• Journal of Life Science
• /
• v.20 no.4
• /
• pp.607-613
• /
• 2010

Osteoporosis is a disease involving a decrease in bone mineral density and an increased risk of fractures. The MC3T3-E1 pre-osteoblastic cell line is a well-accepted model of osteogenesis in vitro. Pine needles have long been used as a traditional health-promoting medicinal food in Korea. In this study, MTT assay, the alkaline phosphatase (ALP) activity and collagen synthesis of osteoblast cells were investigated to determine the effects of pine needle extracts on cell proliferation and differentiation. Pine needle extracts were prepared using hexane, ethanol and water. The effects of the pine needle extracts were examined by comparing the results with those of commercial agents, such as proanthocyanidin. The MC3T3-E1 cells exposed to proanthocyanidin showed increased proliferation in a concentration-dependent manner. The cells exposed to the hexane extract showed a similar increase in proliferation to that observed with proanthocyanidin. The hexane extract showed the highest ALP activity. Moreover, a supplement of pine needle extracts induced collagen synthesis in MC3T3-E1 cells. The pine needle extract produced the highest level of collagen synthesis at concentrations of $10{\sim}50\;{\mu}g/ml$. These results indicate that pine needle extracts have an anabolic effect on bone by promoting osteoblastic differentiation, and may be used in the treatment of common metabolic bone diseases.

• BMB Reports
• /
• v.42 no.7
• /
• pp.427-432
• /
• 2009

Orthodontic tooth movement results from the combinational process of both bone resorption and formation in the compressive and tension sides, respectively. However, the genes responsible for new bone formation in tension sides have not been determined. In this study, we used DNA microarray and real-time RT-PCR to identify genes in human periodontal ligament (PDL) cells that undergo significant changes in expression in response to static tensional forces (2 or 12 hours). The genes found were alkaline phospatase (ALP), matrix metalloproteinases (MMPs), vascular endothelial growth factor (VEGF), and several collagen genes. Furthermore, an ELISA evaluating the expression of VEGF, type IV collagen and MMP-2 found levels significantly increased after 24 and 72 hours (P < 0.05). ALP activity was also increased after 24 hours (P < 0.05). Collectively, we found the genes up-regulated in our study by the static tensional force are related to osteogenic processes such as matrix synthesis and angiogenesis.

• Journal of Periodontal and Implant Science
• /
• v.35 no.4
• /
• pp.1097-1108
• /
• 2005

The present study was to determine the influence of micro-macro biphasic calcium phosphate(MBCP) on proliferation and differentiation of human marrow-derived mesenchymal stem cells. Primary stem cells were cultured from bone marrow and 3-4 passaged cells were used. This study tested the proliferative effects by cell counting. Collagen sythensis, alkaline phosphatase activity, expression of osteocalcin and bone sialoprotein by Western blot analysis were evaluated. The cellular proliferation of ASC was not influenced by MBCP. Collagen synthesis of ASC cultured on MBCP significantly increased at 5th and 7th days(p<0.05). The ALP activity in ASC cultured on MBCP significantly increased at 5th and 7th days(p<0.05). The expression of OC and BSP incresaed in ASC cultured on MBCP. These results suggest that MBCP may stimulates the osteoblastic activity of ASC.

• BMB Reports
• /
• v.45 no.10
• /
• pp.571-576
• /
• 2012

Radiotherapy is considered to cause detrimental effects on bone tissue eventually increasing bone loss and fracture risk. However, there is a great controversy on the real effects of irradiation itself on osteoblasts, and the mechanisms by which irradiation affects osteoblast differentiation and mineralization are not completely understood. We explored how X-ray radiation influences differentiation and bone-specific gene expression in mouse calvarial osteoblasts. Irradiation at 2 Gy not only increased differentiation and mineralization of the cells, but also upregulated the expression of alkaline phosphatase, type I collagen, osteopontin, and osteocalcin at early stages of differentiation. However, irradiation at higher doses (>2 Gy) did not stimulate osteoblast differentiation, rather it suppressed DNA synthesis by the cells without a toxic effect. Additional experiments suggested that transforming growth factor-beta 1 and runt-transcription factor 2 play important roles in irradiation- stimulated bone differentiation by acting as upstream regulators of bone-specific markers.

