| Budget Amount *help |
¥3,500,000 (Direct Cost: ¥3,500,000)
Fiscal Year 2006: ¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 2005: ¥2,200,000 (Direct Cost: ¥2,200,000)
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| Research Abstract |
We examined effects of TNF-a on mineralization ability of human dental pulp (HDP) cells. The quantity of RT-PCR product for BMP-2 from the HDP cells stimulated by TNF-a is increased. However, ALP activity was not increased on the cells incubated with TNF-a. On the other hand, ALP activity was significantly increased on HDP cells treated with Ammonium Pyrrolidinedithiocarbamate (PDTC, NF-κB inhibitor) groups and combined supplementation of TNF-a and PDTC groups. Furthermore, we examined the effect of TNF-a and PDTC on Smad7 expression using RT-PCR and western blot analysis. Western blot analysis revealed that Smad7 protein in HDP cells were increased by TNF-a, but Smad7 mRNA and protein in HDP cells treated with supplementation of TNF-a and PDTC were decreased compared with TNF-a. These results suggest that NF-κB and Smad7 play an important role in the down regulation of ALP activity by TNF-a on HDP cells.
We investigated the effects of Ga-Al-As laser irradiation on the mineralization ability of HDP cells and on Smads production as one mechanism for the transmission of laser photochemical energy to cells. HDP cells in vitro were irradiated once with a Ga-Al-As laser at 1.0 W for 500 s, and calcified nodule formation was assessed by Alizarin red S staining. The laser irradiation was greater in the laser-irradiated group than in the unirradiated control cells. Production of calcium was also increased by laser irradiation. ALP activity was higher after laser irradiation. Expression of mRNAs of Smadl, Smad7, BMPs, ALP, and osteocalcin was greater with laser irradiation. However, Smad6 mRNA expression in HDP cells was inhibited by laser irradiation. Production of BMP-2 and BMP-4 in conditioned medium was also higher after laser irradiation. These results suggest that Smads and BMPs play important roles in ALP activity and calcification upon laser irradiation of HDP cells.
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