Kartogenin enhances rat cartilage defect repair by promoting chondrogenic differentiation of bone marrow mesenchymal stem cells in rats

Zhang Bokai; Li Haoke; Xia Wen; Zhang Chao; Yang Ruiyuan; Zheng Jiehui; Wang Min

doi:10.3969/j.issn.1009-4237.2025.02.010

Abstract：Objective To investigate the specific role and potential mechanisms of Kartogenin(KGN)in the chondrogenic differentiation of rat bone mesenchymal stem cells(BMSCs).Methods A total of 12 eight-week-old male SD rats were used to create a knee joint cartilage defect model(diameter of 1 mm and depth of 2 mm)at the trochlear groove.Rats were randomly divided into KGN group and control group,with 6 rats in each group.The defect site in the KGN group was filled with 20 mg hydrogel containing KGN(1 mg KGN∶31 PBS∶200 mg hydro-gel),while the control group was treated with hydrogel only.At 4 and 8 weeks,rats were sacrificed(3 rats at each time point).The femoral condyles were separated,and the gross therapeutic effects were evaluated.The Internation-al Cartilage Regeneration&Joint Preservation Society(ICRS)score and Wakitan score as well as HE staining and safranin O-fast green staining were used to assess the repair of the cartilage defect.For the in vitro experiments,BM-SCs were cultured:the KGN group with a final concentration of 100 nM KGN and the control group with dimethyl sulfoxide.Expression levels of Collagen Ⅱ(Col Ⅱ),Aggrecan(ACAN),and core-binding factor β(CBF-β)were detected by PCR and western blot.Concurrently,eukaryotic cell transcriptome analysis was performed.Results For the in vivo experiments,the KGN group showed much better cartilage defect repair at both 4 weeks(ICRS score:5.5±0.5 vs.3.0±1.0;Wakitan score:5.5±0.5 vs.11.5±0.5)and 8 weeks after treatment(ICRS score 10.8±0.8 vs.7.2±0.8;Wakitan score:2.5±0.5 vs.6.8±0.3),all P<0.05 compared with control group.For the in vitro experiments,after treatment of BMSCs with KGN,the expression of cartilage extracellular matrix proteins,i.e.,Col Ⅱ and ACAN,significantly increased at both mRNA and protein levels.This suggests that KGN could promote chondrogenic differentiation of BMSCs.To explore the mechanism of action of KGN,protein immunoblotting and RT-PCR detected increased levels of CBF-β protein and mRNA after the adding of KGN,and immunofluorescence fur-ther indicated a significantly increased amount of CBF-β entering the cell nucleus(all P<0.05).Eukaryotic cell transcriptome analysis suggested that after treatment with KGN,the key pathway for chondrogenic differentiation,i.e.,the extracellular signal-regulated kinase pathway,was activated in BMSCs.Conclusion KGN can promote the repair of ar-ticular cartilage defects in rats,possibly by regulating CBF-β to enhance the chondrogenic differentiation of BMSCs.