Fig. 2: Mitochondrial function is impaired in OA-FLSs.

a The heatmap of RNA-Seq analysis for FLSs separated from normal and OA patients. b The biological processes of differentially expressed mRNAs were analysed by GO enrichment analysis. c GSEA of ‘OXPHOS’ gene sets in Nor-FLSs and OA-FLSs. (d) Representative images of Mitotracker staining to observe the mitochondrial network of Nor-FLSs (n  =  12) and OA-FLSs (n  =  11), and the statistical analysis of mean branch length. Scale bar: 40 µm. The white dashed box represents the enlarged image area in the bottom right corner. e Representative images of TEM to observe Nor-FLSs (n  =  5) and OA-FLSs (n  =  12) and the arrows point to the mitochondria. Scale bar: 1 µm. f Representative images of MitoSOX staining to detect mitochondrial superoxide in Nor-FLSs and OA-FLSs. n  =  6 independent biological replicates. Scale bar: 100 µm. g Mitochondrial membrane potential detected by JC-1 assay and the statistical analysis of aggregate-to-monomer ratio (n  =  3 Nor-FLSs, n  =  7 OA-FLSs). h, i OCR of Nor-FLSs and OA-FLSs, and the analysis of mitochondrial respiration. n  =  3 independent biological replicates. j, k PER of Nor-FLSs and OA-FLSs, and the analysis of basal and compensatory glycolysis. n  =  4 independent biological replicates. l Quantification of ATP content in Nor-FLSs and OA-FLSs. n  =  5 independent biological replicates. All data were presented as the means ± SD. P values were determined by two-tailed unpaired Student’s t-test. P < 0.05 was considered statistically significant. Source data are provided as a Source Data file.