新型聚己内酯/磷酸钙支架的制备及生物相容性研究

探讨新型聚己内酯(PCL)/磷酸钙(CPC)复合材料支架的制备方法及对骨髓基质细胞(BMSCs)的生物相容性。采用溶液共混法,利用可溶盐晶体做造孔剂,制备PCL/CPC复合材料支架,以单纯PCL和CPC支架为对照组,Q800型动态力学分析仪进行动态力学性能试验(DMA),采用排水法测量孔隙率;灭菌后通过与犬BMSCs体外共同培养后细胞形态、生长曲线、碱性磷酸酶(ALP)染色和半定量及骨钙素(OC)半定量等方法检测细胞在支架材料上的黏附、增殖及成骨分化情况,动物体内异位成骨检测其成骨情况。结果显示,复合材料的储能模量在PCL/CPC比例为7:3时达到最大,制得的材料孔径为250～350μm,多孔支架的孔隙率为70%～80%;BMSCs在新型PCL/CPC组、CPC组支架表面分布均匀,生长增殖明显较PCL组活跃(P<0.05);PCL/CPC组、CPC组BMSCs成骨行为与PCL组之间有显著差异(P<0.05)。动物体内异位成骨检测提示,4周时PCL/CPC组为13.78%±1.60%、CPC组BMSCs为15.29%±1.20%,成骨显著强于PCL组BMSCs的7.56%±2.20%(P<0.05),表明PCL和CPC的复合明显改善了两种材料的缺陷,获得的PCL/CPC支架具有良好的生物相容性,可与BMSCs共同构建具有成骨能力的三维立体组织工程化骨。     

异种生物衍生骨材料与骨髓间充质干细胞的生物相容性

背景：异种生物衍生骨保存了原骨组织的天然网状孔隙结构,且具有免疫原性低、细胞相容性好的特点。目的：验证异种生物衍生骨材料与骨髓间充质干细胞的生物相容性。方法：取新鲜猪股骨制备生物衍生骨,扫描电镜观察材料结构。将第3代兔骨髓间充质干细胞以2×10⁹ L^-1的浓度接种于生物衍生骨材料的松质骨面,复合培养7 d内,采用扫描电镜观察细胞生长情况;复合培养8 d内,计数材料上附着的细胞数。结果与结论：生物衍生骨表面粗糙,孔隙不规则并相互通联,构成网状结构。复合培养3 d,细胞在衍生骨材料表面发生附着,且细胞形态不均一;复合培养培养 5 d,细胞连接成片呈层状生长,细胞之间紧密接触;复合培养7 d,细胞呈现多层生长状态,成堆生长,部分区域存在细胞外基质分泌现象。复合培养后,前2 d 为潜伏适应期,3-6 d细胞生长呈出线性曲线,处于细胞生长对数期;第 6 天后,细胞生长曲线逐渐变得平缓,细胞增殖速度下降,增殖进入平台期。表明异种生物衍生骨材料与骨髓间充质干细胞具有良好的生物相容性。 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      

聚ε-己内酯组织工程血管研究进展

近年来随着心血管疾病患者不断增多,人工血管在临床上的需求不断增长。人工聚合材料聚ε-己内酯[poly(ε-caprolactone),PCL]因具有生物可降解性、良好的力学性能而成为了组织工程血管材料研究的热点。但是单一PCL血管存在疏水性强、细胞黏附亲和力差等缺陷,限制了PCL材料在组织工程领域的应用。为了增强PCL材料的生物相容性,研究者们应用了各种方法对PCL材料进行表面改性或共混成复合物。本文从PCL的表面改性、复合物等方面对其研究现状进行综述。通过表面改性后的PCL及其复合物具有较好的生物相容性,提高了材料的细胞黏附和组织生长性能,这为进一步构建理想小口径人工血管提供了一定的参考。     

骨植入用生物可降解材料新合成方法及生物相容性的研究

采用 Y(CF3COO) 3/AL(i- Bu) 3络合物催化合成聚己内酯 (Polycaprolactone,PCL)及其与聚乳酸(Polylactic acid,PL A)的共聚物 ,并应用生物化学、细胞毒理及细胞免疫学等实验方法对这一新型骨科生物降解可吸收材料的生物相容性进行评价。用 PCL 和 PCL/PDL L A共聚物作为骨科生物降解可吸收内置物材料 ,国内外属首次研究 ;多聚物的分子量和降解时间可以通过控制反应时间、单体与催化剂的比例来调控产物分子量 ,人为调节降解时间。实验证明该材料细胞相容性好 ,未发现明显毒性及免疫排斥反应。     

