新型高氮无镍不锈钢骨植入材料的体内外生物相容性研究

目的 探讨新型高氮无镍不锈钢(-HNS)骨植入材料的体内外生物相容性,为其临床应用提供安全性方面的科学依据.方法 对HNS开展了细胞毒性、溶血性、遗传毒性(Ames和MLA试验)和致癌性方面的体外实验研究;进一步选择不同的动物评价了其皮内反应、致敏性和急性/亚慢性全身毒性;并以316L医用不锈钢材料为对照,研究兔胫骨内植入4w、12w和26w后HNS材料与骨组织之间的生物相容性.结果 HNS无明显的细胞毒性:无溶血;未诱发鼠伤寒沙门氏菌的体外基因回复突变;未引起体外哺乳动物细胞L5178Y/TK+/-的TK基因突变和染色体诱变;体外细胞转化试验结果为阴性;未引起动物皮肤过敏和皮内反应、不引起小鼠的急性全身毒性反应;亚慢性全身毒性试验中SD大鼠均未见临床全身毒性症状、试验组和对照组之间的体重及主要脏器体重比的差异均无统计学意义(P＞0.05)、血液学和临床生化主要检测指标与对照组之间的差异均无统计学意义(P＞0.05),动物的心、肺、肝、脾、肾、脑等主要脏器均未见异常改变.HNS植入后各期的组织学分析表明:相比316L医用不锈钢,HNS能更明显促进骨种植体周围的新骨形成.结论 新型HNS骨植入材料对生物体全身组织器官无潜在的危害性,生物相容性好,具有临床应用前景.     

镍钛基形状记忆合金体外生物相容性研究进展

近等原子比的镍钛形状记忆合金(NiTi-SMA)因具有特殊的形状记忆效应以及超弹性,多年来一直作为口腔正畸矫治弓丝材料应用于临床。由于镍钛基合金材料含有大量镍元素,在口腔环境中可能会由于金属腐蚀作用析出镍离子,对局部组织有致敏甚至致癌的危害。本文回顾NiTi-SMA生物相容性相关历史文献,总结该合金的表面腐蚀、细胞毒性、基因毒性等方面的研究进展,并指出NiTi-SMA表面处理的必要性。     

正畸合金在口腔内的腐蚀以及镍的生物相容性

随着正畸生物材料深入的研究，正畸合金在口腔环境中的腐蚀越来越受到重视。腐蚀释出的金属离子，特别是镍因其显著的致敏性、致突变性、致癌性和细胞毒性，受到学者们的广泛关注。本文就正畸合金的腐蚀类型、抗腐蚀性和镍的生物相容性作一综述。     

正畸合金在口腔内的腐蚀以及镍的生物相容性

随着正畸生物材料深入的研究,正畸合金在口腔环境中的腐蚀越来越受到重视。腐蚀释出的金属离子,特别是镍因其显著的致敏性、致突变性、致癌性和细胞毒性,受到学者们的广泛关注。本文就正畸合金的腐蚀类型、抗腐蚀性和镍的生物相容性作一综述。     

彩色不锈钢正畸弓丝和托槽的生物安全性评价

目的:评价应用表面化学着色工艺研制的彩色不锈钢正畸弓丝和托槽的生物安全性,为其在口腔临床的应用提供依据. 方法:对材料进行短期经口途径全身毒性试验、口腔黏膜刺激试验、致敏试验和Ames致突变性试验. 结果:材料无明显的短期全身毒性、口腔黏膜刺激性、致敏性及致突变性. 结论:应用表面化学着色工艺研制的彩色不锈钢正畸弓丝和托槽具有良好的生物安全性.     

