• Journal of Periodontal and Implant Science
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• v.23 no.1
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• pp.37-47
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• 1993

The native connective tissue attachment of the periodontium is known to be a complex consisting of gingival fibroblasts, periodontal ligament cells, gingival epithelial cells, cementum, alveolar bone and extensive extracellular matrix (collagen, glycoprotein and proteoglycans). The purpose of this study was to evaluate the effects of natural extracts on DNA, collagen and protein synthesis and inhibition of cytokine production in the gingival and periodontal ligament fibroblasts and gingival epithelial cells. Healthy gingival tissue was obtained from orthodontic treatment patients, and gingival epithelial cells, gingival fibroblasts and periodontal ligament cells were isolated and cultured from the samples. After treated with Ginseng protein, Pluronic F-68, Scutellariae Radix, centella asiatica, PDGF, IGF, DNA synthesis, total protein and collagen synthesis, and cytokine production of gingival epithelial cell, gingival fibroblast and periodontal ligamentcells were measured. MTT method for DNA synthesis, Peterkofsky and Dingerman method for total protein and collagen synthesis, and IL-1 ELISA kit for cytokine production were used. The proliferation of epithelial cells was enhanced in Centella asiatica, Ginseng protein, Pluronic F-68 and Scutellariae Radix. The activities of PDL cells were increased in PDGF, IGF, and Pluronic F-68. Higher collagen synthesis was observed in Scutellariae Radix and total protein synthesis was increased in Scutellariae Radix and PDGF. The inhibitory effects on IL-1, IL-6, $TNF-{\alpha}$ were observed in all exrracts.

• Molecules and Cells
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• v.40 no.8
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• pp.550-557
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• 2017

The periodontal ligament (PDL) is the connective tissue between tooth root and alveolar bone containing mesenchymal stem cells (MSC). It has been suggested that human periodontal ligament stem cells (hPDLSCs) differentiate into osteo/cementoblast and ligament progenitor cells. The periodontitis is a representative oral disease where the PDL tissue is collapsed, and regeneration of this tissue is important in periodontitis therapy. Fibroblast growth factor-2 (FGF-2) stimulates proliferation and differentiation of fibroblastic MSCs into various cell lineages. We evaluated the dose efficacy of FGF-2 for cytodifferentiation of hPDLSCs into ligament progenitor. The fibrous morphology was highly stimulated even at low FGF-2 concentrations, and the expression of teno/ligamentogenic markers, scleraxis and tenomodulin in hPDLSCs increased in a dose dependent manner of FGF-2. In contrast, expression of the osteo/cementogenic markers decreased, suggesting that FGF-2 might induce and maintain the ligamentogenic potential of hPDLSCs. Although the stimulation of tenocytic maturation by $TGF-{\beta}1$ was diminished by FGF-2, the inhibition of the expression of early ligamentogenic marker by $TGF-{\beta}1$ was redeemed by FGF-2 treatment. The stimulating effect of BMPs on osteo/cementogenesis was apparently suppressed by FGF-2. These results indicate that FGF-2 predominantly differentiates the hPDLSCs into teno/ligamentogenesis, and has an antagonistic effect on the hard tissue differentiation induced by BMP-2 and BMP-4.

• Journal of Periodontal and Implant Science
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• v.34 no.3
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• pp.489-498
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• 2004

Recent studies have demonstrated that human periodontal ligament cells express receptor activation of nuclear factor ${\kappa}B$ ligand (RANKL) which enhances the bone resorbing activity of osteoclasts differentiated from hematopoietic preosteoclasts. The purpose of this study is to determine the effects of p38 MAPK and JNK kinase upon regulating RANKL and OPG in response to $IL-1{\beta}$(l ng/ml) in rat periodontal ligament cells. Soluble RANKL was measured by immunoassay. The effects of p38 MAPK on RANKL and OPG expression was determined by RT-PCR. The results were as follows: 1. Periodontal ligament cells which stimulated by $IL-1{\beta}$ increased soluble RANKL synthesis by dose-dependent pattern. 2. p38 MAP kinase inhibitor (SB203580) showed regulation of soluble RANKL expression by dose-dependent manners. 3. p38 MAP kinase inhibitor (SB203580) regulated the expression of RANKL, but it dose regulate the expresseion of OPG. 4. JNK (c-jun $NH_2-terminal$ kinase) inhibitor (PD98059) did not regulate mRANKL and mOPG. These results suggested that p38 MAPK play a significant role in RANKL gene expression.

