The Effects Of TGF-β₁ On The Proliferation And Differentiation Of Osteoblasts On Titanium Disc Surfaces In Vitro

[Objective] The purpose of this study is to investigate the consequential changes of proliferation and differentiation of fetal rat osteoblasts incubated with TGF- β1, and to make a primary understanding of the relationship between TGF- β1 and different surface treatment of titanium during osteoblast growth.[Materials and Methods] The primary osteoblasts separated from calvarium of 10 fetal rats were cultured and a finite cell line was established in vitro. Then cells were seeded on different surfaces of Ti disc(Smooth surface, Sandblasted surface and TPS surface) and TGF- β1 with a dose of l0ng/ml was administrated to osteoblasts incubated on the different surfaces of Ti disc. At the time points 1, 3, 5 and 7days after addition of TGF- β1, cell proliferation activity was evaluated with MTT colorimetric assay At the time points 1, 3, 5 and 10 days after addition of TGF- β1i, ALP activity of cellular layer and OC content of medium were tested to evaluate the differentiational status of osteoblasts. Osteoblasts were cultured on the surface of glass in the same condition as control group and tested as same as the experiment groups.[Results] The results of MTT assay showed that TGF- β1 inhibited proliferation of osteoblasts in all groups in a time-dependent manner. In the early phase, TGF- β1 has significantly decreased proliferation activity of osteoblasts on the smooth surfaces or under control conditions on glass. Osteoblast proliferation of all groups was inhibited obviously compared with non-addition of TGF- β1 at the time point 7 day. The present study showed that TGF- β1, added to the cultured cells in vitro in the early phase, has significant increased ALP activity of cells on all surfaces. Compared with non-addition of TGF- β1 ,cell ALP activity was inhibited on the smooth surfaces while promoted on the sandblasted surfaces and TPS surfaces as time goes by. It was also found that TGF- β1 has significantly increased OC content of osteoblasts of the experiment groups(except TPS) in the early phase. When osteoblasts matured, OC content between addition andnon-addition of TGF- P i on the smooth surface showed no difference while OC content was obviously increased on the rough surfaces (p<0.05).[Conclusion] It is concluded that extraneous TGF-P i with a dose of lng/ml inhibited osteoblast proliferation activity on the different surfaces of Ti disc and the effect was time-dependent, extraneous TGF- i(10ng/ml) increase the ALP activity and OC content of cells on Ti disc surfaces in the early phase. With osteoblasts maturation, extraneous TGF- P i levels affected osteoblast differentiation in the conditioned media in a surface-dependent manner.