Abstract
Titanium and its alloys are frequently used for dental and orthopedic implants. However, the function of osteoblasts around the titanium implants remains unexplored. In this in vitro study, we investigated the proliferation and mitogenic-activated protein kinase (MAPK;p42/p44, p38, JNK) activity of osteoblastic MC3T3-EI cells on titanium plates. Although there were no significant differences in the levels of cell attachment between titanium and plastic plates (used as a control), cell proliferation on titanium plates was delayed compared with the control. The titanium level in the cells on titanium plates was higher compared with the control. Morphological changes in cells on titanium plates were similar to those of control cells. Proliferation on titanium plates was induced by the addition of insulin-like growth factor 1 (IGF-1), but the induction activity was decreased at a low concentration of IGF-1. The phosphorylation activity of p42/p44 in cells on titanium plates was similar to the control, whereas phosphorylated p42/p44 protein levels on titanium plates were delayed compared with the control. On the other hand, the phosphorylation of p38 and JNK in cells on titanium plates was similar to the control. These results suggest that the delay in osteoblast proliferation on titanium plates might be caused by alterations in the pathway upstream of p42/p44.