3D打印镍钛植入物表面去合金化处理及细胞相容性研究

目的 本文通过喷砂、酸蚀、去合金等生物活性处理方法研究3D打印镍钛合金的最佳改性工艺。方法 利用扫描电镜、能谱仪和接触角测量等对试件的表面结构、性能进行检测;本实验用人骨髓间充质干细胞（human bone marrow mesenchymal stem cells,hBMSCs）对不同表面的生物相容性及成骨活性进行研究。结果 去合金化表面亲水性得到了提高,能谱仪分析结果显示表面镍元素从最初的52.1 wt%降至18.6 wt%,不但能加速细胞在其表面的分化和增殖,而且能增强细胞的附着能力。结论 去合金表面构建了更加丰富的纳米级网架结构,对细胞成骨分化和功能的表达具有明显促进作用,这对提高骨结合能力和植入体的长期稳定具有重要意义。     

EH型复合材料短期生物相容性的评价

羟磷灰石与EAM树脂按一定比例调和形成一种新材料——EH型复合材料。该材料可改善纯羟磷灰石易折断、手术中塑型困难的缺陷,按生物学性能测试标准进行细胞毒性试验,热源试验、急性全身毒性试验和溶血试验。均显示该材料对生物体无毒性和刺激性,用于人体内是安全可行的。     

新型医用钛合金生物相容性评价

目的:评价新型医用钛合金Ti12.5Zr2.5Nb2.5Ta (TZNT)的生物相容性,并和3 种标准医用钛材料Ti6Al4V、Ti6Al7Nb和TA2进行对比.方法:通过细胞毒性试验观察细胞在TZNT、Ti6Al4V和Ti6Al7Nb合金离子析出培养液中的生长情况,计算在不同时间组的相对细胞增殖率,评价其毒性等级;通过皮下埋植试验观察4 种材料植入白鼠体内4 周和8 周的组织变化情况,计算炎细胞密度和纤维膜厚度的变化情况,评价其引起的组织反应程度.结果:TZNT、Ti6Al4V和Ti6Al7Nb在3 个时间组(2、 4、 6 d)的相对细胞增殖率均不低于100%,细胞毒性等级评定为0 级.和Ti6Al4V和Ti6Al7Nb相比,TZNT和TA2植入白鼠体内4 周和8 周后,无论是炎细胞密度还是植入物周围的纤维膜厚度均有所降低,引起的组织反应程度较低.结论:TZNT具有良好的生物相容性,是一种理想的生物医用钛合金.     

JJ—磁性固位体金属材料的生物相容性评价

目的 了解JJ－磁性固位体金属材料的生物相容性。方法 选用细胞毒性试验、口腔粘膜刺激试验、急性经口毒性试验、溶血试验、致敏试验、Ames试验等6个试验,分别对JJ－磁性固位体金属材料的毒性、致敏性和致突变性进行研究测试。结果 细胞毒性试验显示,试验组毒性分级为I级;口腔粘膜刺激试验,试验组无论肉眼观察还是组织切片,均与阴性对照无显著性差异;急性经口毒性试验,试验组属于无毒类;溶血试验的试验组溶血率为0．45％;致敏试验显示试验组不引起致敏反应;Ames试验的试验组在各剂量组对TA97,TA98,TA100,TA102的回变菌落数与自发回变数相近,无致基因突变作用。结论 JJ－磁性固位体金属材料具有良好的生物相容性。     

表面等离子渗氮处理钛的生物相容性评价：3．耐腐蚀性能评价

通过进行自然腐蚀实验、阳极极化加速腐蚀实验、四点弱极化实验、失重实验等腐蚀测量实验和原子吸收光谱实验对不同温度和不同时间等离子氪化的金属纯钛和未氮化的纯钛进行对比性研究，发现钛经过表面等离子氮化后耐腐蚀性能有显著提高，离子释放速率有显著下降，而且随氮化温度及时间增加，总体上耐腐蚀性能呈现提高的趋势。     

苹果多酚诱导ACC-M细胞凋亡及caspase-3表达的实验研究

目的:探讨苹果多酚体外诱导人腺样囊性癌ACC-M细胞凋亡的作用机制.方法:MTT法、流式细胞术观察不同浓度苹果多盼对ACC-M细胞凋亡的影响;RT-PCR和Western印迹检测苹果多酚作用下ACC-M细胞caspase-3mRNA和蛋白表达的变化.应用SPSS13.0软件包对数据进行统计学分析.结果:随着苹果多酚浓度的增加,ACC-M细胞凋亡增多(P<0.05),ACC-M细胞中caspase-3 mRNA和蛋白表达量增加(P<0.05),差异有统计学意义.结论:苹果多酚可体外诱导ACC-M细胞凋亡,激活caspase-3基因mRNA及蛋白的表达可能是其作用机制之一.     

