Identification and partial purification of antibacterial compounds against Streptococcus mutans from Galla Rhois / 대한구강보건학회지

OBJECTIVES: This study aims to identify and partially purify antibacterial compounds against Streptococcus mutans from Galla Rhois extract. METHODS: Galla Rhois was extracted with n-hexane or ethanol and concentrated in a rotary evaporator. The antibacterial effect of the Galla Rhois extract against S. mutans was determined by the paper discdiffusion method with n-hexane, ethanol, methanol, ethyl acetate, dimethyl sulfoxide (DMSO), acetone, and distilled water as the solvents. The active compounds were purified by partition chromatography, thin-layer chromatography (TLC), and high-performance liquid chromatography (HPLC). RESULTS: The antibacterial effect of the n-hexane extract was more effective against S. mutans than the ethanol extract (P<0.05). The antibacterial component of Galla Rhois was partially purified using partition chromatography and HPLC, and the antibacterial activity was confirmed. CONCLUSIONS: The partially purified component of Galla Rhois showed strong antibacterial effect against S. mutans. These results confirm that the antibacterial compounds of Galla Rhois can be used for the prevention of dental caries.

Growth inhibition effect of Rubus coreanus Miquel on Candida albicans / 대한구강보건학회지

OBJECTIVES: In this study, the growth inhibition effect of Rubus coreanus Miquel on Candida albicans (C. albicans) was observed. METHODS: The Rubus coreanus Miquel was extracted with 70% methanol and concentrated with a rotary evaporator. Antifungal effect of Rubus coreanus Miquel extract on C. albicans was determined by paper disc diffusion method and standard plate count method. Seven different concentrations (2, 4, 8, 15, 30, 60, 120 mg/ml) of the extract were tested by paper disc diffusion method. Two kinds of concentration (8, 60 mg/ml) of the extract were tested using standard plate count method on C. albicans with different incubating time (for 6, 12, 24 hours immediately after the cultivation). Morphological changes of C. albicans cells after exposure to the extract were observed with scanning electron microscopy (SEM) images. RESULTS: The Rubus coreanus Miquel extract showed an antifungal effect on C. albicans in 8, 15, 30, 60, 120 mg/ml of concentrations (P<0.05). The extract with 8 mg/ml of concentration showed about 30% of growth inhibition at 6 h and with 60 mg/ml it showed about 90% of growth inhibition at 24 h. SEM analysis showed damaged surfaces of C. albicans cells when treated with Rubus coreanus Miquel extract. CONCLUSIONS: The Rubus coreanus Miquel might have the potential as a nobel growth inhibitory agent against C. albicans that causes oral infection.

Xylitol Down-Regulates 1alpha,25-Dihydroxy Vitamin D3-induced Osteoclastogenesis via in Part the Inhibition of RANKL Expression in Osteoblasts

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 1alpha,25(OH)2D3 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 1alpha,25(OH)2D3 in a dose-dependent manner. Furthermore, bone resorption activity, assessed on bone slices in the co-culture 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 1alpha,25(OH)2D3-induced osteoclastogenesis by reducing the sRANKL/OPG expression ratio in osteoblastic cells.

Hyperosmotic Stimulus Down-regulates 1alpha, 25-dihydroxyvitamin D3-induced Osteoclastogenesis by Suppressing the RANKL Expression in a Co-culture System

The hyperosmotic stimulus is regarded as a mechanical factor for bone remodeling. However, whether the hyperosmotic stimulus affects 1alpha, 25-dihydroxyvitamin D3 (1alpha,25(OH)2D3)-induced osteoclastogenesis is not clear. In the present study, the effect of the hyperosmotic stimulus on 1alpha,25(OH)2D3-induced osteoclastogenesis was investigated in an osteoblast-preosteoclast co-culture system. Serial doses of sucrose were applied as a mechanical force. These hyperosmotic stimuli significantly evoked a reduced number of 1alpha,25(OH)2D3-induced tartrate-resistant acid phosphatase-positive multinucleated cells and 1alpha,25(OH)2D3-induced bone-resorbing pit area in a co-culture system. In osteoblastic cells, receptor activator of nuclear factor kappaB ligand (RANKL) and Runx2 expressions were down-regulated in response to 1alpha,25(OH)2D3. Knockdown of Runx2 inhibited 1alpha,25(OH)2D3-induced RANKL expression in osteoblastic cells. Finally, the hyperosmotic stimulus induced the overexpression of TonEBP in osteoblastic cells. These results suggest that hyperosmolarity leads to the down-regulation of 1alpha,25(OH)2D3-induced osteoclastogenesis, suppressing Runx2 and RANKL expression due to the TonEBP overexpression in osteoblastic cells.