聚己内酯/明胶复合纳米材料的细胞相容性

目的:观察真皮成纤维细胞在聚己内酯/明胶(PCL/Gel)复合纳米材料上生长与增殖情况,评价此材料的生物相容性.方法:采用静电纺丝法制备PCL/Gel复合纳米纤维,将原代培养的真皮成纤维细胞接种到材料的表面,扫描电镜观察真皮成纤维细胞在复合纳米材料上的生长情况.实验分两组,材料组和对照组分别在接种后48、72、96 h用MTT法检测细胞的增殖情况.结果:真皮成纤维细胞在PCL/Gel复合纳米材料表面贴附牢固,生长形态良好.MTT检测结果统计显示此材料能够促进真皮成纤维细胞在其表面增殖.结论:PCL/Gel复合纳米材料具有较好的生物相容性,有望作为修复足底软组织创伤的支架材料.     

人骨髓间充质干细胞接种纳米晶胶原骨构建组织工程骨

目的观察体外培养的人骨髓间充质干细胞（mesenchymal stem cells,MSCs）与纳米晶羟基磷灰石/胶原骨（nano-hydroxyapatite/collagen,nHAC）的生物相容性及细胞在nHAC上的生长情况。方法全骨髓法体外培养骨髓间充质干细胞,应用成骨诱导剂诱导向成骨细胞表型转化,通过细胞活性、免疫组化鉴定诱导培养的成骨细胞的细胞学特性。通过倒置显微镜、扫描电镜观察细胞生长及其在nHAC上的生长情况。结果原代培养的骨髓细胞增殖迅速,10～12d左右即可稳定传代,传代细胞7～9d即可传代。经诱导培养的细胞的ALP染色阳性,Von Kossa染色阳性,可见钙化的基质沉积,呈现典型的成骨细胞形态和生物学特征。构建的MSCs与nHAC共培养的模型中,细胞可在nHAC表面良好贴壁。复合培养8天,分布于支架材料上的细胞大量增殖、分泌细胞外基质。第14天,大量细胞在材料表面和孔隙中生长。细胞之间广泛存在突起连接。结论nHAC适合种子细胞的贴附、生长和增殖,是组织工程良好的载体材料。     

成骨诱导人脐带间充质干细胞与纳米羟基磷灰石/聚酰胺66支架材料的生物相容性☆

背景：纳米羟基磷灰石/聚酰胺66材料有利于成骨细胞的长入和新生骨的形成、且抗弯强度、抗压强度等各项参数与正常骨组织的力学性能相接近,能满足实验动物硬组织修复的要求。 目的：分析成骨诱导后人脐带间充质干细胞与纳米羟基磷灰石/聚酰胺66复合支架的生物相容性。 方法：体外培养人脐带间充质干细胞,纯化增殖,成骨诱导。取成骨诱导后的第3代人脐带间充质干细胞接种于纳米羟基磷灰石/聚酰胺66支架材料上,观察细胞的生长、增殖情况及材料细胞毒性。 结果与结论：成骨诱导后人脐带间充质干细胞在复合支架上生长分化良好,增殖活性不受材料影响。成骨诱导14 d内,可见碱性磷酸酶活性随着培养时间延长而逐渐增高。MTT法检测细胞无毒性。扫描电镜观察,1 d后可见细胞在支架表面附着生长;7 d后可见细胞在材料上生长良好,材料空隙有大量充填。说明纳米羟基磷灰石/聚酰胺66支架可作为骨组织工程中人脐带间充质干细胞的细胞载体,具有良好的生物相容性,能满足骨组织工程的需要。关键词：羟基磷灰石/聚酰胺66;人脐带间充质干细胞;细胞培养;骨组织工程;支架;生物相容性 缩略语注释：nHA/PA66：nano-hydroxyapatite crystals and pnolyamide 66,羟基磷灰石/聚酰胺66;hUCMSCs：human umbilical cord mesenchymal stem cells,人脐带间充质干细胞 doi:10.3969/j.issn.1673-8225.2012.16.019     

