Bone remodelling in rabbit ear chambers. A vital microscopical and histological study.

Heterotopic autologous bone tissue was studied by vital microscopy in rabbit ear chambers and correlated with the findings from histological sections prepared from the same tissue. The in vivo morphology and remodelling of different bone types were thereby characterized. Autografts were resorbed in a disordered fashion by osteoclasts and woven-fibred bone tissue formed on such grafts. Later parallel-fibred bone, bounded by a seam of osteoid tissue, formed on this scaffold. Bone flakes growing underneath the cover glass were remodelled into shallow hemi-ossicles containing fat marrow, which were always oriented towards the cover glass. Following en bloc removal of the central part of the bone culture, woven-fibred bone rapidly formed within the new connective tissue, filling in the empty space. Such bone was remodelled into cancellous bone containing fat marrow. A balance between resorption and formation was regularly established in the chambers. The bone cultures were thus useful for vital microscopical studies for half a year or longer. In the present study bone remodelling in rabbit ear chambers closely resembled that of orthotopics bone. Ear chamber bone cultures are therefore a versatile in vivo biological model for dynamic bone tissue studies at both tissue and cellular levels.