内毒素脂多糖促进人牙髓成纤维细胞凋亡及其对caspase-3活性的影响

目的观察内毒素脂多糖(lipopolysaccharide,LPS)对体外培养的人牙髓成纤维细胞的致凋亡作用及其对凋亡相关的半胱氨酸蛋白酶3(caspase-3)活性的影响。方法不同浓度(0μg、100μg、200μg、400μg/mL)的LPS作用细胞,采用噻唑蓝比色法检测LPS对细胞增殖的影响;Hoechst33258荧光染色法观察细胞凋亡;流式细胞术检测细胞周期及凋亡;化学比色法检测细胞凋亡过程中caspase-3活性的变化。结果不同浓度LPS组细胞的生长与对照组相比均受到显著的抑制(P<0.01),细胞增殖抑制率呈剂量依赖关系;Hoechst33258荧光染色显示,给药组部分细胞呈典型的凋亡表现;流式细胞术检测结果显示,不同浓度的LPS作用细胞48h,细胞的凋亡率分别为9.2%,23.8%,31.4%;caspase-3活性检测显示,其活性呈剂量依赖性增高,LPS浓度达到400μg/mL时,其活性为对照组的3.4倍。结论LPS可显著地抑制人牙髓成纤维细胞增殖、诱导细胞凋亡、升高caspase-3活性,并呈明显的量效关系。     

Survivin、bcl-2、caspase-3在牙源性角化囊肿中的表达及意义

目的检测凋亡相关蛋白survivin、bcl-2、caspase-3在角化囊肿中的表达,探讨其在角化囊肿发生发展中的意义。方法免疫组织化学方法检测20例角化囊肿(10例原发和10例复发)、10例含牙囊肿和10例根端囊肿中survivin、bcl-2、cas-pase-3的表达。结果Survivin、bcl-2、caspase-3阳性染色分别见于13(65%)、13(65%)、9(45%)例角化囊肿。Survivin、bcl-2在角化囊肿上皮基底层细胞中阳性表达,阳性率显著高于含牙囊肿和根端囊肿;caspase-3在角化囊肿上皮表层细胞表达。Survivin的表达与bcl-2正相关,与caspase-3无明显相关性。结论Survivin、bcl-2、caspase-3在角化囊肿形成和发展中起一定作用。     

槟榔碱诱导上皮细胞凋亡相关蛋白caspase-3,8,9、Bcl-2和Bax的表达

目的：观察槟榔碱刺激上皮细胞后凋亡相关蛋白caspase-3,-8,-9、Bcl-2和Bax的表达情况.方法：0,25,50,75,100,125 μg/mL槟榔碱刺激上皮细胞Hacat 24 h,Western Blot法检测caspase-3,8,9、B（cl-2和Bax的表达情况.结果：随着槟榔碱浓度的增加,caspase-3、caspase-8表达量逐渐增强,但casapse-9表达未见明显上调;胞内Bcl-2表达受到明显抑制,Bax在槟榔碱浓度为125 g/mL时,可见表达明显上调.结论：槟榔碱可通过内源性和外源性途径诱导上皮细胞Hacat发生凋亡,但高浓度槟榔碱对外源性凋亡途径的活化更为显著;槟榔碱可上调促凋亡蛋白Bax的表达并下调抗凋亡蛋白Bcl-2.     

