贻贝启发接枝骨形态发生蛋白2成骨活性肽的介孔生物玻璃修复股骨髁缺损

背景:骨形态发生蛋白2在胚胎发育、骨骼形成和再生修复中具有重要作用,但高剂量应用与癌症发病密切相关。骨形态发生蛋白2成骨活性段L20能够有效减少癌症等不良反应,并可显著促进骨组织再生。目的:将骨形态发生蛋白2活性肽段以贻贝衍生肽模拟策略接枝在介孔生物玻璃表面,探究其对组织工程成骨性能的影响。方法:(1)采用模板法合成介孔生物玻璃纳米颗粒,采用一步法合成负载骨形态发生蛋白2成骨活性肽L20的介孔生物玻璃纳米颗粒,表征负载骨形态发生蛋白2成骨活性肽L20介孔活性玻璃纳米颗粒的形貌与体外缓释性能。(2)分离提取SD大鼠骨髓间充质干细胞,传2代后分别与PBS(空白组)、介孔生物玻璃纳米颗粒(对照组)、负载骨形态发生蛋白2成骨活性肽L20介孔生物玻璃纳米颗粒(实验组)共培养,采用细胞活死荧光染色和CCK-8法检测细胞毒性和细胞增殖,扫描电镜观察细胞黏附;成骨诱导分化后,进行碱性磷酸酶染色、茜素红S染色与成骨相关基因表达检测。(3)取15只SD大鼠,建立双侧股骨髁缺损模型,采用随机数字表法分为3组:空白组(n=5)不植入任何材料,对照组(n=5)植入介孔生物玻璃纳米颗粒,实验组(n=5)植入负载骨形态发生蛋白2成骨活性肽L20介孔生物玻璃纳米颗粒。术后8周,进行股骨Micro-CT扫描与组织形态观察。结果与结论:(1)扫描电镜下可见负载骨形态发生蛋白2成骨活性肽L20介孔生物玻璃纳米颗粒为球形、单分散颗粒,透射电镜下可见其具有多孔结构,平均粒径为(268.10±0.58) nm,体外可缓释L20。(2)负载骨形态发生蛋白2成骨活性肽L20介孔生物玻璃纳米颗粒无细胞毒性,并且可促进骨髓间充质干细胞的增殖与黏附;与空白组、对照组相比,实验组碱性磷酸酶活性与细胞外基质矿化能力均升高(P <0.05),碱性磷酸酶、Runx2、骨钙素mRNA表达升高(P <0.05)。(3)股骨Micro-CT扫描结果显示,与空白组、对照组相比,实验组新生骨量与骨密度均升高(P <0.05);苏木精-伊红与Masson染色结果显示,与空白组、对照组相比,实验组新骨生成与胶原纤维均增加。(4)结果表明,负载骨形态发生蛋白2活性肽L20介孔生物玻璃纳米颗粒具有良好的生物相容性及体内外促成骨性能,可促进SD大鼠股骨髁缺损的再生修复。

人骨膜间质干细胞移植后成骨能力及成骨起源的研究

目的研究人骨膜间质干细胞异体移植后成骨能力及成骨起源。方法将幼儿骨膜分离培养后获得的骨膜间质干细胞悬液，移植于裸小鼠两侧背部皮下及老年股骨颈骨折处，观察并验证新骨形成。结果移植后第１１天肉眼可见皮下结节，第４周其直径为２～７ｍｍ（平均３．６ｍｍ）。组织学检查证实结节为结缔组织包裹的骨小梁球；人类特有的载脂蛋白Ｂ基因（ａｐｏＢ基因）的ＰＣＲ实验以及抗人类组织沉淀素反应均为阳性。注入无完整活细胞的骨膜间质干细胞冻融液及培养液的两组裸小鼠皮下均未见结节形成。从患者取出的新骨作组织学及ＰＣＲ检查显示，新骨ａｐｏＢ基因有两条电泳带，即含两个个体产物。结论裸小鼠皮下新骨结节含有人类细胞，移植的骨膜间质干细胞可直接成骨；异体移植细胞与宿主骨细胞可能共同成骨，为临床应用提供了重要的理论依据。

三七总皂苷及其诱导成骨的试验和机制

三七总皂苷(PNS)可调节多种成体干细胞的分化,与骨形成密切相关。以微波、超声和超临界流体技术提取PNS,较传统提取时间大大缩短,提取效率大大提高。PNS的诱导成骨试验包括体外试验和体内试验。体外试验显示,PNS可明显促进骨髓基质干细胞的成骨分化及增殖;体内试验显示,PNS可使骨矿化提前。PNS既可通过调节骨形态发生蛋白、胰岛素样生长因子和白细胞介素-6等细胞因子,促进骨改建;还可通过促丝裂原激活蛋白激酶、无翅型小鼠乳房肿瘤病毒整合位点家族、核因子-κB等信号转导通路调节破骨细胞分化,促进骨形成。羟磷灰石作为支架材料具有良好的成骨作用,将其与PNS复合,PNS可定向缓慢地作用于骨缺损部位并在骨缺损组织周围始终保持一定的质量浓度,从而加速骨缺损修复。

成骨蛋白的生物学与应用

成骨蛋白又称骨形态发生蛋白,成骨蛋白-1(OP-1)又称BMP-7,与BMP-2均属转化生长因子β(TGF-β)超家族成员。将重组人OP-1和BMP-2应用于骨缺损的动物实验的结果令人满意,并已开始向临床应用过渡。

