Figure 1: Representative photomicrographs demonstrating toluidine blue stained knee joints (100×, final magnification) taken from OA-prone Hartley guinea pigs (a) and OA-resistant Strain 13 guinea pigs (b). The medial knee compartment is shown: M: menisci; F: femur; and T: tibia. OA scores are reported as median (minimum, maximum). Data was analyzed using one-way ANOVA, Kruskal-Wallis test, followed by Dunn’s multiple comparison post hoc test. As expected, a significant statistical difference () in chondropathy is present between the two guinea pig strains.