Fig. 2

Effects of cartilage degeneration on different methods by histopathological staining (a–c: HE staining, d–f: safranin O fast green staining). Scale bar: 200 μm. a, d Representative cartilage tissues extracted from control groups at 4, 8, and 12 weeks. b, e Representative cartilage tissues extracted from operation groups at 4, 8, and 12 weeks. c, f Representative cartilage tissues extracted from chemical groups at 4, 8, and 12 weeks