Changes in cell proliferation, alkaline phosphatase activity and cAMP production by mechanical strain in osteoblast-like cells differentiated from rat bone marrow

It is well recognized that mechanical strain plays a crucial role in bone remodeling, affecting activities and differentiation of osteoblast, osteocyte and osteoclast. However, little is known on how mechanical strain is transduced into cellular responses and controls the differentiation and maintains the phenotypes of those cells. In this study, we loaded osteoblast-like cells from rat bone marrow with mechanical strain, after differentiating the cells by culturing in an osteoblast-inductive medium. The results show that mechanical strain promoted cell proliferation, enhanced alkaline phosphatase activity and transiently changed production of second messengers such as cAMP and cGMP, indicating that mechanical strain affected the activities of the osteoblast-like cells differentiated from rat bone marrow at molecular and cellular levels.