[An experimental study of the formation of osteoclast-like cell in rat bone marrow culture].

OBJECTIVES: To set up a culture method of osteoclast-like cell (OLC) formation in rat bone marrow and to investigate the effects of 1,25(OH)2D3 and osteoblasts on the formation of OLC. METHODS: The culture of bone marrow from 4-week old rats were studied for the formation of OLC. The culture was divided into four groups: group A, only bone marrow culture as control; group B, bone marrow and osteoblast (from the crania of newborn rats) coculture; group C, bone marrow culture with 1,25(OH)2D3(final concentration 10(-8) mol/L); group D, bone marrow and osteoblast coculture with 1,25(OH)2D3. After 7 days of culture, the number of OLC which was recognized as tartrate resistant acid phosphatase (TRACP) (+) multinucleated cell, the cellular TRACP and the resorption pits on bone slice were examined. RESULTS: No OLC was present at the beginning of the bone marrow culture in any groups. OLC still failed to be detected in group A by the end of culture, and a few of OLCs could be found out in group B and C. The number of OLC in group D was more than that in the other groups (P < 0.01). The cellular TRACP in group A was lower than that in the other groups, and the cellular TRACP activity in group B and C was lower than that in group D (P < 0.01). In group D, several smaller resorption pits on The bone slice were observed. CONCLUSION: The formation of OLC requires 1,25(OH)2D3 and coculture with osteoblasts favors the formation of OLC in bone marrow culture.