OBJECTIVE To investigate the mechanism by which the traditional Chinese medicine formula Xibining Ⅱ modulates cold-stimulus pain sensitivity in rats with cold-damp obstruction-type knee osteoarthritis （KOA） based on the SET domain bifurcated histone lysine methyltransferase 2 （SETDB2）/histone H3 lysine 9 trimethylation （H3K9me3） signaling axis. METHODS Fifty SD rats were randomly divided into control group （intragastric administration and intrathecal injection of equal volumes of normal saline）， model group （intragastric administration and intrathecal injection of equal volumes of normal saline）， Xibining Ⅱ low- and high-dose groups （4， 8 g/kg Xibining Ⅱ， intragastric administration）， and high-dose of Xibining Ⅱ+small interfering RNA （siRNA） group （8 g/kg of Xibining Ⅱ via intragastric administration and intrathecal injection of SETDB2 siRNA at 0.2 mmol/L， 20 μL per rat）， with 10 rats in each group. Except for the control group， cold-damp obstruction-type KOA model was induced in other groups. Drug administration commenced 14 days post-modeling and continued for 28 days. Following the final administration， the following were assessed： behavioral changes in cold-stimulation pain sensitivity， histopathological changes in the articular cartilage of the knee joint， the contents of inflammatory factors [tumor necrosis factor-α （TNF-α）， interleukin-1β （IL-1β）] and pain mediators [calcitonin gene-related peptide （CGRP）， nerve growth factor （NGF）]， as well as the expressions of SETDB2/H3K9me3 signaling axis，inflammatory factors and pain mediators related proteins and mRNAs in dorsal root ganglion （DRG） tissue. RESULTS After 28 days of drug administration， compared with the model group， Xibining Ⅱ low- and high-dose groups exhibited significantly prolonged cold-stimulus paw withdrawal latency （P＜0.05）； the number of positive responses in the acetone low-temperature test was significantly reduced （P＜0.05）； Mankin score and the Osteoarthritis Research Society International score for knee joint tissue， as well as the levels of inflammatory factors and pain mediators in the serum and their expression in DRG tissue were all significantly decreased （P＜0.05）； the protein expressions of SETDB2 and H3K9me3 in DRG tissue were significantly increased （P＜0.05）. Intrathecal injection of SETDB2 siRNA reversed the above effects of high-dose of Xibining Ⅱ （P＜0.05）. CONCLUSIONS Xibining Ⅱ may alleviate inflammatory and pain responses by activating the SETDB2/H3K9me3 signaling axis， ultimately improving cold-stimulus pain sensitivity in rats with cold-damp obstruction-type KOA.

OBJECTIVE To explore the intervention mechanism of Shangke Lengtongtie on cold hyperalgesia in KOA mice based on the HMGB1/CXCL12/CXCR4 signaling axis.METHODS Monosodium iodoacetate(MIA)was used for the intra-articular injec-tion into the knee joint to establish mice model of knee osteoarthritis(KOA).Peripheral blood monocytes were extracted from mice,cultured,and then reinfused into the tail vein of the mice.Subsequently,in vivo animal imaging was used to observe the recruitment sites of these monocytes.The cold hyperalgesia threshold was measured at various time points in each group of mice.Hematoxylin and eosin(HE)staining was used to evaluate the level of synovial pathological changes.ELISA was employed to detect the expression of in-flammatory factors IL-1β,TNF-α,and pain mediators CGRP and Substance P in mouse serum.Western blot and qPCR methods were used to detect the protein and gene expression of cold hyperalgesia-related indicators such as TRPA1,TRPM8,HMGB1,CXCL12,CXCR4,Collagen Ⅰ,and Netrin-1 in synovial tissue,as well as DCC in dorsal root ganglia(DRG)tissue.RESULTS In vivo ima-ging showed that after the monocytes were reinfused into KOA mice,they were recruited to the knee joint area,with the HMGB1 group exhibiting a greater recruitment of circulating monocytes at the knee joint.Additionally,compared to the control group,the KOA group and HMGB1 group showed inflammatory pathological changes in the synovium,increased expression of serum inflammatory factors and pain mediators,reduced cold hyperalgesia threshold,and upregulated protein and gene expression of cold hyperalgesia-related indica-tors in synovial and DRG tissues.The changes were more significant in the HMGB1 group compared to the KOA group(P<0.05).Af-ter treatment with Shangke Lengtongtie or GL intervention,synovial inflammation was alleviated,serum inflammatory factors and pain mediators decreased,cold hyperalgesia threshold increased,and the upregulation of cold hyperalgesia-related indicator protein and gene expression levels was significantly reversed(P<0.05).CONCLUSION Shangke Lengtongtie exerts a beneficial effect on the mitigation of synovitis and cold hyperalgesia in KOA mice,a therapeutic mechanism that possibly mediated through the inhibition of the HMGB1/CXCL12/CXCR4 signaling axis.