• Journal of Periodontal and Implant Science
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• v.25 no.2
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• pp.438-457
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• 1995

The origin of fibroblasts, their proliferative activity and roles in the early stages of periodontal regeneration were investigated in order to better understand the periodontal healing process in furcation defects of the beagle dog after guided tissue regeneration. Newly divided cells were identified and quantitated by immunolocalization of bromodeoxyuridine (BrdU) injected 1 hour prior to sacrificing the animals. The results were as follows :1. During periodontal healing in horizontal furcation defect, three different stages, namely the granulation tissue, connective tissue, and bone formation stages, were identified on the basis of major types of cells and tissue. 2. In the early stages of periodontal regeneration, both the remaining periodontal ligament and alveolar bone compartment were the major sources. 3. The majority of BrdU-labeled fibroblasts were located at the following areas ; 1) the coronal zone of the defect in case of the connective tissue fanned on the root surface. 2) the area within an 400 ${\mu}m$ distance from the remaining bone level in case of the periodontal ligament. 3) the area within an 100 ${\mu}m$ distance from the bone surface in case of areas of active bone formation.4. The highly proliferative fibroblasts adjacent to bone surface played a major role in the formation of osteoblast precursor cells, whereas both paravascular and endosteal cells played a minor role in new bone formation, In conclusion, it was suggested that the fibroblasts in the remaining periodontal ligament and bone will play a major role in periodontal regeneration, whereas both paravascular and endosteal cells will play a minor role in new bone formation.

• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.80-80
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• 2003

Insulin-dependent or Type 1 diabetes mellitus (IDDM) has been associated with an increased severity of periodontal disease. Since periodontal ligament (PDL) cells play a significant role in maintenance and regeneration of mineralized tissue, the success of procedures, such as guided tissue regeneration, is directly related to the ability of these cells to augment mineralized tissue. In this study, we investigated the time- and dose-dependent effect of high glucose on the proliferation and collagen synthesis of human periodontal ligament (PDL) cells. PDL cells were treated with high glucose (22mM, 33mM, 44mM) for 1 or 2 days. High glucose significantly inhibited proliferation of PDL cells as a time- and dose-dependent manner as evidenced by MTT assay. PDL cells were cultured in high glucose media (22mM, 33mM, 44mM) for 24 h. The ratio of collagen content to total protein was evaluated, and the gene expression of type I collagen was assessed by RT - PCR. The high concentration of glucose inhibited collagen synthesis, a marker of bone formation activity. This study indicated high glucose concentration could alter the metabolism of periodontal ligament cell, leading to alveolar bone destruction.

• International Journal of Oral Biology
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• v.38 no.2
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• pp.73-80
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• 2013

Leptin is one of the adipocytokines produced from adipose tissue but its functions in periodontal tissue have not previously been investigated. In our current study, we examined the effects of leptin on the expression of interleukin (IL)-6 and IL-8 in periodontal ligament (PDL) cells and gingival fibroblasts. Leptin receptor expression was evaluated by RT-PCR and the production of cytokines was measured by ELISA. The phosphorylation of Akt and Erk1/2 was assessed by western blotting. mRNA of long and short form leptin receptors were detected in both PDL cells and gingival fibroblasts. Leptin was found to increase the production of IL-6 and IL-8 in both of these cell types, an effect which was not blocked by polymyxin B, an inhibitor of lipopolysaccharide (LPS). Leptin did not alter the production of IL-6 and IL-8 induced by LPS in PDL cells but increased Akt and Erk1/2 phosphorylation in these cells. These results suggest that leptin acts as an inducer of IL-6 and IL-8 in PDL cells and gingival fibroblasts.

