The inhibitory effect of alendronate and taurine on osteoclast differentiation mediated by Porphyromonas gingivalis sonicates in vitro

The objective of this study was to investigate the ability of alendronate and taurine in inhibiting in vitro osteoclast differentiation induced by bacteria. Whole cell sonicates of Porphyromonas gingivalis were used as an osteoclast-stimulating factor in a mouse coculture system and differentiated osteoclasts were confirmed by tartrate-resistant acid phosphatase (TRAP) staining. Alendronate at the concentrations of 10(-7) M, 10(-6) M, and 10(-5) M and taurine at the concentrations of 4 mM, 8 mM, and 12 mM were used. The cytotoxic effects of alendronate and taurine were examined using methylthiazole-tetrazolium bromide (MTT) assay. The amounts of interleukin-6 (IL-6) in culture supernatants were also measured using ELISA. The sonicates of P. gingivalis at the concentration of 0.01-0.1 microg/ml significantly stimulated the formation of osteoclasts (p < 0.05). Alendronate (10(-5) M) and taurine (12 mM) significantly suppressed the sonicate-stimulated osteoclast formation. In MTT assay, no cytotoxic effects were evident in all concentrations of alendronate and taurine. Alendronate and taurine did not affect the amount of IL-6 induced by P. gingivalis sonicates. These data indicate that alendronate and taurine have inhibitory effects on bacteria-stimulated osteoclast formation in vitro and that this inhibitory mechanism is not related to the blocking of IL-6 production.     

葛根素对大鼠下颌骨骨髓源巨噬细胞破骨细胞向分化的影响

目的: 分析不同浓度的葛根素对于下颌骨骨髓源巨噬细胞（Bone marrow-derived macrophages,BMMs）破骨分化的影响。方法: 体外分离培养4周龄雌性大鼠下颌骨BMMs。通过CCK-8分析1 nmol/L、10 nmol/L、100 nmol/L、1 μmol/L、10 μmol/L和100 μmol/L葛根素对BMMs细胞活性的影响。使用RANKL诱导BMMs破骨分化的同时加入不同浓度葛根素,采用抗酒石酸酸性磷酸酶（TRAP）酶化学染色及q-PCR分析破骨细胞形成及破骨相关基因的改变。采用SPSS16.0软件包对数据进行统计学分析。结果: 1 nmol/L、10 nmol/L、100 nmol/L、1 μmol/L、10 μmol/L葛根素组与对照组活细胞数无显著差异,100 μmol/L组活细胞数较对照组降低（P<0.05）。RANKL可诱导BMMs形成多核破骨细胞。10 nmol/L、100 nmol/L及1 μmol/L葛根素组破骨细胞数目及破骨细胞面积均较对照组降低（P<0.05）。q-PCR分析发现,10 nmol/L、100 nmol/L及1 μmol/L葛根素组NFATc1、C-fos、TRAP及CTSK mRNA表达量均较对照组下降（P<0.05）。结论: 葛根素可抑制下颌骨BMMs破骨分化及相关基因表达,为葛根素应用于下颌骨骨质疏松症的预防与治疗提供了依据。     

PCR-based identification of Treponema maltophilum,T amylovorum,T medium,and T lecithinolyticum in primary root canal infections

Objective: Molecular genetic methods have significantly contributed to the knowledge about the microbiota associated with infected root canals. Albeit spirochetes have been commonly observed in primary root canal infections, only recently they have been identified. The purpose of the present study was to investigate the occurrence of four treponemes—Treponema maltophilum, Treponema lecithinolyticum, Treponema amylovorum, and Treponema medium—in cases of primary endodontic infections associated with different forms of periradicular diseases through a 16S rDNA-based nested PCR assay. Design: Samples were taken from thirty-one infected root canals associated with either asymptomatic or symptomatic apical periodontitis. DNA extracted from the samples was initially amplified using universal 16S rDNA primers, followed by a second round of amplification using the first PCR products to detect a specific fragment of the 16S rDNA of each target Treponema species. Results: All cases were positive for the universal bacterial primers, indicating that samples contained bacterial DNA. Of the four target species, T. maltophilum was the most prevalent, being detected in 39% of the cases (33% of the asymptomatic cases and 50% of the symptomatic cases). T. lecithinolyticum was the next more prevalent among the species tested, being found in 26% of the samples (33% of asymptomatic cases and 10% of the symptomatic cases). T. amylovorum was found in 7% of the cases (5% of the asymptomatic cases and 10% of the symptomatic cases), while T. medium was in 13% of the cases (14% of the asymptomatic cases and 10% of the symptomatic cases). None of the species tested was significantly associated with clinical symptoms. Conclusions: This was possibly the hitherto first study to report the occurrence of T. lecithinolyticum, T. amylovorum, and T. medium in infections of endodontic origin. Overall, findings suggested that these oral treponemes, particularly T. maltophilum and T. lecithinolyticum, can be involved in the pathogenesis of periradicular diseases.     

