重组人骨形成蛋白-2对细胞成骨分化的作用

目的 进一步探讨rhBMP-2的促细胞成骨分化作用，以期找到合适的成骨分化标志作为rhBMP-2的定量活性测定指标。方法 首先表达制备rhBMP-2，用小鼠股部肌袋包埋法进行诱骨活性实验，然后检测rhBMP-2作用后的骨髓基质细胞（MSC）、NIH3T3和C2C12等3种细胞的碱性磷酸酶（ALP）和骨钙素（OC）、细胞总蛋白合成量以及细胞增殖的变化。结果 rhBMP-2具有良好的诱导骨形成的活性，可增加3种细胞的OC含量和蛋白合成量，对MSC的ALP活性变化影响明显，且可促进MSC的增殖，抑制NIH3T3细胞的生长。结论 rhBMP-2具有促进上述细胞向成骨细胞分化的作用；在一定剂量范围内，rhBMP-2的作用与细胞骨钙素合成量的增加呈线性正相关，故定量测定OC的含量基本可反映rhBMP-2的活性。     

rhBMP-2/聚乳酸与聚乙醇酸共聚物载药微球的制备及成骨活性研究

目的制备一种具有良好降解性和成骨活性可注射的rhBMP-2载体材料。方法采用复乳-溶剂蒸发技术制备携载rhBMP-2的聚乳酸与聚乙醇酸共聚物P(LGA)微球。测定材料的制备参数及其特性,包括材料的形貌、载药率、释药速度,并将载药微球植入鼠股部肌袋,通过X线、组织学评价载体材料的异位成骨能力。结果载药微球粒径为(253±64)μm,载药率0.52%±0.14%,载药微球rhBMP-2体外释放24h时为15.2%±0.8%,随后呈持续缓慢释放,28d时总计达48.6%±5.3%。载药微球植入鼠股部肌袋4周,材料周围有明显的骨形成。结论载有rhBMP-2的PLGA微球具有良好的缓释效果和生物活性,是一种较为理想的生长因子载体材料和释放系统。     

两种壳聚糖载rhBMP-2纳米微球对SD大鼠体内异位成骨的影响

目的　通过SD大鼠异位成骨实验来探究重组人骨形态发生蛋白-2/壳聚糖/硫酸葡聚糖(rhBMP-2/CS/DS) 复合微球和重组人骨形态发生蛋白-2/壳聚糖 (rhBMP-2/CS) 微球对SD大鼠体内异位成骨的影响。 方法　随机将36只SD大鼠平均分为三组（n=12）,分别为A组 (rhBMP-2), B组(rhBMP-2/CS), C组(rhBMP-2/CS/DS)。制备股四头肌肌袋模型后,分别将三种材料植入股四头肌肌袋肌间隙中。分别在4,8和12周时大体观察植入区组织硬度,每组处死4只大鼠后取出异位骨块,并切取异位骨化的组织行micro-CT扫描及 Mimics软件三维重建;检测各组织块骨体积分数（bone volume fraction,BVF）、骨小梁厚度（trabecular thichness,Tb.Th）、骨密度（bone mineral density,BMD）;并行组织学观察和ALP活性、钙含量检测。 结果 4周时,A、B、C三组植入区周围组织质地均稍硬,三者并无明显区别;8周和12周时,三组植入区硬度明显增加,且C组比A、B组质地更硬。4周时,HE染色可见三组有少量骨组织形成,但不明显;B、C两组BVF、Tb.Th、BMD,碱性磷酸酶（ALP）活性、钙含量均高于A组;B、C两组以上指标差异无统计学意义。8、12周时,HE染色可见到三组骨组织逐渐增多,并逐渐成熟,且B、C两组可见到比A组更成熟的骨组织,C组骨组织比B组更成熟;B、C两组BVF、Tb.Th、BMD,ALP活性、钙含量均高于A组,C组以上指标均高于B组。 结论　rhBMP-2/CS/DS纳米缓释微球的成骨效果明显强于rhBMP-2/CS纳米微球和单独rhBMP-2,其可能在骨组织工程领域有较好的运用前景。     

