Increased serum cholesterol levels enhance osteophyte formation at the margins of the tibial plateau and increase active TGF-β presence. Osteophyte size was digitally measured at the margins of the tibial plateau (A). B shows representative photos (stained with safranin O - fast green) of osteophytes at the lateral side of the tibial plateau. The presence of active TGF-β was found to be increased in LDLr−/− mice on a cholesterol-rich diet compared to WT mice on a cholesterol-rich diet by testing synovial wash-outs on a CAGA-LUC assay (C). *P<0.05; **P<0.01; ***P<0.001. n = 10 mice per group. LDLr, low density lipoprotein receptor; WT, wild type.