The Experimental Study of Constructing Tissue Engineered Bone by Compounding Zinc-sintered Bovine Cancellous Bone with Marrow Stromal Cells

To study the osteogenic ability of tissue-engineered bone constructed by compounding zinc-sintered bovine cancellous bone with rabbit marrow stromal cells (MSCs) in vivo,the zinc-sintered bovine cancellous bone of beta-tricalcium phosphate (TCP) type was prepared by sintering the fresh calf cancellous bone twice and then loading it with zinc-ion.The rabbit MSCs were cultured,induced and seeded onto the zinc-sintered bovine cancellous bones.The tissue-engineered bones were then implanted into the rabbits' back muscles.The newly formed bone tissues were observed by histological methods and the areas of new osseous tissues were measured at the end of the 4th and 8th week.The zinc-sintered bovine cancellous bones alone were implanted on the other side as control.The osteogenic activity of MSCs was identified by alkaline phosphatase (ALP) staining and calcification nod chinalizarin staining.At the end of 4th week,a small amount of new bone tissues was observed.At the end of 8th week,there were many newly formed bone mature tissues.Moreover,the area of the latter was significantly larger than that of the former(P<0.01),while in the control group there was no new bone formation.The tissue-engineered bone,which was constructed by combining zinc-sintered bovine cancellous bone with MSCs,has satisfactory osteogenic capabilities in vivo.

Large-Scale Surface Modification of Decellularized Matrix with Erythrocyte Membrane for Promoting In Situ Regeneration of Heart Valve

In situ regeneration is a promising strategy for constructing tissue engineering heart valves(TEHVs).Currently,the decellularized heart valve(DHV)is extensively employed as a TEHV scaffold.Nevertheless,DHV exhibits limited blood compatibility and notable difficulties in endothelialization,resulting in thrombosis and graft failure.The red blood cell membrane(RBCM)exhibits excellent biocompatibility and prolonged circulation stability and is extensively applied in the camouflage of nanoparticles for drug delivery;however,there is no report on its application for large-scale modification of decellularized extracellular matrix(ECM).For the first time,we utilized a layer-by-layer assembling strategy to immobilize RBCM on the surface of DHV and construct an innovative TEHV scaffold.Our findings demonstrated that the scaffold significantly improved the hemocompatibility of DHV by effectively preventing plasma protein adsorption,activated platelet adhesion,and erythrocyte aggregation,and induced macrophage polarization toward the M2 phenotype in vitro.Moreover,RBCM modification significantly enhanced the mechanical properties and enzymatic stability of DHV.The rat models of subcutaneous embedding and abdominal aorta implantation showed that the scaffold regulated the polarization of macrophages into the anti-inflammatory and pro-modeling M2 phenotype and promoted endothelialization and ECM remodeling in the early stage without thrombosis and calcification.The novel TEHV exhibits excellent performance and can overcome the limitations of commonly used clinical prostheses.

Biocompatibility Studies on Bone Marrow Stromal Cells with Chitosan-gelatin Blends

To study the effect of chitosan-gelatin blends on the growth and proliferation of in vitro cultured bone marrow stromal cells(BMSCs) and explore a new carrier for the application of tissure engineering, cells from long bones of young rabbitsaged less than two weeks were expanded in vitro for one week and seeded onto the surface of pure chitosan and chitosan-gelatin blends. Cells attached to and proliferated on both pure chitosan and chitosan-gelatin blends were monitored with the aid of an inverted light microscope and a scanning electron microscope. The cell viability was monitored by MTT after 2, 4, 6, 8 days seeding. BMSCs could be attached to and proliferated on both pure chitosan and chitosan-gelatin blends and remain their morphologies seen in vivo. Chitosan-gelatin blends could promote BMSCs to proliferate(P<0.01). It is confirmed that chitosan-gelatin blends maintain the bioactivity feature of chitosan and even enhance the growth and proliferation of in vitro cultured BMSCs because of the adding of gelatin. It is a potential carrier for the delivery of cells tissue engineering.

