Fig. 4

Histological observation of meniscus implants. a H&E staining. The general view on the left (scale bar = 100 μm) shows the structure of the outer, intermediate, and inner regions of the new tissue of the meniscus implants, and the high-magnification images on the right (scale bar = 25 μm) correspond to the images inserted in the frame in the left view, respectively. A large number of chondrocyte-like cells (black arrows) were observed in the intermediate and inner regions in PTH + BMSCs–scaffold group implants, which were similar to the native meniscus in the Sham group, while mostly fibroblast-like cells (triangles) were observed in the intermediate region of the implants of the BMSCs–scaffold group. b Toluidine blue (TB) and Picrosirius Red (PR) staining showed the deposition of proteoglycan and collagen type I in the new tissue of meniscus implants and native meniscus, respectively. The PTH + BMSCs–scaffold group had a stronger staining than the BMSCs–scaffold group (scale bar = 100 μm). Asterisks marked the dissolution position of the PCL scaffold in the process of sectioning