Immunohistochemical analysis of apoptosis-related factors (Fas, Fas ligand, caspase-3 and single-stranded DNA) in ameloblastomas

BACKGROUND: To clarify the possible role of apoptotic cell death in oncogenesis and cytodifferentiation of odontogenic epithelium, apoptosis-related factors--Fas, Fas ligand (FasL), caspase-3 and single-stranded DNA (ssDNA)--were analyzed in ameloblastomas as well as in tooth germs. METHODS: Specimens of 5 tooth germs, 29 benign ameloblastomas and 5 malignant ameloblastomas were examined by immunohistochemistry using anti-Fas, FasL, caspase-3 and ssDNA polyclonal antibodies. RESULTS: Immunoreactivity for Fas and FasL was detected in normal and neoplastic odontogenic epithelial cells. Fas expression in ameloblastomas was slightly lower than that in tooth germs, whereas FasL expression was similar in tooth germs and ameloblastomas. Malignant ameloblastomas showed downregulation of Fas expression and upregulation of FasL expression, as compared with benign ameloblastomas, indicating escape from cell death attack by immune cells. Immunoreactivity for caspase-3 was detected chiefly in cells neighboring the basement membrane in tooth germs and ameloblastomas. Expression of caspase-3 and Fas tended to be low in basal cell ameloblastomas and high in desmoplastic ameloblastomas, as compared with other variants of ameloblastomas. Caspase-3 expression was more intense in malignant ameloblastomas than in tooth germs and benign ameloblastomas. Apoptotic bodies reactive with anti-ssDNA antibody were detected in normal and neoplastic odontogenic epithelial cells detached from the basement membrane. Keratinizing cells in acanthomatous ameloblastomas and granular cells in granular cell ameloblastomas showed increased numbers of apoptotic bodies and increased expression of Fas and caspase-3, as compared with other neoplastic cells. Apoptotic reactions in malignant ameloblastomas were less frequent than in benign ameloblastomas, indicating abnormal regulation of cell turnover in odontogenic epithelial cells. CONCLUSION: These apoptosis-related factors were detected in various patterns in normal and neoplastic odontogenic epithelium, suggesting that these factors might be associated with oncogenesis and cytodifferentiation of epithelial odontogenic tumors.     

婴幼儿血管瘤中livin和caspase-3表达及其与细胞凋亡的关系

目的:研究凋亡调控基因livin和caspase-3在婴幼儿血管瘤组织中的表达及与细胞凋亡的关系,探讨其变化对血管瘤病程演化的影响。方法:采用免疫组织化学SABC法检测血管瘤组织标本中livin和caspase-3的表达,同时采用末端转移酶介导的原位缺口末端标记染色(TUNEL)技术检测血管瘤细胞的凋亡情况。应用SPSS17.O软件包对结果进行统计学分析。结果:Caspase-3阳性表达率在增殖期和消退期血管瘤分别为42.31%和81.82%,2组之间差异显著(P<0.01);Caspase-3在血管畸形和正常皮肤组织不表达或低表达。Livin阳性表达率在增殖期和消退期血管瘤分别为88.46%和31.82%,2组之间差异显著(P<0.01);Livin在血管畸形和正常皮肤组织不表达或低表达。Livin与caspase-3的表达呈负相关(r=-0.539,P<0.01)。血管瘤消退期细胞凋亡显著高于增殖期,在血管瘤内皮细胞中,Livin与凋亡呈负相关(r=-0.640,P=0.004),而caspase-3与凋亡呈正相关(r=0.471,P=0.042)。结论:Livin和caspase-3与血管瘤的发生、发展密切相关。     

Effects of dose-dependent response to gamma radiation on circumvallate papilla by expression of caspase-3 in vivo

