• The Journal of Korean Academy of Prosthodontics
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• v.46 no.6
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• pp.620-627
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• 2008

STATEMENT OF PROBLEM: A biochemical approach for surface modification has offered an alternative for physicochemical and morphological methods to obtain desirable bone-implant interfaces. PURPOSE: The purpose of the present study was to investigate cell responses to poly (D,L-lactide-co-glycolide) (PLGA)/$1{\alpha}$,25-(OH)$_2D_3$ coating with reference to cellular proliferation and differentiation in vitro. MATERIAL AND METHODS: 96 titanium discs were fabricated and divided into four groups. Group 1 was anodized under 300 V as control. Group 2, 3 and 4 were anodized then coated with 3 ml PLGA/$1{\alpha}$,25-(OH)$_2D_3$ solutions. Amount of the solutions were 2 ul, 20 ul and 200ul respectively. The osteoblast-like Human Osteogenic Sarcoma (HOS) cells were seeded and cultured for 1, 3 and 7 days. MTSbased cell proliferation assay and ALPase activity test were carried out. RESULTS: PLGA nanoparticles were observed as fine, smooth and round and HOS cells attached to the anodized surfaces through strand-like and sheet-like filopodia. After 3 days of culture, the dendritic filopodia were exaggerated and sheet-like cytoplasmic projections covered the coated titanium surfaces. After 3 days of culture, all of the groups showed increased cellular proliferation and the lowest proliferation rate was measured on group 2. Higher amount of incorporated $1{\alpha}$,25-(OH)$_2D_3$ (Group 3 and 4) improved cellular proliferation but the differences were not significant statistically (P > .05). But they increased the rate of ALP activities than the control group at day 3 (P < .05). CONCLUSION: Biodegradable PLGA nanoparticles incorporated with vitamin D metabolite positively affected proliferation and differentiation of cells on the anodized titanium surface.

• International Journal of Oral Biology
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• v.36 no.4
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• pp.173-178
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• 2011

Tumor necrosis factor alpha ($TNF{\alpha}$) is a multifunctional cytokine that is elevated in inflammatory diseases such as atherosclerosis, diabetes and rheumatoid arthritis. Recent evidence has suggested that ${\beta}2$ adrenergic receptor (${\beta}2AR$) activation in osteoblasts suppresses osteogenic activity. In the present study, we explored whether $TNF{\alpha}$ modulates ${\beta}AR$ expression in osteoblastic cells and whether this regulation is associated with the inhibition of osteoblast differentiation by $TNF{\alpha}$. In the experiments, we used C2C12 cells, MC3T3-E1 cells and primary cultured mouse bone marrow stromal cells. Among the three subtypes of ${\beta}AR$, ${\beta}2$ and ${\beta}3AR$ were found in our analysis to be upregulated by $TNF{\alpha}$. Moreover, isoproterenol-induced cAMP production was observed to be significantly enhanced in $TNF{\alpha}$-primed C2C12 cells, indicating that $TNF{\alpha}$ enhances ${\beta}2AR$ signaling in osteoblasts. $TNF{\alpha}$ was further found in C2C12 cells to suppress bone morphogenetic protein 2-induced alkaline phosphatase (ALP) activity and the expression of osteogenic marker genes including Runx2, ALP and osteocalcin. Propranolol, a ${\beta}2AR$ antagonist, attenuated this $TNF{\alpha}$ suppression of osteogenic differentiation. $TNF{\alpha}$ increased the expression of receptor activator of NF-${\kappa}B$ ligand (RANKL), an essential osteoclastogenic factor, in C2C12 cells which was again blocked by propranolol. In summary, our data show that $TNF{\alpha}$ increases ${\beta}2AR$ expression in osteoblasts and that a blockade of ${\beta}2AR$ attenuates the suppression of osteogenic differentiation and stimulation of RANKL expression by $TNF{\alpha}$. These findings imply that a crosstalk between $TNF{\alpha}$ and ${\beta}2AR$ signaling pathways might occur in osteoblasts to modulate their function.

