Fig. 1

TCG preserved articular cartilage and subchondral bone loss in DMM rats. A Experimental flow chart. SD rats underwent DMM surgery to induce OA and were subsequently administered TCG injections for 8 weeks. B The knee joints of rats in each treatment groups were subjected to HE staining (first row), S–O/FG staining (second row) and Col2a1 immunostaining (third row). Hyaline cartilage (HC) and calcified cartilage (CC) were denoted by double-headed arrows. Scale bar = 400 µm. C The OA lesion was assessed following the OARSI grading system. D Positive staining area for Col2a1 was quantified. E 3D micro-CT images depicted pathological structural changes in the knees from each treatment group. Osteophytes and calcified tissues were highlighted in red arrows. F Sagittal views of medial compartment subchondral bone. G–I micro-CT analysis of tibial subchondral bone, including BMD, BV/TV, and TV. (H) Paw withdrawal threshold at 8 weeks after TCG treatment. Data are presented as mean ± SD (n = 6). *P < 0.05, **P < 0.01, ***P < 0.01