Figure 3: Histological observation of the defects in the two groups at 12 weeks after the injection. The regions in the small boxes are magnified in the figures below. A–F: control group; G–L: the group injected with 5 × 106 cells and 0.01% HA; A, B, G, H: hematoxylin and eosin staining, C, D, I, J: safranin O staining, E, F, K, L: immunochemical staining for type II collagen. (Scale bars=2 mm in the upper row/200 μm in the lower row).