A. Kukita et al., HEAT-TREATED OSTEOBLASTIC CELL (ROS17 2.8)-CONDITIONED MEDIUM INDUCESTHE FORMATION OF OSTEOCLAST-LIKE CELLS/, Bone and mineral, 23(2), 1993, pp. 113-127
To study the effects of osteoblast products on. osteoclast formation,
we added the conditioned medium (CM) of rat osteoblastic cell line ROS
17/2.8 to rat bone marrow cultures, in which tartrate-resistant acid p
hosphatase (TRAP)-positive osteoclast-like multinucleate cells (MNCs)
formed in the presence of 10(-8) M 1,25-dihydroxyvitamin D-3 (1,25(OH)
(2)D-3). The formation of 1,25(OH)(2)D-3-dependent TRAP-positive MNC a
t day 7 of culture was strongly inhibited by the >10 kDa fraction of R
OS1712.8 cell-CM (ROSCM), but heat treated ROSCM (htROSCM) expressed m
arked stimulation in the formation of the MNCs. The expression of seve
ral osteoclastic phenotypes of the MNCs induced by htROSCM and 1,25(OH
)(2)D-3 was more enhanced compared with that of the MNCs induced by 1,
25(OH)(2)D-3 alone. The MNCs induced by htROSCM and 1,25(OH)(2)D-3 wer
e highly motile, were sensitive to calcitonin (CT), and had high bone
resorbing activity. These data suggest that htROSCM promotes the osteo
clast differentiation in the presence of 1,25(OH)(2)D-3 in a rat bone
marrow culture system. The stimulatory activity of TRAP-positive MNC f
ormation in htROSCM is derived from heat-stable protein(s) that is (ar
e) thought to be different from colony-stimulating factors (CSFs) such
as macrophage-CSF (M-CSF) or granulocyte-macrophage-CSF (GM-CSF).