• Journal of Ginseng Research
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• v.39 no.1
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• pp.46-53
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• 2015

Background: Glucocorticoids (GCs) are commonly used in many chemotherapeutic protocols and play an important role in the normal regulation of bone remodeling. However, the prolonged use of GCs results in osteoporosis, which is partially due to apoptosis of osteoblasts and osteocytes. In this study, effects of Korean Red Ginseng (KRG) on GC-treated murine osteoblastic MC3T3-E1 cells and a GC-induced osteoporosis mouse model were investigated. Methods: MC3T3-E1 cells were exposed to dexamethasone (Dex) with or without KRG and cell viability was measured by the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay. Realtime polymerase chain reaction was performed to evaluate the apoptotic gene expression; osteogenic gene expression and alkaline phosphatase (ALP) activity were also measured. Western blotting was performed to evaluate the mitogen-activated protein kinase (MAPK) proteins. A GC-induced osteoporosis animal model was used for in vivo study. Results and conclusion: The MTT assay revealed that Korean Red Ginseng (KRG) prevents loss of cell viability caused by Dex-induced apoptosis in MC3T3E1 cells. Real-time polymerase chain reaction data showed that groups treated with both Dex and KRG exhibited lower mRNA levels of caspase-3 and -9, whereas the mRNA levels of Bcl2, IAPs, and XIAP increased. Moreover, groups treated with both Dex and KRG demonstrated increased mRNA levels of ALP, RUNX2, and bone morphogenic proteins as well as increased ALP activity in MC3T3-E1 cells, compared to cells treated with Dex only. In addition, KRG increased protein kinase B (AKT) phosphorylation and decreased c-Jun N-terminal kinase (JNK) phosphorylation. Moreover, microcomputed tomography analysis of the femurs showed that GC implantation caused trabecular bone loss. However, a significant reduction of bone loss was observed in the KRG-treated group. These results suggest that the molecular mechanism of KRG in the GC-induced apoptosis may lead to the development of therapeutic strategies to prevent and/or delay osteoporosis.

• Journal of Life Science
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• v.34 no.10
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• pp.701-712
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• 2024

Fucoidan is a polysaccharide found in brown algae, which is known for its various bioactive effects, including immune enhancement, anti-cancer, and anti-inflammatory properties. In this study, the effects of fucoidan on cellular and mitochondrial damage, as well as changes in osteogenic and osteoclastic activities induced by advanced glycation end-products (AGEs) in MC3T3-E1 osteoblast-like cells, were investigated. Treatment with AGEs resulted in a time- and dose-dependent decrease in MTT reduction capacity, activation of caspases (-3, -8, and -9), and an increase in apoptosis. Pre-treatment with fucoidan significantly alleviated these cellular damage markers caused by AGEs. In addition, fucoidan protected against AGEs-induced mitochondrial dysfunction by significantly mitigating the loss of mitochondrial membrane potential, reduction in intracellular ATP levels, and occurrence of mitochondrial permeability transition in AGEs-treated cells. Fucoidan also markedly suppressed the production of reactive oxygen species and, lipid and protein peroxidation induced by AGEs. In cells exposed to AGEs, gene expression related to osteogenic differentiation and markers of osteogenic activity increased, while markers of osteoclastic activity decreased. Fucoidan significantly moderated these changes. In conclusion, AGEs induce mitochondrial dysfunction and apoptosis in MC3T3-E1 cells, while decreasing osteogenic differentiation and activity, and increasing osteoclastic activity. Fucoidan appears to reduce cellular and mitochondrial damage and improve osteogenic activity impaired by AGEs.