AIM:To investigate whether Xibining Ⅱ(XBN Ⅱ)attenuates cartilage damage in rats with knee osteoarthritis(KOA)by modulating glycolysis via the AMP-activated protein kinase(AMPK)/peroxisome proliferator-acti-vated receptor γ coactivator 1α(PGC1α)signaling pathway.METHODS:Thirty-two SD rats were randomly divided into sham group,KOA group,XBN Ⅱ group and metformin(AMPK activator)group,with 8 rats in each group.The rats in KOA group were subjected to the anterior cruciate ligament transection procedure to establish the KOA model.Starting from the 14th day after modeling,the rats in XBN Ⅱ group received a daily dose of XBN Ⅱ via gavage once a day,and those in metformin group were administered metformin via intraperitoneal injection once a day for 4 weeks.Subsequently,the histopathological changes of the cartilage were examined by HE and safranin O-fast green staining with matching Mankin and OARSI scores.The protein levels of phosphorylated AMPK(p-AMPK)and PGC1α in cartilage were quanti-fied through immunohistochemistry.In addition,RT-qPCR and Western blot were conducted to measure the mRNA and protein expression levels of glycolysis-related factors,including glucose transporter 1,hexokinase 2 and lactate dehydroge-nase A,biomarkers related to cartilage synthesis and catabolism,such as collagen type Ⅱ,aggrecan,matrix metallopro-teinase 13 and a disintegrin and metalloproteinase with thrombospondin motifs 5,and AMPK/PGC1α signaling pathway-re-lated indicators.RESULTS:Lactate levels in cartilage and serum were higher in KOA group compared with sham group(P<0.05).Similarly,the cartilage in KOA group exhibited significant surface abrasion and structural damage,with faint-stained matrix and significantly higher Mankin and OARSI scores compared with sham group(P<0.05).Further analysis revealed significant decreases in the mRNA and protein expression levels of factors related to cartilage anabolism and AMPK/PGC1α signaling pathway in KOA group compared with sham group(P<0.05).In contrast,there were marked in-creases in the mRNA and protein expression levels of factors related to cartilage catabolism and glycolysis(P<0.05).No-tably,XBN Ⅱ and metformin treatments significantly improved the cartilage morphology,reduced Mankin and OARSI scores,and reversed the changes in mRNA and protein levels of the aforementioned indexes(P<0.05).CONCLU-SION:Treatment with XBN Ⅱ can alleviate cartilage damage in KOA rats by inhibiting glycolysis,through a mechanism involving activation of the AMPK/PGC1α signaling pathway.

