Abstract: Objective To investigate the biologic effects of immunosuppressive cyclosporine A on the osteoclastic cells and osteoblastic colony during the mice bone metabolism in vitro. Methods Bone marrow cells of mice were treated with different concentration of cyclosporine A in vitro. The mice stromal cells were cultured and osteoclastic cells and osteoblastic colony of CFU-F and CFU-OB obtained. TRAP positive multinuclear cells were measured by tartrate-resistant acid phosphatase(TRAP) staining, CFU-F and CFU-OB were checked with alkaline phosphatase(ALP) staining and Von'Kassol staining methods respectively. Results The number of TRAP positive multinuclear cells increased significantly(F=16.496, P<0.001) and depending on the CsA doses(r=0.579, P<0.05). The number of CFU-F and CFU-OB were not significantly changed(F=1.380, F=0.305, P>0.05). Conclusion CsA can induce the osteoclastic cells increasing and has no significant effects for the CFU-F and CFU-OB. One of the major function of CsA for bone metabolism may be upregulation of osteoclast system and induction of osteopenia in the mice.

Key words: cycloporine A, bone, osteoclast, osteoblast, colony-forming unit of fibroblast, colony-forming unit of osteoblast