• Journal of the Korean Society of Food Science and Nutrition
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• v.40 no.10
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• pp.1384-1390
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• 2011

Chrysanthemum indicum L. (Asteraceae) is a common traditional herbal medicine used for the treatment of inflammation, hypertension, and respiratory diseases due to its strong antagonistic function against inflammatory cytokines. In this study, the effects of Chrysanthemum indicum L. extract (CIE) on the function of osteoblastic MC3T3-E1 cells and the production of local factors in osteoblasts were investigated. CIE (100 ${\mu}g/mL$) significantly increased the growth of MC3T3-E1 cells and caused a significant elevation of alkaline phosphatase (ALP) activity, and the deposition of collagen and calcium in the cells (p<0.05). The effect of CIE in increasing cell growth, ALP activity, and collagen content was completely prevented by the presence of 1 ${\mu}M$ tamoxifen, suggesting that CIE's effect might be partly involved in estrogen-related activities. These results indicate that the enhancement of osteoblast functionality by CIE may prevent osteoporosis and inflammatory bone diseases.

• Imaging Science in Dentistry
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• v.30 no.3
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• pp.189-198
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• 2000

Purpose: The study was aimed to detect the induction of apoptosis, cell cycle arrest and calcified nodule formation after irradiation on primarily cultured osteoblasts. Materials and Methods: Using rat calvarial osteoblasts, the effects of irradiation on apoptosis, cell cycle arrest, and calcified nodule formation were studied. The single irradiation of 10 and 20 Gy was done with 5.38 Gy/min dose rate using the l37Cs cell irradiator at 4th and 14th day of culture. Apoptosis induction and cell cycle arrest were assayed by the flowcytometry at 1, 2, 3, and 4 days after irradiation. The formation of calcified nodules was observed by alizarin red staining at 1, 3, 10, 14 days after irradiation at 4th day of culture, and at 1, 4, 5 days after irradiation at 14th day of culture. Results: Apoptosis was not induced by 10 or 20 Gy independent of irradiation and culture period. Irradiation did not induced G1 arrest in post-irradiated ostedblasts. After irradiation at 4th-day of culture, G2 arrest was induced but it was not statistically significant after irradiation at 14th-day of culture. In the case of irradiated cells at 4th day of culture, calcified nodules were not formed and at 14th-day of culture after irradiation, calcified nodule formation did not affected. Conclusion: Taken together, these results suggest that irradiation at the dose of 10-20 Gy would not affect apoptosis induction of osteoblasts. Cell cycle and calcified nodule formation were influenced by the level of differentiation of osteblasts.

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.685-700
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• 1997

The ultimate aim of periodontal treatment is periodontal regeneration, which necessiates the regeneration of bone tissues. This paper investigated the effect of growth factor on bone cells. Platelet-derived growth factor(PDGF) is the one of the polypeptide growth factor that has been reported as a biological mediator which regulates activities of the cell proliferation, migration and metabolism of undifferentiated mesenchymal cells. The purpose of this study is to evaluate the effects of PDGF on bone nodule formation and ALP activity of MC3T3-El cells. Cells were seeded at $1{\times}10^5cells/well$ in alpha-modified eagle medium containing 10% fetal bovine serum, lOml beta-glycerophosphate and $50{\mu}g/ml$ of ascorbic acid. PDGF 0, 0.1, 1, 10 ng/ml were added to the cells at a confluent state and cultured for 3, 7, 14, 21, 28 days. We examined bone nodule formation and alkaline phosphatase activity. The results were as follows : There were bone nodule formation at day 21 both in control and all the experimental groups, and at day 28, all the experimental groups showed much more bone nodules than control groups. Compared to control-l group, ALP activity was increased in PDGF O.1ng/ml group and was decreased in 1,10ng/ml PDGF treated groups.{P< 0.05, P< 0.01) Compared to control-2, ALP activity was decreased in all the experimental groups except PDGF 0.1ng/ml in 21 day group. In the time-response effect, ALP activity was increased by the day 14 in all the experimental groups and thereafter ALP activity was decreased.(P<0.05, P< 0.01) In the dose-response effect, ALP activity was decreased as the dose of PDGF was increased, and after 21 day ALP activity was lowest in 1 ng/ml group, ALP activity was highest in the day 7 in control group and 0.1 ng/ml, 14 day experimental group. In conclusion, PDGF is considered more effective in the proliferation than differentiation of osteoblast-like cells, and it may be useful to study the combined effect of PDGF and other growth factors on osteoblast-like cells.

