Study of Tissue Engineered Dental Implants of human alveolar Bone-Evaluations on their osteogenic activities invitro

INTRODUCTION　　 One of the most often facing problems in the oral maxillofacial and plasticsurgery is the need to repairor constructthe bony defects caused by various reasonssuch as tumor,inflammation and injury. The therapeutical methods thatis availabl…     

In vitro reaction of human osteoblasts on alumina-toughened zirconia

Objectives: Alumina toughening enhances the mechanical properties of zirconia ceramics but the biocompatibility of this material has rarely been addressed. In this study, we examined the osteoblast response to alumina-toughened zirconia (ATZ) with different surface topographies.
Material and methods: Human osteoblasts isolated from maxillary biopsies of four patients were cultured and seeded onto disks of the following substrates: ATZ with a machined surface, airborne-particle abraded ATZ, airborne-particle abraded and acid etched ATZ. Airborne-particle abraded and acid etched titanium (SLA) and polystyrene disks served as a reference control. The surface topography of the various substrates was characterized by profilometry ( R _a, R _p−v) and scanning electron microscopy (SEM). Cell proliferation, cell-covered surface area, alkaline phophatase (ALP) and osteocalcin production were determined. The cell morphology was analyzed on SEM images.
Results: The surface roughness of ATZ was increased by airborne-particle abrasion, but with the R _a and R _p−v values showing significantly lower values compared with SLA titanium (Mann-Whitney U-test P <0.05). The proliferation assay revealed no statistically significant differences between the ATZ substrates, SLA titanium and polystyrene (Kruskal–Wallis test, P >0.05). All substrates were densely covered by osteoblasts. ALP and osteocalcin production was similar on the examined surfaces. Cell morphology analysis revealed flat-spread osteoblasts with cellular extensions on all substrates.
Conclusions: These results indicate that ATZ may be a viable substrate for the growth and differentiation of human osteoblasts. Surface modification of ATZ by airborne-particle abrasion alone or in combination with acid etching seems not to interfere with the growth and differentiation of the osteoblasts.     

Simvastatin increases osteoblasts and osteogenic proteins in ovariectomized rats

Background  Previous reports have indicated that statins could prevent bone loss in ovariectomized (OVX) rats and increase the expressions of osteogenic genes in cultured osteoblasts. In this study, we hypothesized that simvastatin might increase osteoblast number and protein expressions of osteogenic markers localized in bones in concomitance with the prevention of bone loss in OVX rats.
Materials and methods  Fifty-four 3-month-old OVX and sham-operated (SHAM) female Sprague–Dawley rats were used. Simvastatin (10–20 mg kg⁻¹ day⁻¹) was administrated orally for 6 weeks. Trabecular volume, osteoblast number and osteogenic proteins including BMP2, collagen type I and osteocalcin on bone sections obtained from lumbar vertebral body, distal femur and proximal tibia were measured.
Results  The results showed that SHAM rats had significantly less trabecular bone volume and osteoblast number than that of OVX rats 6 weeks after operation. Oral simvastatin treatment (10–20 mg kg⁻¹ day⁻¹) increased bone volume and osteoblast number in the distal femurs, proximal tibiae and vertebrae of OVX rats. Furthermore, the osteoblastic cells with immuno-stained BMP2, collagen type I and osteocalcin in vertebral bones were significantly increased by simvastatin treatment (20 mg kg⁻¹ day⁻¹) in OVX rats.
Conclusions  This study demonstrates that simvastatin enhances the production of osteogenic proteins in bone and this effect may contribute to the prevention of bone loss in OVX rats.     