Fabrication of a Novel Hybrid Scaffold for Tissue Engineered Heart Valve

The aim of this study was to fabricate biomatrix/polymer hybrid scaffolds using an electrospinning technique. Then tissue engineered heart valves were engineered by seeding mesenchymal stromal cells （MSCs） onto the scaffolds. The effects of the hybrid scaffolds on the proliferation of seed cells, formation of extracellular matrix and mechanical properties of tissue engineered heart valves were investigated. MSCs were obtained from rats. Porcine aortic heart valves were decellularized, coated with poly（3-hydroxybutyrate-co-4-hydroxybutyrate） using an electrospinning technique, and reseeded and cultured over a time period of 14 days. In control group, the decellularized valve scaffolds were reseeded and cultured over an equivalent time period. Specimens of each group were examined histologically （hematoxylin-eosin [HE] staining, immunohistostaining, and scanning electron microscopy）, biochemically （DNA and 4-hydroxyproline） and mechanically. The results showed that recellularization was comparable to the specimens of hybrid scaffolds and controls. The specimens of hybrid scaffolds and controls revealed comparable amounts of cell mass and 4-hydroxyproline （P〉0.05）. However, the specimens of hybrid scaffolds showed a significant increase in mechanical strength, compared to the controls （P〈0.05）. This study demonstrated the superiority of the hybrid scaffolds to increase the mechanical strength of tissue engineered heart valves. And compared to the decellularized valve scaffolds, the hybrid scaffolds showed similar effects on the proliferation of MSCs and formation of extracellular matrix. It was believed that the hybrid scaffolds could be used for the construction of tissue engineered heart valves.

Experimental Study on Allogenic Decalcified Bone Matrix as Carrier for Bone Tissue Engineering

The biocompatibility and osteogenic activity of allogenic decalcified bone matrix (DBM) used as a carrier for bone tissue engineering were studied. Following the method described by Urist, allogenic DBM was made. In vitro, DBM and bone marrow stromal cell (BMSC) from rabbits were co-cultured for 3-7 days and subjected to HE staining, and a series of histomorphological observations were performed under phase-contrast microscopy and scanning electron microscopy (SEM). In vivo the mixture of DBM/BMSC co-cultured for 3 days was planted into one side of muscules sacrospinalis of rabbits, and the DBM without BMSC was planted into other side as control. Specimens were collected at postoperative week 1, 2 and 4, and subjected to HE staining, and observed under SEM. The results showed during culture in vitro, the BMSCs adherent to the wall of DBM grew, proliferated and had secretive activity. The in vivo experiment revealed that BMSCs and undifferentiated mesenchymal cells in the perivascular region invaded gradually and proliferated together in DBM/BMSC group, and colony-forming units of chondrocytes were found. Osteoblasts, trabecular bone and medullary cavity appeared. The inflammatory reaction around muscles almost disappeared at the second weeks. In pure DBM group, the similar changes appeared from the surface of the DBM to center, and the volume of total regenerate bones was less than the DBM/BMSC group at the same time. The results indicated that the mixture of DBM and BMSC had good biocompatibility and ectopic induced osteogenic activity.

Modifying oxygen tension affects bone marrow stromal cell osteogenesis for regenerative medicine

AIM To establish a hypoxic environment for promoting osteogenesis in rat marrow stromal cells(MSCs) using osteogenic matrix cell sheets(OMCSs).METHODS Rat MSCs were cultured in osteogenic media under one of four varying oxygen conditions: Normoxia(21% O_2) for 14 d(NN), normoxia for 7 d followed by hypoxia(5% O_2) for 7 d(NH), hypoxia for 7 d followed by normoxia for 7 d(HN), or hypoxia for 14 d(HH). Osteogenesis was evaluated by observing changes in cell morphology and calcium deposition, and by measuring osteocalcin secretion(ELISA) and calcium content. In vivo syngeneic transplantation using OMCSs and β-tricalcium phosphate discs, preconditioned under NN or HN conditions, was also evaluated by histology, calcium content measurements,and real-time quantitative PCR.RESULTS In the NN and HN groups, differentiated, cuboidal-shaped cells were readily observed, along with calcium deposits. In the HN group, the levels of secreted osteocalcin increased rapidly from day 10 as compared with the other groups, and plateaued at day 12(P < 0.05). At day 14, the HN group showed the highest amount of calcium deposition. In vivo, the HN group showed histologically prominent new bone formation, increased calcium deposition, and higher collagen type Ⅰ?messenger RNA expression as compared with the NN group.CONCLUSION The results of this study indicate that modifying oxygen tension is an effective method to enhance the osteogenic ability of MSCs used for OMCSs.

