Isolation and culture of primary chicken osteoclasts

Osteoclasts originate from hematopoietic myeloid progenitors that differentiate into specialized multinucleated cells uniquely capable of resorbing bone in both physiological and pathological conditions. Osteoclast numbers and degradative activities increase in various inflammatory disorders of bone and certain bone oncologies, thereby causing bone loss that may weaken the skeleton, increase fracture incidence, and disturb marrow function. Many valuable insights have been obtained through the use of osteoclasts directly isolated from the bones of chickens fed a low calcium diet to enhance osteoclastogenesis and bone resorption. Particular advantages of this system include the abundance and highly resorptive nature of isolated chicken osteoclasts compared with those directly obtained from other species. After enzymatic release from the harvested bones, osteoclasts may be partially purified by density gradient sedimentation, bone substrate attachment, and/or immunomagnetic capture. Thereafter, osteoclast preparations may be analyzed, either directly or following some period of culture, to investigate their properties (biochemical, immunological, molecular, cell biological), resorptive function, and modulatory responses to various stimuli. Here, we present common procedures for the isolation, culture, and general study of chicken osteoclasts.