Objectives: To explore the mechanism by which Tougu Xiaotong Capsule (TXC) promotes chondrogenic differentiation and cartilage repair in mice with osteoarthritis (OA).
Methods: Fifty 8-week-old male C57BL mice were randomly divided into normal control group, cartilage damage (induced by subchondral ring-shaped drilling) model group and TXC treatment groups at low, moderate and high doses (184, 368 and 736 mg/kg, respectively). Saline (in normal control and model groups) and TXC were administered after modeling by daily gavage for 6 consecutive weeks. The changes of cartilage damage in the mice were assessed by measuring thermal withdrawal latency (TWL) and mechanical withdrawal threshold (MWT) and using micro-CT, modified safranine O and fast green staining, HE staining, and qPCR. Primary cultures of mouse synovial mesenchymal stem cells (SMSCs) with lentivirus vector transfection for interfering CXCL12, TXC treatment, or both for 24 h were examined for chondrogenic differentiation using immunofluorescence staining, scratch assay, immunocytochemistry, and Western blotting.
Results: In mouse models with cartilage damage, TXC treatment at the moderate dose significantly alleviated joint pain, promoted cartilage repair, and upregulated the mRNA expression levels of CXCL12, GDF5, collagen II, aggrecan, Comp and Sox9 in the cartilage tissue. In primary mouse SMSCs, CXCL12 knockdown resulted in significant reduction of GDF5 protein expression, migration ability and Sox9 protein expression, and these changes were obviously reversed by TXC treatment.
Conclusions: TXC promotes chondrogenic differentiation of mouse SMSCs to promote repair of cartilage damage in mice by activating the CXCL12/GDF5 pathway.
目的: 从CXCL12与GDF5对话角度探讨透骨消痛胶囊（TXC）促进小鼠滑膜间充质干细胞（SMSCs）成软骨分化修复骨关节炎（OA）软骨损伤的作用机制。方法: 将50只8周龄C57BL雄性小鼠按随机数字表法分为正常组（NC，n=10）和实验组（n=40），实验组动物采用软骨下环型钻孔法建立软骨损伤模型，随机分为模型组（Model）、TXC-L（184 mg/kg）、TXC-M（368 mg/kg）、TXC-H（736 mg/kg）组，10只/组；NC组和Model组均采用等量生理盐水灌胃，1次/d，连续干预6周；采用热痛、机械痛、micro-CT、番红O-固绿、HE染色及qPCR验证TXC对软骨损伤的修复效果。提取原代SMSCs，经纯化培养、鉴定后采用CXCL12慢病毒转染，将细胞随机分为空白组（Control）、空载组（sh-NC）、TXC组、sh-CXCL12组、sh-CXCL12+TXC组，干预24 h后采用免疫荧光、划痕实验、免疫细胞化学染色及Western blotting阐明TXC对SMSCs成软骨分化的作用机制。结果: 体内实验结果显示，与模型组相比，TXC-M组（368 mg/kg）可缓解关节疼痛，促进OA软骨损伤的修复，并上调趋化因子CXCL12、细胞生长分化关键因子GDF5及成软骨分化关键因子Collagen II，Aggrecan，Comp，Sox9的mRNA表达水平（P<0.05）。体外实验结果显示，当CXCL12基因敲减后，SMSCs中GDF5蛋白表达量降低，同时SMSCs迁移能力减弱，Sox9蛋白表达量降低，然而经TXC干预后可逆转这一趋势（P<0.05）。结论: TXC可通过CXCL12/GDF5通路促进小鼠SMSCs成软骨分化修复OA软骨损伤，可为TXC保护软骨的临床应用提供科学依据。.
Keywords: CXCL12/GDF5 pathway; Tougu Xiaotong Capsule; cartilage damage; synovial mesenchymal stem cells.