Fig. 8

Safranin O and fast green staining of rabbit menisci after five different treatments for 3 months. a–d The wounded meniscus treated with saline at day 90 post-surgery. e–h The wounded meniscus treated with KGN at day 90 post-surgery. i–l The wounded meniscus treated with KGN-PRP gel at day 90 post-surgery. m–p The wounded meniscus treated with BMSCs-containing PRP gel at day 90 post-surgery. q–t The wounded meniscus treated with BMSC-containing KGN-PRP gel at day 90 post-surgery. The images of d, h, l, p, and t were enlarged box areas in the images of c, g, k, o, and s, respectively. Large unhealed wound areas were still found in the saline-treated meniscus (red arrows in a–c) and KGN-treated meniscus (yellow arrows in e–g). Although the wounds were healed with KGN-PRP gels, new formed tissues were thinner than around tissues (black arrows in i–k) and less cells in new formed tissues were fibrocartilage-like cells (pink arrow in l) than the wounds treated either with BMSCs-containing PRP gel (m–p) or with BMSCs-containing KGN-PRP gels (q–t). There was no unhealed wound area found in the meniscus treated either with BMSCs-containing PRP gel or with BMSCs-containing KGN-PRP gel, but the new formed tissues in these two groups were different, more collagen fiber-like tissues were found in PRP-BMSC-treated meniscus (black dash arrows in m–p), and more cartilage-like cells were found in the wound area treated with BMSCs-containing KGN-PRP gel (white arrows in q–t)