Electrical stimulation induces the level of TGF-beta1 mRNA in osteoblastic cells by a mechanism involving calcium/calmodulin pathway.

It is well-known that electrical stimulation can prompt healing of bone fractures. However, the mechanism involved is less clear. In this study, we found that capacitively coupled electric field-induced proliferation of osteoblastic cells (MC3T3-E1) accompanied increased levels of transforming growth factor-beta 1 (TGF-beta1) mRNA determined by quantitative reverse transcription/polymerase chain reaction. Previous reports have shown that verapamil and W-7, both of which block voltage gated calcium channels and inhibit the activation of cytosolic calmodulin, respectively, blocked capacitively coupled electric field-induced proliferation of the osteoblast cells. Interestingly, we found that verapamil and W-7 can also block capacitively coupled electric field-induced elevation of TGF-beta1 mRNA. This result suggested that electrical stimulation induces the level of TGF-beta1 mRNA in osteoblastic cells by a mechanism involving calcium/calmodulin pathway. The potential roles of TGF-beta in the electrical signal-induced osteogenesis was discussed.