• Nutrition Research and Practice
• /
• v.4 no.5
• /
• pp.356-361
• /
• 2010

Zinc is an essential trace element required for bone formation, however not much has been clarified yet for its role in osteoblast. We hypothesized that zinc would increase osteogenetic function in osteoblasts. To test this, we investigated whether zinc treatment enhances bone formation by stimulating osteoblast proliferation, bone marker protein alkaline phosphatase activity and collagen synthesis in osteoblastic MC3T3-E1 cells. MC3T3-E1 cells were cultured and treated with various concentrations of zinc (0, 1, 3, 15, 25 uM) along with a normal osteogenic medium (OSM) as control for 1, 5, 10 days. As measured by MTT assay for mitochondrial metabolic activity, cell proliferation was stimulated even at low zinc treatment (1-3 ${\mu}M$) compared to OSM, and it was stimulated in a zinc concentration-dependent manner during 5 and 10 days, with the most pronounced effect at 15 and 25 uM Zn. Cellular (synthesized) alkaline phosphatase (ALP) activity was increased in a zinc concentration-dependent manner, so did medium (secreted) ALP activity. Cellular collagen concentration was increased by zinc as time went by, therefore with the maximum zinc stimulatory effect in 10 days, and medium collagen concentration showed the same pattern even on 1 and 5 day. This zinc stimulatory effect of collagen synthesis was observed in cell matrix collagen staining. The study results imply that zinc can increase osteogenic effect by stimulating cell proliferation, ALP activity and collagen synthesis in osteoblastic cells.

• Natural Product Sciences
• /
• v.14 no.1
• /
• pp.21-26
• /
• 2008

The leaves of Acanthopanax species have traditionally been used as a tonic and a sedative as well as in the treatment of rheumatism and diabetes. Chiisanoside is the major active lupane triterpenoid of Acanthopanax leaves. To investigate the bioactivities of chiisanoside, which act on bone metabolism, the effects of chiisanoside on the function of osteoblastic MC3T3-E1 cells were studied. Chiisanoside $(0.02{\sim}20\;{\mu}M)$ significantly increased the growth of MC3T3-E1 cells and caused a significant elevation of alkaline phosphatase (ALP) activity, collagen content, and nodules mineralization in the cells (P < 0.05). The effect of chiisanoside (2 ${\mu}M$) in increasing ALP activity was completely prevented by the presence of tamoxifen, suggesting that the effect of chiisanoside might be partly estrogen receptor mediated. Moreover, cotreatment of p38 inhibitor SB203580 or JNK inhibitor SP600125 inhibited chiisanoside-mediated ALP upregulation, suggesting that the induction of differentiation by chiisanoside is associated with increased activation of p38 and JNK mitogen-activated protein kinases. Our data indicate that the enhancement of osteoblast function by chiisanoside may result in the prevention for osteoporosis.

• Imaging Science in Dentistry
• /
• v.38 no.4
• /
• pp.195-202
• /
• 2008

Purpose : To characterize the effects of 2-deoxy-D-glucose (2-DG) and quercetin (QCT) on gene expression of osteonectin (ON) and osteopontin (OP) in irradiated MC3T3-El cells. Materials and Methods : When MC3T3-El osteoblastic cells had reached 70-80% confluence, cultures were transferred to a differentiating medium supplemented with 5 mM 2-DG or 10 ${\mu}M$ QCT and then irradiated with 2, 4, 6, and 8 Gy. At various times after irradiation, the cells were analyzed for the expression of bone mineralization genes such as ON and OP. Results : The mRNA expression of both ON and OP was increased according to the culture time in the differentiation medium, and the increase of the genes peaked at 14 days after the differentiation induction. In the case of OP, the increase of mRNA expression was maintained to 28 days after the differentiation, while the mRNA level of ON was reduced to the basal level at the same time. Irradiation adding 2-DG showed a significant peak value in the expression pattern of ON at 4 Gy 7 days after irradiation. Irradiation adding QCT increased the mRNA expression of ON and OP in a dose-dependant manner, but irradiation adding 2-DG did not show any differences between the control and experiments 14 days after irradiation. Irradiation adding QCT increased significantly the expression patterns of ON 21 days after irradiation. Conclusion : The results showed that QCT acted as a radiosensitizer in the gene expression of ON and OP during differentiation of the late stage of irradiated MC3T3-E1 osteoblastic cells in vitro. (Korean J Oral Maxillofac Radiol 2008; 38: 195-202)