Wnt3a-induced ST2 decellularized matrix ornamented PCL scaffold for bone tissue engineering

The limited bioactivity of scaffold materials is an important factor that restricts the development of bone tissue engineering.Wnt3a activates the classicWnt/β-catenin signaling pathway which effects bone growth and development by the accumulation ofβ-catenin in the nucleus.In this study,we fabricated 3D printed PCL scaffold with Wnt3a-induced murine bone marrow-derived stromal cell line ST2 decellularized matrix(Wnt3a-ST2-dCM-PCL)and ST2 decellularized matrix(ST2-dCM-PCL)by freeze-thaw cycle and DNase decellularization treatment which efficiently decellularized>90%DNA while preserved most protein.Compared to ST2-dCM-PCL,Wnt3a-ST2-dCM-PCL significantly enhanced newly-seeded ST2 proliferation,osteogenic differentiation and upregulated osteogenic marker genes alkaline phosphatase(Alp),Runx2,type I collagen(Col 1)and osteocalcin(Ocn)mRNA expression.After 14 days of osteogenic induction,Wnt3a-ST2-dCM-PCL promoted ST2 mineralization.These results demonstrated that Wnt3a-induced ST2 decellularized matrix improve scaffold materials’osteoinductivity and osteoconductivity.

Comparative study on seeding methods of human bone marrow stromal cells in bone tissue engineering

Background In general the traditional static seeding method has its limitation while the dynamic seeding method reveals its advantages over traditional static method. We compared static and dynamic seeding method for human bone marrow stromal cells (hBMSCs) in bone tissue engineering. Methods DNA assay was used for detecting the maximal initial seeding concentration for static seeding. Dynamic and static seeding methods were compared, when scaffolds were loaded with hBMSCs at this maximal initial cell seeding concentration. Histology and scanning electron microscope (SEM) were examined to evaluate the distribution of cells inside the constructs. Markers encoding osteogenic genes were measured by fluorescent RT-PCR. The protocol for dynamic seeding of hBMSCs was also investigated. Results DNA assay showed that the static maximal initial seeding concentration was lower than that in dynamic seeding. Histology and SEM showed even distribution and spread of cells in the dynamically seeded constructs, while their statically seeded counterparts showed cell aggregation. Fluorescent RT-PCR again showed stronger osteogenic potential of dynamically seeded constructs. Conclusion dynamic seeding of hBMSCs is a promising technique in bone tissue engineering.

Early in vivo experience with tissue-engineered heart valve leaflets from autologous bone marrow-derived cells

Background Currently used heart valve prostheses are associated with anticoagulation complications or limited durability. The advancement of stem cell study and tissue-engineered heart valve research may offer a relatively ideal solution to these problems. Methods Bone marrow was aspirated from sternum of lamb goats to isolate BMCs. Cells were identified by flow cytometry and its capacity of differentiation. Cellular viability was assessed with Rhdomine 123 staining. 1 × 10^7cells were seeded on a patch of PGA sheet. After two-day in vitro culture, autologous cell/ scaffold sheets were used to replace the right posterior pulmonary valve leaflets under cardiopulmonary bypass. The leaflets were explanted at 2 days, 2, 6, 8 and 10 weeks after implantation. The samples were examined macroscopically, histologically, immunohistochemically, and by Scanning Electron Microscope （SEM）. Two goats were implanted with acellular sheets and established as a control group. Results BMCs exhibited fibroblastoid morphology with good viability. Flow cytometry showed negative CD14 and CD45 expression. In vitro cultured BMCs demonstrated the potential to differentiate into adipocytes. The explanted leaflets resembled the characteristics of native extracellular matrix was leaflets macroscopicaIly in the cellular group. Histology showed synthesized and cells were distributed in the single-layered leaflets.Immunohistochemistry revealed positive staining for yon Willebrand factor, α-SMA, vimentin. A confluent cell surface was formed on the explanted TEHLs. No calcium deposited on the leaflets. In control group, the acellular scaffolds were completely degraded, without leaflet remained at 8 weeks. Conclusions It is possible to create tissue-engineered heart valves in vivo using autologous bone marrow-derived cells.