煅烧骨/壳聚糖复合材料对成骨细胞增殖黏附的影响

文题释义：壳聚糖：是甲壳素的脱乙酰产物,属于天然聚合物,广泛存在于低等生物体内,其代谢产物为N-乙酰葡萄糖和氨基多糖,是天然代谢产物,对人体组织无毒无害,具有良好的生物相容性和生物降解性。 体外细胞毒性实验：是运用体外细胞培养技术检测待测物质和(或)其浸提液是否造成细胞生长受到抑制、变异、溶解、死亡等情况,是生物材料评价体系中非常重要的指标之一,也是各种生物材料运用到临床前安全性评价的必选和首选项目。背景：前期研究制备了不同配比的煅烧骨/壳聚糖复合材料,体外细胞实验显示该复合材料安全无毒。目的：观察煅烧骨/壳聚糖复合材料对成骨细胞增殖与黏附的影响。方法：采用溶液共混法制备煅烧骨与壳聚糖质量比分别为1/2、1/1、2/1的复合材料,将新生大鼠成骨细胞分别接种于3种复合材料上,以单独培养的细胞为对照。采用CCK-8法检测细胞增殖情况,DAPI荧光染色观察细胞在材料上的生长情况,扫描电镜观察细胞在复合材料表面的黏附。 结果与结论：①CCK-8检测显示4组成骨细胞增殖良好,在培养的第1-3天增殖较慢,第3天后增殖加快,第3-7天进入对数生长期,第7天后进入平台期,复合材料组细胞增殖与对照组无差异;②培养3 d后的DAPI荧光染色显示,成骨细胞在3种复合材料表面生长良好,组间无明显差异;③扫描电镜显示,培养3 d后成骨细胞紧密黏附于3种复合材料表面,伸展完全,胞体丰满并伸出伪足嵌入材料内部;培养7 d后细胞铺满材料表面,生长密集,其中质量比为2/1煅烧骨/壳聚糖复合材料表面的细胞最密集;④结果表明,成骨细胞可在煅烧骨/壳聚糖复合材料表面增殖与黏附。ORCID: 0000-0003-3519-4485(廖健) 中国组织工程研究杂志出版内容重点：生物材料;骨生物材料; 口腔生物材料; 纳米材料; 缓释材料; 材料相容性;组织工程     

改性纳米羟基磷灰石/PLGA材料同骨髓基质干细胞复合后相关生物学评价

背景：改性纳米羟基磷灰石/聚乙交酯-丙交酯复合材料(L-lactic acid oligomer/Poly(lactide-co-glycolde),PLGA/g-HA)因具有良好的稳定性及机械性能,目前备受关注。 目的：观察骨髓基质干细胞和改性PLGA/g-HA体外复合后的细胞活性及生物相容性。 方法：原代培养兔骨髓基质干细胞,传代培养至第3代,MTT比色法检测在不同浓度PLGA/g-HA浸提液(10%、30%、50%、80%)中骨髓基质干细胞的增殖情况,以及骨髓基质干细胞在PLGA/g-HA表面的黏附性及其细胞形态。 结果与结论：于培养后1,3 d测得在不同浓度浸提液下骨髓基质干细胞的A值,10%浸提液组和对照组相比无显著性差异,4种浓度浸提液的细胞毒性均为1级;扫描电镜观察到骨髓基质干细胞在PLGA/g-HA表面逐渐伸展,形成伪足,最终牢固锚定在材料表面。提示在PLGA/g-HA的浸提液中骨髓基质干细胞能够发生增殖,对细胞无毒性。骨髓基质干细胞可以黏附在PLGA/g-HA表面且形态正常,生长状态良好,证明PLGA/g-HA具有良好的相容性和黏附性,可作为修复骨缺损的复合组织工程骨。     

多孔碳酸化羟基磷灰石骨水泥的生物相容性研究

目的探讨一种新型的代骨材料--多孔碳酸化羟基磷灰石骨水泥的组织相容性.方法合成碳酸化羟基磷灰石骨水泥,添加成孔剂,制备能原位固化形成多孔结构的碳酸化羟基磷灰石代骨材料,并通过细胞毒性实验和肌内埋植实验检测其组织相容性.结果多孔碳酸化羟基磷灰石骨水泥的浸提液对骨髓基质细胞的生长无影响.细胞于材料表面的生长速度、形态与空白对照组无差别.肌内植入实验发现,材料周围纤维组织包膜的最大厚度为22.5μm,未发现炎性细胞反应.结论多孔碳酸化羟基磷灰石骨水泥具有良好的组织相容性,材料测试结果符合和标准.     

