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Figure 1. BMP-7-transduced human oral keratinocytes (A) and fibroblasts (B) produce ossicles after subcutaneous implantation. 106 ex vivo BMP-7-transduced human oral (gingival) keratinocyte cells and gingival fibroblasts were harvested, suspended in a collagen thermoset hydrogel, and injected subcutaneously into immunocompromised mice. The ossicles were harvested after 3 wks in vivo and prepared for histological analyses. The overall bone mass is greater in the keratinocyte-produced ossicles, while bony trabeculae (arrow) and marrow (double arrow) are prominent in the fibroblast-produced ossicles. The keratinocyte-induced ossicles contained keratin-producing cells (C, arrow), while the gingival fibroblast ossicles did not (E). Developing the specimen with non-immune IgG instead of anti-keratin antibody demonstrates the specificity of the immuncytochemical assay for keratin production (D). The preparations in panels A and B were stained with H&E. Bar = 700 µm.