携载rhBMP-2微球的新型复合人工骨的制备及生物相容性研究

目的制备一种具有良好生物相容性、降解性和成骨活性、可注射的自凝固新型骨修复材料。方法采用复乳溶剂挥发方法制备携载rhBMP-2的聚乳酸与聚乙醇酸共聚物（PLGA）微球，并将其与rhBMP-2／磷酸钙骨水泥（CPC）复合，制备出rhBMP-2／PLGA微球／CPC复合人工骨。探讨材料特性包括形貌和体外rhBMP-2释放速度，采用体外细胞培养的方法测定复合材料的细胞黏附能力及其浸提液对于人骨髓基质干细胞（MSCs）增殖和成骨分化的影响。结果与单纯rhBMP-2／CPC材料相比较，复合材料rhBMP-2体外释药明显提高。材料与MSCs可良好黏附并使其增殖。体外培养时材料不同时间的浸提液对MSCs细胞的增殖具有促进作用，对于细胞成骨分化的影响与单纯CPC无明显差别。结论rhBMP-2／PLGA微球／磷酸钙骨水泥新型复合人工骨具有良好的生物相容性和活性因子缓释功能，是一种有良好应用前景的骨修复材料。     

人骨髓间质干细胞与新型可降解材料生物相容性的实验研究

目的：本研究利用人骨髓间质干细胞（MSC）的增殖与分化潜能作为指标，对可降解偏磷酸钙（dCMP）材料和羟基磷灰石（HA）材料的生物相容性进行体外研究。 方法： 通过扫描电镜观察MSC在dCMP表面粘附的情况，并利用ICP和IC分析dCMP和HA的降解产物元素含量，同时采用FACS、ALP活性检测及ARS等方法对降解产物的毒性效应进行检测。 结果： dCMP对MSC的增殖有促进作用，且不影响MSC的成骨分化进程及分化后的矿化功能；而HA对MSC的成骨分化进程无影响，但对MSC的增殖和成骨分化后的矿化功能均有抑制作用。 结论： dCMP的生物相容性较HA为佳，更适合作为骨替代材料。     

聚醚醚酮/58S生物活性玻璃骨植入材料的成骨活性

目的探讨聚醚醚酮/58S生物活性玻璃(PEEK/58S)骨植入材料的成骨活性。方法 MG-63成骨细胞在PEEK和PEEK/58S表面培养一段时间后,扫描电镜(SEM)观察MG-63成骨细胞的黏附铺展状态;CCK-8法检测MG-63成骨细胞的增殖活性;碱性磷酸酶(ALP)活性检测评价MG-63成骨细胞的成骨分化能力;实时荧光定量PCR(RT-qPCR)检测成骨分化相关基因ALP、BMP-2、COL-I、OCN、OPN mRNA表达。PEEK和PEEK/58S植入大鼠胫骨近端12周后,组织学染色和生物力学拔出实验评价骨植入材料与周围骨组织之间的骨整合能力。结果与纯PEEK相比,PEEK/58S更有利于MG-63成骨细胞的黏附铺展,能显著改善MG-63成骨细胞的增殖活性和ALP活性(P0.05),显著促进ALP、BMP-2、COL-I、OCN、OPN mRNA的表达(P0.05)。PEEK/58S比纯PEEK表现出更好的骨整合能力。结论 PEEK/58S骨植入材料能显著改善成骨细胞的黏附、铺展、增殖与成骨分化活性,增强其与周围骨组织之间的骨整合能力,有望作为新型骨植入材料用于临床。     

骨髓基质干细胞与骨基质明胶复合培养体内异位成骨的实验研究

目的：探讨骨髓基质干细胞(MSC)与骨基质明胶复合培养体内异位成骨的可行性。方法：将SD大鼠来源的MSC与同种异体的骨基质明胶复合培养后植入SD大鼠背部竖脊肌肌膜内，分别于术后不同的时间点处死大鼠，标本进行碱性磷酸酶(ALP)活性测定及组织形态学观察：结果：实验组标本自术后第3周ALP活性起就表现出阳性，第4周MSC与骨基质明胶复合体内大量成骨。结论：MSC与骨基质明胶复合培养体内异位成骨完全可行的。     

