Figure 6

H&E staining of the articular knee joints of RA rats after intra-articular injection of Dex-M, Met-HA, or Met-HA/Dex-M at 1–6 weeks (200× magnification). Arrows show chondrocytes. *In accordance with one referee’s suggestion, the experiment for intra-articular injection of free Met was performed. The images of H&E staining showed almost no chondrocytes at 1, 3, 6 weeks (Supplementary information), indicating that intra-articular injection of free drug failed to produce significant effects owing to the rapid clearance of the drugs from the articular joint. Thus this result demonstrates that the injectable formulations in this work can improve the therapeutic effectiveness.