Figure 4.

Human bone marrow–derived mesenchymal stem cells (hBMSCs) from donor #1, 21 years old, at passage 3 (P3) were prepared into scaffold-free cartilage-like cell-sheets and assessed macroscopically and by histology for safranin-O staining. (A) The center of sheets cultured in condition A, no fetal bovine serum (FBS), was recessed slightly but did not shrink. The surface of sheets cultured in condition B, includes FBS, was stable at 5 mm diameter and flat. (B) As assessed by histology, the margins of sheets in condition A had curled, while the surface of those in condition B were flat. The sheet cultured in condition A stained more intensely for safranin-O than those cultured in condition B. Bar: 500 μm.