• Journal of the korean academy of Pediatric Dentistry
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• v.24 no.1
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• pp.1-17
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• 1997

The purpose of this study was to investigate the aspects of proliferation and bone nodule formation of osteogenic precursor cells. To determine the effects of ascorbic acid and dexamethasone upon capacity of osteoblast proliferation and bone nodule formation, cells were maintained in the presence of one or some of these additives for up to 30 days. Group I culture was maintained in standard medium(DMEM plus 10% plus antibiotics), group II was maintained in supplemented medium containing dexamethasone, group III was maintained in supplemented medium containing ascorbic acid and sodium-${\beta}$-glycerophosphate, and group IV was maintained in supplemented containing ascorbic acid, sodium-${\beta}$-glycerophosphate and dexamethasone. Morphology of bone nodules was observed with light microscope and electron microscope. The results were as follows: ${\bullet}$ Proliferation capacity of osteoblasts was not affected by single use of dexamethasone, but it was chiefly affected by ascorbic acid. ${\bullet}$ Cellular morphology was fibroblastic appearance initially, but, it was gradually changed to polygonal shape accompanied by confluency stage. ${\bullet}$ Pluripotent mesenchymal cells existed during primary culture, they were differentiated to adipocyte, chondrocyte, osteocyte according to culture condition. ${\bullet}$ Dexamethasone increased bone nodule formation under the condition that the culture was maintained with supplemented medium ascorbic acid and sodium-${\beta}$-glycerophosphate. ${\bullet}$ when the cultures were stained with alizarin red, the group supplemented with dexamethasone, ascorbic acid and sodium-${\beta}$-glycerophosphate showed the marked increase of bone nodule formation, but the group supplemented with ascorbic acid and sodium-${\beta}$-glycerophosphate revealed only small amounts of bone nodules. And the groups cultured without ascorbic acid showed no observed any of bone-like mass independent of dexamethasone addition.

• 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.

• Journal of Periodontal and Implant Science
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• v.41 no.4
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• pp.167-175
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• 2011

Purpose: Periodontal ligament (PDL) cell differentiation into osteoblasts is important in bone formation. Bone formation is a complex biological process and involves several tightly regulated gene expression patterns of bone-related proteins. The expression patterns of bone related proteins are regulated in a temporal manner both in vivo and in vitro. The aim of this study was to observe the gene expression profile in PDL cell proliferation, differentiation, and mineralization in vitro. Methods: PDL cells were grown until confluence, which were then designated as day 0, and nodule formation was induced by the addition of 50 ${\mu}g$/mL ascorbic acid, 10 mM ${\beta}$-glycerophosphate, and 100 nM dexamethasone to the medium. The dishes were stained with Alizarin Red S on days 1, 7, 14, and 21. Real-time polymerase chain reaction was performed for the detection of various genes on days 0, 1, 7, 14, and 21. Results: On day 0 with a confluent monolayer, in the active proliferative stage, c-myc gene expression was observed at its maximal level. On day 7 with a multilayer, alkaline phosphatase, bone morphogenetic protein (BMP)-2, and BMP-4 gene expression had increased and this was followed by maximal expression of osteocalcin on day 14 with the initiation of nodule mineralization. In relationship to apoptosis, c-fos gene expression peaked on day 21 and was characterized by the post-mineralization stage. Here, various genes were regulated in a temporal manner during PDL fibroblast proliferation, extracellular matrix maturation, and mineralization. The gene expression pattern was similar. Conclusions: We can speculate that the gene expression pattern occurs during PDL cell proliferation, differentiation, and mineralization. On the basis of these results, it might be possible to understand the various factors that influence PDL cell proliferation, extracellular matrix maturation, and mineralization with regard to gene expression patterns.