• Journal of Periodontal and Implant Science
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• v.29 no.1
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• pp.15-30
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• 1999

The purpose of this study was to evaluate the effect of mixed extracts of aralia cortex and phellodendron cortex (P55A) on activities of human gingival fibroblasts and periodontal ligament cells in vitro. First experiment was done to evaluate the effect of P55A in normal condition. In control group, the cells($4.5{\times}10^4$ cells/ml) were cultured with Dulbecco's Modified Eagle's Medium contained with 10% fetal bovine serum. In experimental groups, P55A was added to the above culture condition at the final concentrations of 0.1 ${\mu}g/ml$(Test group 1), 1 ${\mu}g/ml$(Test group 2) and 10 ${\mu}g/ml$(Test group 3). Then each group was tested for the cell proliferation rate at $\frac{1}{2}$, 2, 5 days, protein levels at 2, 5 days, and alkaline phosphatase activity at 2, 5 days. Second experiment was done to evaluate the effect of P55A in high glucose condition. 200 mg/dl glucose was added to the same culture condition of all groups in first experiment. Then each group was tested for the cell proliferation rate at $\frac{1}{2}$ , 2, 5 days, protein levels at 2, 5 days, and alkaline phoaphatase activity at 2, 5 days. The results were as follows ; 1. First experiment 1) As P55A concentration increased, cell proliferation rate increased significantly in test group 2 at 2 days, and test group 2 and 3 at 5 days in human gingival fibroblasts and periodontal ligament cells(P<0.05). 2) In human gingival fibroblasts, all test groups showed significantly increased protein levels as compared to control group at 5 days. In periodontal ligament cells, test group 2 and 3 showed significantly increased protein levels as compared to control group at 2, 5 days(P<0.05). 3) Alkaline phosphatase activity of human periodontal ligament cells increased as P55A concentration increased. The test group 2 and 3 showed significant increase as compared to control group at 5 days(P<0.05). 2. Second experiment 1) As P55A concentration increased, cell proliferation rate increased significantly in test group 2 at 2 days, and test group 2 and 3 at 5 days in human gingival fibroblasts and periodontal ligament cells(P<0.05). 2) In human gingival fibroblasts, test group 3 showed significantly increased protein levels as compared to control group at 2 days, and all test groups at 5 days. In periodontal ligament cells, test group 2 and 3 showed significantly increased protein levels as compared to control group at 2, 5 days(P<0.05). 3) Alkaline phosphatase activity of human periodontal ligament cells increased as P55A concentration increased. The test group 2 and 3 showed significant increase as compared to control group at 2 days, and all test groups at 5 days(P<0.05). From the above results, mixed extracts of aralia cortex and phellodendron cortex appeared to enhance cellular activities including cell proliferation rate, protein levels and alkaline phosphatase activity of human gingival fibroblasts and periodontal ligament cells in normal and high glucose condition. This study suggests that mixed extracts of aralia cortex and phellodendron cortex seem to be able to subside the inflammation of periodontal tissue and regenerate the destructed periodontal tissue.

• The korean journal of orthodontics
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• v.42 no.5
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• pp.249-254
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• 2012

Objective: To investigate the stem cell-like characteristics of human periodontal ligament (PDL) stromal cells outgrown from orthodontically extracted premolars and to evaluate the potential for myogenic differentiation. Methods: PDL stromal cells were obtained from extracted premolars by using the outgrowth method. Cell morphological features, self-replication capability, and the presence of cell-surface markers, along with osteogenic, adipogenic, and chondrogenic differentiation, were confirmed. In addition, myogenic differentiation was induced by the use of 5-aza-2'-deoxycytidine (5-Aza) for DNA demethylation. Results: PDL stromal cells showed growth patterns and morphological features similar to those of fibroblasts. In contrast, the proliferation rates of premolar PDL stromal cells were similar to those of bone marrow and adipogenic stem cells. PDL stromal cells expressed surface markers of human mesenchymal stem cells (i.e., CD90 and CD105), but not those of hematopoietic stem cells (i.e., CD31 and CD34). PDL stromal cells were differentiated into osteogenic, adipogenic, and chondrogenic lineages. Myotube structures were induced in PDL stromal cells after 5-Aza pretreatment, but not in the absence of 5-Aza pretreatment. Conclusions: PDL stromal cells isolated from extracted premolars can potentially be a good source of postnatal stem cells for oromaxillofacial regeneration in bone and muscle.