Engineering of implantable cartilaginous structures from bone marrow-derived mesenchymal stem cells

Fabrication of implantable cartilaginous structures that could be secured in the joint defect could provide an alternative therapeutic approach to prosthetic joint replacement. Herein we explored the possibility of using biodegradable hydrogels in combination with a polyglycolic acid (PGA) scaffold to provide an environment propitious to mesenchymal stem cells (MSCs) chondrogenic differentiation.We examined the influence of type I collagen gel and alginate combined with PGA meshes on the extracellular matrix composition of tissue-engineered transplants. MSCs were isolated from young rabbits, expanded in monolayers, suspended in each hydrogel, and loaded on PGA scaffolds. All constructs (n=48) were cultured in serum-free medium containing transforming growth factor beta-1, under dynamic conditions in specially designed bioreactors for 3-6 weeks. All cell-polymer constructs had a white, shiny aspect, and retained their initial size and shape over the culture period. Their thickness increased substantially over time, and no shrinkage was observed. All specimens developed a hyalin-like extracellular matrix containing glycosaminoglycans (GAGs) and type II collagen, but significant differences were observed among the three different groups. In PGA/MSCs and collagen-PGA/MSCs constructs, the cell growth phase and the chondrogenic differentiation phase of MSCs occurred during the first 3 weeks. In alginate-PGA/MSCs constructs, cells remained round in the hydrogel and cartilage extracellular matrix deposition was delayed. However, at 6 weeks, alginate-PGA/MSCs constructs exhibited higher contents of GAGs and lower contents of type I collagen. These results suggest that the implied time for the transplantation of in vitro engineered constructs depends, among other factors, on the nature of the scaffold envisioned. In this study, we demonstrated that the use of a composite hydrogel-PGA scaffold supported the in vitro growth of implantable cartilaginous structures cultured in a bioreactor system.     

The stimulation of the cardiac differentiation of mesenchymal stem cells in tissue constructs that mimic myocardium structure and biomechanics

We investigated whether tissue constructs resembling structural and mechanical properties of the myocardium would induce mesenchymal stem cells (MSCs) to differentiate into a cardiac lineage, and whether further mimicking the 3-D cell alignment of myocardium would enhance cardiac differentiation. The tissue constructs were generated by integrating MSCs with elastic polyurethane nanofibers in an electrical field. Control of processing parameters resulted in tissue constructs recapitulating the fibrous and anisotropic structure, and typical stress-strain response of native porcine myocardium. MSCs proliferated in the tissue constructs when cultured dynamically, but retained a round morphology. mRNA expression demonstrated that cardiac differentiation was significantly stimulated. Enhanced cardiac differentiation was achieved by 3-D alignment of MSCs within the tissue constructs. Cell alignment was attained by statically stretching tissue constructs during culture. Increasing stretching strain from 25% to 75% increased the degree of 3-D cell alignment. Real time RT-PCR results showed that when cells assuming a high degree of alignment (with application of 75% strain), their expression of cardiac markers (GATA4, Nkx2.5 and MEF2C) remarkably increased. The differentiated cells also developed calcium channels, which are required to have electrophysiological properties. This report to some extent explains the outcome of many in?vivo studies, where only a limited amount of the injected MSCs differentiated into cardiomyocytes. It is possible that the strain of the heartbeat (～20%) cannot allow the MSCs to have an alignment high enough for a remarkable cardiac differentiation. This work suggests that pre-differentiation of MSCs into cardiomyocytes prior to injection may result in a greater degree of cardiac regeneration than simply injecting un-differentiated MSCs into heart.     

