Fig. 6

Effect of diet-induced obesity on synovial inflammation and hyperplasia. a Representative coronal sections of the medial compartment of the knee stained with toluidine blue from mice fed either control chow, high-fat, or western diets for 24 or 40 weeks. Images are oriented with medial femoral condyle (MFC) located superiorly, and the medial tibial plateau (MTP) inferiorly. Black arrows indicate synovial hyperplasia. b Histopathological scoring assessed indicators of synovial hyperplasia and inflammatory infiltration. Summed scores represent the sum of the medial and lateral compartments scores across 7 serial sections. Mice fed a high-fat diet showed a significant increase in synovial inflammation and hyperplasia compared to chow-fed control at both the 24 and 40 week timepoint, while mice fed a western diet showed a significant increase in synovitis at only the 24-week timepoint. n = 8–12 animals per diet/per timepoint. Analyzed by Kruskal-Wallis test. All data are plotted mean ± 95% CI, **P < 0.01