocytes were swollen,ruptured,reduced in number,and arranged disorderly;while the cartilage surface of the rat's knee joints in the acupotomy group was relatively smooth,and the chondrocytes were high in number and arranged in an orderly manner,with the structure basically clear.Immunohistochemical staining results showed that compared with the normal group,the positive expressions of OSCAR and TRAIL were increased in the model group(P<0.01),while the positive expression of OPG was decreased(P<0.01).Compared with the model group,the positive expressions of OSCAR and TRAIL in the acupotomy group were decreased(P<0.01),while the positive expression of OPG was increased(P<0.01).TUNEL staining results showed that compared with the normal group,the number of apoptotic cells in the model group were increased(P<0.01);compared with the model group,the number of apoptotic cells in the acupotomy group decreased(P<0.01).RT-qRCR and western blot results showed that compared with the normal group,the protein expressions of OSCAR,TRAIL and Bax in the model group were increased(P<0.01),and the protein expressions of OPG and Bcl-2 were decreased(P<0.01);compared with the model group,the protein expressions of OSCAR,TRAIL,and Bax in the acupotomy group were decreased(P<0.01),and the protein expressions of OPG and Bcl-2 were increased(P<0.01).To conclude,acupotomy can reduce cartilage injury of the knee joint in rats with knee osteoarthritis,which may be related to the blockage of mitochondrial pathway apoptotic signaling release by the OSCAR-TRAIL-OPG pathway.

Investigation of the hydromechanical threshold of high-mobility group box 1 release from synovial cells and chondrocytes / 口腔疾病防治

Objective@#To investigate the effect of fluid flow shear stress (FFSS) on the fluid mechanic threshold of high-mobility group box 1 (HMGB1) release by synovial cells and chondrocytes. Moreover, the mechanism of chondrocyte and synovial cell damage induced by abnormal mechanical force was investigated to provide an experimental basis for exploring the pathogenesis and pathology of temporomandibular joint osteoarthritis.@*Methods@#With the approval of the Ethics Committee for Animal Experiments of the hospital, synovial tissue and cartilage tissue blocks were obtained from the knee joints of Sprague-Dawley (SD) rats, and synovial cells and chondrocytes were cultured and digested for subsequent experiments. Synovial cells and chondrocytes of 3-4 generations were acquired, and FFSS was applied to synovial and cartilage cells using a fluid shear mechanical device. The cells were divided according to the FFSS values of different sizes. Synovial cells were stimulated for 1 h with 1, 3, 5, or 10 dyn/cm2 of FFSS, and chondrocytes were stimulated for 1 h with 4, 8, 12, or 16 dyn/cm2 of FFSS. Resting cultures (0 dyn/cm2) were used as the control group. Changes in the morphology of the cells were observed. The expression and distribution of HMGB1 and interleukin-1β (IL-1β) were observed by immunohistochemistry. The expression of HMGB1 and IL-1β in the supernatant was analyzed by ELISA. The protein expression levels of intracellular HMGB1 and IL-1β were detected by Western blot.@*Results@#With increasing FFSS, the synovial cells and chondrocytes gradually swelled and ruptured, and the number of cells decreased. With increasing FFSS, the localizationof HMGB1 and IL-1β gradually shifted from the nucleus to the cytoplasm. In synovial cells, compared with those in the control group, the expression levels of HMGB1 and IL-1β were increased both in the supernatant and cells in the 1, 3, 5 and 10 dyn/cm2 intervention groups (P<0.01). In chondrocytes, compared with those in the control group, the expression levels of HMGB1 in the supernatant were increased in the 4, 12 and 16 dyn/cm2 intervention groups (P<0.05), and the protein expression levels of HMGB1 were significantly increased (P<0.01). The expression levels of HMGB1 in the supernatant were significantly increased in the 8 dyn/cm2 intervention groups (P<0.01); however, the protein expression levels of HMGB1 were significantly decreased. Compared with those in the control group, the expression levels of IL-1β in the supernatant gradually increased in the 4, 8, 12 and 16 dyn/cm2 intervention groups (P<0.01). With the exception of those in the 4 dyn/cm2 group, the protein expression levels of IL-1β gradually increased with increasing FFSS (P<0.05).@*Conclusion@#With increasing FFSS, synovial cells and chondrocytes gradually swelled and burst, and the hydromechanical thresholds of HMGB1 release were 1 dyn/cm2 and 8 dyn/cm2, respectively. Therefore, upon stimulation with a mechanical force, synovial damage was damaged before chondrocytes.