重组人骨形态发生蛋白-7对NIH3T3细胞生物学行为的影响

目的:探讨重组人骨形态发生蛋白-7(rhBMP-7)对NIH3T3增殖和骨向分化的影响。方法:向培养的成纤维细胞NIH3T3中加入不同浓度的rhBMP-7,观察NIH3T3增殖、碱性磷酸酶(ALP)活性和骨钙素(OCN)含量的变化。结果:rh-BMP-7在一定浓度范围内可以明显促进NIH3T3细胞增殖、提高ALP活性与OCN水平。结论:rhBMP-7可以刺激NIH3T3细胞增殖,诱导NIH3T3细胞向成骨细胞表型分化。     

rhBMP-2聚氰基丙烯酸正丁酯纳米微球缓释系统对骨髓间充质干细胞影响的实验研究

目的探讨rhBMP-2聚氰基丙烯酸正丁酯纳米微球缓释系统作用BMSCs后对成骨标志蛋白表达的影响。方法采用免疫细胞化学染色及图像分析方法，观察rhBMP-2纳米微球作用后对细胞中骨钙素、骨涎蛋白及Ⅰ型胶原表达的影响，并与单纯rhBMP-2作用细胞后的结果进行比较。结果rhBMP-2纳米微球作用后细胞中骨钙素、骨涎蛋白及Ⅰ型胶原的表达均明显强于单纯rhBMP-2作用后的效果。结论rhBMP-2纳米微球缓释系统促进BMSCs向成骨方向分化的作用强于单纯rhBMP-2的作用。     

缓释型重组人骨形态发生蛋白2/壳聚糖生物骨修复材料诱导骨形成

背景：重组人骨形态发生蛋白2在体内半衰期短、易降解代谢,达不到理想的骨再生效果。 目的：制备缓释型重组人骨形态发生蛋白2/壳聚糖生物骨修复材料,并观察其缓释性能、骨诱导活性。 方法：将重组人骨形态发生蛋白2与壳聚糖混合制备壳聚糖膜,涂覆于生物骨修复材料表面,ELISA方法检测其体外释药性能。茜素红染色检测缓释型人骨形态发生蛋白2/壳聚糖生物骨材料、重组人骨形态发生蛋白2生物骨材料、单纯骨填充材料诱导C2C12细胞骨钙蛋白的形成,观察其诱导成骨细胞能力。同时将3种骨修复材料植入清洁级KM小鼠股部肌袋内,2周后检测新生骨Ca2+离子含量,评价其异位骨诱导能力。 结果与结论：材料表面的壳聚糖膜分布均匀,负载的重组人骨形态发生蛋白2呈团簇状。重组人骨形态发生蛋白2/壳聚糖生物骨修复材料体外释药存在突释,前4 d释放量达总药量的50%,持续至12 d,释药量达到90%,第18天时释放完全。与单纯骨填充材料、重组人骨形态发生蛋白2生物骨材料相比,缓释型人骨形态发生蛋白2/壳聚糖生物骨修复材料诱导C2C12细胞向成骨晚期分化能力与异位骨形成能力显著增强(P < 0.05)。结果提示缓释型人骨形态发生蛋白2/壳聚糖生物骨修复材料缓释性能好,促进骨形成能力强。     

纤维蛋白胶复合重组人骨形态发生蛋白2微球对犬骨髓基质细胞增殖与分化的影响

背景：前期实验证实聚乳酸-聚乙醇酸微球/纤维蛋白胶能作为重组人骨形态发生蛋白2的良好可注射性缓释载体。 目的：观察可注射性骨形态发生蛋白缓释体系对犬骨髓基质细胞增殖与分化的影响。 方法：采用复乳-溶剂挥发法制备重组人骨形态发生蛋白2/聚乳酸-聚乙醇酸共聚物载药微球,然后将微球与纤维蛋白胶复合制备出重组人骨形态发生蛋白2/聚乳酸-聚乙醇酸共聚物/纤维蛋白胶复合材料,采用细胞培养及组织化学等方法观察微球对犬骨髓基质细胞的增殖与分化的影响。 结果与结论：重组人骨形态发生蛋白2/聚乳酸-聚乙醇酸共聚物/纤维蛋白胶微球对骨髓基质细胞的增殖无明显影响,但对细胞的分化功能有明显的促进作用。说明纤维蛋白胶复合重组人骨形态发生蛋白2微球能够提高骨髓基质细胞的体外成骨能力,可作为骨形态发生蛋白的良好载体。     

