The biological characteristics of osteoblasts and osteoclasts in co culture system

Objective To establish osteoblasts osteoclasts co culture system in vitro for the study of the biological characteristics of osteoblasts and osteoclasts and also to analyze the interactions between osteoblasts and osteoclasts. Methods The osteoblasts and osteoclasts were isolated from cancellous bone in illium. Osteoblasts osteoclasts co culture system was built to prevent these two kinds of cells from contact with each other although with the facility of their medium exchange. The osteogenety of osteoblasts was evaluated by MTT and ALP activity; the resorption activity of osteoclasts was investigated by TRAP activity and the area of absorption lacuna. Results Osteoblasts are full fusiform, ALP stain positive cells, while osteoclasts are multinuclear and TRAP stain positive, with the ability of forming bone lacuna; while in the co culture system, the proliferation of osteoblasts in co culture (0.60±0.08)OD is quicker(P=0.000)than that in mono culture (0.36±0.03)OD, and the ALP activity increased significantly (P=0.000)from (18.33±0.34)u/mg to (23.37±2.48) u/mg; while the average area of bone resorption formed by osteoclasts [(6.55±0.34)×10-2] μm2 was also increased obviously(P=0.000)from [(5.15±0.17)×10-2] μm2. Conclusion In co culture system, osteoclasts were able to enhance ossification effects of osteoblasts by accelerating their proliferation and differentiation; at the same time, osteoblasts upregulated the ability of bone resorption of osteoclasts. This implied that osteoblasts and osteoclasts can promote each others function. This study provide reliable model for bone metabolism research.