Network pharmacology and molecular docking to study the mechanism of action of alpinumisoflavone in a temporomandibular joint osteoarthritis cell model / 口腔疾病防治

Objective@#To explore the potential role of alpinumisoflavone (AIF) in the treatment of temporomandibular joint osteoarthritis (TMJOA) cell model through network pharmacology and molecular docking and to provide a research basis for AIF in the treatment of TMJOA.@*Methods@#GeneCards, OMIM, DisGeNET, and PharmGKB databases were used to screen TMJOA disease targets, and PharmMapper and HERB were used to retrieve AIF-related targets. The intersection targets of the compounds and diseases were uploaded to the STRING database to obtain the key targets for GO and KEGG enrichment analysis, while the key targets in related signaling pathways were evaluated through molecular docking. Approval was obtained from the Ethics Committee to extract condylar chondrocytes from 3-week-old SD rats. The CCK-8 assay was used to detect AIF cytotoxicity on condylar chondrocytes. Condylar chondrocytes were induced with 10 ng/mL interleukin 1β (IL-1β) for 24 h to construct a TMJOA cell model. The experiment was divided into three groups: control group, comprising condylar chondrocytes cultured in DMEM for 48 h; IL-1β group, comprising condylar chondrocytes pre-cultured in DMEM for 24 h, after which IL-1β was added to the original culture medium to obtain a medium concentration of 10 ng/mL and allowed to culture for 24 h; and the IL-1β+10 μmol/L AIF group, comprising condylar chondrocytes pre-cultured in DMEM medium containing 10 μmol/L AIF for 24 h, after which IL-1β was added to the original culture medium to obtain a medium concentration of 10 ng/mL and allowed to culture for 24 h. The effect of AIF on condylar chondrocyte apoptosis in the TMJOA cell model was detected by flow cytometry. The experiment was divided into four groups: control group, IL-1β group, IL-1β+10 μmol/L AIF group, and IL-1β+30 μmol/L AIF group. The IL-1β+30 μmol/L AIF group was pre-cultured in DMEM containing 30 μmol/L AIF for 24 h, after which IL-1β was added to the original culture medium to obtain a medium concentration of 10 ng/mL and allowed to culture for 24 h. The remaining three groups were cultured in the same manner as before. The mRNA and protein expression of apoptosis-associated B-cell leukemia/lymphoma-2 (Bcl2), cysteinyl aspartate specific protease 3 (caspase-3), matrix degradation-associated a disintegrin and metalloproteinase with thrombospondin motifs 4 (ADAMTS4), matrix metalloproteinase 3 (MMP3), and matrix metalloproteinase 13 (MMP13) were detected by qPCR and western blot, by AIF in the TMJOA cell model.@*Results@#The PharmMapper and HERB database search yielded 300 AIF compound targets. The GeneCards, OMIM, DisGeNET, and PharmGKB databases yielded 378 TMJOA disease targets. Thirty-three potential common targets were obtained by intersecting compounds with disease targets. The common targets were uploaded into the STRING database to obtain 31 key targets that were mainly associated with apoptosis and extracellular matrix degradation. This process may be associated with the MAPK, estrogen, and TNF signaling pathways. The molecular docking results showed that AIF has good binding activity with extracellular signal-regulated kinase 1/2 (ERK1/2) and estrogen receptor gene 1/2 (ESR1/2), which are key targets in the MAPK and estrogen signaling pathways. The CCK-8 assay showed that AIF had no obvious cytotoxicity to condylar chondrocytes. The cell experiments showed that AIF inhibited apoptosis in the IL-1β+10 μmol/L AIF group compared to the IL-1β group. Compared to the IL-1β group in the IL-1β+10 μmol/L AIF group and the IL-1β+30 μmol/L AIF group, AIF upregulated Bcl2 and downregulated caspase-3 mRNA and protein expression and inhibited ADAMTS4, MMP3, and MMP13 mRNA and protein expression.@*Conclusion@#AIF inhibited apoptosis in the TMJOA cell model by upregulating Bcl2 and downregulating caspase-3 mRNA and protein expression, and inhibited extracellular matrix degradation induced by IL-1β, thereby delaying TMJOA progression.

Effects of VX765 on osteoarthritis and chondrocyte inflammation in rats / 中国修复重建外科杂志

OBJECTIVE@#To investigate the effects and underlying mechanisms of VX765 on osteoarthritis (OA) and chondrocytes inflammation in rats.@*METHODS@#Chondrocytes were isolated from the knee joints of 4-week-old Sprague Dawley (SD) rats. The third-generation cells were subjected to cell counting kit 8 (CCK-8) analysis to assess the impact of various concentrations (0, 1, 5, 10, 20, 50, 100 μmol/L) of VX765 on rat chondrocyte activity. An in vitro lipopolysaccharide (LPS) induced cell inflammation model was employed, dividing cells into control group, LPS group, VX765 concentration 1 group and VX765 concentration 2 group without obvious cytotoxicity. Western blot, real-time fluorescence quantitative PCR, and ELISA were conducted to measure the expression levels of inflammatory factors-transforming growth factor β 1 (TGF-β 1), interleukin 6 (IL-6), and tumor necrosis factor α (TNF-α). Additionally, Western blot and immunofluorescence staining were employed to assess the expressions of nuclear factor erythroid 2-related factor 2 (Nrf2) and heme oxygenase 1 (HO-1). Thirty-two SD rats were randomly assigned to sham surgery group (group A), OA group (group B), OA+VX765 (50 mg/kg) group (group C), and OA+VX765 (100 mg/kg) group (group D), with 8 rats in each group. Group A underwent a sham operation with a medial incision, while groups B to D underwent additional transverse incisions to the medial collateral ligament and anterior cruciate ligament, with removal of the medial meniscus. One week post-surgery, groups C and D were orally administered 50 mg/kg and 100 mg/kg VX765, respectively, while groups A and B received an equivalent volume of saline. Histopathological examination using HE and safranin-fast green staining was performed, and Mankin scoring was utilized for evaluation. Immunohistochemical staining technique was employed to analyze the expressions of matrix metalloproteinase 13 (MMP-13) and collagen type Ⅱ.@*RESULTS@#The CCK-8 assay indicated a significant decrease in cell viability at VX765 concentrations exceeding 10 μmol/L ( P<0.05), so 4 μmol/L and 8 μmol/L VX765 without obvious cytotoxicity were selected for subsequent experiments. Following LPS induction, the expressions of TGF-β 1, IL-6, and TNF-α in cells significantly increased when compared with the control group ( P<0.05). However, intervention with 4 μmol/L and 8 μmol/L VX765 led to a significant decrease in expression compared to the LPS group ( P<0.05). Western blot and immunofluorescence staining demonstrated a significant upregulation of Nrf2 pathway-related molecules Nrf2 and HO-1 protein expressions by VX765 ( P<0.05), indicating Nrf2 pathway activation. Histopathological examination of rat knee joint tissues and immunohistochemical staining revealed that, compared to group B, treatment with VX765 in groups C and D improved joint structural damage in rat OA, alleviated inflammatory reactions, downregulated MMP-13 expression, and increased collagen type Ⅱ expression.@*CONCLUSION@#VX765 can improve rat OA and reduce chondrocyte inflammation, possibly through the activation of the Nrf2 pathway.

