Fig. 2

The expression of cartilage matrix genes, IGFs and related genes in OA and control cartilage. Cartilage tissues were obtained from control (Control) and OA knees (OA), and the gene expression was determined in superficial (S), middle (M) and deep cartilage zones (D). a, Schematic illustrations of control (left) and OA cartilage (right). While control cartilage retained all three cartilage zones, OA cartilage might retain three (S-M-D), two (M-D) or only one zone (D), as they were obtained from both macroscopically preserved areas (Preserved) and degenerated areas with various degrees of degeneration (Degenerated). Open and closed arrowheads indicate surface of preserved and degenerated cartilage, respectively. b-g, The expression of COL2A1 (b), ACAN (c), IGF1 (d), IGF2 (e), IGF1R (f) and IRS1 (g) is shown by ratios against the GAPDH expression. The findings from superficial, middle and deep cartilage zones are shown by open, shaded and closed bars, respectively. Values are the mean and SE of 7–19 samples. a and b indicate p < 0.05 compared to the corresponding zone in control cartilage, or compared to the corresponding zone in preserved areas of OA cartilage, respectively