• Journal of Periodontal and Implant Science
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• v.35 no.2
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• pp.289-298
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• 2005

Bone morphogenetic protein-7(BMP-7), a member of the transforming growth factor superfamily, stimulates osteoblast differentiation and bone formation. There are lots of evidences supporting a direct participation of periodontal ligament(PDL) cells on periodontal tissue regeneration. The purpose of this study was to evaluate the effect of recombinant human(rh) BMP-7 on primary rat PDL cells in vitro, with special focus on the ability of bone formation. The PDL cells were cultured with rhBMP-7 at the concentration of 0, 10, 25, 50, 100 and 200ng/ml for MTT assay. We evaluated the alkaline phosphatase activity at 3 and 5 days of incubation and the ability to produce mineralized nodules of rat PDL cells at 14 days of cell culture in concentration of 0, 10, 25, 50 and 100ng/ml. The cell activity was not reduced in cells treated with BMP-7 at $10{\sim}100ng/ml$, whereas the cell activity was reduced in the concentration of 200ng/ml than the control at day 1 and 3(p<0.01). At 3 and 5 day, alkaline phosphatase activity was significantly increased in cells treated with BMP-7 at 50ng/ml and 100ng/ml(p<0.05). The area of mineralized bone nodule was greater in cells treated with BMP-7 at 50 and 100 ng/ml than the control(p<0.01). These results suggest that rhBMP-7 stimulate rat PDL cells to differentiate toward osteoblast phenotype and secretion of the extracellular matrix of rat PDL cells.

• Journal of Periodontal and Implant Science
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• v.31 no.2
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• pp.287-298
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• 2001

Recently, many natural medicines, which have advantage of less side effects and possibility of long-term use have been studied for their capacity of anti-bacterial, anti-inflammatory and regenerative potential of periodontal tissues. Olibanum has the effects to hemostasis, analgesic and anti-inflammatory, and it also has been traditionally used as a drug for the treatment of bone disease in oriental medicine. The purpose of the present study was to investigate the effects of Olibanum extracts on the activity and differentiation of MC3T3-E1 cells, alkaline phosphatase(ALP) synthesis, formation of bone nodules and expression of type I collagen of MC3T3-E1 cells. To examine the cellular activity, MC3T3-E1 cells were cultured with ${\alpha}-MEM(control)$ and each concentration of Olibanum for 2 days and 4 days. To compare the ALP synthesis, MC3T3-E1 cells were cultured with ${\alpha}-MEM(negative\; control)$, dexamethasone(positive control), and each concentration of Olibanum for 2 days and 4 days. To compare the bone nodule formation, MC3T3-E1 ells were cultured for 21 days, and to compare the type I collagen expression, MC3T3-E1 cells were cultured for 4 days. The cellular activity of MC3T3-E1 cells treated with $1{\mu}g/ml$ of Olibanum extracts was significantly increased at 4-day(p<0.05) to control. The activity of ALP in MC3T3-E1 cells treated with $1{\mu}g/ml$ Olibanum extracts was significantly increased at 4-day(p<0.05). All the experimental groups showed much more bone nodule formation than control groups. The group treated with $1{\mu}g/ml$ of Olibanum extracts was the highest bone nodule formation, and showed much more type I collagen expression than negative control. These results indicate that Olibanum extracts may be considered effective in the activity and differentiation of MC3T3-E1 cells.

• The Journal of Korean Obstetrics and Gynecology
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• v.25 no.2
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• pp.23-42
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• 2012

Objectives: This study was performed to evaluate the effect of Samkieumgamibang (SKG) on osteoporosis. Methods: The osteoclastogenesis and gene expression were determined in RANKL-stimulated RAW 264.7 cell. And, osteoblastogenesis was also determined in rat calvarial cell. Results: SKG decreased the number of TRAP positive cell in osteoclast. It also decreased the expression of Cathepsin K, MMP-9, TRAP, c-fos, NAFTc1 and JNK1 in osteoclast. SKG increased the expression of iNOS in RANKL-stimulated in osteoclast. Otherwise, SKG inhibited TRAP activity in osteoclast. SKG increased cell proliferation, ALP activity, bone martix protein, collagen and nodule in osteoblast. Conclusions: It is concluded that SKG might decrease the bone resorption resulted from decrease of osteoclast differentiation and it's related gene expression. And, SKG might increase the bone formation resulted from increase of osteoblast function.