AIM:This study aimed to investigate the inhibitory effects and potential mechanisms of cyasterone(CYA)on inflammation and apoptosis of chondrocytes in knee osteoarthritis(KOA).METHODS:A rat model of KOA was established through anterior cruciate ligament transection(ACLT).Rats were randomly divided into 5 groups(n=6 in each group):normal control(NC),ACLT,ACLT+CYA(10 mg/kg),ACLT+CYA+SR9009(BMAL1 inhibitor),and ACLT+CYA+LY294002(PI3K inhibitor).Pathological changes in cartilage were evaluated using hematoxylin-eosin(HE)and safranin O/fast green staining,graded according to the Osteoarthritis Research Society International(OARSI)system.Immunohistochemistry was employed to measure the expression levels of BMAL1,phosphorylated phosphati-dylinositol 3-kinase(p-PI3K),phosphorylated protein kinase B(p-AKT)and phosphorylated nuclear factor-κB(p-NF-κB)in cartilage.An in vitro KOA model was created by stimulating rat chondrocytes with interleukin-1β(IL-1β).Cell vi-ability was assessed using the CCK-8 assay,while enzyme-linked immunosorbent assay(ELISA)was used to quantify pro-inflammatory cytokines(IL-6,IL-1β and TNF-α).Apoptosis was analyzed via flow cytometry,and the protein expression levels of BMAL1,PI3K,p-PI3K,AKT,p-AKT,NF-κB and p-NF-κB were evaluated using Western blot.RESULTS:In vivo,the rats in ACLT group exhibited significant chondrocyte degradation and lacunae formation compared with NC group,confirming the successful establishment of the KOA model.The rats in ACLT+CYA,ACLT+CYA+SR9009 and ACLT+CYA+LY294002 groups showed improved cartilage integrity compared with ACLT group,with reduced OARSI scores(P<0.05),increased BMAL1 expression(P<0.05),and decreased levels of p-PI3K,p-AKT and p-NF-κB(P<0.05).In vitro,the chondrocytes in IL-1β+CYA,IL-1β+CYA+SR9009 and IL-1β+CYA+LY294002 groups exhibited lower levels of IL-6,IL-1β and TNF-α(P<0.05),decreased apoptosis rates(P<0.01),increased BMAL1 protein ex-pression(P<0.05),and reduced p-PI3K/PI3K,p-AKT/AKT and p-NF-κB/NF-κB ratios(P<0.05),compared with IL-1β group.CONCLUSION:Cyasterone alleviates chondrocyte inflammation and apoptosis in KOA by activating BMAL1,which subsequently inhibits the phosphorylation of PI3K/AKT/NF-κB signaling pathway.

AIM:To investigate whether Xibining Ⅱ(XBN Ⅱ)attenuates cartilage damage in rats with knee osteoarthritis(KOA)by modulating glycolysis via the AMP-activated protein kinase(AMPK)/peroxisome proliferator-acti-vated receptor γ coactivator 1α(PGC1α)signaling pathway.METHODS:Thirty-two SD rats were randomly divided into sham group,KOA group,XBN Ⅱ group and metformin(AMPK activator)group,with 8 rats in each group.The rats in KOA group were subjected to the anterior cruciate ligament transection procedure to establish the KOA model.Starting from the 14th day after modeling,the rats in XBN Ⅱ group received a daily dose of XBN Ⅱ via gavage once a day,and those in metformin group were administered metformin via intraperitoneal injection once a day for 4 weeks.Subsequently,the histopathological changes of the cartilage were examined by HE and safranin O-fast green staining with matching Mankin and OARSI scores.The protein levels of phosphorylated AMPK(p-AMPK)and PGC1α in cartilage were quanti-fied through immunohistochemistry.In addition,RT-qPCR and Western blot were conducted to measure the mRNA and protein expression levels of glycolysis-related factors,including glucose transporter 1,hexokinase 2 and lactate dehydroge-nase A,biomarkers related to cartilage synthesis and catabolism,such as collagen type Ⅱ,aggrecan,matrix metallopro-teinase 13 and a disintegrin and metalloproteinase with thrombospondin motifs 5,and AMPK/PGC1α signaling pathway-re-lated indicators.RESULTS:Lactate levels in cartilage and serum were higher in KOA group compared with sham group(P<0.05).Similarly,the cartilage in KOA group exhibited significant surface abrasion and structural damage,with faint-stained matrix and significantly higher Mankin and OARSI scores compared with sham group(P<0.05).Further analysis revealed significant decreases in the mRNA and protein expression levels of factors related to cartilage anabolism and AMPK/PGC1α signaling pathway in KOA group compared with sham group(P<0.05).In contrast,there were marked in-creases in the mRNA and protein expression levels of factors related to cartilage catabolism and glycolysis(P<0.05).No-tably,XBN Ⅱ and metformin treatments significantly improved the cartilage morphology,reduced Mankin and OARSI scores,and reversed the changes in mRNA and protein levels of the aforementioned indexes(P<0.05).CONCLU-SION:Treatment with XBN Ⅱ can alleviate cartilage damage in KOA rats by inhibiting glycolysis,through a mechanism involving activation of the AMPK/PGC1α signaling pathway.

