Figure 7
Histologic and immunohistochemical evaluation of ectopic cartilage-like transplants.
Human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) were cultured in collagen sponges at 21% O2 for 14 days, in incomplete chondrogenic medium in the absence or presence of 50 ng/ml of BMP-2 and 10 ng/ml of TGF-β1. They were then implanted subcutaneously in nude mice and explanted 28 days later. Serial paraffin sections were stained with hematoxylin-eosin-safran, Alcian blue, analysed immunohistochemically for aggrecan, type II and I collagens, and alizarin red S-stained for calcium deposition. Parallel sections incubated without primary antibody were negative. (A) Empty sponge implanted in mice. (B) Undifferentiated UCB-MSCs cultured in collagen sponges for 24 hours before implantation. (C) UCB-MSCs cultured in collagen sponges in the absence of growth factors for 14 days before implantation. (D) UCB-MSCs cultured in the presence of BMP-2 and TGF-β1 for 14 days before implantation. (Control) Healthy human articular cartilage and human bone. The scale bar corresponds to 100 μm. The global aspect of the sponge construct, at lower magnification, is presented in the inset of the left images (A–D).