Segmental bone regeneration using an rhBMP-2-loaded gelatin/nanohydroxyapatite/fibrin scaffold in a rabbit model

We aimed to develop a hybrid scaffold with a porous structure and similar composition as natural bone for the controlled release of bone morphogenetic protein-2 (BMP-2) to enhance bone regeneration. We fabricated a gelatin/nanohydroxypatite (nHAP) scaffold by glutaraldehyde chemical cross-linking a gelatin aqueous solution with nHAP granules at a 5:1 ratio (v/w). Then, fibrin glue (FG) mixed with recombinant human BMP-2 (rhBMP-2) was infused into the gelatin/nHAP scaffold and lyophilized to develop an rhBMP-2-loaded gelatin/nHAP/FG scaffold. On scanning electron microscopy, the composite had a 3-D porous structure. The rhBMP-2 release kinetics from the hybrid scaffold was sustained and slow, and release of rhBMP-2 was complete at 40 days. Immunohistochemistry, azo-coupling and alizarin S-red staining were used to study in vitro differentiation of human bone-marrow mesenchymal cells (hBMSCs). Strong positive staining results confirmed that rhBMP-2 released from the scaffold could improve osteocalcin (OCN) and alkaline phosphatase (ALP) expression and calcium deposition formation. RT-PCR results showed significantly high mRNA expression of ALP and OCN in hBM-MSCs cultured on the gelatin/nHAP/FG scaffold with rhBMP-2. DNA assay demonstrated that the scaffold was noncytotoxic and could promote hBMSC proliferation from the components of the hybrid scaffold, not released rhBMP-2. The hybrid scaffolds were then used to repair critical-size segmental bone defects of rabbit radius. Gross specimen, X-ray, bone histomorphology and bone mineral density assay demonstrated that the rhBMP-2-loaded gelatin/nHAP/FG scaffold had good osteogenic capability and could repair the segmental bone defect completely in 12 weeks.     

Retention and activity of BMP-2 in hyaluronic acid-based scaffolds in vitro.

Bone morphogenetic protein-2 (BMP-2) delivered in a suitable implantable matrix has the potential to repair local skeletal defects by inducing new bone formation from undifferentiated pluripotent stem cells resident in host tissue. In this study, we examined in vitro the potential of a derivatized hyaluronic acid (Hyaff-11) scaffold as a delivery vehicle for recombinant human BMP-2 (rhBMP-2) in bone and cartilage repair therapies. Hyaff-11 scaffolds were fabricated using a phase inversion/particulate leaching method and soak-loaded with rhBMP-2. In vitro release kinetics of rhBMP-2, demonstrated using enzyme-linked immunosorbant assay and alkaline phosphatase (ALP) assay revealed a slow, sustained rhBMP-2 release during 28 days, with a cumulative release of 31.82% of the initial rhBMP-2 loaded. rhBMP-2 was released in bioactive form as demonstrated by ALP induction of pluripotent cell line, C3H10T1/2 (T1/2), down the osteoblast lineage when incubated with the release supernatants. rhBMP-2 retention in Hyaff-11 scaffolds was greater than that from collagen gels, which released most of the initially loaded rhBMP-2 by 14 days. rhBMP-2-loaded Hyaff-11 scaffolds were also seeded with T1/2 cells and evaluated at 3, 7, 14, and 28 days for viability and expression of osteoblast phenotype. Cells remained viable throughout the study and expressed a time- and dose-dependent ALP and osteocalcin expression in the rhBMP-2 groups. Based on these observations, Hyaff-11 scaffolds may be suitable delivery systems for rhBMP-2 in bone/cartilage repair because of their ability to retain rhBMP-2, release low levels of bioactive rhBMP-2 to the local environment in a sustained manner, and stimulate differentiation of pluripotent stem cells.     