转化生长因子β对体外破骨细胞分化的影响

目的:研究在核因子κB受体活化因子配基(RANKL)和巨噬细胞集落刺激因子(M-CSF)联合应用诱导体外骨髓细胞培养系统中,转化生长因子(TGF-β)对破骨细胞分化的影响。方法:选用小鼠M-CSF依赖性非附着性骨髓细胞,在含有25 ng/m l sM-CSF和30 ng/m l sRANKL的α-MEM培养液中进行培养,比较加入和不加入1 ng/m lTGF-β1培养4、9 d后,所形成的抗酒石酸酸性磷酸酶染色(TRAP)阳性多核细胞的数目和骨吸收面积。结果:小鼠骨髓细胞在RANKL和M-CSF共同作用下可形成TRAP阳性多核巨细胞,并具有骨吸收功能。加入TGF-β后,破骨样细胞的数目及骨吸收面积显著增加。结论:TGF-β对RANKL和M-CSF诱导的破骨细胞的分化及其功能的促进作用,可能为炎症状态下发生过度骨吸收的机制之一。     

微小RNAs在破骨细胞分化调控中的研究进展

微小RNAs（miRNAs）是一组由22~25个核苷酸构成的非编码单链RNA,具有基因转录后调控功能,广泛参与细胞增殖、分化、凋亡、组织炎症及肿瘤发生等过程。破骨细胞是体内唯一具有骨吸收功能的细胞,受成骨细胞及炎症因子的调控,在牙周炎骨吸收过程中具有重要作用。miRNAs对破骨细胞的分化、成熟及功能具有多重调控作用。本文就miRNAs调控破骨细胞分化和功能的可能机制,及其在牙周炎骨吸收过程中的作用进行综述。     

白介素-23对破骨细胞分化及功能直接调节作用的实验研究

目的检测白介素-23（IL-23）是否对破骨细胞分化及功能有直接调节作用。方法在体外培养小鼠破骨细胞的过程中加入不同浓度的IL-23,观察破骨细胞形成数量及吸收陷窝的变化以及组织蛋白酶-K mRNA的表达变化。同时,以RAW264.7诱导破骨细胞,采用RT-PCR及FACS方法检测IL-23刺激下,RANK mRNA及蛋白的表达变化情况。结果 IL-23作用下,小鼠破骨细胞数量增加,形成的吸收陷窝增多,组织蛋白酶-K mRNA的表达增强。同时在IL-23刺激下,破骨前体细胞表面RANK mRNA及蛋白的表达增强。结论 IL-23可以通过调高破骨前体细胞表面RANK的表达,直接促进小鼠破骨细胞分化。     

Effect of glucose on Treponema denticola cell behavior

Introduction:  Treponema denticola inhabits the oral subgingival environment and is part of a proteolytic benzoyl- dl -arginine-naphthylamide-positive 'red complex' associated with active periodontal disease. Spirochetes have a unique form of chemotactic motility that may contribute to their virulence. Chemotaxis is essential for efficient nutrient-directed translocation.
Methods:  We examined the effect of glucose on T. denticola cell velocity, expression of periplasmic flagella proteins, and chemotaxis, e.g. translocation into capillary tubes.
Results:  The presence of glucose did not significantly effect T. denticola cell velocity in high viscosity conditions nor did it alter periplasmic flagella protein expression. The addition of glucose to capillary tubes resulted in greater numbers of T. denticola cells in tubes containing glucose. A non-motile mutant did not migrate into capillary tubes containing glucose.
Conclusion:  These results are consistent with a chemotactic response to glucose that is motility dependent.     