Effects of the fat mass and obesity-associated gene on apoptosis and the inflammatory response of chondrocytes in osteoarthritis / 中华老年医学杂志

Objective:To explore the effects of the fat mass and obesity-associated gene(FTO)on apoptosis and the inflammatory response of chondrocytes in osteoarthritis(OA).Methods:Differences in FTO expression between normal human cartilage tissue samples and OA cartilage tissue samples were examined.Primary OA chondrocytes were isolated and cultured, and a rat OA model was constructed.The expression of FTO was detected in clinical, animal and cellular samples.Cells were treated with an FTO knockdown lentivirus vector(sh-FTO)and an m 6A methylation inhibitor(cycloleucine). The amount of m 6A and the expression levels of inflammatory cytokines, interleukin-6(IL-6)and tumor necrosis factor-α(TNF-α), were detected.Flow cytometry was used to detect apoptosis in OA chondrocytes, and Western blot was used to detect the expression levels of B-cell lymphoma 2(Bcl-2)and Bcl-2-associated X protein(Bax). Results:Compared with the normal control group, FTO mRNA and protein expression in human OA cartilage tissue, rat OA cartilage tissue and OA chondrocytes was significantly increased(all P<0.05). After FTO knockdown, the level of m 6A increased, the levels of IL-6 and TNF-α decreased considerably, the apoptosis rate decreased, the expression of the proapoptotic protein Bax decreased considerably, and the expression of Bcl-2 increased considerably in primary OA chondrocytes.However, cycloleucine intervention clearly reduced the level of m6A, increased the levels of IL-6 and TNF-α, promoted cell apoptosis and the expression of apoptosis-related proteins, and reversed the effect induced by the FTO knockdown lentivirus in OA chondrocytes(all P<0.05). Conclusions:FTO may be involved in mechanisms related to the action of m 6A to promote OA chondrocyte apoptosis and the inflammatory response, thus accelerating the progression of OA.

Down-regulation of long noncoding RNA HOXA11-AS nullifies the impact of microRNA-506-3p on chondrocytes proliferation and apoptosis in osteoarthritis

Abstract Objectives This study was directed towards exploring the impacts of lncRNA HOXA11-AS-mediated microRNA (miR)-506-3p on chondrocytes proliferation and apoptosis in osteoarthritis (OA). Methods The articular cartilages were provided by OA patients who received total knee arthroplasty, and Human Chondrocyte (HC)-OA (HC-OA) was also attained. The miR-506-3p and HOXA11-AS expressions in articular cartilages from OA patients and HC-OA cells were analyzed via qPCR. After gain- and loss-of-function assays in HC-OA cells, MTT assay and flow cytometry (FC) were used for assessing cell viability and apoptosis, accordingly. The levels of PIK3CA, AKT, and mTOR as well as AKT and mTOR phosphorylation levels assessed using western blotting (WB). The targeting correlation of HOXA11-AS and miR-506-3p as well as miR-506-3p and PIK3CA was assessed through Dual-Luciferase Reporter gene Assay (DLRA). Result The articular cartilages from OA patients and Human Chondrocyte (HC)-OA (HC-OA) cells showed increased HOXA11-AS and decreased miR-506-3p. Mechanistically, HOXA11-AS was capable of binding to miR-506-3p to increase PIK3CA, the target gene of miR-506-3p. miR-506-3p suppression facilitated HC-OA cell proliferation and reduced their apoptosis, which was nullified by further silencing HOXA11-AS or silencing PIK3CA. The down-regulation of HOXA11-AS disrupted the PI3K/AKT/mTOR pathway, which was counteracted by further miR-506-3p inhibition. Conclusion The silencing of HOXA11-AS might block the PI3K/AKT/mTOR pathway through miR-506-3p up-regulation, thereby restricting HC-OA cell proliferation and provoking apoptosis.

