Generation of osteochondral tissue constructs with chondrogenically and osteogenically predifferentiated mesenchymal stem cells encapsulated in bilayered hydrogels

This study investigated the ability of chondrogenic and osteogenic predifferentiation of mesenchymal stem cells (MSCs) to play a role in the development of osteochondral tissue constructs using injectable bilayered oligo(poly(ethylene glycol) fumarate) (OPF) hydrogel composites. We hypothesized that the combinatorial approach of encapsulating cell populations of both chondrogenic and osteogenic lineages in a spatially controlled manner within bilayered constructs would enable these cells to maintain their respective phenotypes via the exchange of biochemical factors even without the influence of external growth factors. During monolayer expansion prior to hydrogel encapsulation, it was found that 7 (CG7) and 14 (CG14) days of MSC exposure to TGF-β3 allowed for the generation of distinct cell populations with corresponding chondrogenic maturities as indicated by increasing aggrecan and type II collagen/type I collagen expression. Chondrogenic and osteogenic cells were then encapsulated within their respective (chondral/subchondral) layers in bilayered hydrogel composites to include four experimental groups. Encapsulated CG7 cells within the chondral layer exhibited enhanced chondrogenic phenotype when compared to other cell populations based on stronger type II collagen and aggrecan gene expression and higher glycosaminoglycan-to-hydroxyproline ratios. Osteogenic cells that were co-cultured with chondrogenic cells (in the chondral layer) showed higher cellularity over time, suggesting that chondrogenic cells stimulated the proliferation of osteogenic cells. Groups with osteogenic cells displayed mineralization in the subchondral layer, confirming the effect of osteogenic predifferentiation. In summary, it was found that MSCs that underwent 7 days, but not 14 days, of chondrogenic predifferentiation most closely resembled the phenotype of native hyaline cartilage when combined with osteogenic cells in a bilayered OPF hydrogel composite, indicating that the duration of chondrogenic preconditioning is an important factor to control. Furthermore, the respective chondrogenic and osteogenic phenotypes were maintained for 28 days in vitro without the need for external growth factors, demonstrating the exciting potential of this novel strategy for the generation of osteochondral tissue constructs for cartilage engineering applications.     

体外构建人羊膜间充质干细胞膜片及成骨分化潜能

文题释义：细胞膜片技术：该技术避免了蛋白酶的消化和外源性支架材料的应用,通过细胞外基质分泌形成膜片组织,然后将膜片用于修复组织缺损和改善器官功能。该技术保留了大量自体细胞分泌的细胞外基质,为细胞的增殖和分化提供与体内极度相似的微环境,目前该技术已经用于临床眼角膜和食管损伤的修复。人羊膜间充质干细胞：取自于废弃的胎盘,贴壁生长,具有低免疫原性和生长周期短等特点,不仅具有成体间充质干细胞的特性还具有部分胚胎间充质干细胞的特性。  摘要背景：人羊膜间充质干细胞属于成体干细胞,其来自于废弃的胎盘,来源广泛,可以无创获取,具有免疫原性低、生长周期短等特点,是组织工程种子细胞的重要来源,目前人羊膜间充质干细胞已经用于临床糖尿病的治疗。目的：探索一种简便的方法构建人羊膜间充质干细胞膜片,并研究其成骨分化潜能。方法：将第3代人羊膜间充质干细胞高密度接种于普通培养皿中,加入成膜片诱导培养基以构建人羊膜间充质干细胞膜片,通过组织学染色以及扫描电镜观察细胞膜片的特性。取第3代人羊膜间充质干细胞高密度接种于培养皿中,加入成膜片诱导培养基培养7 d,再换用成骨诱导培养基培养14 d以构建成骨诱导的人羊膜间充质干细胞膜片。通过茜素红染色、免疫组化染色、碱性磷酸酶活性、RT-PCR以及Western blot检测人羊膜间充质干细胞膜片的成骨分化潜能。结果与结论：①苏木精-伊红染色可见人羊膜间充质干细胞膜片由多层细胞累积而成,细胞分布均匀;②扫描电镜观察可见人羊膜间充质干细胞膜片呈复层结构,胞外有大量的胞外基质产生,细胞包埋于胞外基质中;③人羊膜间充质干细胞膜片成骨诱导14 d,茜素红染色后可见橘红色沉淀,免疫组化染色后细胞周围有大量Ⅰ型胶原产生;④与未诱导的人羊膜间充质干细胞膜片相比,成骨诱导14 d后人羊膜间充质干细胞膜片碱性磷酸酶活性显著升高(P < 0.01),Ⅰ型胶原、骨钙蛋白、Runt相关转录子2的mRNA和蛋白表达量显著升高(P < 0.05);⑤该实验应用一种简便、经济的方法在普通培养皿上成功构建了人羊膜间充质干细胞膜片,体外研究证实人羊膜间充质干细胞膜片具有良好的成骨分化潜能。ORCID: 0000-0003-2163-3897(邹刚)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     