OBJECTIVE To explore the intervention mechanism of Shangke Lengtongtie on cold hyperalgesia in KOA mice based on the HMGB1/CXCL12/CXCR4 signaling axis.METHODS Monosodium iodoacetate(MIA)was used for the intra-articular injec-tion into the knee joint to establish mice model of knee osteoarthritis(KOA).Peripheral blood monocytes were extracted from mice,cultured,and then reinfused into the tail vein of the mice.Subsequently,in vivo animal imaging was used to observe the recruitment sites of these monocytes.The cold hyperalgesia threshold was measured at various time points in each group of mice.Hematoxylin and eosin(HE)staining was used to evaluate the level of synovial pathological changes.ELISA was employed to detect the expression of in-flammatory factors IL-1β,TNF-α,and pain mediators CGRP and Substance P in mouse serum.Western blot and qPCR methods were used to detect the protein and gene expression of cold hyperalgesia-related indicators such as TRPA1,TRPM8,HMGB1,CXCL12,CXCR4,Collagen Ⅰ,and Netrin-1 in synovial tissue,as well as DCC in dorsal root ganglia(DRG)tissue.RESULTS In vivo ima-ging showed that after the monocytes were reinfused into KOA mice,they were recruited to the knee joint area,with the HMGB1 group exhibiting a greater recruitment of circulating monocytes at the knee joint.Additionally,compared to the control group,the KOA group and HMGB1 group showed inflammatory pathological changes in the synovium,increased expression of serum inflammatory factors and pain mediators,reduced cold hyperalgesia threshold,and upregulated protein and gene expression of cold hyperalgesia-related indica-tors in synovial and DRG tissues.The changes were more significant in the HMGB1 group compared to the KOA group(P<0.05).Af-ter treatment with Shangke Lengtongtie or GL intervention,synovial inflammation was alleviated,serum inflammatory factors and pain mediators decreased,cold hyperalgesia threshold increased,and the upregulation of cold hyperalgesia-related indicator protein and gene expression levels was significantly reversed(P<0.05).CONCLUSION Shangke Lengtongtie exerts a beneficial effect on the mitigation of synovitis and cold hyperalgesia in KOA mice,a therapeutic mechanism that possibly mediated through the inhibition of the HMGB1/CXCL12/CXCR4 signaling axis.