• Imaging Science in Dentistry
• /
• v.34 no.2
• /
• pp.99-106
• /
• 2004

Purpose: To investigate the effects of irradiation on the phenotypic expression of the MC3T3-El osteoblastic cell line, especially on the osteonectin and bone sialoprotein. Materials and Methods: Cells were irradiated with a single dose of 0.5, 1, 4 and 8 Gy at a dose rate of 5.38 Gy/min using Cs-I37 irradiator. After specimens were harvested, total RNA was extracted on the 3rd, 7th, 14th, 21st day after irradiation. The total RNA was reverse-transcribed and the resulting cDNAs were subjected to amplification by PCR with a pair of primers. Results: The irradiated cells showed a dose-dependent increase in osteonectin mRNA expression when compared with the unirradiated control group. The irradiated cells showed no difference in bone sialoprotein mRNA expression when compared with the unirradiated control group. In accordance with the duration of culture period after irradiation, the level of osteonectin mRNA expression showed no difference, but it increased a little at the 21st day in the 4 and 8 Gy exposure groups. In the case of bone sialoprotein, however, the level of mRNA expression increased significantly at the 3rd and 7th day after irradiation, but it showed no difference at the 14th and 21st day when compared with the control group. Conclusion: These results showed that each single dose of 0.5, 1, 4 and 8 Gy influenced the mRNA expression of osteonectin and bone sialoprotein at the calcification stage of osteoblastic cells, suggesting that single dose of irradiation affected the osteoblastic bone formation at the cell level.

• The korean journal of orthodontics
• /
• v.28 no.6 s.71
• /
• pp.915-926
• /
• 1998

The cytoskeleton has been shown to form a network, connecting the extracelluar matrix via integrin with the nucleus and the cytoplasmic constituents of the cell. It is therefore assumed that the cytoskeleton may mediate signals generated by perturbations originating in the matrix. The purpose of this study is to examine the effect of cytoskeletal change on osteoblastic cell activities. The author cultured osteoblastic cells obtained from neonatal mouse calvaria. The cells were teated with cytochalasin B(CB) or colchicine (COL) at four concentrations for 3 hours and after another 24 hours the conditioned media was collected and assayed for prostaglandin $E_2\;(PGE_2)$, interleukin-6(IL-6), tumor necrosis factor-$\alpha$ (TNF-$\alpha$) and matrix metalloproteinase-1(MMP-1). In addition, the cytoskeletal protein actin were observed by immuno-fluorescence. The results were as follows: 1. The production of $PGE_2$ showed the tendency to be increased in CB-treated group. $PGE_2$ was increased in COL-treated group dose-dependantly, 2. IL-6 production, in CB-treated group, was increased, except at 1.0 ${\mu}g/ml$. IL-6 was induced in COL-treated group. 3. TNF-$\alpha$ production was increased in CB-treated group, except at 1.0 ${\mu}g/ml$, and in COL-treated group, that was increased. 4. The MMP-1 production was decreased in CB-treated soup and was not changed in COL-treated group, which could be selectively visualized by immunoblotting with monospecific antibody. 5. The cytoskeletal actin stress fibers were disappeared and the cells showed to be rounded in CB-treated group. These results indicated that there are a relationship between the cytoskeletal rearrangements and osteoblastic cell activities, especially in release of paracrine/autocrine factors, such as $PGE_2$, IL-6, and TNF-$\alpha$.