Immunomodulation by mesenchymal stem cells combats the foreign body response to cell-laden synthetic hydrogels

The implantation of non-biological materials, including scaffolds for tissue engineering, ubiquitously leads to a foreign body response (FBR). We recently reported that this response negatively impacts fibroblasts encapsulated within a synthetic hydrogel and in turn leads to a more severe FBR, suggesting a cross-talk between encapsulated cells and inflammatory cells. Given the promise of mesenchymal stem cells (MSCs) in tissue engineering and recent evidence of their immunomodulatory properties, we hypothesized that MSCs encapsulated within poly(ethylene glycol) (PEG) hydrogels will attenuate the FBR. In vitro, murine MSCs encapsulated within PEG hydrogels attenuated classically activated primary murine macrophages by reducing gene expression and protein secretion of pro-inflammatory cytokines, most notably tumor necrosis factor-α. Using a COX2 inhibitor, prostaglandin E2 (PGE2) was identified as a mediator of MSC immunomodulation of macrophages. In vivo, hydrogels laden with MSCs, osteogenically differentiating MSCs, or no cells were implanted subcutaneously into C57BL/6 mice for 28 days to assess the impact of MSCs on the fibrotic response of the FBR. The presence of encapsulated MSCs reduced fibrous capsule thickness compared to acellular hydrogels, but this effect diminished with osteogenic differentiation. The use of MSCs prior to differentiation in tissue engineering may therefore serve as a dynamic approach, through continuous cross-talk between MSCs and the inflammatory cells, to modulate macrophage activation and attenuate the FBR to implanted synthetic scaffolds thus improving the long-term tissue engineering outcome.     

Differential effect of hypoxia on human mesenchymal stem cell chondrogenesis and hypertrophy in hyaluronic acid hydrogels

Photocrosslinked hyaluronic acid (HA) hydrogels provide a conducive 3-D environment that supports the chondrogenesis of human mesenchymal stem cells (hMSCs). The HA macromer concentration in the hydrogels has a significant impact on the chondrogenesis of the encapsulated MSCs due to changes in the physical properties of the hydrogels. Meanwhile, hypoxia has been shown to promote MSC chondrogenesis and suppress subsequent hypertrophy. This study investigates the combinatorial effect of tuning HA macromer concentration (1.5–5% w/v) and hypoxia on MSC chondrogenesis and hypertrophy. To decouple the effect of HA concentration from that of crosslinking density, the HA hydrogel crosslinking density was adjusted by varying the extent of the reaction through the light exposure time while keeping the HA concentration constant (5% w/v at 5 or 15 min). It was found that hypoxia had no significant effect on the chondrogenesis and cartilaginous matrix synthesis of hMSCs under all hydrogel conditions. In contrast, the hypoxia-mediated positive or negative regulation of hMSC hypertrophy in HA hydrogels is dependent on the HA concentration but independent of the crosslinking density. Specifically, hypoxia significantly suppressed hMSC hypertrophy and neocartilage calcification in low HA concentration hydrogels, whereas hypoxia substantially enhanced hMSC hypertrophy, leading to elevated tissue calcification in high HA concentration hydrogels irrespective of their crosslinking density. In addition, at a constant high HA concentration, increasing hydrogel crosslinking density promoted hMSC hypertrophy and matrix calcification. To conclude, the findings from this study demonstrate that the effect of hypoxia on hMSC chondrogenesis and hypertrophy is differentially influenced by the encapsulating HA hydrogel properties.     