Tanshinone IIA alleviates IL-1β-induced chondrocyte apoptosis and inflammation by regulating FBXO11 expression

Abstract Objective This study explored the pharmacological mechanism of Tanshinone IIA (TAN IIA) in the treatment of Osteoarthritis (OA), which provided a certain reference for further research and clinical application of Tan IIA in OA. Methods CHON-001 cells were stimulated with 10 μg/mL IL-1β for 48 h and treated with 10 μM TAN IIA for 48 h. Cellular viability and apoptosis were evaluated by CCK-8 assay and flow cytometry, and Cleaved caspase-3 was measured by Immunoblot assay and RT-qPCR. TNF-α, IL-6, and iNOS in CHON-001 cells were determined by RT-qPCR and ELISA. To further verify the effect of TAN IIA on OA, a rat model of OA in vivo was established by right anterior cruciate ligament transection. TAN IIA was administered at 50 mg/kg or 150 mg/kg for 7 weeks. The degree of cartilage destruction in OA rats was observed by TUNEL and HE staining. Cleaved caspase-3 and FBXO11 were measured by immunohistochemical staining, RT-qPCR, and Immunoblot. TNF-α, IL-6, and iNOS in chondrocytes of OA rats were detected by ELISA. Results IL-1β stimulated CHON-001 cell apoptosis and inflammation, and TAN IIA had anti-apoptosis and anti-inflammatory effects on IL-1β-regulated CHON-001 cells. TAN IIA down-regulated FBXO11 and inhibited PI3K/AKT and NF-κB pathways, thereby alleviating apoptotic and inflammatory reactions in CHON-001 cells under IL-1β treatment. Moreover, TAN IIA treatment improved chondrocyte apoptosis and inflammations in OA rats. Conclusion TAN IIA inhibits PI3K/Akt and NF-κB pathways by down-regulating FBXO11 expression, alleviates chondrocyte apoptosis and inflammation, and delays the progression of OA.

Treatment of Chondral Lesions in the Knee / Tratamento das lesões condrais no joelho

Abstract Articular cartilage injuries are common and lead to early joint deterioration and osteoarthritis. Articular cartilage repair techniques aim at forming a cartilaginous neo-tissue to support the articular load and prevent progressive degeneration. Several techniques are available for this purpose, such as microfracture and chondrocyte transplantation. However, the procedural outcome is often fibrocartilage, which does not have the same mechanical resistance as cartilaginous tissue. Procedures with autologous osteochondral graft have a morbidity risk, and tissue availability limits their use. As such, larger lesions undergo osteochondral transplantation using fresh or frozen grafts. New techniques using minced or particulate cartilage fragments or mesenchymal stem cells are promising. This paper aims to update the procedures for treating chondral lesions of the knee.

Resumo As lesões da cartilagem articular são comuns e levam à deterioração precoce da articulação e ao desenvolvimento da osteoartrite. As técnicas de reparo da cartilagem articular visam a formação de um neo-tecido cartilaginoso capaz de suportar carga articular e evitar a progressão da degeneração. Há várias técnicas disponíveis para esse fim, como a microfratura e o transplante de condrócitos. Entretanto muitas vezes o desfecho do procedimento é a formação de fibrocartilagem, que não possui a mesma resistência mecânica do tecido cartilaginoso. Em outros procedimentos, nos quais é realizado enxerto osteocondral autólogo, há risco de morbidade associada ao procedimento, além da disponibilidade limitada de tecido. Por esse motivo, o transplante osteocondral, utilizando enxertos a fresco ou congelados tem sido utilizado para lesões de maior volume. Por fim, novas técnicas utilizando fragmentos de cartilagem picada ou particulada, assim como o uso de células tronco mesenquimais se apresentam como promissores. O objetivo desse artigo é realizar uma atualização dos procedimentos para tratamento das lesões condrais do joelho.

Effects of Tuina on cartilage degradation and chondrocyte terminal differentiation in rats with knee osteoarthritis (KOA) via the Wnt/β-catenin signaling pathway / 针灸推拿医学（英文版）

