体外rhIL—1β诱导髁状突软骨细胞HSP70的表达及其意义

目的 明确热休克蛋白70（HSP70）在人重组白细胞介素－1（rhIL-1β）刺激下对下颌骨髁状突软骨细胞的保护作用。方法 通过原代细胞培养获得兔髁状突软骨细胞,在生长良好的第三代软骨细胞中分别加入不同浓度的rhIL-1β,并利用原位杂交及免疫组织化学技术检测rhIL-1β处理软骨细胞后HSP70的表达变化。结果 正常髁状突软骨细胞胞浆内有HSP70蛋白弱表达,rhIL-1β（10ng/ml）作用12h后HSP70出现表达升高,部分细胞核内也可见表达,48h后信号开始减弱。HSP70mRNA的表达与蛋白表达基本一致。结论 一定浓度的rhIL-1β刺激髁状突软骨细胞可诱导HSP70的转录及蛋白合成,提示HSP70可能在骨关节炎症损伤中对软骨细胞起到保护作用。     

rhIL—1β及TGF—β对髁状突软骨细胞增殖影响的研究

目的：探讨rhIL-1β及TGF－β对髁状突软骨细胞增殖的影响。方法：以酶消化法获得兔髁状突软骨细胞。用MTT法及PCNA免疫组化染色检测不同浓度rhIL-1β及TGF－β对体外培养的兔髁状突软骨细胞增殖的影响。结果：MTT检测，rhIL-1β（10，20ng/ml）处理软骨细胞48h后，可明显抑制软骨细胞增殖，经统计学检验，处理3－6d有显著性差异（P＜0．01,t检验）；加入TGF－β（10，20ng/ml)可明显拮抗rhIL-1β对软骨细胞增殖的抑制作用，并且浓度愈高对rhIL-1β的抑制作用愈强。PCNA检测，rhIL-1β处理软骨细胞后PCNA阳性细胞率降低，随rhIL-1β的刺激浓度增加，阳性率明显降低；加入外源性TGF－β可以使PCNA的阳性率提高。结论：rhIL-1β对髁状突软骨细胞增殖具有报制作用，外源性TGF－β对该作用具有明显的拮抗效应。     

rhTGF-β1对大鼠髁突软骨细胞SZP表达的影响

目的:观察rhTGF-β1对大鼠髁突软骨细胞SZP表达的影响.方法:酶消化法获取大鼠髁突软骨细胞,甲苯胺蓝和Ⅱ型胶原染色鉴定.细胞培养液中分别加入10 μg/L、20μg/L rhTGF-β1后,不同时间点应用RT-PCR和ELISA法检测SZP mRNA和蛋白的表达.结果:加入10μg/L、20μg/L rhTGF-...     

rhIL-1β及TGF-β对髁状突软骨细胞增殖影响的研究

目的 :探讨rhIL 1β及TGF β对髁状突软骨细胞增殖的影响。 方法 :以酶消化法获得兔髁状突软骨细胞。用MTT法及PCNA免疫组化染色检测不同浓度rhIL 1β及TGF β对体外培养的兔髁状突软骨细胞增殖的影响。结果 :MTT检测 ,rhIL 1β( 10、2 0ng/ml)处理软骨细胞 4 8h后 ,可明显抑制软骨细胞增殖 ,经统计学检验 ,处理 3～ 6d有显著性差异 (P <0 .0 1,t检验 ) ;加入TGF β( 10、2 0ng/ml)可明显拮抗rhIL 1β对软骨细胞增殖的抑制作用 ,并且浓度愈高对rhIL 1β的抑制作用愈强。PCNA检测 ,rhIL 1β处理软骨细胞后PCNA阳性细胞率降低 ,随rhIL 1β的刺激浓度增加 ,阳性率明显降低 ;加入外源性TGF β可以使PCNA的阳性率提高。 结论 :rhIL 1β对髁状突软骨细胞增殖具有抑制作用 ,外源性TGF β对该作用具有明显的拮抗效应     