Transfect bone marrow stromal cells with pcDNA3.1-VEGF to construct tissue engineered bone in defect repair

Background We previously showed that nano-hydroxyapatite/carboxymethyl chitosan （n-Ha/CMCS） displayed excellent mechanical properties, good degradation rates and exceptional biocompatibility, with negligible toxicity. The aim of this study was to determine the effect of the same composite with vascular endothelial growth factor （VEGF）transfected bone marrow stromal cells （BMSCs） in a rabbit radial defect model.

The ectopic study of tissue-engineered bone with hBMP-4 gene modified bone marrow stromal cells in rabbits

Background Tissue-engineering techniques combined with gene therapy have beenrecently reported to improve osteogenesis. In this study, tissue-engineered bone constructed byhuman Bone Morphogenetic Protein 4 (hBMP-4) gene-modified bone marrow stromal cells (bMSCs) wasexplored in an ectopic bone formation model in rabbits. Methods A pEGFP-hBMP-4 mammalian plasmid (EGFP: Enhanced Green Fluorescent Protein) was constructed by subcloning techniques. bMSCs obtainedfrom rabbits were cultured and transfected with either pEGFP-hBMP-4, pEGFP or left uninfected invitro. Transfer efficiency was detected through the expression of EGFP. Transcription of the targetgene was detected by RT-PCR. Alkaline phosphatase (ALP) and Von Kossa tests were also conducted toexplore the phenotypes of osteoblasts. The autologous bMSCs of the 3 groups were then combined withNatural Non-organic Bone ( NNB) , a porous hydroxyapatite implant with a dimension of 6 mm x 6 mm x3 mm, at a concentration of 5 x 10~7 cells/ml. They were subsequently implanted into 6 rabbitssubcutaneously using NNB alone as a blank control (6 implants per group). Four weeks after surgery,the implants were evaluated with histological staining and computerized analysis of new boneformation. Results pEGFP-hBMP-4 expression plasmid was constructed. Under optimal conditions, genetransfer efficiency reached more than 30% , Target gene transfer could strengthen the transcriptionof BMP-4, and increase the expression of ALP as well as the number of calcium nodules. In theectopic animal model, NNB alone could not induce new bone formation. The new bone area formed in thebMSCs group was (17.2 ± 7.1)%, and pEGFP group was (14.7 ± 6.1) % , while pEGFP-hBMP-4 group was(29.5 ± 8.2) % , which was the highest among the groups (F = 7.295, P < 0. 01). Conclusions Themammalian hBMP-4 expression plasmid was successfully constructed and a comparatively high transferefficiency was achieved. The gene transfer technique enhanced the expression of BMP-4 and promoteddifferentiation from bMSCs to osteoblasts. These in vivo results suggested that transfection ofbMSCs with hBMP-4 might be a suitable method to enhance their inherent osteogenic capacity for bonetissue engineering applications.

An ectopic study of tissue-engineered bone with Nell-1 gene modified rat bone marrow stromal cells in nude mice

Background Tissue engineering techniques combined with gene therapy have been recently used to improve osteogenesis. NEL-like molecule-1 （Nell-1）, a novel growth factor, has been reported to have specificity for osteochondral lineage. The study assessed the osteogenic differentiation of rat bone marrow stromal cells （bMSCs） after Nell-1 gene modification and examined its ectopic bone formation ability in a nude mice model with tissue engineering technique. Methods bMSCs obtained from Fischer 344 rats were transduced with either AdNell-1 （Nell-1 group） or Ad-β-galactosidase （AdLacZ, LacZ group） or left untransduced （untransduced group）. The expression of Nell-1 protein was determined by Western blotting and transfer efficiency was assessed, mRNA expressions of osteopontin （OP）, bone sialoprotein （BSP） and osteocalcin （OC） were assessed by real-time PCR 0, 3, 7, 14, and 21 days after gene transfer. Alkaline phosphatase （ALP） activity was measured and von Kossa test was also conducted. Finally, with a tissue engineering technique, gene transduced bMSCs, combining with β-tricalcium phosphate （β-TCP） at a concentration of 2×10^7 cells/ml, were implanted at subcutaneous sites on the back of nude mice. Four weeks after surgery, the implants were evaluated with histological staining and computerized analysis of new bone formation. Results Under current transduction conditions, gene transfer efficiency reached （57.9±6.8）%. Nell-1 protein was detected in Nell-1 group but not in untransduced group and LacZ group. Induced by Nell-1, BSP and OP expression were increased at intermediate stage and OC expression was increased at later stage. ALP activity and the number of calcium nodules were highest in Nell-1 group. Four weeks after implanted into nude mice subcutaneously, the percentage of new bone area in Nell-1 group was （18.1±5.0）%, significantly higher than those of untransduced group （11.3±3.2）% and LacZ group （12.3±3.1）% （P〈0.05）. Conclusions This study has demonstrated the ability of Nell-1 to induce osteogenic differentiation of rat bMSCs in vitro and to enhance bone formation with a tissue engineering technique. The results suggest that Nell-1 may be a potential osteogenic gene to be used in bone tissue engineering.