Isolation,culture and osteogenic induction of rabbit bone marrow mesenchymal stem cells

背景：骨髓间充质干细胞具有多向分化潜能,且可大量体外扩增培养,是重要的组织工程种子细胞。但尚无统一的体外培养及定向诱导方法。 目的：探讨体外定向诱导兔骨髓间充质干细胞分化为成骨细胞的可行性。 方法：应用密度梯度离心法从兔四肢骨中分离纯化间充质干细胞,应用密度为1.073 g/mL的Percoll分离液,3 000 r/min×30 min离心,区别于相关报道的Ficoll分离液,2 000-2 500 r/min×(20-30) min离心以及全骨髓培养法体外扩增至第3代,分别在普通培养基(对照组)和成骨诱导培养基(实验组)中培养。 结果与结论：成功获得大量高纯度骨髓间充质干细胞。经成骨诱导后,实验组骨钙素含量明显高于对照组(P < 0.05)。实验组碱性磷酸酶和钙结节染色阳性,对照组均阴性。结果表明使用密度梯度离心法可成功建立兔骨髓间充质干细胞的分离培养体系,骨髓间充质干细胞可定向诱导为成骨细胞。     

Comparative study of osteogenic differentiation potential of mesenchymal stem cells derived from bone marrow and adipose tissue of osteoporotic female rats

Osteoporosis causes reduction of osteogenic differentiation of mesenchymal stem cells (MSCs) from bone marrow and adipose tissue. This study was designed to compare the osteogenic potential of bone marrow mesenchymal stem cells (BMMSCs) and adipose-derived stem cells (ADSCs) of ovariectomized (OVX) rats. MSC were harvested from bone marrow and inguinal fat pads of six OVX rats. The limitations of this report are that cells from different animals were pooled for the purpose of the experiments that were carried out in this study. At 7, 14 and 21?d of osteogenic differentiation, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) conversion, alkaline phosphatase activity and gene expression for collagen I, osteocalcin, bone sialoprotein, osteopontin and bone morphogenetic protein-2 bone morphogenetic protein-2 (BMP-2) were analyzed. At 21?d, percentage of cells per field and percentage of mineralized nodule were analyzed. The data were subjected to analysis of variance, and the means were compared by Student–Newman–Keuls test. The cells, regardless of group, showed phenotypic characteristics consistent with stem cells. MTT conversion, alkaline phosphatase activity, percentage of mineralized nodule and expression of collagen I, osteocalcin and BMP-2 of ADSCs from OVX rats were higher when compared to BMMSCs from OVX rats in at least one of the evaluated periods (p?p?相似文献   

Effects of tricalcium silicate cements on osteogenic differentiation of human bone marrow-derived mesenchymal stem cells in vitro

Tricalcium silicate cements have been successfully employed in the biomedical field as bioactive bone and dentin substitutes, with widely acclaimed osteoactive properties. This research analyzed the effects of different tricalcium silicate cement formulations on the temporal osteoactivity profile of human bone marrow-derived mesenchymal stem cells (hMW-MSCs). These cells were exposed to four commercially available tricalcium silicate cement formulations in osteogenic differentiation medium. After 1, 3, 7 and 10 days, quantitative real-time polymerase chain reaction and Western blotting were performed to detect expression of the target osteogenic markers ALP, RUNX2, OSX, OPN, MSX2 and OCN. After 3, 7, 14 and 21 days, alkaline phosphatase assay was performed to detect changes in intracellular enzyme level. An Alizarin Red S assay was performed after 28 days to detect extracellular matrix mineralization. In the presence of tricalcium silicate cements, target osteogenic markers were downregulated at the mRNA and protein levels at all time points. Intracellular alkaline phosphatase enzyme levels and extracellular mineralization of the experimental groups were not significantly different from the untreated control. Quantitative polymerase chain reaction results showed increases in downregulation of RUNX2, OSX, MSX2 and OCN with increasing time of exposure to the tricalcium silicate cements, while ALP showed peak downregulation at day 7. For Western blotting, OSX, OPN, MSX2 and OCN showed increased downregulation with increased exposure time to the tested cements. Alkaline phosphatase enzyme levels generally declined after day 7. Based on these results, it is concluded that tricalcium silicate cements do not induce osteogenic differentiation of hBM-MSCs in vitro.     

