Isolated osteoclasts in primary culture: first observations on structure and survival in culture media.

Osteoclasts were isolated mechanically from the medullary bone of laying hens kept 7 days on a low calcium diet. Osteoclast enrichment was achieved with 3-4 sedimentations of the cell suspension in test-tubes prepared by layering on the bottom with BSA 10% in MEM-HEPES or PBS, above which the cells were suspended in MEM-HEPES or PBS. The final suspension of osteoclasts was cultivated in MEM with 10% FCS for 3 weeks. The cultures were observed by phase-contrast and scanning electron microscopy (SEM). By the third day, the osteoclasts were completely spread onto the plastic dishes and a variety of morphologies and of intercellular contacts was established. Osteoclasts in culture do not lose their morphology; they survive for long periods and can be used in many experimental systems.