Fig. 5

Histopathological and IHC analyses and pain behavior tests in kOA rats treated with normal hucMSCs, hucMSCs with MMP13 overexpression, SF-stimulated hucMSCs and SF-stimulated knockdown MMP13-hucMSCs. A Safranin O and Fast green staining of the cartilage, with black arrows indicating hypertrophy or loss of chondrocytes. Scale bars = 50 μm. B IHC staining of Col2 and MMP13 on cartilage, with red arrows indicating positive cells. Scale bars = 50 μm. C OARSI and Mankin’s scoring of histopathology. D Quantitative measurements of the percentage of Col2-positive area and MMP13-positive cells. E Measurement of MWT and TWL of rats. Data are expressed as mean ± SD. The different letter symbols (a, b, c, cd, d, and e) indicate significant difference between each other (Fisher's LSD, P < 0.05 or P < 0.01) in descending order of data from a to z. Although the overlapped letters (c versus cd, and cd versus d) were statistically different, their difference between each other was not significant. All experiments were repeated at least three times