Figure 4

Immunohistochemistry of meniscus at 4 weeks after intra-articular injection. (A) Immunohistochemistry of vascular endothelial growth factor (VEGF; upper) and fibroblast growth factor-2 (FGF2; lower). VEGF and FGF2 expressed intensely on the surface of the meniscus, around the injured site and in the red zone in the miR-210 group compared with the control group. Arrow, injured site. Bar = 100 μm. (B) Immunohistochemistry of type 2 collagen. Type 2 collagen expression was observed around the injured site of the meniscus in the miR-210 group compared with the control group. Arrow, injured site. Bar = 100 μm. (C) Isolectin B4 staining and the number of blood vessels. Newly formed vessels were observed around the injured site in the miR-210 group, while little blood vessels were observed in the control. White arrow, injured site; yellow arrow, blood vessels. Bar = 100 μm. Number of blood vessels in the miR-210 group was significantly higher than that in the control group (*P < 0.05, n = 5 for each group). (D) Immunohistochemistry of Ki67 and the ration of proliferative cells. In the miR-210 group, many proliferative cells were observed around the injured site. Arrow, injured site. Proliferative cells in the miR-210 group were significantly higher than that in the control group (*P < 0.05, N.S. (no significant difference), n = 5 for each group).