• The Journal of Korean Obstetrics and Gynecology
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• v.27 no.2
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• pp.23-33
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• 2014

Objectives: In this study, the author aimed to evaluate the effect of EtOH extract of Ganoderma lucidum (GLE) on osteoblast proliferation in rat fetus calvarial cells. Methods: The osteoblast separated from rat fetus calvariae was cultivated for 6~21 days and evaluated the cell function. After the addition of GLE on the culture medium, we determined the effect of GLE on the cell viability, cell proliferation, bone matrix protein synthesis, alkaline phosphatase (ALP) activity, collagen synthesis and calcified nodule formation of the cultivated osteoblast. Results: GLE did not change the survival rate of rat calvarial osteoblast. GLE increased the proliferation of rat calvarial osteoblast. GLE increased ALP activity of rat calvarial osteoblast. GLE increased bone matrix protein synthesis of rat calvarial osteoblast. GLE increased collagen synthesis of rat calvarial osteoblast. GLE slightly affected calcified nodule formation of rat calvarial osteoblast. Conclusions: This study suggests that Ganoderma lucidum might improve the osteoporosis resulted from augmentation of osteoblast proliferation.

• Journal of Periodontal and Implant Science
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• v.31 no.1
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• pp.163-180
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• 2001

The aim of this study was to evaluate the effects of chitosan coating on the attachment, proliferation, functional and morphological change of periodontal ligament cells. Primary human periodontal ligament cells were cultured in dulbecco's modified Eagle's medium with 10% fetal bovine serum and 1% antibiotics. In experimental group, cells of 4th to 7th passage were inoculated in the multiwell plates coated with chitosan in concentration of 0.22, 0.2, and $2mg/m{\ell}$. Cell counting and MTT assay were done after 0.5, 1.5, 3, 6 and 24 hours of incubation to evaluate the cell attachment, and then after 2 and 7 days of culture to evaluate the cell proliferation. The alkaline phosphatase activity was measured after 4 and 7 days of culture and the ability to produce mineralized modules was evaluated after 21 days of culture. The results were as follows : 1. The morphology of periodontal ligament cells on the chitosan coating was round or spheric. Round cells were aggregated after 6 hours of culture. Aggregated cells on the chitosan coated surface showed nodule-like appearance after 24 hours of culture and not achieved confluency at 7 days. 2. During early period of culture, the attachment of periodontal ligament cells were inhibited by chitosan coating. Inhibition of cell attachment tended to increase with the concentration of chitosan. 3. At the chitosan concentration of 0.02 and $0.2mg/m{\ell}$, periodontal ligament cells were more rapidly proliferated at 7 days, compared to the control group. At the concentration of $2mg/m{\ell}$, the proliferation of periodontal ligament cells was inhibitied(p<0.01). 4. Alkaline phosphatase activity of periodontal ligament cells was increased in chitosan coated group, especially at the concentration of $0.02mg/m{\ell}$after 4 days of culture.5. Periodontal ligament cells produced mineralized nodules on chitosan coated wells without the addition of mineralized nodule forming materials (ascorbic acid, ${\beta}-glycerophosphat$, dexamethasone). With the addition of mineralized nodule forming materials, periodontal ligament cells produced more mineralized nodules at the concentration of $0.02mg/m{\ell}$, compared to the control. In summary, the attachment, proliferation, cell activity, and alkaline phosphatase activity of periodontal ligament cells depended on the concentration of coated chitosan. Chitosan stimulated mineralized nodule formation by periodontal ligament cells. At the appropriate concentration($0.02mg/m{\ell}$), chitosan could increase alkaline phosphatase activity and stimulate the formation of mineralized nodule by periodontal ligament cells. These results suggest that chitosan can be used as an adjunct for bone graft material, and the matrix of tissue engineering for periodontal regeneration, especially bone regeneration.