Immunolocalization of osteoclast differentiation factor in rat periodontium.

The aim here was to observe the immunohistochemical localization of osteoclast differentiation factor (ODF)/receptor activator of NF kappa B ligand (RANKL) in the rat periodontium. Rat mandibles were demineralized and embedded in paraffin, and horizontal and frontal sections were prepared for immunohistochemical analysis. In horizontal sections, immunolocalization of RANKL was marked in the distal area of the periodontium of molars in which osteoclasts appeared, due to physiological tooth drift. In frontal sections, RANKL immunoreactivity was localized on spindle-shaped mesenchymal cells around blood vessels near the bone surface in the periodontium. In addition, immunoreaction for RANKL was detected on structures that appeared to be elongated cell processes near blood vessels in frontal sections. Immunohistochemical examination for the general antigen of nerve-specific protein suggested a similarity between these structures and nerve fibres.     

BioAggregate和MTA对体内破骨细胞分化和功能的影响

目的研究口腔生物陶瓷材料Bio Aggregate及MTA对体内LPS诱导的炎性骨吸收的影响。方法 6周龄C57/BL6雄性小鼠随机分为四组:PBS组、LPS组、Bio Aggregate+LPS组和MTA+LPS组,每组6只。LPS干预小鼠7 d后,取出颅盖骨进行显微-CT扫描、HE染色、酶组织化学染色和组织免疫荧光染色,观察骨破坏面积、破骨细胞的形成以及组织蛋白酶K(cathepsin K)的表达。结果 Bio Aggregate和MTA浸提液明显减少LPS诱导的破骨细胞形成和小鼠颅盖骨炎性骨破坏。与破骨细胞功能密切相关的组织蛋白酶K的表达在Bio Aggregate和MTA浸提液的作用下被显著下调。结论新型口腔生物陶瓷材料Bio Aggregate和传统材料MTA能够抑制体内炎性骨吸收。     

Combined effects of hydrogen sulfide and lipopolysaccharide on osteoclast differentiation in rats

Background: Lipopolysaccharide (LPS) stimulates osteoclast differentiation through toll‐like receptors (TLRs) 2 and 4, and hydrogen sulfide (H₂S) induces osteoclast differentiation. If H₂S activates TLRs, H₂S may enhance the effects of LPS on osteoclast differentiation. The purpose of the present study is to examine the combined effects of sodium hydrogen sulfide (NaHS, an H₂S donor drug) and LPS on osteoclast differentiation and TLR expression in rat periodontal tissue. Methods: Twenty‐eight male Wistar rats (8 weeks old) were divided into four groups (n = 7 per group): a control (no treatment) group and three experimental groups (NaHS group, LPS group, and a combination [NaHS + LPS] group). At 1 day after topical application of NaHS and/or Porphyromonas gingivalis LPS into the gingival sulcus of first molars, the number of tartrate‐resistant acid phosphate (TRAP)‐positive osteoclasts in the periodontal tissue was counted. Expression of TLR2 and TLR4 mRNAs and proteins in the gingival was also assessed. Results: The number of TRAP‐positive osteoclasts was significantly higher in the combination group than in any other group (P <0.01). The combination group had 11.0‐fold higher TLR4 mRNA levels than the control group. TLR4 protein levels were also higher in the combination group than in the NaHS or LPS group. However, the TLR2 mRNA and protein levels were not significantly different in the combination group and the LPS group. Conclusion: In rat periodontal tissue, NaHS and LPS had an additive effect on osteoclast differentiation through activation of the TLR4 pathway but not the TLR2 pathway.     