• Journal of Periodontal and Implant Science
• /
• v.28 no.4
• /
• pp.769-786
• /
• 1998

The purpose of the present study is to examine the effect of cell proliferation and alkaline phosphatase activity in osteoblastic cells and to compare the bone healing ability of rat calvarial defects between the control group and the safflower seed extract treated group. Osteoblastic cells were obtained from calvariae of a fetal rat. Cells were cultured containing DMEM and safflower seed extract ($10^{-6}g/ml$, $10^{-3}g/ml$) at $37^{\circ}$ with 5% $CO_2$ in 100% humidity for 3 days. MTT was performed to examine the viability of the cells, and alkaline phosphatase activity was analyzed to examine the mineralization in vitro. Rat calvarial defects($5{\times}5mm$) in 250g Sprague-Dawly were made using round bur. Rats were administrated with safflower seed extract(0.35g/kg/day) for experimental periods. Calvarial defects were studied histopathologically and immunohistochemically at 1,4, and 8 weeks. High concentration group($10^{-3}g/ml$) of safflower seed extract significantly increased in the cell proliferation and alkaline phos phatase synthesis in osteoblastic cells. The infiltration of inflammatory cells and osteoclastic activities were decreased in the safflower seed extract treated group as compared with control group. Bone maturation was accelerated in the safflower seed extract treated group as compared to control group. No difference in osteoinductive process was observed between the control and the safflower seed extract treated group. Immunohistochemical observation revealed that protein expression of TGF-$\beta$and osteonectin during early healing phase in the safflower seed extract treated group was slightly increased as compared to control group. These results indicate that safflower seed extract promotes the healing process in bony defect of rat calvariae, and retains a potential applicability as an adjuvant therapeutic modality for regeneration of periodontal bony defect.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.28 no.6
• /
• pp.549-558
• /
• 2006

During distraction osteogenesis, the angiogenic activity is crucial factor in the new bone formation. The aim of this study was to detect the autocrine growth activity in the cellular components of the distracted periosteum with observation of the expression of vascular endothelial growth factor (VEGF) and its receptors following the mandibular distraction osteogenesis. Unilateral mandibular distraction (0.5 mm twice per day for 10 days) was performed in six mongrel dogs. Two animals were sacrificed at 7, 14, and 28 days after completion of distraction, respectively. The distracted lingual periosteum was harvested and processed for immunohistochemical examinations. After then, we observed the expression of VEGF, Flt-1 (VEGFR-1), and Flk-1 (VEGFR-2) in the osteoblasts and immature mesenchymal cells of the distracted periosteum. At 7 days after distraction, the expression of VEGF and its receptors were significantly increased in the cellular components of the distracted periosteum. Up to 14 days following distraction, the increased expressions were maintained in the osteoblastic cells. At 28 days after distraction, the expression of VEGF and its receptors decreased, but VEGF was still expressed weak or moderate in the osteoblastic cells of distracted periosteum. The expression pattern of VEGF and its receptors shown here suggested that VEGF play an important role in the osteogenesis, and these osteoblastic cell-derived VEGF might act as autocrine growth factor during distraction osteogenesis. In the other word, the cellular components in the distracted periosteum, such as osteoblasts and immature mesenchymal cells, might have autocrine growth activity during distraction osteogenesis.

• The Korean Journal of Physiology and Pharmacology
• /
• v.6 no.3
• /
• pp.165-169
• /
• 2002