AIM:This study aimed to investigate the inhibitory effects and potential mechanisms of cyasterone(CYA)on inflammation and apoptosis of chondrocytes in knee osteoarthritis(KOA).METHODS:A rat model of KOA was established through anterior cruciate ligament transection(ACLT).Rats were randomly divided into 5 groups(n=6 in each group):normal control(NC),ACLT,ACLT+CYA(10 mg/kg),ACLT+CYA+SR9009(BMAL1 inhibitor),and ACLT+CYA+LY294002(PI3K inhibitor).Pathological changes in cartilage were evaluated using hematoxylin-eosin(HE)and safranin O/fast green staining,graded according to the Osteoarthritis Research Society International(OARSI)system.Immunohistochemistry was employed to measure the expression levels of BMAL1,phosphorylated phosphati-dylinositol 3-kinase(p-PI3K),phosphorylated protein kinase B(p-AKT)and phosphorylated nuclear factor-κB(p-NF-κB)in cartilage.An in vitro KOA model was created by stimulating rat chondrocytes with interleukin-1β(IL-1β).Cell vi-ability was assessed using the CCK-8 assay,while enzyme-linked immunosorbent assay(ELISA)was used to quantify pro-inflammatory cytokines(IL-6,IL-1β and TNF-α).Apoptosis was analyzed via flow cytometry,and the protein expression levels of BMAL1,PI3K,p-PI3K,AKT,p-AKT,NF-κB and p-NF-κB were evaluated using Western blot.RESULTS:In vivo,the rats in ACLT group exhibited significant chondrocyte degradation and lacunae formation compared with NC group,confirming the successful establishment of the KOA model.The rats in ACLT+CYA,ACLT+CYA+SR9009 and ACLT+CYA+LY294002 groups showed improved cartilage integrity compared with ACLT group,with reduced OARSI scores(P<0.05),increased BMAL1 expression(P<0.05),and decreased levels of p-PI3K,p-AKT and p-NF-κB(P<0.05).In vitro,the chondrocytes in IL-1β+CYA,IL-1β+CYA+SR9009 and IL-1β+CYA+LY294002 groups exhibited lower levels of IL-6,IL-1β and TNF-α(P<0.05),decreased apoptosis rates(P<0.01),increased BMAL1 protein ex-pression(P<0.05),and reduced p-PI3K/PI3K,p-AKT/AKT and p-NF-κB/NF-κB ratios(P<0.05),compared with IL-1β group.CONCLUSION:Cyasterone alleviates chondrocyte inflammation and apoptosis in KOA by activating BMAL1,which subsequently inhibits the phosphorylation of PI3K/AKT/NF-κB signaling pathway.

OBJECTIVE To investigate the improvement effect and potential mechanism of “Layers adjusting external application” paste on synovial fibrosis （SF） in rats with knee osteoarthritis （KOA）. METHODS Male SD rats were randomly divided into sham operation group， KOA group and Layers adjusting external application group， with 8 rats in each group. KOA model was induced by the anterior cruciate ligament disruption method in KOA group and Layers adjusting external application group. Fourteen days after modeling， the Layers adjusting external application group was given “Layers adjusting external application” paste [Sanse powder （8 g for every 100 cm2）， Compound sanhuang ointment （5 g for every 100 cm2）] on the knee joint， 8 h every day， for 28 d in total. After the last administration， the degree of synovitis and fibrosis in rats was observed， and Krenn scoring was performed in each group. The expressions of collagen Ⅰ， high mobility group protein B1 （HMGB1） and phosphorylated nuclear factor-κB p65 （p-NF-κB p65） were detected in the synovial membrane； the contents of interleukin-1β （IL- 1β）， IL-6 and tumor necrosis factor-α （TNF-α） in serum as well as the expressions of fibrosis-related and HMGB1/Toll-like receptor 4 （TLR4）/NF-κB signaling pathway-related proteins and mRNA were detected in synovial tissue. RESULTS Compared with the sham operation group， the synovial lining cells in the KOA group showed significant proliferation and disordered arrangement， the inflammatory cell infiltration and collagen fiber deposition were obvious； the positive expressing cells of collagen Ⅰ， HMGB1 and p-NF-κB p65 were increased significantly； the contents of IL-1β， IL-6 and TNF-α in serum， the expressions of fibrosis-related protein （transforming growth factor-β， collagen Ⅰ， tissue inhibitor of metalloproteinase 1， α-smooth muscle actin） and their mRNA as well as theexpressions of HMGB1， TLR4 protein and their mRNA， the expressions of p-NF-κB p65 protein and NF-κB p65 mRNA were all increased significantly in synovial tissues of rats （P＜0.01）. Compared with the KOA group， the pathological changes in the synovial tissue of rats in Layers adjusting external application group were significantly improved， and the above quantitative indicators were significantly reversed （P＜0.05 or P＜0.01）. CONCLUSIONS “Layers adjusting external application” paste could significantly improve SF in KOA rats， the mechanism of which may be associated with the inhibition of the activation of HMGB1/ TLR4/NF-κB signaling pathway.

