Osteoclast is one of the basic function cells involved in bone metabolism during the process of bone remodeling.Osteoclasts are responsible for destruction and absorption of the old bone tissue.Thus,a tiny change of osteoclast apoptosis may change the process of bone remodeling.Osteoclast apoptosis is regulated by many factors including estrogen,bisphosphonates and so on.However,fewer researches on effect of mechanical loading on the biological activity of osteoclasts has been carried out.In this paper,the effect of mechanical loading on the biological activity of osteoclasts and its regulation on apoptosis of cells and osteoclast are reviewed.

Extracellular matrix (ECM) keeps cell's shape, protects and nourishes cells; it plays a great role in cell proliferation and differentiation. Therefore, ECM is very important in cell and tissue engineering. In this study, after primary mouse osteoblasts and fibroblasts maintained at confluence in vitro were removed, their ECM coated on cell culture plate was prepared, and bone morphogenetic proteins 2 (BMP-2) was detected in the osteoblasts ECM. MC3T3-E1 preosteoblasts cells were seeded on cell culture plates covered with fibroblasts ECM and osteoblasts ECM respectively. The proliferative activity of the cells cultured on fibroblasts ECM was higher than that on osteoblasts ECM and the control group. The alkaline phosphatase activity, relative protein levels of BMP-2 and osteopontin, secreted calcium of the cells cultured on osteoblasts ECM were all the highest. The results indicate that the two different ECMs produced in vitro had different bioactivities, the fibroblasts ECM coated on cell culture plates could accelerate MC3T3-E1 cells proliferation, and the osteoblasts ECM could promote cells osteogenic differentiation.
3T3 Cells ; Alkaline Phosphatase ; metabolism ; Animals ; Animals, Newborn ; Bone Morphogenetic Protein 2 ; metabolism ; Calcium ; metabolism ; Cell Differentiation ; physiology ; Cell Proliferation ; drug effects ; Cells, Cultured ; Extracellular Matrix ; metabolism ; physiology ; Mice ; Osteoblasts ; cytology ; Osteopontin ; metabolism