Fig. 1

Angiogenesis in cartilage of OA rat. a, b Immunofluorescence staining of CD34. CD34 immunofluorescence showed the stained microvessels. The number of new blood vessels visualized by CD34⁺ vascular endothelial cells was counted per high-power field (× 400). (*P = 0.0004 vs. sham, n = 5, scale bar = 20 μm). c, d Immunohistochemical staining of VEGF. The severity of proteoglycan depletion in OA cartilage was demonstrated by safranin-O staining. e The levels of IL-1β and TNF-α were measured by ELISA (*P = 0.0001 vs. others, n = 5)