Figure 4.

Binding sites for ASF in human OA cartilage and chondrocytes. (a, b) Reactivity for ASF in OA cartilage. (a) Intense reactivity of ASF with chondrocytes and matrix of MS ≥9 cartilage. The inset shows stained complex chondrons. (b) In MS ≤4 regions, positive chondrocytes were scattered across the superficial zone of cartilage (inset and arrows). Bars in insets of (a) and (b): 50 μm. (c) Shown is a quantitative comparison between MS ≤4 and MS ≥9 regions of OA cartilage. Each bar represents the mean percentage of stained (reactive for ASF) chondrons in the respective areas (n = 7; see Additional file 3: Table S3). The asterisk indicates a significant difference of cell reactivity between cartilage areas of mild and severe degeneration (P = 0.0015; n = 7; paired t-test). (d) Subcellular distribution of ASF reactivity in cultured OA chondrocytes. Cells were incubated with biotinylated ASF and stained with streptavidin-phycoerythrin. ASF reactivity (red) was observed using laser scanning microscopy. Nuclei were counterstained with DAPI (blue). ASF, asialofetuin; DAPI, 4′,6-diamidino-2-phenylindole; MS, Mankin score; OA, osteoarthritis; PE, phycoerythrin.

Toegel et al. Arthritis Research & Therapy 2013 15:R147   doi:10.1186/ar4330
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