低氧对大鼠髁突软骨细胞HIF-1α和VEGF表达的影响

目的:探讨低氧诱导因子-1α(hypoxia inducible factor-lα,HIF-1α)和血管内皮生长因子(vascular endothelial growthfactor,VEGF)的表达变化在髁突软骨生长发育中的意义。方法:选用3周龄SD大鼠的髁突软骨进行原代细胞培养,建立二氯化钴(CoCl2)化学低氧的细胞培养模型,RT-PCR检测常氧状态下与低氧后12、24、48 h内大鼠髁突软骨细胞HIF-1α和VEGF的mRNA表达。结果:髁突软骨细胞低氧培养后12、24 h、48 h时间点HIF-1α和VEGF的mRNA表达均明显升高(P<0.05);并且VEGF、HIF-1α表达12 h与24 h、12 h与48 h、24 h与48 h比较差异均有统计学意义;HIF-1α表达逐次升高,而VEGF在12 h达到最高点后逐次下降,但是均高于常氧状态下。结论:低氧早期可上调髁突软骨细胞HIF-1α、VEGF mRNA表达,可能在髁突软骨血管形成及生长发育发挥重要作用。     

IGF-1信号通路相关蛋白在大鼠髁突软骨细胞增殖分化中的表达

目的:研究胰岛素样生长因子-1(IGF-1)信号转导通路在大鼠髁突软骨细胞增殖分化调控过程中相关基因的表达。方法:体外单层培养并鉴定出生后1、7、14、28 d共4组SD大鼠髁突软骨细胞。免疫组织化学方法检测细胞内IGF-1表达情况,Real-time PCR及Western印迹法检测细胞内IGF-1R、Bcl-2、Bax mRNA及蛋白表达。饥饿培养24 h后,实验组加入质量浓度为100 ng/mL的重组大鼠IGF-1细胞因子(rrIGF-1)继续培养24、48 h,CCK-8检测细胞增殖情况,Real-time PCR技术检测各组髁突软骨细胞内IGF-1R、IGF-2R、Raf1、GSK-3、IGFBP3、NF-κB、Bcl-2、Bax、integrin、TGF-βmRNA表达情况;对照组培养液不加rrIGF-1。结果:各鼠龄组SD大鼠髁突软骨细胞内IGF-1表达均阳性,IGF-1R mRNA及蛋白表达相对平稳,Bcl-2、Bax mRNA及蛋白表达逐渐增强,在出生14 d后表达下降(P<0.05)。加入100 ng/mL rrIGF-1后,髁突软骨细胞增殖速度显著增加,细胞凋亡减少,Real-time PCR结果显示实验组IGF-1R、GSK-3、Bax、integrin mRNA表达整体呈下降趋势;IGF-2R、Raf1、IGFBP3、NF-κB、Bcl-2、TGF-βmRNA表达水平总体呈上调趋势,差异有统计学意义。结论 :IGF-1介导的信号转导途径参与了髁突软骨细胞的增殖、分化以及软骨形成早期的调控,并可能与integrin、TGF-β等其他蛋白相互作用,共同参与髁突发育过程。     

静压力对髁突软骨转化生长因子β1表达影响的体外研究

目的:观察静压力对体外培养髁突软骨细胞表达TGF-β1的影响。方法:解剖、培养SD大鼠髁突软骨,应用静压力加载装置对实验组软骨加载强度为10kPa的持续静压力1h。对照组除软骨不加力外,其它培养条件与实验组相同,加力完成后2组同时收集样本。用免疫组化技术检测2-实验组和对照组髁突软骨TGF-β1的含量和分布,用彩色病理图像分析仪检测髁突软骨各层TGF-β1表达的强度。结果:实验组的髁突软骨各层细胞TGF-β1表达均增强,与对照组比较差异有显著性(P<0.05)。其中成软骨细胞层改变最明显(P<0.01)。结论:静压力促进髁突软骨各层细胞TGF-β1表达增强,其中成软骨细胞层表达增强最为明显。     