Effects of vascular endothelial growth factor-C and -D on osteoclast differentiation and function in human peripheral blood mononuclear cells

ObjectiveThe purpose of this study was to clarify the interaction of vascular endothelial growth factors (VEGFs)-C and -D with cell surface foetal liver kinase-1 (Flk-1) and fms-like tyrosine kinase-4 (Flt-4) receptors in the induction and activity of osteoclasts in cultured human peripheral blood mononuclear cells (PBMCs).DesignPBMCs were cultured on chamber slides or on ivory discs for 2 or 3 weeks in the presence of macrophage-colony stimulating factor (M-CSF), VEGF-A, -C or -D, or placental growth factor (PlGF) with or without receptor activator of nuclear factor kappa-B ligand (RANKL). The number of osteoclasts in each group was counted and the area of ivory resorption was measured. In addition, osteoclast differentiation was further analysed under the same conditions, but with the addition of specific neutralizing antibodies against Flk-1 and Flt-4.ResultsRANKL was essential for the induction of osteoclasts in PBMCs. However, significant differences were found in the number of osteoclasts induced by VEGF-A, -C, -D or M-CSF with RANKL compared with control groups lacking or containing RANKL. Blocking of either Flk-1 or Flt-4 resulted in a reduction in the enhancement of osteoclast differentiation in PBMCs by VEGF-C or -D with RANKL. The osteoclasts induced by VEGF-A, -C, -D or M-CSF with RANKL formed significantly larger resorption lacunae than those formed by osteoclasts induced by RANKL alone.ConclusionsThis study showed that VEGF-C and -D play a role in the induction of osteoclast differentiation through both Flk-1 and Flt-4 receptors and influence the area of the ivory resorption in PBMCs.     

Augmentation of TNF-induced osteoclast differentiation by inhibition of ERK and activation of p38: Similar intracellular signaling between RANKL- and TNF-induced osteoclast differentiation

Research in osteoclast differentiation has been greatly advanced since the identification of receptor activator of nuclear factor-κB ligand (RANKL) as osteoclast differentiation factor. The mechanisms of RANKL-induced osteoclast differentiation have been extensively investigated. Mitogen-activated protein kinases (MAPKs) were shown to play crucial roles in RANKL-induced osteoclast differentiation. RANKL-induced osteoclast differentiation was enhanced by inhibition of extracellular signal-regulated kinase (ERK), whereas it was suppressed by inhibition of p38 MAPK. It was reported that tumor necrosis factor (TNF), a major proinflammatory cytokine, induced osteoclast differentiation independently of RANKL. A report showed that inhibition of p38 suppressed TNF-induced osteoclast differentiation, whereas inhibition of ERK did not augment TNF-induced osteoclast differentiation. In this study we reevaluated the roles for MAPKs in TNF-induced osteoclast differentiation. In contrast with the previous report, pretreatment of mouse monocytic RAW264 cells with MAPK/ERK kinase (MEK) inhibitors including PD98059 and U-0126 augmented TNF-induced osteoclast differentiation. Furthermore, we found that U-0126 was more effective in augmentation of osteoclast differentiation than PD98059. Western blot analysis showed that U-0126 inhibited ERK phosphorylation and enhanced p38 phosphorylation, whereas PD98059 inhibited both ERK and p38 phosphorylation. SB203580, a p38 inhibitor, suppressed TNF-induced osteoclast differentiation, and inhibited p38 phosphorylation whereas it augmented ERK phosphorylation. These results demonstrate that ERK inhibition and p38 activation play crucial roles in both RANKL- and TNF-induced osteoclast differentiation.     

机械力作用下人牙周膜细胞ODF及OCIF的表达及意义

目的 :观察周期性机械牵张力对人牙周膜细胞破骨细胞分化因子 (ODF)及破骨细胞生成抑制因子(OCIF)mRNA表达的影响 ,探讨正畸牙周组织改建的分子机制。方法 :通过体外细胞培养加载系统施于人牙周膜细胞周期性牵张力 ,利用RT PCR检测技术 ,观察人牙周膜细胞ODF及OCIFmRNA表达的相对强度。结果 :体外培养的人牙周膜细胞在正常情况下表达ODF及OCIF ,当间歇性牵张力作用 6、12、2 4h后 ,随着作用时间的延长 ,人牙周膜成纤维细胞ODFmRNA的表达有减弱趋势 ;而OCIFmRNA的表达有增强趋势。结论 :机械牵张力可以调节人牙周膜细胞ODF、OCIF的表达 ,从而可以调节骨吸收作用。