Objective: To investigate the therapeutic effects of Tuina (Chinese therapeutic massage) in a knee osteoarthritis (KOA) rat model and its influence on proteins associated with the Wnt/β-catenin signaling pathway. Methods: A total of 32 specific-pathogen-free grade Sprague-Dawley rats were used. Eight rats were randomly selected as the control group (CG). The remaining 24 rats underwent intra-articular injections with 0.2 mL of 4％ papain to prepare the KOA rat models. After the model was established, the 24 rats were randomly and equally assigned to 3 groups, including a model group (MG), a Tuina group (TG), and a positive medicine group (PMG), with 8 rats in each group. The Lequesne score was applied to evaluate the success of model development. After the model was successfully established, the CG did not receive any intervention, and the TG was treated with local, clockwise annular Rou-Kneading around the knee joint with the thumbs. The pressure in the longitudinal direction was 3 N, and the frequency was designed to be 120-140 times/min for 15 min, followed by flexing the joint 10 times. The PMG was intragastrically administered with celecoxib [24 mg/(kg·bw)] every day. These interventions were performed once a day, 6 d per week, for a total of 4 weeks. After treatment, the Lequesne score was applied again to assess the severity of the KOA in the rats; hematoxylin-eosin (HE) staining and a mixture of equal volumes of aqueous solutions of safranin O-fast green were used to stain and observe the cartilage morphology and structure; the modified Mankin score was applied to evaluate the pathology; enzyme-linked immunosorbent assay method was used to quantify the C-telopeptide fragments of type Ⅱ collagen (CTX-Ⅱ) and cartilage oligomeric matrix protein (COMP); Western blotting was then applied to quantify Wnt4, β-catenin, matrix metalloproteinase 13 (MMP-13), and bone morphogenetic protein 2 (BMP-2) protein expression; immunohistochemistry was conducted to determine the percentage of collagen type X (ColX)-positive cells. Results: The Lequesne score of the TG and PMG was both lower than that of the MG (P<0.01); the HE staining, safranin O-fast green stained morphology and structure, and modified Mankin scores of the TG and the PMG were also better than those in the MG (P<0.01). Compared with the CG, the amounts of CTX-Ⅱ and COMP in the serum were significantly increased (P<0.01); the expression of Wnt4, β-catenin, MMP-13, and BMP-2 proteins in the cartilage tissue was significantly increased (P<0.01), and the percentage of ColX-positive chondrocytes was significantly increased (P<0.01) in the MG. In comparison with those in the MG, the amounts of CTX-Ⅱ and COMP were significantly decreased (P<0.01), the expression of Wnt4, β-catenin, MMP-13, and BMP-2 proteins was significantly decreased (P<0.01), and the percentage of ColX-positive chondrocytes was significantly decreased (P<0.01) in the TG and PMG. Compared with the PMG, the contents of CTX-Ⅱ and COMP and the expression of Wnt4, β-catenin, MMP-13, and BMP-2 proteins were decreased (P<0.05 or P<0.01); the percentage of ColX-positive chondrocytes was significantly decreased (P<0.01) in the TG. Conclusion: Tuina can relieve the degeneration of KOA, and the mechanism may be related to the down-regulation of the Wnt/β-catenin signaling pathway, the decrease in MMP-13 and BMP-2 protein expression, the reduction in chondrocyte extracellular matrix degradation, and slowing down the terminal cell differentiation.

Effect of aloperine on chondrocyte injury induced by interleukin-1β and its mechanism / 中国生物制品学杂志

@#Objective To investigate the effect of aloperine(ALO)on interleukin-1β(IL-1β)-induced chondrocyte injury and its mechanism. Methods Chondrocytes were randomly divided into control(Con)group,IL-1 β group,IL-1β + ALO-L(25 mg/L)group,IL-1β + ALO-M(50 mg/L)group and IL-1 β + ALO-H(100 mg/L)group;Con group,IL-1βgroup,IL-1β + miR-NC group and IL-1β + miR-16-5p group;Con group,IL-1β group,IL-1β + si-NC group and IL-1β + siSOX5 group. Cells in IL-1β group were treated with 10 ng/mL IL-1β,while no treatment was given in Con group. The transcription levels of miR-16-5p and SOX5 mRNA in chondrocytes were detected by qRT-PCR;The contents of IL-6,TNF-αand IL-1β were detected by ELISA;The expression levels of Bcl-2,Bax and SOX5 protein were detected by Western blot and the apoptosis was detected by flow cytometry. Results Compared with IL-1 β group,the contents of IL-6,TNF-α and IL-1βin IL-1β + ALO-L group,IL-1β + ALO-M group and IL-1β + ALO-H group decreased significantly(t = 5. 002～20. 653,each P < 0. 001),the apoptosis rate decreased significantly(t = 5. 473～17. 371,each P < 0. 001),the expression level of Bcl-2 protein increased significantly(t = 7. 800～16. 100,each P < 0. 001),and the expression level of Bax protein decreased significantly(t = 4. 993～14. 311,each P < 0. 001);The mRNA transcription level of miR-16-5p gene increased significantly(t = 6. 688～16. 545,each P < 0. 001),while the mRNA transcription level and protein expression level of SOX5 gene decreased significantly(t = 4. 609～15. 393,each P < 0. 001). Compared with the IL-1β + miR-NC group,the mRNA transcription level of miR-16-5p in the IL-1β + miR-16-5p group increased significantly(t = 17. 106,P < 0. 001),the contents of IL-6,TNF-α and IL-1 β decreased significantly(t = 15. 030～20. 013,each P < 0. 001),the apoptosis rate decreased significantly(t = 12. 273,P < 0. 001),the expression level of Bcl-2 protein increased significantly(t = 15. 652,P < 0. 001),and the expression level of Bax protein decreased significantly(t = 12. 999,P < 0. 001). Compared with IL-1β +si-NC group,the expression level of SOX5(t = 13. 444,P < 0. 001),IL-6,TNF-α and IL-1β in IL-1β + si-SOX5 group decreased significantly(t = 14. 087～17. 103,each P < 0. 001),the apoptosis rate decreased significantly(t = 11. 991,P < 0. 001),the expression level of Bcl-2 protein increased significantly(t = 13. 864,P < 0. 001),and the expression level of Bax protein decreased significantly(t = 11. 818,P < 0. 001). Conclusion Alo inhibited the apoptosis of chondrocytes induced by IL-1β,thus reducing the injury of chondrocytes,of which the mechanism might be regulating the expression of miR-16-5p and SOX5 and the secretion of inflammatory factors in chondrocytes.