静张应力与TGF-β_1对大鼠髁突软骨细胞增殖效应调节初步研究

目的：探讨转化生长因子-β(TGF-β1)在静张应力环境下对髁突软骨细胞增殖效应的影响。方法：（1）将传代培养至第4代大鼠下颌髁突软骨细胞在12孔培养板上培养，采用流式细胞仪测定加入不同浓度TGF-β1（0.1、1、10ng/ml）0.6、12、18、24h后，对髁突软骨细胞增殖活性（PI值）的影响。（2）将第4代大鼠下颌髁突软骨细胞增殖活性（PI值）的影响。结果：不同浓度TGF-β1（0.1、1、10ng/ml）在模拟生理环境下以剂量依赖型的方式整体促进了髁突软骨细胞增殖效应，对髁突软骨细胞的增殖活性调节作用主要在12、18h段，增殖峰值在18h左右；在5kPa静张应力联合TGF-β1刺激下培养较TGF-β1的单独效应具有更强的促髁突软骨细胞增殖作用。结论：静张应力联合TGF-β1可以调节髁突软骨细胞的增殖活性。     

兔下颌持续前导后髁突软骨中核心结合因子α1的表达及意义

目的:探讨兔下颌持续功能前导后髁突软骨中核心结合因子α1(corebindingfactorα1,Cbfα1)蛋白的表达及与髁突改建的关系。方法:60只8周龄日本大耳白兔,随机分为实验组和对照组,实验组动物每天24h戴用咬合前导矫正器。实验组与对照组动物分别在3天、1周、2周、4周、8周及12周时处死并取材,用免疫组化方法检测髁突组织内Cbfα1的分布和表达变化,并对其表达进行灰度测定,采用t检验和单因素方差分析对灰度值进行统计学分析。结果:Cbfα1主要在髁突软骨过渡层和肥大层软骨细胞的胞核和胞质中表达,钙化层的软骨细胞和成骨细胞中也可见Cbfα1的表达。实验组兔髁突软骨各层Cbfα1的表达强度均显著高于同期对照组(P<0.05),其中治疗后4周过渡层、肥大层和钙化层的表达均最为明显,分别是71.00±1.52,50.00±0.75和82.00±0.39。结论:下颌持续前导后,Cbfα1的动态变化与下颌髁突适应性生长改建关系密切。     

TNF-α刺激髁突软骨细胞产生白细胞介素-34的研究

目的通过观察TNF-α对髁突软骨细胞分泌白细胞介素-34(IL-34)及表达IL-34 mRNA基因的影响,探讨IL-34在颞下颌关节紊乱病中的致病机制。方法取第三代髁突软骨细胞,培养过程于培养液中加入不同浓度(0、1、10、20、50 ng/m L)的TNF-α培养24 h以及同一浓度(10 ng/m L)TNF-α分别培养1、3、6、10、24 h后,收集培养上清液及细胞,分别用ELISA和RT-PCR方法测定IL-34浓度以及IL-34 mRNA的表达情况。结果 1实验组和对照组髁突软骨细胞上清液中均能检测到IL-34。2TNF-α刺激髁突软骨细胞IL-34mRNA基因表达,并呈正相关关系。结论 TNF-α能刺激髁突软骨细胞产生IL-34。     

Hypermethylation of CpGs in the promoter of the COL1A1 gene in the aged periodontal ligament

Although the human periodontal ligament shows age-associated histological alterations, the molecular mechanisms are not yet understood. We previously found that COL1A1 gene expression declines with age. In this study, we asked whether DNA methylation in the regulatory region of the gene alters in the aging process, as a possible cause of the decline. The method used was a bisulfite modification of cytosine and nucleotide sequencing of DNA. While the 1st intron region was kept demethylated at young and old ages, the levels of methylation at most CpG sites in the proximal and distal regions of the promoter showed elevation at older ages. Analysis of the data indicates the possible importance of DNA hypermethylation in the promoter region for the age-associated decrease of COL1A1 gene expression.     

