Objective:To investigate the effects of the taurochenodeoxycholic acid(TCDCA)on cartilage degeneration in tem-poromandibular joint osteoarthritis(TMJ OA).Methods:36 female SD rats aged 6 weeks were randomly divided into 3 groups:con-trol group(CON),unilateral anterior crossbite group(UAC),UAC plus TCDCA injection group(UAC+TCDCA).UAC model was es-tablished in all rats in UAC and UAC+TCDCA groups.Samples were collected at 8 and 12 weeks(control group,UAC group,UAC+TCDCA group)after set up of the experiment(n=6),and TMJ morphological examination was performed.The expression of CYP7A1,BAAT and TGR5 in the tissue and cells was examined by immunohistochimical staining.Results:(1)Compared with the CON group of the same age,the cells in the condylar cartilage were disordered,the cartilage matrix was reduced and thinner in UAC group.Compared with UAC group of the same age,cell arrangement,cell number,cartilage matrix and cartilage thickness were im-proved in UAC+TCDCA group(P＜0.05).(2)Compared with the CON group of the same age,the positive cells for TCDCA-specific receptor TGR5 and the key enzymes CYP7A1 and BAAT were mainly distributed in the anterior hypertrophic layer and hypertrophic layer at each time point.The number of positive cells in the UAC group was significantly reduced compared with the CON group.Conclusion:TCDCA has obvious therapeutic effects on the degeneration in TMJ OA.

Objective:To investigate the response of mandibular condylar chondroprogenitors to flow fluid shear stress(FFSS).Methods:Chondroprogenitors were in vitro cultured and stimulated with FFSS that can cause cell degeneration,and treated with sec-ond-generation high-throughput RNA sequencing.Differential gene expression was screened using DESeq2 software for gene ontology(GO)functional enrichment analysis,kyoto encyclopedia of genes and genomes(KEGG)pathway enrichment analysis and protein-protein interaction(PPI)network analysis.qRT-PCR was performed to validate the core genes screened by PPI.Results:A total of 1996 differentially expressed genes were obtained,mainly including inflammatory response and cell cycle related molecules.Among them,Actal,Atf3,Ccl2,116,Nfkbia,Ret and Vcaml were identified as the core genes.Conclusion:FFSS stimulation affects chondroprogenitor function by acting on inflammatory responses and cell cycle-related signaling pathways in chondroprogenitors.