Expression of osteoclastogenesis related factors in dental implant patients

INTRODUCTION: Bone resorption is a unique function of osteoclasts. Osteoclasts are a specialized macrophage polykaryon whose differentiation is regulated principally by macrophage colony-stimulating factors, receptor activator of nuclear factor kappaB ligand (RANK) ligand, osteoprotegerin (OPG), and interleukins (IL). Reflecting the integrin-mediated signals, osteoclasts develop a specialized cytoskeleton that allows it to establish an isolated micro-environment between itself and the bone, wherein matrix degradation occurs by a process involving proton transport. The levels of IL-1, IL-6, OPG, and prostaglandin E2 (PGE2) expression were evaluated to study the correlations between dental implant teeth and the adjacent teeth. MATERIALS AND METHODS: The exudate of the gingival crevice acquired from dental implants, adjacent teeth, opposite teeth and contralateral teeth of 24 patients. RESULTS: 1. The levels of IL-1, IL-6, OPG and PGE2 expression in dental implant teeth were higher than those of the contralateral teeth. 2. IL-1 revealed a higher expression level in the adjacent teeth than in dental implant teeth. 3. The dental implant teeth and adjacent teeth did not show a remarkable difference in the level of IL-1 expression. 4. All the other cytokines were strongly expressed in the dental implant compared to the adjacent teeth. CONCLUSION: These results suggest that there might be close correlation between dental implant teeth and adjacent teeth in terms of the expressions of cytokines that affect the development and regulation of osteoclasts.

The effect of progressive tensional force on mRNA expression of osteoprotegerin and receptor activator of nuclear factor kappa B ligand in the human periodontal ligament cell / 대한치과교정학회지

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 kappa B 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 PGE2 and ALP synthesis were measured after 1, 3, 6 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 and TIMP-1 which regulate the resolution of collagen and resorption of the osteoid layer. According to the results, we concluded that progressively increased, continuous force application to human PDL cells reduces PGE2 synthesis, and increases OPG mRNA expression.

Effect of sonicates of Treponema denticola on osteoblast differentiation / 대한치주과학회지

No abstract available.

The Effect of Cyclosporin A on Osteoblast in vitro / 대한치주과학회지

Cyclosporin A(CsA) is an immunosuppressive agent widely used for preventing graft rejecting response in organ transplantation. The basic properties of CsA to osteoblast has not been well known yet. A better understanding of the mechanisms of CsA function on bone could provide valuable information regarding basic properties of bone remodeling, pharmacotherapeutic intervention in metabolic bone disease, and the consequences of immunosuppression in bone physiology. The purpose of this study was to investigate the effect of CsA on osteoblast by evaluating parameters of proliferation, collagen synthetic activity, alkaline phosphatase activity, and ALP mRNA expression in mouse calvarial cell. 1. CsA(3microgram/ml) treated mouse calvarial cell showed statistically significant increase in cell proliferation.(P<0.05) 2. CsA(1, 3microgram/ml) treated MC3T3 cell line showed statistically significant increase in cell proliferation. 3. The amount of collagen of CsA(3microgram/ml) treated mouse calvarial cell was decreased statistically significantly. 4. Alkaline phosphatase activity was increased statistically significantly in CsA treated group(1microgram/ml). 5. mRNA expression of ALP was increased in CsA treated group These results suggest that CsA could affect bone remodeling by modulating proliferation & differentiation of osteoblast.

The Effects of Deer(Cervus nippon) Antler Extracts on Differentiation of MC3T3 Cells / 대한치주과학회지

Deer antler has been widely prescribed in Chinese and Korean pharmacology. Although there have been several reports concerning the effects of deer antler, such as anti-aging action, anti-inflammatory activity, antifungal action and regulatory activity of the level of glucose, the effect on bone has not determined yet. The purpose of this study was to examine the effect of deer antler on osteoblast differentiation. Hexane extract(CNH) and chloroform extract(CN-C) were acquired from deer antler(Cervus nippon) and MC3T3-E1 preosteoblasts were cultured in the presence or absence of each extract. Osteoblast differentiation was estimated with the formation of mineralized nodules and the mRNA expression of alkaline phosphatase(ALP), osteocalcin(OC) and bone sialoprotein(BSP) which are markers of osteoblast differentiation. Non-treated group did not show mineralized nodule. CN-C or CN-H-treated group showed minerlaized nodules in 16 days. In northern blot analysis, CN-C or CN-H-treated group showed the elevated expression of ALP, BSP and OC in 16 days. These results suggest the possibility to develop deer antler as a bone regenerative agent in periodontal therapy by showing the stimulating activity of deer antler on differentiation of osteoblast.