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Figure 1. Co-culture of human umbilical vein endothelial cells and human pulp fibroblasts. Human pulp fibroblasts and L929 fibroblastic cell line were fluorescence-labeled by transduction with the Enhanced Green Fluorescent Protein; endothelial cells were labeled with the Discosoma Red Fluorescent Protein-2. In co-cultures, pulp fibroblasts and endothelial cells remained separated after 3 hrs (A). Endothelial cells started to elongate and form closed structures at 24 hours (B,C). At 48 hrs, most endothelial cells were organized (D), and at 6 days, they formed a complete tubular network (E,F). Endothelial cells co-cultured with L929 cells remained separated from each other after 3 hrs (G), and no organization was found even after day 6 (H,I). Green and red fluorescence was simultaneously examined (A,B,D,E,G,H). The other photographs (C,F,I) were visualized by the red fluorescence only. Scale bar = 200 µm.
