Fig. 4.

P2X7R antagonists inhibit human osteoclast formation but are not toxic. Osteoclasts were generated from human blood monocytes cultured on 6-mm coverslips in recombinant M-CSF and RANKL-supplemented medium. Antagonists were introduced throughout the culture by inclusion in the medium at each medium change at the concentrations shown. Vehicle was complete α-MEM plus recombinant RANKL (30 ng/ml) and M-CSF (25 ng/ml) and 0.1% DMSO for KN62, and AZ15d. The coverslips were fixed in acetone and stained for tartrate-resistant acid phosphatase (TRAP) using a commercially available kit used according to the manufacturer’s protocol or fixed in formalin and stained as previously described [25]. Typical fields of view of cells following treatment in μM as indicated. Scale bar 30 μ