Fig. 3.

Safranin O staining in rat cartilage. CON and EXP groups, respectively: (A, B) 4 weeks; (C, D) 8 weeks; (E, F) 12 weeks. A′–F′ show higher magnifications of boxed areas in A–F. The safranin O and fast green histochemical staining showed that the amount of matrix proteoglycans was significantly reduced, the cartilage surface was rougher and thinner, and the chondrocytes were disordered in the experimental group at 8 and 12 weeks after surgery. In D′, F′, we observed the number of chondrocytes in the superficial and middle zone was significantly reduced, which was consistent with OA. (G): Mankin score for trochlear cartilage: higher Mankin scores in the cartilage at different stages and worsened over time. CON, control; EXP, experimental. *P < 0.05.