• Natural Product Sciences
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• v.11 no.2
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• pp.103-108
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• 2005

Bioflavone quercetin is thought to have an important role to inhibit bone loss by affecting osteoclastogenesis and regulating a number of systemic and local factors such as hormones and cytokines. In this study, we examined how quercetin acts on cytokine production and mineralization of osteoblast in the presence of tumor necrosis factor-alpha $(TNF-{\alpha})$ which has been known to play a pivotal role in bone metabolic diseases. Quercetin inhibited $TNF-{\alpha}-induced$ secretion of $IFN-{\gamma}$ and IL-6 in differentiated MC3T3-E1 cells. As indicated by the markers that are characteristics of the osteoblast phenotype, such as alkaline phosphatase (ALP) activity and calcium deposition, quercetin treatment slightly prevented the $TNF-{\alpha}-induced$ dramatic inhibition of differentiation and mineralization of MC3T3-E1 cells. Further, quercetin inhibited the production of nitric oxide induced by $TNF-{\alpha}$ in the cells. Collectively, our findings indicate that quercetin inhibites $TNF-{\alpha}-induced$ secretion of inflammatory cytokines in differentiated MC3T3-E1 cells without any cytotoxic effects.

• The Journal of Korean Obstetrics and Gynecology
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• v.31 no.4
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• pp.1-15
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• 2018

Objectives: Osteoporosis is considered a serious human disease. We developed an extract of mixed herbs containing root of Platycodon grandiflorum (ExMH-PGR), which is expected to be effective in preventing or treating osteoporosis. The aim of this study was to investigate the anti-osteoporotic effect of ExMH-PGR in osteoblastic MC3T3-E1 cells and osteoclastic RAW 264.7 cells. Methods: To examine the anti-osteoporotic effect of ExMH-PGR, osteoblast and osteoclast differentiation were induced and cultured with various concentrations of ExMH-PGR. Alkaline phosphatase (ALP) activity, collagen synthesis, osteocalcin production, and mineralization in MC3T3-E1 cells were analyzed. Tartrate-resistant acid phosphatase (TRAP) activity and the formation of actin ring in RAW 264.7 cells were analyzed. Results: ExMH-PGR at concentration up to $25{\mu}g/mL$ significantly increased ALP activity, collagen synthesis, osteocalcin production, and mineralization in MC3T3-E1 cells. ExMH-PGR at 50 to $200{\mu}g/mL$ significantly inhibited TRAP activity and the formation of actin ring in RAW 264.7 cells. Conclusions: These results demonstrate that ExMH-PGR stimulates osteoblastic activities and inhibits osteoclastic activities in in vitro systems, suggesting that ExMH-PGR might be considered as an anti-osteoporotic candidate for treatment of osteoporosis disease.

• Korean Journal of Plant Resources
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• v.26 no.5
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• pp.658-662
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• 2013

Rubus coreanus and Astragalus membranaceus Bunge have been used as a traditional medicine with various pharmacological properties for a long time in Asia. We investigated the proliferative and differentiative effects on osteoblastic cells, MG-63 in various mixture ratios of immature fructus extracts of R. coreanus and root extracts of A. membranaceus. With preliminary in vivo ovariectomized mice, we confirmed the effects of the supplementation of various mixture on alkaline phosphatase (ALP) activity in serum. The ratio of 7:3 is considered as the most effective ratio for the proliferation of osteoblastic cells as they increased by 56.8% similar to estradiol. ALP activity in osteoblast increased by the combination of R. coreanus and A. membranaceus and peaked in the ratio of 72:28 and 68:32 respectively. These results indicate that the optimal combination of R. coreanus and A. membranaceus in 7:3 has the most beneficial effects on the activation of osteoblast cells, and give further possibilities that it can be used clinically in the treatment of osteoporosis.