Fig. 4

Resorption biomarkers released from osteoclasts cultured on osteochondral extracellular matrix (ECM). Osteoclasts were cultured on osteochondral ECM from bovine femoral condyles in the presence or absence of resorption inhibitors. Resorption of calcified ECM and collagen type I was assessed by measuring the Ca²⁺ (a) and C-terminal type I collagen (CTX-I) (b) concentrations, respectively, in the medium. Resorption of collagen type II was assessed by measuring C2M (c) concentrations in the medium. Cell viability was assessed using alamarBlue (d) and tartrate-resistant acid phosphatase (TRAP) activity in the medium was measured for relative osteoclast quantification (e). Data are presented as percent of vehicle with error bars representing the SEM. Statistical significance is indicated by ^*p < 0.05, ^**p < 0.01, ^***p < 0.001, ^****p < 0.0001 for comparisons against the vehicle and ^#p < 0.05, ^##p < 0.01, ^###p < 0.001, ^####p < 0.0001 for comparisons against E-64/GM6001 (only shown for E-64 and GM6001); the post hoc test used is indicated in the top left corner of each graph