骨髓间充质干细胞Notch1信号通路异常与骨髓瘤骨病

背景：多发性骨髓瘤骨病的发病机制目前尚未完全明确,骨髓间充质干细胞向成骨细胞分化障碍参与其中,而Notch1信号通路在间充质干细胞的增殖分化中起重要作用。 目的：探讨Notch1信号通路在多发性骨髓瘤骨病中的作用。 方法：分离培养多发性骨髓瘤患者和正常人骨髓间充质干细胞,Real-time PCR和Western blot检测成骨诱导分化前后Notch1和成骨基因Runx2的表达,以及Von Kossa染色鉴定钙质沉积程度。在多发性骨髓瘤患者间充质干细胞成骨诱导分化过程中,加入Notch1信号通路抑制剂DAPT和安慰剂,48 h后real-time PCR和western blot鉴定Notch1信号通路下游分子Hes1和成骨指标Runx2表达,2周后Von Kossa染色鉴定钙质沉积程度。 结果与结论：成骨诱导48 h后,间充质干细胞的Notch1表达减低,但是骨髓瘤患者间充质干细胞的降低幅度小于正常对照间充质干细胞;48 h后Runx2的表达在骨髓瘤患者间充质干细胞的表达明显弱于正常对照间充质干细胞;2周后,Von Kossa染色鉴定钙质沉积程度,骨髓瘤患者间充质干细胞明显弱于正常对照间充质干细胞;48 h后Hes1表达在DAPT组明显低于安慰剂组;而Runx2的表达在DAPT组明显高于安慰剂组。2周后 DAPT组钙质沉积明显强于安慰剂组。实验说明多发性骨髓瘤患者的间充质干细胞中,Notch1信号通路失活缺陷可能抑制其向成骨细胞分化。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

骨形态发生蛋白2诱导C3H10T1/2细胞成骨分化中长链非编码RNA的作用

背景：人类长链非编码RNA是现今的研究热点,已有研究报道其在肿瘤发生中的作用机制,但其在成骨分化方面的机制并不明确。 目的：观察人类长链非编码RNA在经骨形态发生蛋白2诱导小鼠C3H10T1/2细胞成骨分化中的作用,并探讨其分子机制。 方法：首先进行碱性磷酸酶染色和成骨指标基因检测。对C3H10T1/2细胞在骨形态发生蛋白2诱导下的成骨分化过程长链非编码RNA表达变化进行芯片分析。采用高通量测序比较骨形态发生蛋白2诱导组和未经骨形态发生蛋白2诱导组的表达变化,筛选出表达下降的基因。过表达相应长链非编码RNA后观察对骨形态发生蛋白2诱导成骨分化的影响。 结果与结论：骨形态发生蛋白2诱导C3H10T1/2细胞导致碱性磷酸酶活性增加。骨形态发生蛋白2诱导72 h后,碱性磷酸酶、Id1、骨钙素、Runx2、sp7表达上升(P < 0.05)。未诱导C3H10T1/2细胞与骨形态发生蛋白2诱导细胞芯片杂交后结果比较,下降达1.5倍的长链非编码RNAs有24条,其中只有AK035085有内含子。与未过表达AK035085的对照组相比,骨形态发生蛋白2诱导72 h后AK035085过表达的C3H10T1/2细胞碱性磷酸酶、Id1、骨钙素、Runx2、sp7表达均下降(P < 0.05)。提示骨形态发生蛋白2可刺激C3H10T1/2细胞发生成骨分化,AK035085可能对C3H10T1/2细胞的成骨分化存在抑制作用。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

骨形态发生蛋白2诱导C2C12和MC3T3-E1的成骨分化与自噬

背景：一系列研究表明自噬与分化有密切联系;骨形态发生蛋白2是诱导C2C12、MC3T3-E1成骨分化经典途径,是研究成骨分化过程的理想模型。 目的：观察自噬与骨形态发生蛋白2诱导细胞株C2C12、MC3T3-E1成骨分化的关系。 方法：Real-Time PCR检测MC3T3-E1与C2C12在骨形态发生蛋白2(100 μg/L)诱导培养3 d后成骨与自噬相关指标变化。碱性磷酸酶染色检测不同浓度3-甲基腺嘌呤(0,1,5,10 mmol/L)对骨形态发生蛋白2(100 μg/L)诱导培养7 d MC3T3-E1与C2C12成骨指标碱性磷酸酶变化,Western Blot检测C2C12和MC3T3-E1在骨形态发生蛋白2(100 μg/L)诱导不同时间点(0,12,24,48,72,96 h)LC3-Ⅰ/Ⅱ蛋白表达水平。 结果与结论：在骨形态发生蛋白2诱导细胞株C2C12、MC3T3-E1成骨分化过程中,诱导自噬相关mRNA与蛋白水平均有增高趋势,且自噬相关蛋白LC3水平增高与时间相关。同时,抑制自噬成骨分化过程中碱性磷酸酶表达水平降低。因此,自噬与骨形态发生蛋白2诱导细胞株C2C12、MC3T3-E1成骨分化过程有密切关系。 中国组织工程研究杂志出版内容重点：组织构建;骨细胞;软骨细胞;细胞培养;成纤维细胞;血管内皮细胞;骨质疏松;组织工程全文链接：     

