The effect of inhibiting proteolysis during osteoclastic resorption. Mature human osteoclasts were seeded on bone slices and cultured for 5 days in the presence or absence of E64, GM6001 or a combination of E64 and GM6001. A-C) CTX-I release measured in culture supernatants. D-F) Calcium release measured in culture supernatants. G-I) Cell viability measured by Alamar Blue. All results are plotted as % of control. Statistical tests were performed by ANOVA with Dunnet's multiple comparison test against the vehicle group.