BackgroundRadiotherapy is one of the most significant treatment modality of head and neck cancers. However, it has various hazards on the normal tissues in the radiation field. One of these affected tissues is the lingual mucosa with their papillae such as circumvallate papilla. The effects of radiation on the lingual specialized mucosa may be represented by radiation-induced mucositis and taste alteration including partial or complete loss of taste.ObjectivesThe aim of the study was to evaluate the dose-dependent response of circumvallate papillae to gamma radiation by immunohistochemical expression of caspase-3.Material and methodsTwenty-four adult male albino rats were divided into 3 equal groups irradiated at 2.0, 4.0 and 6.0 Gy whole-body gamma radiation doses. Six non-irradiated rats were used as the control group. The radiation effects on circumvallate papillae were evaluated three days after irradiation via histomorphometric investigation of the papillary size and taste buds’ distortion in addition to an immunohistochemical assessment of the apoptotic activity using Caspase-3 marker.ResultsDose-related changes were observed in the circumvallate papillae size and morphology and taste buds affection. The changes were obviously detected in rats irradiated at 4 Gy and 6 Gy doses. The detection of caspase-3 marker was evident in a dose-dependent manner in all the irradiated groups, more noticeably in the taste bud cells.ConclusionsIt could be concluded that circumvallate papillae are adversely affected in a dose-dependent manner by gamma radiation particularly in 4 Gy and 6 Gy doses.     

Comparative study on corrosion resistance and in vitro biocompatibility of bulk nanocrystalline and microcrystalline biomedical 304 stainless steel

Objectives

SUS 304 stainless steels have been widely used in orthodontics and implants such as archwires, brackets, and screws. The purpose of present study was to investigate the biocompatibility of both the commercial microcrystalline biomedical 304 stainless steel (microcrystalline 304ss) and novel-fabricated nanocrystalline 304 stainless steel (nanocrystalline 304ss).

Methods

Bulk nanocrystalline 304ss sheets had been successfully prepared by microcrystalline 304ss plates using severe rolling technique. The electrochemical corrosion and ion release behavior immersion in artificial saliva were measured to evaluate the property of biocorrosion in oral environment. The cell lines of murine and human cell lines from oral and endothelial environment were co-cultured with extracts to evaluate the cytotoxicity and provide referential evidence in vivo.

Results

The polarization resistance trials indicated that nanocrystalline 304ss is more corrosion resistant than the microcrystalline 304ss in oral-like environment with higher corrosion potential, and the amount of toxic ions released into solution after immersion is lower than that of the microcrystalline 304ss and the daily dietary intake level. The cytotoxicity results also elucidated that nanocrystalline 304ss is biologically compatible in vitro, even better than that of microcrystalline 304ss.

Significance

Based on the much higher mechanical and physical performances, nanocrystalline 304ss with enhanced biocorrosion property, well-behaved in vitro cytocompatibility can be a promising alternative in orthodontics and fixation fields in oral cavity.     

Effects of nanostructured,diamondlike, carbon coating and nitrocarburizing on the frictional properties and biocompatibility of orthodontic stainless steel wires

Objective:To evaluate and compare the effects of nanostructured, diamondlike, carbon (DLC) coating and nitrocarburizing on the frictional properties and biocompatibility of orthodontic stainless steel archwires.Materials and Methods:Plasma-enhanced chemical vapor deposition technology was applied to coat DLC films onto the surface of austenitic stainless steel wires, and salt-bath nitrocarburizing technology was employed to achieve surface hardening of other wires. Surface and cross-sectional characteristics, microhardness, modulus of elasticity, friction resistance, corrosion resistance, and cell toxicity of the modified and control wires were analyzed.Results:The surfaces of the DLC-coated and nitrocarburized wires were both smooth and even. Compared with the control, the DLC-coated wires were increased in surface hardness 1.46 times, decreased in elastic modulus, reduced in kinetic friction coefficient by 40.71%, and decreased in corrosion current density by two orders of magnitude. The nitrocarburized wire was increased in surface hardness 2.39 times, exhibited an unchanged elastic modulus, demonstrated a decrease in maximum static friction force of 22.2%, and rose in corrosion current density two orders of magnitude. Cytotoxicity tests revealed no significant toxicity associated with the modified wires.Conclusions:DLC coating and nitrocarburizing significantly improved the surface hardness of the wires, reduced friction, and exhibited good biocompatibility. The nanostructured DLC coating provided excellent corrosion resistance and good elasticity, and while the nitrocarburizing technique substantially improved frictional properties, it reduced the corrosion resistance of the stainless steel wires to a lesser extent.