Epo stimulates inflammatory neovascularization in vivo. In the control group, subcutaneous implantation of a polyvinyl sponge for 2 weeks resulted in ingrowth of new vessels. (A) Representative picture of the native disc. (B) Functional neovascularization of the disc was visualized by perfusion with space-filling fluorescent microspheres prior to explantation of the disc. (C) Vessel caliber and density of the network shown by microscopic picture with a × 10 objective (detailed view of tagged area in panel B). Epo increased the vascularized area of the disc (D-E) and the vessel density in the disc (F). Panel F presents a detailed view of tagged area in panel E. Quantification of the vascularized area of the disc (G) as well as the fluorescence intensity of the vascularized area (H) revealed significant differences between PBS- and Epo-treated animals. Data are given as means ± SD.