• The korean journal of orthodontics
• /
• v.35 no.4 s.111
• /
• pp.262-274
• /
• 2005

Tooth movement is a result of mutual physiologic responses between the periodontal ligament and alveolar bone stimulated by mechanical strain. The PDL cell and osteoblast are known to have an influence on bone formation by controlling collagen synthesis and alkaline phosphatase activation. Moreover. recent studies have shown that the PDL cell and osteoblast release osteoprotegerin (OPG) and the receptor activator of nuclear factor ぉ ligand (RANKL) to control the level of osteoclast differentiation and activation which in turn influences bone resorption. In this study. progressively increased, continuous tensional force was applied to PDL cells. The objective was to find out which kind of biochemical reactions occur after tensional force application and to illuminate the alveolar bone resorption and apposition mechanism. Continuous and progressively increased tensile force was applied to PDL cells cultured on a petriperm dish with a flexible membrane The amount of $PGE_2$ and ALP synthesis were measured after 1, 3, 0 and 12 hours of force application. Secondly RT-PCR analysis was carried out for OPG and RANKL which control osteoclast differentiation and MMP-1 -8, -9, -13 aud TIMP-1 which regulate the resolution of collagen and resorption of the osteoid layer According to the results. we concluded that progressively increased, concluded force application to human PDL cells reduces $PGE_2$ synthesis, and increases OPG mRNA expression.

• The Journal of Korean Medicine
• /
• v.27 no.1 s.65
• /
• pp.220-228
• /
• 2006

Objectives : Interleukin-1 (IL-1)${\beta}$ in articular chondrocytes regulates differentiation, apoptosis, and inflammatory responses. It is still controversial, So, we investigated IL- $1{\beta}$ induces chondrocytes dedifferentiation and death. Also, we studied the role of the mitogen-activated protein kinase (MAPK) subtypes on IL-$1{\beta}$-induced dedifferentiation and apoptosis. Methods : To evaluation of dedifferentiation by chemokines of chondrocytes, we assessed such as proteoglycan, collagen, MMP-3 and MMP-13 by RT-PCR analysis. Also, to assess of apoptosis effect by chemokines, we measured annexin V/propidium iodode (PI) and sub G1 cells in chondrocytes by flowcytometric analysis Results : IL-$1{\beta}$ treatment did not affect activation of ERK-1/2, but stimulation of p38 kinase. Inhibition of phospho ERK-1/2 with PD98059 enhanced IL-1b-induced dedifferentiation, and apoptosis up to 13.5%, whereas inhibition of phospho p38 kinase with SB203580 inhibited dedifferentiation, and apoptosis. Conclusions : Our results indicate that SB203580, p38 kinase inhibitor, inhibits IL-$1{\beta}$-induced dedifferentiation, and apoptosis by the inhibition of type II collagen expression and proteoglycan synthesis of rabbit articular chondrocytes.

• Biomolecules & Therapeutics
• /
• v.20 no.3
• /
• pp.299-305
• /
• 2012

Endochondral bone formation is the process by which mesenchymal cells condense to become chondrocytes, which ultimately form new bone. The process of chondrogenic differentiation and hypertrophy is critical for bone formation and as such is regulated by many factors. In this study, we aimed to indentify novel factors that regulate chondrogenesis. We investigated the possible role of isopsoralen in induction of chondrogenic differentiation in clonal mouse chondrogenic ATDC5 cells. Isopsoralen treatment stimulated the accumulation of cartilage nodules in a dose-dependent manner. Further, ATDC5 cells treated with isopsoralen were stained more intensely with Alcian blue than control cells, suggesting that isopsoralen increases the synthesis of matrix proteoglycans. Similarly, isopsoralen markedly induced the activation of alkaline phosphatase activity compared with control cells. Isopsoralen enhanced the expressions of chondrogenic marker genes such as collagen II, collagen X, OCN, Smad4 and Sox9 in a time-dependent manner. Furthermore, isopsoralen induced the activation of extracellular signal-regulated kinase (ERK) and p38 MAP kinase, but not that of c-jun N-terminal kinase (JNK). Isopsoralen significantly enhanced the protein expression of BMP-2 in a time-dependent manner. PD98059 and SB 203580, inhibitors of ERK and p38 MAPK, respectively, decreased the number of stained cells treated with isopsoralen. Taken together, these results suggest that isopsoralen mediates a chondromodulating effect by BMP-2 or MAPK signaling pathways, and is therefore a possible therapeutic agent for bone growth disorders.