Bismuth UPD on the modified Au(1 1 1) electrode

The bismuth UPD was studied on Au(1 1 1) electrodes modified by silver intermediates and adsorbed thymine. Cyclic voltammetry, potential step experiments and X-ray photoelectron spectroscopy were used for investigation. The results were compared to the results of the analogous experiments performed on bare Au(1 1 1) and on bulk silver. In the first part it is shown that the Bi UPD on Ag_ML/Au(1 1 1) differs completely from the UPD on Au(1 1 1) as well as on bulk Ag due to changed electronic properties of the substrate. The 2nd part focuses on the Bi UPD in presence of the nucleobase thymine. Thymine undergoes a reorientation from the chemisorbed state to the physisorbed state on Au(1 1 1) at potentials where the Bi UPD takes place. During the UPD adsorbed thymine is replaced by Bi species on the electrode surface. It does not re-adsorb on top of the deposited Bi layer. An energetic advantage due to re-adsorption on topmost layer as described for the Cu UPD on thymine modified Au(1 1 1) does not occur.     

Bisphosphonate-associated osteonecrosis of the jaws 1

Bisphosphonates are generally administered either orally or intravenously. Orally administered bisphosphonates are primarilly used in the treatment of postmenopausal osteoporosis, glucocorticoid-induced osteoporosis, and Paget's disease. When orally administered, only about 1% is absorbed from the tractus from the tractus digestivus. With intravenous administration, higher blood levels levels are reached. Intravenously administered bisphosphonates are used in the treatment of hypercalcaemia, Kahler's disease, and bone metastases of other malignancies. A few cases of osteonecrosis of the jaw(s) are seen especially when more powerful bisphosphonates are administered intravenously. This osteonecrosis is most often provoked by means of an invasive oral treatment. Bisphosphonate-associated osteonecrosis is very difficult to treat. Therefore, dental preventive measures and treatment of dental foci and other inflammations are recommended before starting bisphosphonate therapy.     

Occlusal stimuli influence on the expression of IGF-1 and the IGF-1 receptor in the rat periodontal ligament

OBJECTIVE: To test the hypothesis that hypofunction/recovered occlusal function has no effect on the changes in insulin-like growth factor-1 (IGF-1) and IGF-1 receptor expressions and cell proliferation of periodontal ligament (PDL) cells. MATERIALS AND METHODS: To produce occlusal hypofunction, the appliances were attached to the rats' maxillary and mandibular incisors. Subsequently, occlusal contact of the molar area was thoroughly recovered by removal of the appliances. RESULTS: In periodontal sections, localization of IGF-1, the IGF-1 receptor, and proliferating cell nuclear antigen (PCNA) immunoreactive cells was significantly more expressed in the control group compared with the hypofunctional group (P < .01). In addition, after the recovery of the occlusion, IGF-1, IGF-1 receptor, and PCNA were detected significantly much more than in the hypofunction group (P < .01). CONCLUSION: The hypothesis was rejected. This study suggests that occlusal stimuli induce cell proliferation of PDL cells by increasing IGF-1 and IGF-1 receptor expression.     

Application of the mean spherical approximation and ion association to describe the activity coefficients of aqueous 1:1 electrolytes1

The unrestricted version of the mean spherical approximation has been applied to describe the concentration dependence of the mean ionic activity coefficients for 12 aqueous electrolyte solutions for which extensive permittivity data are also available. By using the actual solvent permittivity rather than that of the pure solvent, it is shown that this primitive model fits the experimental data in almost all cases to the maximum concentrations for which the permittivity can be described by the use of three adjustable parameters, namely, an effective ionic diameter, σ₊ or σ_?, the effective ion pair diameter σ_ip, and the association constant K_as for ion pair formation. The values of K_as obtained are discussed with respect to results from experiments reported in the literature.