Reconstruction of chemically burned rat corneal surface by bone marrow-derived human mesenchymal stem cells

To examine whether transplantation of human mesenchymal stem cells (MSCs) could reconstruct the corneal damage and also whether grafted MSCs could differentiate into corneal epithelial cells, we isolated MSCs from healthy donors. After growth and expansion on amniotic membrane, cells were transplanted into rat corneas 7 days after chemical burns. Reconstruction of the damaged cornea and the rat vision were measured once a week by slit lamp and by an optokinetic head-tracking instrument, respectively. Corneas were then cut out, fixed, and imbedded for immunofluorescent study of the expression of keratin 3 and keratin-pan as epithelial cell markers. Expression of CD45, interleukin 2, and metalloproteinase-2 was also investigated for inflammation and inflammation-related angiogenesis. The data showed that transplantation of MSCs, like limbal epithelial stem cells, successfully reconstructed damaged rat corneal surface. Interestingly, the therapeutic effect of the transplantation may be associated with the inhibition of inflammation and angiogenesis after transplantation of MSCs rather than the epithelial differentiation from MSCs. This study provides the first line of evidence that MSCs can be used for reconstruction of damaged corneas, presenting a new source for autotransplantation in the treatment of corneal disorders.     

神经生长因子转染骨髓间充质干细胞诱导分化成神经样细胞

目的探讨神经生长因子(NGF)转染大鼠骨髓间充质干细胞(MSCs)后的表达及其对MSCs分化成神经样细胞的影响。方法在体外低密度扩增大鼠骨髓MSCs。应用基因重组技术,构建pEGFP-NGF真核表达质粒,并将其转染至MSCs中。免疫荧光标记法检测中间神经丝蛋白(NF-M)和胶质纤维酸性蛋白(GFAP)的表达。在荧光显微镜下观察MSCs阳性荧光的表达率、细胞的形态变化和类型。结果MSCs阳性荧光的表达率约为30%。转染后,MSCs呈现多突起,且几个突起之间互相连接成网状,似神经元样的形态。免疫荧光标记法鉴定其中一部分细胞表达NF-M,另一部分细胞表达GFAP。结论转染的MSCs可表达NGF并在含有NGF的微环境中分化成神经样细胞。     

人胎盘绒毛膜来源间充质干细胞的生物学特性

背景：骨髓是间充质干细胞的主要来源,但骨髓中间充质干细胞数量和质量会随着年龄的增长而逐渐降低。因此,寻找一种新的干细胞来源具有重要意义。 目的：分离研究了一种新的间充质干细胞来源——人绒毛膜来源间充质干细胞,并研究其生物学特性。 方法：将胎盘冲洗干净后,分离出脐带和羊膜组织,将剩余的胎盘组织进行原代和传代培养。通过短串联重复序列分析检测细胞是否来源于绒毛膜,用MTT法检测细胞生长方式,流式细胞仪分析细胞表型及干细胞标记,使用不同的诱导分化培养基检测其多向分化的能力。将该细胞与植物血凝素刺激的外周血单个核细胞共培养,用酶联免疫吸附试验检测上清γ-干扰素的水平。 结果与结论：短串联重复序列分析证明所得到的细胞来源于绒毛膜,这种绒毛膜来源的细胞生长呈典型的成纤维细胞形态。细胞表达常见的间充质干细胞表面标记CD90、CD73、CD105、CD44,不表达CD45,CD11b和CD34。同时,细胞也表达Nestin和Sox-2。在不同的条件培养基培养状态下,细胞可向成骨、成脂方向分化。这些结果证明所得到的细胞为人绒毛膜间充质干细胞。这些绒毛膜间充质干细胞能抑制植物血凝素刺激的人外周血单个核细胞分泌γ-干扰素。可见绒毛膜来源的间充质干细胞具有和传统的骨髓来源间充质干细胞具有相似的生物学特性。     

