No significant difference was observed in newly formed vessel densities in the hyperplastic synovia and pannus between pX mice and pX Vegfr-1 tk^–/– mice. (A-B) Staining for VWF in the newly formed capillary vessels in the hyperplastic synovia and pannus. Scale bars, 50 μm. Images were taken with a Nikon Eclipse TE600 microscope, using AxioVision 3.0 software and a 40×/0.75 NA objective lens, then processed with Photoshop CS. (C) Vascular densities in the hyperplastic synovia are slightly lower in pX Vegfr-1 tk^–/– mice than in pX mice (P = .623). The data represent the mean ± SEM.