<p><i>Epas1</i><sup>fl/fl</sup> mice were IA-injected with Ad-C or Ad-<i>Cre</i> (1×10<sup>9</sup> PFU), immunized with type II collagen (CIA) or NI, and maintained for 3 wk. (A) HIF-2α in joint tissues was detected by immunostaining (<i>n</i> = 10). (B) Synovitis, cartilage destruction, pannus formation, and angiogenesis were detected by H&E staining, safranin-O staining, safranin-O/hematoxylin staining, and CD31 immunostaining, respectively. Representative images were obtained from more than 10 independent experiments. P, pannus. (C) Quantification of synovitis, pannus formation, blood vessels in the synovium, and Mankin score (<i>n</i>>10). Values are means ± SEM (*<i>p</i><0.0005). Scale bar, 50 µm.</p