In vitro behaviour of adult mesenchymal stem cells seeded on a bioactive glass ceramic in the SiO(2)-CaO-P(2)O(5) system

This work describes the evaluation of a glass ceramic (55S41C4P-1300) as a potential substrate for bone tissue engineering. For that purpose, the capacity of mesenchymal stem cells (MSCs), isolated from rabbit bone marrow, to adhere, proliferate and differentiate into osteoblast (OBs) with or without 55S41C4P-1300 was investigated. Two types of culture medium, i.e. growth medium (GM) and osteogenic medium (OM), were evaluated. The bioactive 55S41C4P-1300, containing pseudowollastonite, wollastonite, tricalcium phosphate and crystoballite as crystalline phases, was obtained by heat treatment of a sol-gel glass (55SiO(2), 41CaO, 4P(2)O(5) (mol.%)) at 1300 degrees C. The results showed that the MSCs adhered, spread, proliferated and produced mineralized extracellular matrix on 55S41C4P-1300 regardless of the culture medium used. As the same time, they showed an osteoblastic phenotype, and this phenomenon was accompanied by the gradual diminution of the marker CD90 expression. The 55S41C4P-1300 was able to induce the differentiation of MSCs into OBs in the same way as OM without glass ceramic. This effect increased with the combination of 55S41C4P-1300 with OM. The glass ceramic evaluated in this work is bioactive, cytocompatible and capable of promoting the differentiation of MSCs into OBs. For that reason, it could be regarded as a suitable matrix in tissue engineering for bone tissue regeneration.     

Cartilage repair using an in vitro generated scaffold-free tissue-engineered construct derived from porcine synovial mesenchymal stem cells

The objective was to in vitro generate a mesenchymal stem cell (MSC)-based tissue-engineered construct (TEC) to facilitate in vivo repair in a porcine chondral defect model. Porcine synovial MSCs were cultured in monolayer at high density and were subsequently detached from the substratum. The cell/matrix complex spontaneously contracted to develop a basic TEC. Immunohistochemical analysis showed that the basic TEC contained collagen I and III, fibronectin, and vitronectin. The basic TEC exhibited stable adhesion to the surface of a porcine cartilage matrix in an explant culture system. The TEC cultured in chondrogenic media exhibited elevated expression of glycosaminoglycan and chondrogenic marker genes. The TEC were implanted in vivo into chondral defects in the medial femoral condyle of 4-month-old pigs, followed by sacrifice after 6 months. Implantation of a TEC into chondral defects initiated repair with a chondrogenic-like tissue, as well as secure biological integration to the adjacent cartilage. Histologically, the repair tissue stained positively with Safranin O and for collagen II. Biomechanical evaluation revealed that repair tissue exhibited mechanical properties similar to those of normal porcine cartilage in static compression and friction tests. This technology is a unique and promising method for stem cell-based cartilage repair.     