Immobilization of Decellularized Valve Scaffolds with Arg-Gly-Asp-containing Peptide to Promote Myofibroblast Adhesion

The cell adhesive properties of decellularized valve scaffolds were promoted by immobilization of valve scaffold with arginine-glycine-aspartic acid （RGD）-containing peptides. Porcine aortic valves were decellularized with trypsin/EDTA, and detergent Triton X-100. With the help of a coupling reagent Sulfo-LC-SPDP, the valve scaffolds were immobilized with glycine-arginine-glycine-aspartic acid-serine-proline-cysteine （GRGDSPC） peptide. X-ray photoelectron spectroscopy （XPS） was used for surface structure analysis. Myofibroblasts harvested from rats were seeded onto the valve scaffolds. Cell count by using microscopy and modified MTT assay were performed to assess cell adhesion. Based on the spectra of XPS, the conjugation of GRGDSPC peptide with decellularized valve scaffolds was confirmed. Both cell count and MTT assay showed that myofibroblasts were much easier to adhere to the modified valve scaffolds, which was also confirmed histologically. Our findings suggest that it is feasible to immobilize RGD-containing peptides onto decellularized valve scaffolds. And the technique can effectively promote cell adhesion, which is beneficial for in vitro tissue engineering of heart valves.

Construction of tissue-engineered heart valves by using decellularized scaffolds and endothelial progenitor cells

Background Tissue-engineered heart valves have the potential to overcome the limitations of present heart valve replacements. This study was designed to develop a tissue engineering heart valve by using human umbilical cord blood-derived endothelial progenitor cells （EPCs） and decellularized valve scaffolds. Methods Decellularized valve scaffolds were prepared from fresh porcine heart valves. EPCs were isolated from fresh human umbilical cord blood by density gradient centrifugation, cultured for 3 weeks in EGM-2-MV medium, by which time the resultant cell population became endothelial in nature, as assessed by immunofluorescent staining. EPC-derived endothelial cells were seeded onto the decellularized scaffold at 3 × 10^6 cells/cm^2 and cultured under static conditions for 7 days. Proliferation of the seeded cells on the scaffolds was detected using the MTT assay. Tissue-engineered heart valves were analyzed by HE staining, immunofluorescent staining and scanning electron microscopy. The anti-thrombogenic function of the endothelium on the engineered heart valves was evaluated by platelet adhesion experiments and reverse transcription-polymerase chain reaction （RT-PCR） analysis for the expression of endothelial nitric oxide synthase （eNOS） and tissue-type plasminogen activator （t-PA）.Results EPC-derived endothelial cells showed a histolytic cobblestone morphology, expressed specific markers of the endothelial cell lineage including von Willebrand factor （vWF） and CD31, bound a human endothelial cell-specific lectin, Ulex Europaeus agglutinin-1 （UEA-1）, and took up Dil-labeled low density lipoprotein （Dil-Ac-LDL）. After seeding on the decellularized scaffold, the cells showed excellent metabolic activity and proliferation. The cells formed confluent endothelial monolayers atop the decellularized matrix, as assessed by HE staining and immunostaining for vWF and CD31. Scanning electron microscopy demonstrated the occurrence of tight junctions between cells forming the confluent monolayer. Platelets adhesion experiments suggested that the neo-endothelium was non-thrombogenic. The expression levels of eNOS and t-PA genes in the neo-endothelium were quite similar to those in human umbilical vein endothelial cells. Conclusions EPCs isolated from the human umbilical cord blood can differentiate into endothelial cells in vitro and form a functional endothelium atop decellularized heart valve scaffolds. Thus, EPCs may be a promising cell source for constructing tissue-engineered heart valves.

