Figure 4

Analysis of aggrecan and type II collagen in OF and OA cartilage. Ratio of aggrecan to type II collagen in the cartilage matrix of OA and OF femoral heads and comparison between areas (SP and IP). Aggrecan and type II collagen were quantified using ELISA after cartilage proteoglycan extraction. Aggrecan was assessed from supernatant soluble fraction, and collagen was assessed from pellet fraction of the same tube. The horizontal bar indicates the median, the box is the interquartile range, and the vertical lines indicate the atypical values. *Significant differences between OA and OF heads were found (p < 0.05) using the Mann-Whitney U test. These differences were found for both poles. No significant differences between weight-bearing areas were found, but a trend was found between poles for OF hips (p = 0.057) using the Wilcoxon signed rank test. ELISA, enzyme-linked immunosorbent assay; IP, inferior pole; n, number of femoral heads used in the experiment for each cartilage condition (osteoarthritis or osteoporotic fracture); OA, osteoarthritis; OF, osteoporotic fracture; SP, superior pole.