• Preventive Nutrition and Food Science
• /
• v.1 no.1
• /
• pp.80-86
• /
• 1996

Parathyroid hormone(PTH) is known to stimulate bone resorption and to inhibit bone collagen synthesis. In contrast, as the evidence of stimulation of bone formation by PTH has recently been observed, the study on the role of PTH involved in osteoporosis draws remarkable attention. This study has dealt with the role of alkaline phoshatase(AP), a marker enzyme for bone formation and osteoblast action, Animals(BALS/cmice) were divided into three dietary groups(high and medium Ca and Ca-free) and hormones including PTH, calcitonin(CT), cholecalciferol(citamin D) were i.p. injected. AP in the serum and liver was measured using Sigma 221 alkaline buffer solutions containing 9mM of p-nitrophenyl phoshate. Enzume was reacted at 37$^{\circ}C$ for 10 minutes and the reaction was stopped by 1.8ml of 0.1N NaOH and measured at 410nm. We found that serum and liver AP activity was increased by low dietary Ac. Compared to the control, and serum Ap activity was enhanced by PTH and vitamin D regardless of the dietary Ca. On the other hand, liver AP activity was inhibited by OTH and vitamin D at all levels of dietary Ca. CT inhibited the action of PTH and vitamin D in the serum. But, the inhibition of PTH and vitamin D action by CT was not observed in the liver, unlike in the case of serum.

• The korean journal of orthodontics
• /
• v.20 no.3 s.32
• /
• pp.499-517
• /
• 1990

Electrical stimulation among several factors that influence bone remodeling has been studied by many investigators with great enthusiasm in orthodontic field. The action mechanisms of Pulsed Electromagnetic Field (PEMF) are different from those of the conventional electrode application method in that PEMF induces endogenous current in the living tissues. PEMF is known to have the healing effect in nonunion of bone and osteoporosis. It is widely used in orthopaedic scopes and the possibility of using the method in clinical orthodontics Is also conceivable. But the exact mechanisms by which the PEMF exerts its effects are not clearly understood. Therefore, the author wanted to see the effect of PEMF on five groups of rat calvarial cells obtained by sequential enzyme digestion method, and observed the changes in enzyme activation, collagen synthesis and $^3H-thymidine$ incorporation. The results were as follows: 1. Under the effect of PEMF, there were no changes in the alkaline phosphatase activity in five groups of cell populations. 2. Both the PEMF group and the PTH with PEMF group shelved no changes in acid phosphatase activities and there were no differences between two experimental groups. 3. Under the effect of PEMF, there was significant increase of collagen synthesis in the group V cell population. 4. Under the effect of PEMF, there were significant increases of $^3H-thymidine$ incorporation in the group IV and V cell populations.

• Polymer(Korea)
• /
• v.37 no.6
• /
• pp.669-676
• /
• 2013

Demineralized bone particle (DBP) is a biomaterial used widely in the field of tissue engineering. In this study, in order to study the effect of DBP/poly(lactic-co-glycolic acid) (PLGA) scaffold on disc regeneration in vivo environment, we prepared the porous DBP/PLGA hybrid scaffold. Disc defect was induced by removing the nucleus pulposus tissue after incision the annulus fibrosus tissue in half and scaffolds were transplanted. After 1, 2 and 3 months later, the extracted discs were confirmed by collagen synthesis and glycosaminoglycan (sGAG). We conducted histology (H&E, Safranin-O, Alcian blue, Type I Collagen, Type II Collagen). From the results, it was confirmed that collagen and sGAG content were high in DBP/PLGA scaffold, and the regeneration of intervertebral disc was possible.