Fig 1: Exosomes reverse IL-1β-induced chondrocyte injury. (A) Gene expression changes in chondrocytes of COL2A1, SOX9, ACAN, MMP-13, ADAMTS5, and COL1A2 after stimulation with IL-1β and exosomes. This experiment was repeated 3 times. *, P<0.05; **, P<0.01 compared to untreated chondrocytes by independent-samples Student’s t-test with Bonferroni correction. (B) COL2A1-, ACAN-, MMP-13-, ADAMTS5-, and COL1A2-positive cells and representative images of fields showing green-colored cytoplasm of chondrocytes in each group. SOX9-positive cells and representative images of fields showing red-colored nucleus of chondrocytes in each group. Hoechst 33342 staining was performed to detect nuclear localization (blue color). Scale bar: 100 μm. (C,D) Protein expression levels of COL2A1, SOX9, ACAN, MMP-13, ADAMTS5, and COL1A2 in chondrocytes were detected using western blotting. This experiment was repeated 3 times. *, P<0.05; **, P<0.01; ***, P<0.001 compared to untreated chondrocytes by independent-samples Student’s t-test with Bonferroni correction. IL-1β, interleukin 1 beta.