骨髓间充质干细胞分离培养的研究进展

骨髓间充质干细胞具有较强的自我增殖能力和多向分化潜能。随着对其细胞免疫学研究的深入 ,目前已建立了多种分离纯化并扩增的方法 ,为其在细胞工程和组织工程上的应用提供了基础     

骨髓间充质干细胞在骨形态发生蛋白2/注射式硫酸钙载体上的成骨

背景：将生长因子复合到支架上构建复合材料可同时具备骨诱导和骨传导作用。 目的：观察骨形态发生蛋白2/注射式硫酸钙复合载体对大鼠骨髓间充质干细胞体外诱导成骨的影响。 方法：取生长状态良好的第2代SD大鼠骨髓间充质干细胞悬液,分3组培养：实验组将细胞悬液滴加到骨形态发生蛋白2/注射式硫酸钙复合材料表面,对照组在细胞悬液中加入骨形态发生蛋白2,空白对照组正常培养。 结果与结论：3组细胞随培养时间延长逐渐增多,实验组细胞数量最多,明显多于对照组及空白对照组(P < 0.05)。实验组培养不同时间点碱性磷酸酶活性高于对照组及空白对照组(P < 0.05)。体外实验显示骨形态发生蛋白2/注射式硫酸钙复合载体可促进骨髓间充质干细胞向成骨细胞分化。     

不同材料因素影响骨髓间充质干细胞的增殖及成骨分化

文题释义：表面微观形貌：材料表面所具有的所有微观几何形状及相关物理量统称为表面微观形貌,包括孔径大小、孔径率、表面凹凸程度、底物刚度、弹性模量、表面能等方面,同一种材料不同的表面微观形貌将会对材料表面的物质产生不同的影响。 表面能/润湿性：表面能是指恒温、恒压、恒组成情况下可逆地增加物系表面积须对物质所做的非体积功,润湿性是指一种液体在一种固体表面铺展的能力或倾向性。 背景：在利用组织工程技术治疗骨缺损或骨损伤的过程中,生物材料对移植的骨髓间充质干细存活率与增殖分化潜能有影响。 目的：对生物材料如何影响骨髓间充质干细胞的增殖及成骨分化的研究进展进行综述,指导材料合理应用。 方法：应用计算机检索中国知网、PubMed、Web of science及万方数据库,检索词为“骨髓间充质干细胞、成骨分化、生物材料、微观形貌、Bone marrow mesenchymal stem cells、Osteogenic differentiation、Biological materials、The microstructure”,根据标准纳入不同生物材料因素影响骨髓间充质干细胞增殖及成骨分化的文献。结果与结论：①金属材料具有良好的生物相容性、骨传导性、机械性能,非金属材料具有良好的生物相容性、骨传导性、再吸收性及三维塑形性;②材料的表面微观形貌因素众多,即使是同一种材料,表面能/润湿性越高越利于骨髓间充质干细胞的增殖与成骨分化,表面粗糙程度相对越高越利于细胞的增殖、黏附及分化,孔径直径越大、孔径率越小越利于细胞的成骨分化,底物刚度相对高及弹性模量相对大有利于骨髓间充质干细胞的成骨分化,以上材料的各种因素等都能够影响骨髓间充质干细胞的增殖及成骨作用,这些新的研究进展进一步提高了骨髓间充质干细胞种植于各类生物材料用于临床治疗的应用。ORCID: 0000-0001-8325-9867(王旸昊) 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     

Direct and indirect co-culture of chondrocytes and mesenchymal stem cells for the generation of polymer/extracellular matrix hybrid constructs

In this work, the influence of direct cell–cell contact in co-cultures of mesenchymal stem cells (MSCs) and chondrocytes for the improved deposition of cartilage-like extracellular matrix (ECM) within nonwoven fibrous poly(∊-caprolactone) (PCL) scaffolds was examined. To this end, chondrocytes and MSCs were either co-cultured in direct contact by mixing on a single PCL scaffold or produced via indirect co-culture, whereby the two cell types were seeded on separate scaffolds which were then cultured together in the same system either statically or under media perfusion in a bioreactor. In static cultures, the chondrocyte scaffold of an indirectly co-cultured group generated significantly greater amounts of glycosaminoglycan and collagen than the direct co-culture group initially seeded with the same number of chondrocytes. Furthermore, improved ECM production was linked to greater cellular proliferation and distribution throughout the scaffold in static culture. In perfusion cultures, flow had a significant effect on the proliferation of the chondrocytes. The ECM contents within the chondrocyte-containing scaffolds of the indirect co-culture groups either approximated or surpassed the amounts generated within the direct co-culture group. Additionally, within bioreactor culture there were indications that chondrocytes had an influence on the chondrogenesis of MSCs as evidenced by increases in cartilaginous ECM synthetic capacity. This work demonstrates that it is possible to generate PCL/ECM hybrid scaffolds for cartilage regeneration by utilizing the factors secreted by two different cell types, chondrocytes and MSCs, even in the absence of juxtacrine signaling.     