We have previously demonstrated that phytoestrogens isolated from safflower seeds significantly attenuated bone loss in ovariectomized rats, and directly stimulated proliferation and differentiation of cultured osteoblastic cells. In an attempt to elucidate underlying cellular mechanisms, in the present study we investigated effects of $17{\beta}-estradiol\;(E_2)$ and phytoestrogens such as matairesinol and acacetin, a type of lignan and flavonoid, respectively, on activation of mitogen activated protein (MAP) kinases, extracellular signal-regulated kinase 1 (ERK1) and ERK2, in cultured osteoblastic ROS 17/2.8 cells. Western blot analysis with anti-MAP kinase antibody showed that a wide range concentrations $(10^{-14}\;to\;10^{-6}\;M)\;of\;E_2$ as well as both phytoestrogens induced rapid and transient activation of ERK1/2 through phosphorylation within minutes. Maximum activation of MAP kinases by $E_2$ and phytoestrogens were observed at 10 and 15 min, respectively. $E_2-induced$ phosphorylation of ERK1/2 returned to the control level at 30 min, whereas phytoestrogen-induced phosphorylation was maintained at high level until 30 min. PD-98059, a highly selective inhibitor of MAP kinase, prevented phosphorylation of ERK1/2 in the cells treated either with $E_2$ or phytoestrogens. To examine a possible involvement of estrogen receptor in the activation process of MAP kinase, Western blot analysis was performed in the presence and absence of the estrogen receptor antagonists, ICI 182,780 and tamoxifen. These antagonists blocked MAP kinase phosphorylation induced not only by $E_2,$ but also by the phytoestrogens. To the best our knowledge, this study is the first to demonstrate that phytoestrogens such as flavonoid and lignan extracted from safflower seeds produce a rapid activation of MAP kinase, at least partially via membrane estrogen receptor of the cultured osteoblastic cells.

• Food Science and Biotechnology
• /
• v.14 no.5
• /
• pp.593-598
• /
• 2005

Osteoporosis is recognized as one of the major hormonal deficiency diseases, especially in menopausal women and the elderly. When the estrogen level is reduced in the body, local factors, which are known to be related with bone resorption, are increased and promote osteoclastogenesis. In our previous study, we validated the estrogenicity of silkworm pupa. In this study, we investigated the effect of silkworm pupa extract (SPE) on the function of osteoblastic MC3T3-E1 cells. SPE (10 and $50\;{\mu}g/mL$) significantly elevated cell viability, alkaline phosphatase (ALP) activity, and collagen content in the cells. The effect of SPE ($50\;{\mu}g/mL$) in increasing cell viability, ALP activity, and collagen content was completely inhibited by the presence of $10^{-6}\;M$ of cycloheximide and $10^{-6}\;M$ of tamoxifen, suggesting that SPE's effect results from a newly synthesized, protein component and that it might be partly involved in estrogen action. Furthermore, we examined the effect of SPE on the $H_2O_2-induced$ apoptosis and production of local factors in osteoblasts. Treatment with SPE ($50\;{\mu}g/mL$) decreased the 0.2 mM $H_2O_2-induced$ apoptosis and the production of tumor necrosis factor (TNF)-${\alpha}$, interleukin (IL)-6 and nitric oxide (NO) in osteoblasts. Our data indicate that the enhancement of osteoblast function by silkworm pupa may prevent osteoporosis and inflammatory bone diseases.

• International Journal of Oral Biology
• /
• v.38 no.3
• /
• pp.127-134
• /
• 2013

Xylitol is a sugar alcohol with a variety of functions including bactericidal and anticariogenic effects. However, the cellular mechanisms underlying the role of xylitol in bone metabolism are not yet clarified. In our present study, we exploited the physiological role of xylitol on osteoclast differentiation in a co-culture system of osteoblastic and RAW 264.7 cells. Xylitol treatment of these co-cultures reduced the number of tartrate-resistant acid phosphatase (TRAP)-positive multinucleated cells induced by 10 nM $1{\alpha},25(OH)_2D_3$ in a dose-dependent manner. A cell viability test revealed no marked cellular damage by up to 100 mM of xylitol. Exposure of osteoblastic cells to xylitol decreased RANKL, but not OPG, mRNA expression in the presence of $10^{-8}M$ $1{\alpha},25(OH)_2D_3$ in a dose-dependent manner. Furthermore, bone resorption activity, assessed on bone slices in the coculture system, was found to be dramatically decreased with increasing xylitol concentrations. RANKL and OPG proteins were assayed by ELISA and the soluble RANKL (sRANKL) concentration was decreased with an increased xylitol concentration. In contrast, OPG was unaltered by any xylitol concentration in this assay. These results indicate that xylitol inhibits $1{\alpha},25(OH)_2D_3$-induced osteoclastogenesis by reducing the sRANKL/OPG expression ratio in osteoblastic cells.