ObjectiveTo observe the effects of Xibining （XBN） and adipose stem cell exosome （ADSC-Exos） in the cases of separate or joint application on cartilage degeneration and mitochondrial autophagy and explore its mechanism of action to improve knee osteoarthritis （KOA）. MethodSD rats were divided into a sham operation group （sham group）， a model group， an ADSC-Exos group （Exos group）， an XBN group， and an ADSC-Exos+XBN group （Exos+XBN group）. KOA model was established by using anterior cruciate ligament transection （ACLT）. The pain sensitivity status of rats was evaluated， and the degeneration degree of the knee joint and cartilage tissue was detected by Micro-CT and pathological staining. The expression of p62 and LC3B was observed by immunofluorescence， and the serum levels of TNF-α， IL-1β， IL-6， and IL-15 in rats were detected by ELISA. The Western blot was used to detect the protein expression levels of MMP-3， MMP-13， ADAMTS5， ColⅡ， TIMP， ACAN， PINK1， Parkin， p62， and LC3A/B. ResultCompared with the sham group， rats in the model group showed decreased cold-stimulated foot-shrinkage thresholds and mechanical pain sensitivity thresholds， varying degrees of abrasion and loss of cartilage tissue， degeneration of cartilage tissue， elevated serum IL-1β， IL-6， IL-15， and TNF-α levels （P<0.01）， and increased protein expression of MMP-3， MMP-13， and ADAMTS5 in cartilage tissue. In addition， the protein expression of ColⅡ， TIMP1， and ACAN was decreased （P<0.01）. Compared with the model group， rats in each treatment group showed higher cold-stimulated foot-shrinkage thresholds and mechanical pain sensitivity thresholds， reduced cartilage tissue degeneration， lower serum levels of IL-1β， IL-6， IL-15， and TNF-α （P<0.05，P<0.01）， decreased protein expression of MMP-3， MMP-13， and ADAMTS5， and higher protein expression of Cold， TIMP1， and ACAN in cartilage tissue （P<0.05，P<0.01）. Moreover， the changes were the most obvious in the Exos+XBN group. ConclusionBoth ADSCs-Exos and XBN can increase the level of mitochondrial autophagy in chondrocytes and delay cartilage tissue degeneration by promoting the expression of the PINK1/Parkin signaling pathway， and the combination of the two can enhance the therapeutic effect.

OBJECTIVE To explore the effect and mechanism of warming channels and activating blood circulation external treat-ment to alleviate peripheral hyperalgesia in knee osteoarthritis(KOA)based on NGF/TrKA signaling pathway.METHODS 30 SD rats were randomly divided into normal group,KOA group and Yiceng group.KOA model was established by anterior cruciate ligament transection(ACLT).14 days after model establishment,rats in Yiceng group were treated with Yiceng patch.The peripheral pain threshold of rats was measured at different time points.The cartilage sections were stained with HE,Aggrecan and type II collagen.The synovial sections were stained with HE,Sirius red,silver and performed with immunostaining.The protein expression of key molecules NGF and TrKA of NGF/TrKA signaling pathway,inflammatory index IL-1β,pain mediator TRPV1,pan-neural mark-ers PGP9.5 and S100 in synovium and complexes transported to dorsal root ganglia(DRG)tissues via nerve endings was determined by Western Blot.The corresponding gene expression was determined by qPCR.The levels of NGF and SP in peripheral blood of rats were determined by ELISA.RESULTS Compared with the KOA group,the cold allodynia and mechanical allodynia thresholds of the rats in the Yiceng group increased(P<0.05,P<0.01);the protein and gene expression of NGF,TrKA,TRPV1,IL-1β,PGP9.5 in the synovial tissue decreased(P<0.05,P<0.01);the protein and gene expression levels of TRPV1,PGP9.5,S100 in the DRG tissue were downregulated(P<0.05,P<0.01).CONCLUSION The warming channels and activating blood circulation external treatment can inhibit the NGF/TrKA signaling pathway,downregulate the gene and protein expressions of NGF,TrKA,TRPV1,IL-1β,PGP9.5,and may inhibit the sprouting of sensory nerve fibers and improve the peripheral hyperalgesia state of rats with KOA.