成人骨髓间充质干细胞体外培养、鉴定与成骨诱导

背景：骨髓间充质干细胞具有自我增殖和多向分化潜能,然而间充质干细胞在骨髓中含量极少,体外纯化、扩增与成骨诱导是进行骨组织工程研究的关键。 目的：拟建立一套简便可靠的成人骨髓间充质干细胞体外培养及鉴定体系,并定向诱导其向成骨细胞分化。 方法：抽取髂前上棘处骨髓,采用密度梯度离心法与贴壁筛选法相结合,对骨髓间充质干细胞分离、纯化、培养并扩增。将地塞米松、β-甘油磷酸钠、维生素Ｃ配制成骨诱导液,将细胞分为成骨诱导组和空白对照组进行观察。 结果与结论：成人骨髓间充质干细胞呈典型的长梭形、纺锤状。8-11 d细胞进入快速增殖期,生长曲线呈S型,CD44、CD90均呈阳性表达,而CD34、CD45呈阴性表达。碱性磷酸酶活性随培养时间而增高,并在第12天达到高峰,成骨诱导组各时间点碱性磷酸酶活性均高于空白对照组。说明实验建立的成人骨髓间充质干细胞体外培养、鉴定及诱导成骨细胞分化体系可以获得纯度较高、成骨分化能力较好的间充质干细胞。     

间充质干细胞培养中分化现象及c-fos表达研究

目的观察不同的培养基对间充质干细胞(MSC)体外自发分化的影响及c鄄fos的表达情况。方法以密度梯度离心法从SD大鼠骨髓中培养MSC,分别以L鄄DMEM、RPMI鄄1640与MSCGM作为培养基,观察对MSC在体外培养扩增的影响,流式细胞仪鉴定MSC,以免疫组化方法检测原癌基因c鄄fos的蛋白表达情况。结果MSCGM培养的MSC体外基本维持较均一的梭形,并能保持6代以上较少分化,而用L鄄DMEM和RPMI鄄1640培养,原代MSC形态基本较好,两代后开始大量分化。大部分MSC表达FOS蛋白。结论专用培养基对MSC体外培养中保持未分化状态很关键。FOS可能是MSC的增殖与分泌作用的胞内信号之一。     

The effects of platelet-rich plasma on the osteogenic induction of bone marrow mesenchymal stem cells

Bone marrow mesenchymal stem cells (BMSCs) are multipotent stem cells. Finding methods to improve the osteogenic potential of these cells is a key factor in bone tissue engineering. Platelet-rich plasma (PRP) contains powerful growth factors that produce changes in a variety of cell types. The purpose of this study was to explore the effects of PRP on the osteogenic differentiation of BMSCs in vitro. Rabbit BMSCs were harvested and cultured in vitro in control media or in media enhanced with PRP. BMSCs began to attach 12–24 hours after seeding. A MTT assay demonstrated that PRP-induced BMSCs grew rapidly compared with the control group. The PRP group also showed strongly positive staining of alkaline phosphatase and mineralized nodules whereas the control group showed negative staining. However, the alkaline phosphatase activity and the mRNA level of the osteogenic markers (osteocalcin and osteopontin) remained higher in the PRP group. These results confirmed that PRP could enhance the proliferation of BMSCs and effectively promote the osteogenic differentiation of BMSCs in vitro.     