Immobilization of RGD Peptidcs onto Decellularized Valve Scaffolds to Promote Cell Adhesion

Porcine aortic valves were decellularized with trypsinase/EDTA and Triton-100. With the help of a coupling reagent Sulfo-LC-SPDP, the biological valve scaffolds were immobilized with one of RGD （arginine-glycine-aspartic acid） containing peptides, called GRGDSPC peptide. Myofibroblasts harvested from rats were seeded onto them. Based on the spectra of X-ray photoelectron spectroscopy, we could find conjugation of GRGDSPC peptide and the scaffolds. Cell count by both microscopy and MTT assay showed that myofibroblasts were easier to adhere to the modified scaffolds. It is proved that it is feasible to immobilize RGD peptides onto decellularized valve scaffolds, and effective to promote cell adhesion, which is beneficial for constructing tissue engineering heart valves in vitro.

组织工程肋骨移植修复胸壁巨大缺损

目的 应用组织工程技术构建的肋骨和带蒂皮瓣移位修复 1例 2 5岁女性患者胸壁巨大韧带样纤维瘤切除后 ,合并软组织、肋骨缺损的早期效果。方法 经髂骨穿刺抽取骨髓组织 ,按 Houghton法分离培养骨髓基质干细胞 ,经定向诱导分化为成骨样细胞 ;用同种异体肋骨经去细胞、去抗原、部分脱钙和冻干处理 ,制成保存天然框架的生物衍生骨支架 ,将 5× 10 6 /ml骨髓基质干细胞与骨支架材料联合培养 6天 ;待完整切除肿瘤后 ,用膈肌瓣修复胸膜腔 ,组织工程肋骨修复 3根肋骨 ,同侧带蒂侧腹壁皮瓣移位修复胸壁软组织缺损。结果 手术经过顺利 ,伤口 期愈合。术后 3个月随访 ,植入组织工程肋骨在体内逐渐发育成成熟肋骨 ,心肺功能显著改善。结论 应用自体骨髓基质干细胞构建的组织工程肋骨在个体化治疗中显示了优越性。

地塞米松对骨髓基质细胞生物学特性的影响

目的 探讨地塞米松对体外培养的骨髓基质细胞增殖和分化等生物学特性的影响。方法 取4～ 6周龄新西兰兔双侧股骨骨髓 3 ml,体外分离 ,培养至第 3代骨髓基质细胞 ,分别用地塞松浓度为 0、10 - 1 0 、10 - 9、10 - 8、10 - 7和 10 - 6 m ol/ L 的培养基 ,作用 2、4及 6天后 ,测定骨髓基质细胞的分裂增殖能力和碱性磷酸酶活性。结果 地塞米松对骨髓基质细胞的增殖起抑制作用 ,并随地塞米松浓度的升高而增强 ,其浓度大于 10 - 8mol/ L 后抑制作用越显著。地塞米松在抑制增殖的同时 ,可显著增强骨髓基质细胞的碱性磷酸酶活性 ,浓度越高作用也越显著 ,但超过 10 - 8mol/ L后各浓度的作用效果无显著差别 ;这种作用随时间的延长而增强 ,至 6天时与对照组相比可增强 2～ 4倍。结论 地塞米松抑制骨髓基质细胞的增殖 ,但可促进其分化为成骨细胞 ,浓度为 10 - 8mol/

