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Updated: Aug 14, 2026

A Simple Pit Assay Protocol to Visualize and Quantify Osteoclastic Resorption In Vitro
Published on: June 16, 2022
Osteoclasts; culprits in inflammatory osteolysis
1Department of Pathology and Immunology, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8118, St Louis, MO 63110, USA. teitelbs@wustl.edu
Abstract:
Periarticular osteolysis, a crippling complication of rheumatoid arthritis, is the product of enhanced osteoclast recruitment and activation. The osteoclast, which is a member of the monocyte/macrophage family, is the exclusive bone resorptive cell, and its differentiation and activation are under the aegis of a variety of cytokines. Receptor activator of NF-kappaB ligand (RANKL) and macrophage colony-stimulating factor are the essential osteoclastogenic cytokines and are increased in inflammatory joint disease. Tumor necrosis factor-alpha, which perpetrates arthritic bone loss, exerts its osteoclastogenic effect in the context of RANKL with which it synergizes. Achieving an understanding of the mechanisms by which the three cytokines affect the osteoclast has resulted in a number of active and candidate therapeutic targets.
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