Matrix Stiffness Affects Mitochondrial Heterogeneity of Tibial Plateau Chondrocytes in Knee Osteoarthritis / 医用生物力学

Objective To investigate the difference of matrix stiffness in different regions of tibial plateau in osteoarthritis (OA) and its effects on morphology of the cartilage and mitochondria. Methods The tibial plateau cartilage specimens of OA were obtained for nanoindentation test, transmission electron microscopy and histological analysis. The stiffness of cartilage matrix in different regions of OA tibial plateau was detected by nano-indentation. The morphology of cartilage mitochondria in different regions was observed by transmission electron microscopy, and the changes of mitochondrial plane area, shape and ridge volume density were quantitatively analyzed. Cartilage injury in different regions of OA tibial plateau was observed by histological staining. Results The cartilage of OA tibial plateau showed regional heterogeneity, and the cartilage and mitochondria on medial side of varus knee OA were more severe, and the matrix stiffness was higher. The OA scores were positively correlated with matrix stiffness. There was also a significant correlation between OA scores and mitochondrial morphology: the higher OA scores, the larger and rounder mitochondrial plane area, and the lower cristae volume density. Conclusions The differences of tibial plateau revealed the correlation between cartilage matrix stiffness, OA scores and mitochondrial morphological parameters. The increased cartilage matrix stiffness may be the main cause of chondrocyte mitochondrial injury, and further aggravate the progression of OA.

The role and mechanism of MMP13 and LRP1 in abnormal autophagy function of articular chondrocytes in patients with Kashin-Beck disease / 中华地方病学杂志

Objective:To investigate the impact of matrix metalloproteinase 13 (MMP13) and low-density lipoprotein receptor-related protein 1 (LRP1) on autophagy of articular chondrocytes in patients with Kashin-Beck disease (KBD).Methods:Human articular cartilage samples obtained from 4 KBD patients and 4 control subjects were collected from Shaanxi Institute for Endemic Disease Prevention and Control, and the expression levels of MMP13 and LRP1 in cartilage tissue were determined using immunohistochemistry (IHC). Chondrocytes were extracted and cultured in vitro, the mRNA and protein expression levels of LRP1 and the autophagy related genes [Beclin 1 (BECN1), microtubule associated protein 1 light chain 3 (LC3)], cartilage injury related genes [MMP13, caspase-3 (CASP3)], chondrocyte differentiation related genes [collagen type Ⅱ alpha 1 chain (COL2A1), and SRY-box transcription factor 9 (SOX9)] were detected by real-time fluorescence quantitative PCR (qRT-PCR) and Western blot (WB), respectively. Chondrocytes from 3 KBD patients were extracted, and MMP13 gene silencing experiment was performed by RNA interference (RNAi) technology, the mRNA and protein expression levels of the above genes were detected by qRT-PCR and WB, respectively. In addition, the antagonist receptor associated protein (RAP) of LRP1 was used to block the LRP1 of human normal chondrocytes (C28/I2 cells), and qRT-PCR and WB were used to detect the mRNA and protein expression levels of LRP1, chondrocyte autophagy, differentiation and cartilage injury related genes, respectively. Results:The IHC results showed that the expression levels of MMP13 (1.67 ± 0.21, 0.59 ± 0.15, 0.51 ± 0.12) in the surface, middle, and deep layers of cartilage tissue of KBD patients were significantly higher than those of control subjects (0.25 ± 0.03, 0.26 ± 0.04, 0.06 ± 0.01), and the differences were statistically significant ( t = - 11.38, P < 0.001; t = - 3.82, - 6.26, P = 0.019, 0.003). The expression levels of LRP1 (0.10 ± 0.02, 0.03 ± 0.01, 0.17 ± 0.03) were significantly lower than those of control subjects (1.63 ± 0.40, 0.44 ± 0.12, 0.34 ± 0.08), and the differences were statistically significant ( t = 6.61, 5.61, 3.64, P = 0.003, 0.005, 0.022). The mRNA and protein expression levels of MMP13, CASP3, SOX9 in chondrocytes of KBD patients were significantly higher than those of control subjects, and the differences were statistically significant ( P < 0.05). The mRNA expression levels of LRP1, LC3, COL2A1 were significantly lower than those of control subjects, and the differences were statistically significant ( P < 0.05). After silencing the MMP13 gene in chondrocytes of KBD patients, there were no significant differences in the mRNA and protein expression levels of LRP1, BECN1, LC3, CASP3, COL2A1, and SOX9 ( P > 0.05). After blocking LRP1 with RAP, the protein expression levels of LRP1, BECN1, LC3, MMP13, COL2A1 and SOX9 in chondrocytes were significantly lower than those in control group ( P < 0.05). Conclusions:There is no direct correlation between MMP13 and abnormal autophagy of articular chondrocytes in KBD patients. After blocking LRP1, the expression of the autophagy related genes BECN1 and LC3 in chondrocytes is decreased.