诱导骨髓间质干细胞分化为角膜上皮样细胞的初步研究

目的: 观察人骨髓间质干细胞（MSCs）移植到兔角膜基质后的分化发育情况，探讨MSCs分化为角膜上皮细胞的可行性。方法: 24只新西兰兔随机分为2组。实验组：将人MSCs接种在保存人羊膜上培养4 d，用5-溴脱氧尿嘧啶（BrdU）标记后移植到兔角膜基质；对照组：采用保存羊膜移植到兔角膜基质。分别于移植后1、2、3、4、6和8周，摘取各组实验眼行组织学和免疫组织化学检查，检查移植到兔角膜基质的MSCs的存活、形态变化以及移植局部的反应等情况；免疫组织化学检测移植到角膜基质的带有BrdU标记的细胞角蛋白K3/12（CK3/CK12）和角蛋白K13（CK13）的表达。结果: MSCs接种到羊膜后能在羊膜上生长，与羊膜共培养4 d后，MSCs贴附羊膜生长迅速，组织学特征无明显改变。羊膜负载MSCs移植到兔角膜基质表面, 术后免疫组织化学检测角膜上皮层CK3/CK12表达阳性， CK13表达阴性，在重建的角膜上皮层可检测到BrdU核阳性细胞并同时表达角膜上皮细胞特异性表面标志蛋白K3/K12，未发生免疫排斥反应，未见异常增殖细胞。结论: 羊膜负载MSCs移植到兔眼表角膜基质后，MSCs能存活、增殖并向角膜上皮样细胞分化。     

Cell-matrix interactions regulate mesenchymal stem cell response to hydrostatic pressure

Both hydrostatic pressure (HP) and cell-matrix interactions have independently been shown to regulate the chondrogenic differentiation of mesenchymal stem cells (MSCs). The objective of this study was to test the hypothesis that the response of MSCs to hydrostatic pressure will depend on the biomaterial within which the cells are encapsulated. Bone-marrow-derived MSCs were seeded into either agarose or fibrin hydrogels and exposed to 10 MPa of cyclic HP (1 Hz, 4 h per day, 5 days per week for 3 weeks) in the presence of either 1 or 10 ng ml(-1) of TGF-β3. Agarose hydrogels were found to support a spherical cellular morphology, while MSCs seeded into fibrin hydrogels attached and spread, with clear stress fiber formation. Hydrogel contraction was also observed in MSC-fibrin constructs. While agarose hydrogels better supported chondrogenesis of MSCs, HP only enhanced sulfated glycosaminoglycan (sGAG) accumulation in fibrin hydrogels, which correlated with a reduction in fibrin contraction. HP also reduced alkaline phosphatase activity in the media for both agarose and fibrin constructs, suggesting that this stimulus plays a role in the maintenance of the chondrogenic phenotype. This study demonstrates that a complex relationship exists between cell-matrix interactions and hydrostatic pressure, which plays a key role in regulating the chondrogenic differentiation of MSCs.     

Enhanced MSC chondrogenesis following delivery of TGF-β3 from alginate microspheres within hyaluronic acid hydrogels in vitro and in vivo

Mesenchymal stem cells (MSCs) are being recognized as a viable cell source for cartilage repair and members of the transforming growth factor-beta (TGF-β) superfamily are a key mediator of MSC chondrogenesis. While TGF-β mediated MSC chondrogenesis is well established in in vitro pellet or hydrogel cultures, clinical translation will require effective delivery of TGF-βs in vivo. Here, we investigated the co-encapsulation of TGF-β3 containing alginate microspheres with human MSCs in hyaluronic acid (HA) hydrogels towards the development of implantable constructs for cartilage repair. TGF-β3 encapsulated in alginate microspheres with nanofilm coatings showed significantly reduced initial burst release compared to uncoated microspheres, with release times extending up to 6 days. HA hydrogel constructs seeded with MSCs and TGF-β3 containing microspheres developed comparable mechanical properties and cartilage matrix content compared to constructs supplemented with TGF-β3 continuously in culture media, whereas constructs with TGF-β3 directly encapsulated in the gels without microspheres had inferior properties. When implanted subcutaneously in nude mice, constructs containing TGF-β3 microspheres resulted in superior cartilage matrix formation when compared to groups without TGF-β3 or with TGF-β3 added directly to the gel. However, calcification was observed in implanted constructs after 8 weeks of subcutaneous implantation. To prevent this, the co-delivery of parathyroid hormone-related protein (PTHrP) with TGF-β3 in alginate microspheres was pursued, resulting in partially reduced calcification. This study demonstrates that the controlled local delivery of TGF-β3 is essential to neocartilage formation by MSCs and that further optimization is needed to avert the differentiation of chondrogenically induced MSCs towards a hypertrophic phenotype.