Degradable hydrogels for spatiotemporal control of mesenchymal stem cells localized at decellularized bone allografts

The transplantation of cells, such as mesenchymal stem cells (MSCs), has numerous applications in the field of regenerative medicine. For cell transplantation strategies to be successful therapeutically, cellular localization and persistence must be controlled to maximize cell-mediated contributions to healing. Herein, we demonstrate that hydrolytic degradation of poly(ethylene glycol) (PEG) hydrogels can be used to spatiotemporally control encapsulated MSC localization to decellularized bone allografts, both in vitro and in vivo. By altering the number of hydrolytically degradable lactide repeat units within PEG-d,l-lactide-methacrylate macromers, a series of hydrogels was synthesized that degraded over ∼1, 2 and 3 weeks. MSCs were encapsulated within these hydrogels formed around decellularized bone allografts, and non-invasive, longitudinal fluorescence imaging was used to track cell persistence both in vitro and in vivo. Spatiotemporal localization of MSCs to the exterior of bone allograft surfaces was similar to in vitro hydrogel degradation kinetics despite hydrogel mesh sizes being ∼2–3 orders of magnitude smaller than MSC size throughout the degradation process. Thus, localized, cell-mediated degradation and MSC migration from the hydrogels are suspected, particularly as ∼10% of the total transplanted MSC population was shown to persist in close proximity (within ∼650 μm) to grafts 7 weeks after complete hydrogel degradation. This work demonstrates the therapeutic utility of PEG-based hydrogels for controlling spatiotemporal cell transplantation for a myriad of regenerative medicine strategies.     

骨髓间质干细胞与纤维蛋白胶生物相容性的实验研究

目的 采用体外细胞培养法对纤维蛋白胶的生物相容性进行研究，探讨它作为骨组织工程的载体材料的可行性。方法 取2月龄新西兰兔，麻醉后无菌条件下自股骨大转子处抽取骨髓4～6ml，淋巴细胞分离液离心后取单核细胞层，D-Hanks液洗涤离心2遍，悬浮于含10％FBS的DMEM培养液中，行原代培养。传代的细胞分为2组，一组继续用完全培养基培养，一组用条件培养基培养。分别收集细胞接种于含纤维蛋白胶的培养板中。不含材料的培养板中接种细胞作为对照。于不同时间进行处理，用于相差显微镜与扫描电镜观察，行MTT及碱性磷酸酶的含量测定。结果 骨髓间质干细胞可以在纤维蛋白胶表面生长，逐渐粘附。对照组与实验组在细胞光吸收值(OD值)、碱性磷酸酶的含量方面相近，统计学分析无显著差异。结论 纤维蛋白胶对兔骨髓间质干细胞的形态学，细胞生长增殖、分化都无影响。具有良好的生物相容性，可作为骨髓间质干细胞的生物载体。     

骨髓间质干细胞与纤维蛋白胶生物相容性的实验研究

目的采用体外细胞培养法对纤维蛋白胶的生物相容性进行研究,探讨它作为骨组织工程的载体材料的可行性.方法取2月龄新西兰兔,麻醉后无菌条件下自股骨大转子处抽取骨髓4~6ml, 淋巴细胞分离液离心后取单核细胞层,D-Hanks液洗涤离心2遍,悬浮于含10%FBS的DMEM培养液中,行原代培养.传代的细胞分为2组,一组继续用完全培养基培养,一组用条件培养基培养.分别收集细胞接种于含纤维蛋白胶的培养板中.不含材料的培养板中接种细胞作为对照.于不同时间进行处理,用于相差显微镜与扫描电镜观察,行MTT及碱性磷酸酶的含量测定.结果骨髓间质干细胞可以在纤维蛋白胶表面生长,逐渐粘附.对照组与实验组在细胞光吸收值(OD值)、碱性磷酸酶的含量方面相近,统计学分析无显著差异.结论纤维蛋白胶对兔骨髓间质干细胞的形态学,细胞生长增殖、分化都无影响.具有良好的生物相容性,可作为骨髓间质干细胞的生物载体.