Fig. 8

Histological evaluation of synovium tissues after the clearence experiment. Representative images showed the target region of cavitation bubbles. A Preoperative MSU-induced inflammatory region showed characterized disorderly collagen fibers and recruitment of inflammatory cells, distributed within 200 μm on one side exposed to synovial fluid. The dotted line repres ents the boundary between the inflammatory foci at the top and normal tissue at the bottom. B After debridement by cavitation devices, aligned collagen fibers in zone of normal tissue were preserved while most of the inflammatory areas were removed. C No impairment was observed in the cartilage and subchondral bone of the same joint with Masson staining. D–F Zoom- in image of (A–C), respectively. The black arrow shows deposition of MSU crystals in tissue. Scale bar: 100 μm (A–C), 50 μm (D–F)