It is well known that radiotherapy has profound influence on histocompatibility of titanium plate used for the reconstruction of the jaw in patients with oral cancer. In this study effects of radiation from 10 Gy to 50 Gy on proliferation and differentiation of osteoblast-like cells on the titanium plate were investigated.
MC3T3-E1 cells were used as osteoblast-like cells. Proliferation was evaluated by crystal violet staining and cell differentiation was estimated by measuring ALP-ase activity. At first, the cells suspended in medium were radiated and placed on the titanium plate to study the potentiality of cell proliferation. The results showed that these cells could attach to the plate, though the number of cells was less than that of non-radiated cells. However, these radiated cells did not show further proliferation, and then these cells released from the plate with culture. Next, effects of radiation on cells proliferated on the plate were studied. The cells were radiated at the subconfluent stage. While further proliferation of cells ceased after radiation, the cells still attached to the plate during culturing periods. Expression of alkaline phosphatase (ALP-ase) was not seen. When the cells that were already expressed ALP-ase were radiated at the confluent stage, further increase of the enzyme activity was not shown such as nonradiated cell. However, the enzyme activity was not inhibited by radiation. Though the calcium accumlation on the titanium plate of radiated cells was less than that of non-radiated cells, calcification was confirmed in the radiated cells.
These results suggested that radiation has profound influence on the proliferation and differentiation of osteoblast-like cells attached to the titanium plate.