超声诊断胎儿软骨发育不全的应用(附1例报告)

软骨发育不全（achondroplasia，ACH）是一种先天性骨发育异常疾病，发病率1／15000—1／26000，为常染色体显性遗传^[1]。男女均可发病，10％～20％为家族遗传，80％-90％为散发病例肼，表现为软骨化骨缺陷而膜性化骨正常[31。软骨的骨化过程不能正常进行，致辞使全身软骨内成骨发生障碍，尤以颅底骨与四肢长骨纵向生长严重受累，椎骨、肋骨受累次之。但全身膜内成骨不受影响，故颅顶骨与长骨横向生长正常，造成本病患儿四肢粗短、头、前额突出巨颅、特殊面容（前额突出、鼻梁扁平、宽下颌）、短指（趾）、三叉戟手畸形、肋骨粗短，

Effect of BMPs on hematopoietic injury of acute radiation sickness in mice

Objective: To investigate the effect of bone morphogenetic proteins (BMPs) on hematopoietic injury of acute radiation sickness in mice. Methods: Mice were subjected to whole-body 60Co γ ray irradiation, then bpBMP was put into spatium intermusculare or rhBMP-2m, PBK/ hBMP-2 -NIH3T3 cells were injected into abdominal cavity. The effect of BMPs on hematopoiesis including some hematological parameters, the survival rate of 30 d and formation of bone marrow CFU-GM colony were detected at postradiation. Results: pbBMP (purified bovine bone morphogenetic protein) increased the formation of bone marrow CFU-GM colony (P<0. 05) on d 10 after irradiation. rhBMP-2m increased the survival rate of mice irradiated by 7. 5 Gys Mice in control group died in 30 days, while 10%, 15% and 35% mice survived when they were injected i. p. with 0. 5 mg, 1. 0 mg and 2. 0 mg of rhBMP-2m respectively. All hematological parameters of treated mice were significantly higher than those of control group (P<0. 01). PBK/ hBMP-2 -NIH3T3 cells were established and transplanted into mice irradiated by 7. 0 Gy γ ray with i. p. . The survival ratio of treated mice was higher than that of negative control group (P<0. 01), and all hematopoietic parameters were increased statistically significantly (P<0. 01). Conclusion: Results indicate that in adult mice, BMPs can recover or treat the hematopoietic injury of acute radiation sickness, the mechanism may be related with repairing of hematopoietic injury.

Calcium citrate： a new biomaterial that can enhance bone formation in situ

Objective： To investigate the effect of a new biomaterial combining calcium citrate and recombinant human bone morphogenetic protein-2 （rhBMP-2） on bone regeneration in a bone defect rabbit model. Methods： Totally 30 male New Zealand white rabbits were randomly and equally divided into calcium citraterhBMP-2 （CC-rhBMP-2） group and rhBMP-2 only group. Two 10 ram-long and 5 ram-deep bone defects were respectively created in the left and right femoral condyles of the rabbits. Subsequently 5 pellets of calcium citrate （10 mg） combined with rhBMP-2 （2 rag） or rhBMP-2 alone were implanted into the bone defects and compressed with cotton swab. Bone granules were obtained at 2, 4 and 6 weeks after procedure and received histological analysis. LSD t-test and a subsequent t-test were adopted for statistical analysis. Results： Histomorphometric analysis revealed newlyformed bones, and calcium citrate has been absorbed in the treatment group. The percent of newly formed bone area in femoral condyle in control group and CC-rhBMP-2 group was respectively 31.73%±1.26% vs 48.21%±2.37% at 2 weeks; 43.40%±1.65% vs 57.32%±1.47% at 4 weeks, and 51.32%±7.80% vs 66.74%±4.05% at 6 weeks （P〈0.05 for all）. At 2 weeks, mature cancellous bone was observed to be already formed in the treatment group. Conclusion： From this study, it can be concluded that calcium citrate combined with rhBMP-2 signifcantly enhances bone regeneration in bone defects. This synthetic gelatin matrix stimulates formation of new bone and bone marrow in the defect areas by releasing calcium ions.

Odontoblast β-catenin signaling regulates fenestration of mouse Hertwig's epithelial root sheath

The interaction between Hertwig＇s epithelial root sheath （HERS） and the adjacent mesenchyme is vitally important in mouse tooth root development. We previously generated odontoblast-specific Ctnnbl （encodingβ-catenin） deletion mice, and demon- strated that odontoblast β-catenin signaling regulates odontoblast proliferation and differentiation. However, the role of odon- toblast β-catenin signaling in regulation of HERS behavior has not been fully investigated. Here, using the same odonto- blast-specific Ctnnbl deletion mice, we found that ablation of β-catenin signaling in odontoblasts led to aberrant HERS for- mation. Mechanistically, odontoblast-specific Ctnnbl deletion resulted in elevated bone morphogenetic protein 7 （Bmp7） ex- pression and reduced expression of noggin andfollistatin, both of which encode extracellular inhibitors of BMPs. Furthermore, the levels of phosphorylated Smadl/5/8 were increased in HERS cells. In vitro tissue culture confirmed that BMP7 treatment disrupted the HERS structure. Taken together, we demonstrated that odontoblast f3-catenin signaling may act through regula- tion of BMP signaling to maintain the integrity of HERS cells.