Figure 7From: Intra-articular injection of collagenase in the knee of rats as an alternative model to study nociception associated with osteoarthritisHistopathological scoring. Histopathological assessment of cartilage degenerative changes in the medial tibial plateau (MTP) of control animals and animals injected with 250 or 500 U collagenase, one, two, four and six weeks after injection. The following parameters were evaluated: cartilage matrix loss width (CMLW) measured along the surface (0% depth, A), the midzone (50% depth, B) and tidemark (100% depth, C); total cartilage degeneration width (TCDW, D); significant cartilage degeneration width (SCDW, E); osteophyte score (OS, F); zonal depth ratio (ZDR) of lesions at zone 1 (at the medial edge of the joint, G), zone 2 (at the centre of the MTP, H) and zone 3 (adjacent to the cruciate ligaments, I); cartilage degeneration score (CDS) at zones 1 (J), 2 (K) and 3 (L); synovial membrane inflammation score (SMIS, M); medial joint capsule width (MJCW, N); growth plate thickness (GPT, O). Mean ± SEM. Measured parameters were analysed by one-way ANOVA followed by Tukey post-hoc test; scored parameters were analysed by the Kruskal-Wallis test with Dunn’s post-hoc test. *P <0.05, **P <0.01, ***P <0.001, for comparisons between collagenase injected and control animals within each time point; +P <0.05, +++P <0.001, for comparisons between the 250 and 500 U groups within each time-point; #P <0.05, ###P <0.001, for comparisons between week 1 and week 6 within each group; ‡P <0.05, ‡‡P <0.01, ‡‡‡P <0.001, for comparisons between week 2 and week 6 within each group; †P <0.05, ††P <0.01, †††P <0.001, for comparisons between week 4 and week 6 within each group; ¥P <0.05, ¥¥P <0.01, ¥¥¥P <0.001, between collagenase injected and control animals from a different time point.Back to article page