• Journal of Periodontal and Implant Science
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• v.26 no.3
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• pp.641-654
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• 1996

In infectious disease, invasion of host tissue by bacteria or their products frequently induces a wide variety of inflammatory and immunopathologic reaction. Evidence indicates that cytokines are involved in the initiation and progression of chronic inflammatory diseases, such as periodontitis. Interleukin-6, which is a multifunctional cytokine, has important roles in acute and chronic inflammation and may also be implicated in bone resorption. Periodontal diseases are characterized by chronic inflammation of the periodontium with alveolar bone resoption. A principal driving force behind this response appears to lie in the immune system's response to bacteria. Many of the cell components which have been shown to function as virulence factors in gram-negative bacteria are associated with the bacterial surface. Of these, lipopolysaccharide has been characterized as one that mediates a number of biological activities which can lead to the destruction of host tissue. Non-steroidal antiinflammatory drug is used for reduce inflammation, and most of NSAIDs inhibit prostaglandine $E_2$ production, but it is shown that $PGE_2$ production is stimulated by IL-1 in recent study. So, the influence of other cytokines except $PGE_2$ on periodontium can not be avoided. Therefore, new antiinflammatory drug is needed. Rhizoma coptidis is used in oriental medicine for anti-inflammation and antiseptics. In this present study, we examined the IL-6 release in periodontal ligament cells treated with the lipopolysaccharide, and also the effect of rhizoma coptidis on cellular activity and IL-6 production of periodontal ligament cells. To evaluate the effect of rhizoma coptidis on cellular activity, the cells were seeded at a cell density of $1{\times}10^4$ cells/well in 24-well culture plates. After one day incubation, 1-6, 10-9 and 10-12 g/ml of rhizoma coptidis and 5, $10{\mu}g/ml$ of LPS were added to the each well and incubated for 1 and 2 days, respectively. Then, MTT assay were carried out. To evaluate the effect of rhizoma coptidis on IL-6 production, the cells were seeded at a cell density of $1.5{\times}10^4$ cells/well in 24-well culture plates. After one day incubation, 10-9 g/ml of rhizoma coptidis and 5, $10{\mu}g/ml$ of LPS were added to the each well and incubated for 3, 6, 12 and 24 hours. Then, amounts of IL-6 production is measured by IL-6 ELISA kit used. The results were as follows : 1. Rhizoma coptidisrbelow to ($10^{-6}g/ml$) significantly increaed cellular activity of periodontal ligament cells than control. 2. Rhizoma coptidist ($10^{-9}g/ml$) significantly increased cellular activity of LPS($5{\mu}g/ml$)-treated periodontal ligament cells than control. 3. LPS(5 and $10{\mu}g/ml$) significantly increased IL-6 production of periodontal ligament cells than control. 4. Rhizoma coptidis($10^{-9}g/ml$) decreased IL-6 production of LPS ($5{\mu}g/ml$)-treated periodontal.ligarnent cells than LPS only tested group. These findings suggest that stimulation of the IL-6 release of periodontal ligament cells by LPS may have a role in the progression of inflammation and alveolar bone resoption in periodontal disease, and that inhibition of the IL-6 release of cells and stimulation of cellular activity by rhizoma coptidis may help the periodontal regeneration.

• Journal of Periodontal and Implant Science
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• v.39 no.1
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• pp.45-52
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• 2009

Purpose: Fibronectin(FN), one of the major components of ECM, mediates wide variety of cellular interactions including cell adhesion, migration, proliferation and differentiation. In this study, we used synthetic peptides based on fibrin binding sites of amino-terminal of FN and evaluated their biologic effects on periodontal ligament(PDL) cells. Materials and methods: PDL cells were cultured on synthetic oligopeptides coated dishes and examined for cell adhesion, proliferation via confocal microscope. For detection of ERK1/2, cells were plated and Western blot analysis was performed. Results: PDL cells on synthetic oligopeptide coated dishes showed enhanced cell adhesion and proliferation. Western blot analysis revealed increased level of ERK1/2 phosphorylation in cells plated on FN fragment containing fibrin-binding domain(FF1 and FF5) coated dishes. Conclusion: These results reveals that FN fragment containing fibrin-binding domain possess an enhanced biologic effect of PDL ligament cells.