骨髓基质干细胞构建组织工程心脏瓣膜的初步研究

目的:探讨用骨髓基质干细胞(BMSCs)和脱细胞天然瓣膜支架体外构建组织工程心脏瓣膜(TEHV)的可行性。方法:髂嵴穿刺抽取狗骨髓液,Percoll密度梯度离心法获取BMSCs,DMEM培养液体外培养扩增,免疫组化染色及流式细胞术分析鉴定分化细胞表型。采用去污剂和酶消化法制作脱细胞猪主动脉瓣膜支架,将BMSCs分化细胞接种于瓣膜支架上构建TEHV。分别行石蜡包埋切片H-E染色、免疫组化染色、扫描电镜及透射电镜检查观察TEHV的组织学结构并鉴定细胞类型。结果:BMSCs分化细胞呈梭形,α-SMA及Vimentin染色阳性,其α-SMA表达与血管壁肌成纤维细胞相近。异种瓣膜支架细胞去除完全,纤维支架结构保留完整。石蜡切片示BMSCs在脱细胞支架上呈复层生长,α-SMA阳性。扫描电镜示TEHV表面光滑,细胞层完整,透射电镜示其细胞成分为有活性的分泌型细胞,呈梭形,复层生长。结论:BMSCs的自然分化细胞具有肌成纤维细胞的特性,种植于脱细胞瓣膜支架上构建TEHV简便可行。TEHV的在体改建尚需进一步研究。

以珊瑚转化羟基磷灰石为支架材料构建组织工程骨的实验研究

目的 探讨以珊瑚转化羟基磷灰石 (CHA )作为骨组织工程支架材料的可行性 ,寻找最佳支架材料 ,为组织工程研究开辟新的途径。方法 取 4周龄兔骨髓 ,分离骨髓基质细胞 ,体外培养 ,诱导分化为成骨细胞 ,胰酶消化后离心收集细胞 ,接种至高温灭菌的 CHA材料 ,无菌条件下植入 8只裸鼠皮下组织中。对照组为同体单纯植入 CHA。分别于 6、8周取材 ,行大体观察、X线摄片及组织学染色 ,观察新骨形成情况。结果 实验组 6周时大体标本浅红色 ,X线片有较高密度阻射影像 ,组织学检查可见有新骨形成 ;8周时大体标本呈红色 ,质硬 ,X线阻射影像密度更高 ,镜下可见大量新骨形成并相互连接成骨小梁样结构 ,骨细胞位于陷窝中。对照组 8周大体标本均为白色 ,周围软组织包裹 ,X线片仅见 CHA阻射影响 ,组织学检查无新骨形成 ,为大量纤维组织长入 CHA孔洞内。结论 CHA可作为骨组织工程的支架材料 ,具有广阔的应用前景。

骨髓基质细胞与关节软骨细胞生物学特性的比较研究

目的 观察兔骨髓基质细胞 (MSCs)诱导和基因修饰后的主要生物学特性 ,并与关节软骨细胞进行比较。 方法 抽取成年雄性新西兰大白兔髂骨骨髓 ,密度梯度离心获得骨髓基质细胞 ,培养传至第 5代 ,按处理方法分为常规培养液组 (A组 )、条件培养液组 (B组 )及重组缺陷型腺病毒携带肝细胞生长因子 c DNA转染组 (C组 )。条件培养液为常规培养液中含转化生长因子 - β1 (10 ng/ml)、碱性成纤维细胞生长因子 (2 5 ng/ml)和地塞米松 (10 - 7mol/L)。切取兔膝关节软骨 ,3mg/ml 型胶原酶消化传代培养至第 3代 (D组 )。观察原代 MSCs及第 5代 MSCs(体外培养 8～ 10周后 )细胞形态 ,对第 5代 MSCs及第 3代软骨细胞进行 、 型胶原免疫组织化学染色 ,MTT法检测细胞增殖情况。阿利新蓝法检测细胞培养上清液中糖胺多糖 (GAG)含量。提取各组培养细胞总 RNA,RT- PCR检测 、 型胶原表达。 结果 原代 MSCs为短梭形、簇状生长 ,传代细胞呈长梭形、旋涡样生长。A组细胞爬片 型胶原免疫组织化学染色阳性 , 型胶原免疫组织化学染色阴性 ,GAG含量低 ,与 D组比较 ,差异有统计学意义 (P<0 .0 5 )。B组细胞爬片 、 型胶原免疫组织化学染色阳性 ,GAG含量升高 ,与 D组比较差异无统计学意义 (P>0 .0 5 ) ;C组转染后第