降钙素基因相关肽联合重组人骨形态发生蛋白对兔成骨样细胞增殖和碱性磷酸酶活性的影响

目的研究降钙素基因相关肽(CGRP)及重组人骨形成蛋白-2(rhBMP-2)在促进兔骨髓来源成骨样细胞增殖和分化方面是否有协同作用。方法取经诱导第三代兔骨髓基质细胞获得的兔成骨样细胞以2×10~6/ml的浓度接种于96孔板,分为6组,用含有不同条件的培养基进行培养。包括①A组:空白对照组,②B组:0.05 ng/ml CGRP,③C组:5 ng/ml CGRP,④D组:100 ng/ml rhBMP-2,⑤E组:5 ng/ml CGRP+100ng/ml rhBMP- 2,⑥F组:0.05ng/ml CGRP+100 ng/ml rhBMP-2。用四唑盐比色法(MTT)法测定细胞增殖情况和碱性磷酸酶( ALP)染色法检测其对ALP活性的影响。结果①100ng/ml rhBMP-2组、0.05ng/ml CGRP+100ng/ml rhBMP-2组、5ng/ml CGRP+100ng/ml rhBMP-2组细胞增殖OD值比对照组显著增强(P<0.05),其中0.05ng/ml CGRP+100ng/ml rhBMP-2组最强(P<0.01)。②100ng/ml rhBMP-2组、0.05ng/ml CGRP+100ng/ml rhBMP-2组、5ng/ml CGRP+100ng/ml rhBMP-2组,3组之间的ALP表达无明显差异(P>0.05).但3组与对照组相比显著增强( P<0.05)。结论CGRP和rhBMP-2合用对兔骨髓来源成骨样细胞的增殖有一定的协同作用,但对ALP无协同作用,与单用rhBMP-2的效果相当。     

Preparation of stem cell aggregates with gelatin microspheres to enhance biological functions

The objective of this study is to improve the viability and osteogenic differentiation of cultured rat bone marrow-derived mesenchymal stem cells (MSC) by the use of gelatin hydrogel microspheres. Gelatin was dehydrothermally crosslinked at 140° C for 48 h in a water in oil emulsion state. When cultured with the gelatin hydrogel microspheres in round, U-bottomed wells of 96-well plates coated with poly(vinyl alcohol) MSC formed aggregates homogeneously incorporating the microspheres. The viability of the cell aggregates was significantly higher compared with that of aggregates formed without microspheres. MSC proliferation in the aggregates depended on the number and diameter of the incorporated microspheres. Higher MSC proliferation was observed for aggregates incorporating a greater number of larger gelatin microspheres. When evaluated as a measure of aerobic glycolysis the ratio of l-lactic acid production/glucose consumption in MSC was significantly lower for MSC cultured with gelatin microspheres than those without microspheres. MSC production of alkaline phosphatase (ALP) and sulfated glycosaminaglycan (sGAG) was examined to evaluate their potential osteogenic and chondrogenic differentiation. The amount of ALP produced was significantly higher for MSC aggregates cultured with gelatin microspheres than that of MSC cultured without microspheres. On the other hand, the amount of sGAG produced was significantly lower for MSC aggregates containing microspheres. It is concluded that the incorporation of gelatin hydrogel microspheres prevents the aggregated MSC suffering from a lack of oxygen, resulting in enhanced MSC aggregation and cell proliferation and osteogenic differentiation.     

The role of recombinant human bone morphogenetic protein-2 in PLGA capsules at an extraskeletal site of the rat.