Research progress of cell transplantation in the treatment of osteochondral lesions of the talus / 中华创伤杂志

Osteochondral lesions of the talus (OLT) frequently manifest following ankle joint trauma, causing ankle pain, swelling and impaired mobility, thereby significantly impeding daily activities of the patients. Presently, clinical treatment approaches encompass both conservative management and surgical intervention. Conservative management endeavors to alleviate symptoms, while patients experiencing persistent symptoms resort to surgical intervention. Commonly employed surgical treatments encompass bone marrow stimulation, autologous osteochondral transplantation, and allogeneic osteochondral transplantation. Bone marrow stimulation is employed as a therapeutic approach for the management of smaller OLT, demonstrating favorable short-term effectiveness; however, the long-term prognosis remains uncertain. Autologous osteochondral transplantation is a viable option for larger OLT lesions, albeit it carries the potential of complications at the donor site. Conversely, allogenic osteochondral transplantation exhibits a diminished success rate. In recent times, the utilization of cell transplantation techniques has garnered escalating interest in the treatment of OLT due to their capacity to regenerate cartilage resembling hyaline and their diverse range of cellular origins. The authors reviewed the progress of cell transplantation in the treatment of OLT, providing a reference for the clinical treatment.

A study on the biological effects of electromagnetic pulse with different high⁃intensity on condylar cartilage in rats / 口腔疾病防治

Objective@#To explore the biological effects of electromagnetic pulse (EMP) with different high intensities on condylar cartilage in rats. @*Methods@#SD rats were randomly divided into a sham group (Sham) and an irradiation group (EMP1: 500 kV/m, 10 Hz; EMP2: 270 kV/m, 10 Hz). Then, they were sacrificed at 1 h, 3 h, 12 h, 24 h and 3 d after irradiation. The degree of cartilage degeneration was evaluated by HE, safranine O-fast green, type Ⅱ collagen immunohistochemistry and TUNEL staining. Immunohistochemistry and western blot were performed to detect the expression of the matrix degradation factors: matrix metalloproteinase-13 (MMP-13), a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS-5) and the apoptosis key factor cleaved-cysteinyl aspartate specific proteinase (cleaved-Caspase3) in condylar cartilage. @*Results @#HE staining showed that, compared with the Sham group, a small amount of exfoliation was found on the fibrous surface layer of the cartilage after irradiation in the EMP1 and EMP2 groups. Compared with the Sham group, the percentage of safranine O-fast green-positive area decreased significantly at 12 h and 24 h (both P<0.01) in the EMP1 group and 12 h and 24 h in the EMP2 group (both P<0.05); the percentage of type Ⅱ collagen-positive area decreased significantly at 3 h and 12 h (P<0.05, P<0.001) in the EMP1 group. In addition, the number of TUNEL-positive apoptotic cells increased significantly at 1 h, 3 h, 12 h, and 24 h in the EMP1 group and 1 h, 3 h, and 12 h in the EMP2 group (P<0.05). Moreover, at different timepoints (except at 3 d) in the EMP1 group and EMP2 group, the percentage of MMP-13, ADAMTS-5- and cleaved Caspase3-positive chondrocytes and their protein levels in condylar cartilage increased significantly after irradiation (P<0.05). @* Conclusion@# EMP with a certain degree of high-intensity can induce early transient damage to condylar cartilage. This effect is dose-and time-dependent.

Fracturas osteocondrales de la rodilla

Introducción: Las fracturas osteocondrales que afectan la articulación de la rodilla se presenta de forma aislada o asociada a otras afecciones traumáticas. El diagnóstico inicial es en ocasiones difícil de realizar por la convergencia de signos clínicos e imagenológicos. Objetivo: Brindar información actualizada sobre los elementos más importantes de esta enfermedad traumática. Métodos: La búsqueda y el análisis de la información se realizó en un periodo de 31 días (del primero al 31 de agosto de 2021) y se emplearon las siguientes palabras del idioma ingles: osteochondral lesions, osteochondral fractures, osteochondral injuries a partir de la información obtenida se realizó una revisión bibliográfica de un total de 315 artículos publicados en las bases de datos PubMed, Hinari, SciELO y Medline mediante el gestor de búsqueda y administrador de referencias EndNote. Resultados: Se hace referencia al mecanismo de producción, aspecto artroscópico, localización, características en cuanto a extensión, profundidad, clasificación y desplazamiento. Se describen las modalidades imagenológicas empleadas en el diagnóstico y su utilidad. Con relación al diagnóstico diferencial se describen un grupo de enfermedades con características similares. Se mencionan las modalidades de tratamiento basadas en el tamaño y tiempo de evolución. Conclusiones: Las fracturas osteocondrales son lesiones frecuentes, para su diagnóstico se necesita de un alto índice de sospecha, ya que el diagnóstico clínico e imagenológico inicial no son concluyentes en la mayoría de los pacientes por estar combinada con otras afecciones.