MAPK-ERK1/2信号通路调控成骨性基因表达和细胞增殖

目的观察在不同浓度大鼠血清作用下,激活或抑制MAPK-ERK1/2信号通路对大鼠成骨细胞的成骨性基因表达和增殖
的影响。方法原代培养大鼠成骨细胞,进行形态和碱性磷酸酶初步鉴定后,分别用1%和5%的大鼠血清进行培养24 h,WB检
测MAPK-ERK1/2信号通路蛋白p-ERK1/2和ERK1/2表达,同时检测成骨性基因（Runx2、Ⅰ型胶原和碱性磷酸酶）和增殖蛋白
PCNA的表达;MAPK-ERK1/2信号通路阻断剂PD0325901抑制P-ERK1/2的表达后观察对Runx2、Ⅰ型胶原和碱性磷酸酶和增
殖蛋白PCNA的表达。结果5%大鼠血清激活p-ERK1/2水平明显高于1%大鼠血清（P<0.05）,在MAPK-ERK1/2高水平激活状
态下,成骨性基因如Runx2、Ⅰ型胶原和碱性磷酸酶的表达水平出现显著的增加及促进PCNA的表达;当抑制MAPK-ERK1/2
信号通路时,成骨性基因Runx2、Ⅰ型胶原和碱性磷酸酶的表达水平也随之下调,且PCNA 表达也受到抑制。结论激活
MAPK-ERK1/2通路促进成骨基因表达和成骨细胞增殖,抑制此通路将抑制成骨性基因表达和细胞增殖,此通路可能作为治疗
骨质疏松症的药物靶点。
     

无机纳米粒子掺杂生物活性碳纳米纤维的制备及性能评价

背景：已有研究表明向生物惰性碳纳米纤维中引入具有成骨活性的β-磷酸三钙纳米粒子,可显著提高碳纳米纤维的生物活性,而某些二价离子掺杂的β-磷酸三钙也被报道能够促进新骨的生成。 目的：考察适量锌离子、镁离子的引入对β-磷酸三钙@碳纳米纤维材料形貌及成骨活性的影响。 方法：以聚丙烯腈、磷酸三乙酯、硝酸钙、硝酸锌、硝酸镁等为原料,采用溶胶-凝胶、静电纺丝与原位烧结碳化相结合的方法制备锌或镁离子掺杂的β-磷酸三钙@碳纳米纤维材料。将所得复合纳米纤维材料及未掺杂锌或镁离子掺杂的β-磷酸三钙@碳纳米纤维与成骨细胞MC3T3-E1体外共培养,观察细胞的黏附、增殖和形态变化。 结果与结论：β-磷酸三钙@碳纳米纤维形貌均匀,表面可见直径为数十纳米的无机粒子均匀分布,锌或镁离子的引入对纤维形貌无明显影响;复合纤维主要由碳元素组成,钙、锌、镁元素等均匀分布于纤维中,且各元素相对含量与投料比相符。与未掺杂锌或镁离子的β-磷酸三钙@碳纳米纤维相比,MC3T3-E1成骨细胞更易在锌或镁离子掺杂的β-磷酸三钙@碳纳米纤维材料表面黏附,细胞增殖和铺展状态也更好。表明在β-磷酸三钙@碳纳米纤维的基础上,引入锌或镁离子掺杂,能进一步提高材料的细胞相容性及生物活性。