Bone morphogenetic protein-2 (BMP-2) is a member of the transforming growth factor-beta (TGF-beta) superfamily and has strong bone-inductive activity in vivo. To examine the role of BMP-2 in an extraskeletal site of rat using a controlled release system of peptides, we encapsulated the recombinant human BMP-2 (rhBMP-2) with poly(DL-lactide-co-glycolide) (PLGA) and implanted the rhBMP-2/PLGA capsules in the subcutaneous area of rats. Upon histochemical examination, it was found that bone-inducing cells having alkaline phosphatase (ALP) activity appeared around the capsules by the suitably released rhBMP-2. In addition, the temporal histological examination showed that direct bone formation without cartilage occurred in the process of this ectopic bone induction. These data indicate that the role of rhBMP-2 in the extraskeletal site of rats is to induce the differentiation of mesenchymal cells into the osteoblasts.Copyright 1999 John Wiley & Sons, Inc.     

Effect of rhBMP-7 combined with two bone grafts on human periodontal ligament cell differentiation

The purpose of this study was to evaluate the in vitro effect of recombinant human bone morphogenetic protein-7 (rhBMP-7) combined with demineralised freeze-dried bone allograft (DFDBA) and an inorganic bovine material with a synthetic peptide (PepGen P-15) on human periodontal ligament (hPDL) cell differentiation, in a time-dependent manner. hPDL cells were cultured and treated with: (1) 500 ng/ml of rhBMP-7, (2) 10 mg of DFDBA or PepGen P-15 and (3) their combination. Cell differentiation was estimated after 48 and 72 h by measuring alkaline phosphatase (ALPase) activity and osteocalcin (OC) secretion. The presence of rhBMP-7, DFDBA, PepGen P-15, rhBMP-7 + DFDBA and rhBMP-7+ PepGen P-15 promoted a significant increase of ALPase activity after 48 and 72 h. The combination of rhBMP-7 with DFDBA or PepGen P-15 did not lead to significant OC secretion. The results of this study imply that rhBMP-7 stimulates the early osteoblastic differentiation of hPDL cells and that DFDBA and PepGen P-15 could serve as carriers for rhBMP-7.     

Interaction of TGF-beta1 and rhBMP-2 on human bone marrow stromal cells cultured in collagen gel matrix.

Transforming growth factor-beta1 (TGF-beta1) and bone morphogenetic protein-2 (BMP-2) are abundant proteins in the bone matrix. However, their interaction in controlling osteoblast differentiation is not clearly understood. In this study, HBMSCs were cultured in collagen gel matrix with different condition of exogenous rhBMP-2 and TGF-beta1 in order to determine the interaction of BMP-2 and TGF-beta1 on human bone marrow stromal cells (HBMSCs) differentiation. The cultured cells were analyzed for cell proliferation, alkaline phophatase (ALP) activity and mineralization staining with Von-Kossa. The cells treated with TGF-beta1 exhibited a higher rate of cell growth than those without. However, the cells cultured in collagen gel matrix showed a lower rate of cell growth than the cells cultured in a monolayer. To investigate the effects of both cytokines on osteoblast differentiation, the cells were treated with 0, 1, 5, 10 ng/ml of TGF-beta1 for 2 days. This was followed by culturing with 0, 1, 5, and 10 ng/ml of TGF-beta1 and 100 ng/ml of rhBMP-2 together for 3 days with the alkaline phosphatase (ALP) activity measured. The cells treated with 1 ng/ml of TGF-beta1 responded efficiently to rhBMP-2 and expressed ALP activity with a level equivalent to that exhibited by cells that were not treated with TGF-beta1. The cells treated with 5 and 10 ng/ml of TGF-beta1 showed a dramatic decrease in ALP activity. The cells treated with 10 ng/ml of TGF-beta1 followed by rhBMP-2 alone exhibited an intermediate ALP activity. The cells treated with 100 ng/ml of rhBMP-2 demonstrated Von-Kossa positive solid deposits after 3 weeks, while there were few Von-Kossa positive solid deposits when the cells treated with 10 ng/ml of TGF-beta1. These results show that TGF-beta1 inhibits the effects of rhBMP-2 on the osteoblast differentiation of HBMSCs in a dose dependant manner. Furthermore, the effects of TGF-beta1 on HBMSCs are reversible. This suggest that TGF-beta1 and rhBMP-2 are coordinately controlled during the osteoblast differentiation of HMBSCs.