Introduction: Osteochondral fractures that affect the knee joint occur in isolation or associated with other traumatic conditions. The initial diagnosis is sometimes difficult to make due to the convergence of clinical and imaging signs. Objective: To provide updated information on the most important elements of this traumatic entity. Methods: The search and analysis of the information was carried out in a period of 31 days (from August the first to the 31st, 2021) and the following words of the English language were used: osteochondral lesions, osteochondral fractures, osteochondral injuries from the Information obtained, a bibliographic review of a total of 315 articles published in the PubMed, Hinari, SciELO and Medline databases was carried out using the EndNote search manager and reference manager. Results: Reference is made to the mechanism of production, arthroscopic appearance, location, characteristics in terms of extension, depth, classification and displacement. The imaging modalities used in diagnosis and their usefulness are described. Regarding the differential diagnosis, a group of entities with similar characteristics are described. Treatment modalities based on size and time of evolution are mentioned. Conclusions: Osteochondral fractures are frequent injuries, for their diagnosis a high index of suspicion is needed, since the initial clinical and imaging diagnosis are not conclusive in most patients because they are combined with other conditions.

Effect of Quercetin on LPS-induced Chondrocyte Matrix Metabolism and Inflammation by Activating Autophagy / 中国实验方剂学杂志

ObjectiveTo investigate the mechanism of quercetin in regulating chondrocyte extracellular matrix metabolism and inflammatory response in knee osteoarthritis （KOA） from the perspective of autophagy. MethodChondrocytes were extracted and cultured， and the primary cells were identified by immunofluorescence staining with collagen Ⅱ. The chondrocytes induced by lipopolysaccharide （LPS） were divided into a control group （without any treatment）， a model group （10 mg·L-1 LPS treatment for 48 h）， and low-， medium-， and high-dose quercetin group （10 mg·L-1 LPS treatment for 48 h combined with 50， 100， and 150 mmol·L-1 quercetin for 24 h）. The inhibitory effects of LPS （2.5， 5， 7.5， 10， 12.5 mg·L-1） on the proliferation of chondrocytes for different periods （24， 48， 72 h） were detected by cell counting kit-8 （CCK-8）. The effects of quercetin （50， 100， 150， 200 mmol·L-1） on the LPS-induced proliferation of chondrocytes for different periods （12， 24， and 48 h） were investigated. The expression of microtubule-associated protein 1 light chain 3Ⅱ （LC3Ⅱ） and ubiquitin-binding protein p62 was detected by Western blot. LPS-induced chondrocytes were treated with 3-methyladenine （3-MA）. The resultant cells were divided into a control group （without any treatment）， a model group （10 mg·L-1 LPS）， a quercetin group （model group + 100 mmol·L-1 quercetin）， a 3-MA group （model group + 100 μmol·L-1 3-MA）， and a 3-MA + quercetin group （model group + 100 μmol·L-1 3-MA + 100 mmol·L-1 quercetin， specifically， LPS for 48 h， 3-MA for 2 h， and then quercetin for 24 h）. The content of interleukin （IL）-1β and tumor necrosis factor （TNF）-α was determined by enzyme-linked immunosorbent assay （ELISA）. The protein expression of matrix metalloproteinase 13 （MMP-13） and tissue inhibitor of metalloproteinase 1 （TIMP1） was detected by Western blot. ResultCollagen Ⅱ immunofluorescence staining showed that the extracted cells were consistent with the characteristics of chondrocytes. As revealed by CCK-8， the optimum concentration of LPS was 10 mg·L-1 with an action time of 48 h， and the optimum concentration of quercetin was 100 mmol·L-1 with an action time of 24 h. Western blot results showed that compared with the control group， the model group showed decreased expression of LC3Ⅱ （P<0.01） and increased expression of p62 （P<0.01）. The expression of LC3Ⅱ in the quercetin groups was higher than that in the control group （P<0.01）， especially in the medium-dose quercetin group. The p62 expression in the quercetin groups was lower than that in the control group （P<0.01）， especially in the medium-dose quercetin group. Compared with the control group， the model group showed increased expression of MMP-13 （P<0.05） and decreased expression of TIMP1 （P<0.01）. Compared with the model group， the quercetin groups and the 3-MA + quercetin group showed decreased expression of MMP-13 （P<0.05， P<0.01）， especially the quercetin groups， and increased expression of TIMP1 （P<0.01）， especially the quercetin groups. Morphological changes in chondrocytes under the inverted microscope showed that quercetin could restore the morphology of damaged chondrocytes. CCK-8 showed that compared with the control group， the model group showed inhibited chondrocyte proliferation （P<0.01）， and compared with the model group， the quercetin groups and the 3-MA + quercetin group showed promoted chondrocyte proliferation （P<0.01）， especially the quercetin groups. ELISA results showed that IL-1β and TNF-α levels in the model group were higher than those in the control group （P<0.01）， and the levels of IL-1β and TNF-α in the quercetin groups and the 3-MA + quercetin group were lower than those in the model group （P<0.05， P<0.01）， and the decrease in the quercetin groups was the most significant. ConclusionQuercetin can promote LPS-induced chondrocyte proliferation， regulate chondrocyte extracellular matrix synthesis and metabolic balance， inhibit the inflammatory response， and restore chondrocyte function. The mechanism may be related to the activation of autophagy by quercetin.