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.923-939
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• 1997

This study was performed to evaluate the effect of mixed culture of rat's calvaria cells and periodontal ligament cells on calcification. These cells have been known to do important role on the periodontal tissue regeneration, especially alveolar bone and cementum. Experimental groups were made which based on the different rate of rat's calvaria cells and periodontal ligament cells, and then these cells were cultured with Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum, $50{\mu}g/ml$ ascorbic acid, and 10mM/ ml $Na-{\beta}-glycerophosphate$. Each group was characterized by examining the cell proliferation rate, amount of total protein synthesis, alkaline phosphatase activity, and the number of calcified nodules in vitro. In cell proliferation rate , the cells of control groups were cultured Dulbecco's Modified Eagle's Medium contained with 10 % fetal bovine serum. The results were as follows : 1. The cell proliferation rate in control groups decreased stastically significantly along with the decrease of the rate of bone cells at 7 day and 20 day(P < 0.01). 2. The cell proliferation rate in experimental groups decreased stastically significantly along with decrease of the rate of bone cells at 3 day and 14 day(P < 0.01). 3. The amount of total protein synthesis was significantly decreased along with decrease of the rate of bone cells at 3 day and 6 day(p < 0.01). 4. Alkaline phosphatase activity showed reverse time dependent pattern and was significantly decreased along with decrease of the rate of bone cells during the experimental periods (P < 0.01). 5. Calcified nodules were observed in group 1 (Rat calvaria cells alone) for the first time, and the number of calcified nodule decreased stastically significantly along with the decrease of the rate of bone cells at 12 day(P < 0.01). From the above results, When bone cells and periodontal ligament cells were mixed cultured, the cell proliferation rate was mostly dependent on the actual rate of bone cells and same pattern was showed in amount of total protein synthesis, alkalinephosphatase activity, and the number of calcified nodules. And the calcified nodule forming capacity of bone cells was inhibited by periodontal ligament cells

• Journal of Periodontal and Implant Science
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• v.27 no.4
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• pp.669-684
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• 1997

Polypeptide growth factors belong to a class of potent biologic mediators which regulate cell differentiation, proliferation, migration and metabolism. IGF-I is polypeptides secreted by skeletal cells and is considered as regulators of bone formation. The purpose of this study is to evaluate the effects of IGF-I on bone nodule formation and alkaline phosphatase activity of MC3T3-E1 cells. MC3T3-E1 cells were seeded at $1{\times}10^4$ cells/well, $1{\times}10^5$ cells/well in alpha-modified Eagle medium containing 10% fetal bovine serum, 10 mM ${\beta}-glycerophosphate$ and $5O{\mu}g/ml$ of ascorbic acid. Before 48 hours of indicated time, medium were changed with serum free medium. After 24 hours, 0.1, 1, 10 ng/ml IGF-I were added to the cells and cultured for 3, 7, 14, 21, 28 days. And histochemical analysis was done and ALP activity was measured and was expressed as nmol/min/mg of protein. The bone nodule formation in MC3T3-E1 cells of IGF-I was seen at 21, 28 days, but there were no difference between control group and experimental groups. The ALP activity decreased when it is compare to control 2 group except for 1 ng/ml, 10 ng/ml IGF-I of 21-day-groups and 1 ng/ml IGF-I of 28-day-groups. Dose response effects of IGF-I of ALP activity in MC3T3-E1 cells were seen the highest ALP activity at 1ng/ml until 21days and the highest ALP activity at 10 ng/ml of 28 daygroups. The peak times were seen at 7-day group, 14-day group on control group and experimental group respectively, and 1 ng/ml group was the highest ALP activity, From the above results, IGF-I was not seen notable effect on bone nodule formation and decreased ALP activity of MC3T3-E1 cells but the use of IGF-I to mediate biological stimulation of MC3T3-E1 cells shows promise for future therapeutic application.