Effects of osteoblasts on the formation of osteoclasts in vitro

Objective: By culturing the osteoclasts together with the osteoblasts directly to investigate the effect of osteoblasts on the formation of mature osteoclasts. Methods: The bone marrow mononuclear cells of rats were treated with 30 μg/L M-CSF and 50 μg/L RANKL and cultured for 6 days. Subsequently, the primary osteoblasts which were of the same quantity as the osteoclasts were co-cultured directly. In the co-culture system, we added the liquid containing 1, 25-(OH)₂D₃ 1 × 10^-8 mol/L and PGE₂ 1 × 10^-6 mol/L. The morphological observation, TRAP staining and pit staining were adopted to identify osteoclasts. Results: When the osteoclasts were co-cultured with primary osteoblasts, the growth of osteoblasts had more preponderances. After staining, we could see more osteoblasts than osteoclasts. Conclusion: The relationship between osteoblasts and osteoclasts is related to the relative quantities of the two cells. When osteoblasts outnumber osteoclasts, osteoblasts would inhibit the formation and differentiation of osteoclasts.