Polyurethane scaffolds seeded with autologous cells can regenerate long esophageal gaps: An esophageal atresia treatment model

BackgroundPediatric patients suffering from long gap esophageal defects or injuries are in desperate need of innovative treatment options. Our study demonstrates that two different cell sources can adhere to and proliferate on a retrievable synthetic scaffold. In feasibility testing of translational applicability, these cell seeded scaffolds were implanted into piglets and demonstrated esophageal regeneration.MethodsEither porcine esophageal epithelial cells or porcine amniotic fluid was obtained and cultured in 3 dimensions on a polyurethane scaffold (Biostage). The amniotic fluid was obtained prior to birth of the piglet and was a source of mesenchymal stem cells (AF-MSC). Scaffolds that had been seeded were implanted into their respective Yucatan mini-swine. The cell seeded scaffolds in the bioreactor were evaluated for cell viability, proliferation, genotypic expression, and metabolism. Feasibility studies with implantation evaluated tissue regeneration and functional recovery of the esophagus.ResultsBoth cell types seeded onto scaffolds in the bioreactor demonstrated viability, adherence and metabolism over time. The seeded scaffolds demonstrated increased expression of VEGF after 6 days in culture. Once implanted, endoscopy 3 weeks after surgery revealed an extruded scaffold with newly regenerated tissue. Both cell seeded scaffolds demonstrated epithelial and muscle regeneration and the piglets were able to eat and grow over time.ConclusionsAutologous esophageal epithelial cells or maternal AF-MSC can be cultured on a 3D scaffold in a bioreactor. These cells maintain viability, proliferation, and adherence over time. Implantation into piglets demonstrated esophageal regeneration with extrusion of the scaffold. This sets the stage for translational application in a neonatal model of esophageal atresia.     

尿道移行上皮细胞与生物可降解尿道支架体外复合培养的研究

目的：研究体外培养的兔尿道上皮细胞在生物可降解性网状尿道支架上的贴附和生长增殖情况,观察其对尿道上皮细胞形态和功能的影响,利用组织工程技术培养种植细胞的尿道内支架。方法：应用机械分离与酶消化法分离培养兔尿道移行上皮细胞,并在体外行原代培养与扩增后制成细胞悬液接种在网状尿道支架上,形成尿道移行上皮细胞-支架复合物。采用免疫组织化学、荧光染色法鉴定尿道上皮细胞及其活性;采用倒置显微镜、扫描电镜观察尿道上皮细胞在支架表面吸附与生长状态。结果：网状尿道支架具有良好的生物相容性,能使尿道移行上皮细胞增殖,不影响其活性。尿道移行上皮细胞在尿道支架上贴附生长良好,1～2天后完全贴壁,3～7天细胞生长增殖活跃,支架网眼内充满上皮细胞,长期培养仍保持尿道移行上皮细胞特性,扫描电镜可见上皮细胞与网状支架贴附紧密,适度伸展并有基质分泌。结论：网状尿道支架适合尿道移行上皮细胞黏附生长．可作为尿道组织工程的细胞载体,利用组织工程方法可获得适于移植尿道细胞的组织工程化尿道。     

软骨细胞与静电纺丝聚已内酯支架灌流培养构建组织工程软骨的实验研究

目的 采用静电纺丝聚已内酯(polycaprolactone,PCL)支架与软骨细胞复合培养,比较静态和灌流生物反应器培养条件下对细胞增殖及基质分泌的影响.方法 构建PCL支架,自制灌流生物反应器,分离兔软骨细胞,培养后接种于PCL支架,分为灌流培养组和静态培养组.在培养第3、7、14天对支架-细胞复合体行扫描电镜观察,DNA、糖胺聚糖和总胶原定量检测;在培养第14天分析软骨特异性基因表达并观察软骨基质分泌情况.结果 电镜观察PCL支架纤维直径(1.67±0.76) μm,孔径(17.65土7.11)μm,可见支架中软骨细胞黏附生长良好,灌流培养条件下细胞增殖快,且较好地保持了软骨细胞特征形态.在培养第7天,灌流培养组DNA定量高于静态培养组;在培养第3、7和14天,灌流培养组糖胺聚糖定量均高于静态培养组,灌流培养组糖胺聚糖/DNA比值均高于静态培养组.在培养第14天,灌流培养组Ⅱ型胶原、蛋白聚糖基因表达增加;软骨分化指数高于静态培养组.在培养第14天,组织学染色可见灌流培养促进细胞的增殖和渗透生长,提高了软骨基质的分泌,并见软骨陷窝样结构.结论 在灌流生物反应器培养条件下,静电纺丝PCL支架与软骨细胞复合培养可促进软骨细胞的增殖和基质的分泌,提高了组织工程软骨的质量.     

人工生物可降解支架构建组织工程食管的实验研究

目的 研究食管上皮细胞在聚乳酸-聚乙醇酸[poly（1actic-co-glyeolic acid），PLGA]三维支架材料上的黏附和生长情况，探索利用组织工程技术构建组织工程食管的可行性。方法 应用粒子浸出常温模压法制作PLGA三维多孔支架材料；分离培养6只犬食管上皮细胞，体外扩增后，种植到预涂Ⅳ型胶原的PLGA支架材料上。在体外和犬腹腔内分别培养食管上皮细胞-支架复合物，分期终止培养，体外培养3d，1、2、3和4周，其中将体外培养3d后细胞-支架复合物植入同只犬腹腔内，于体内培养1、2、3和4周后行组织学、扫描电镜观察，以及细胞角蛋白抗体免疫组织化学检测。结果 分离培养的犬原代食管上皮细胞呈铺路石样，体外可大量扩增，细胞角蛋白抗体免疫组织化学染色呈阳性；体外及体内培养可见食管上皮细胞在支架材料上黏附、生长良好，持续培养仍保持食管上皮细胞特性；犬腹腔内培养4周后，可形成食管黏膜样组织。结论预涂Ⅳ型胶原的PLGA支架材料适合食管上皮细胞黏附生长，可作为组织工程食管的支架材料。利用组织丁程的方法在体外和犬腹腔内培养有可能获得适于移植的组织工程食管。     

人脐带间充质干细胞与蚕丝素多孔支架的体外复合培养

目的观察蚕丝素多孔支架对人脐带间充质干细胞（human umbilical cord mesenchymal stem cells,hUCMSCs）吸附作用及支架对hUCMSCs形态、功能及活性的影响,为脂肪组织工程支架选择提供实验依据。方法将hUCMSCs制成细胞悬液接种在蚕丝素多孔支架,荧光倒置相差显微镜、扫描电镜和四甲基偶氮唑蓝（MTT）法观察hUCMSCs的吸附和生长情况。结果培养1～2d后可见hUCMSCs与蚕丝素多孔支架充分附着。培养5～7d细胞生长增殖十分活跃,10d左右时,蚕丝素多孔支架孔中hUCMSCs成片状融合。荧光倒置相差显微镜和扫描电镜见细胞与支架黏附良好并有大量基质分泌,且活性指标与正常培养的hUCMSCs比较差异无统计学意义（P〉0．05）。结论蚕丝素多孔支架对hUCMSCs具有良好的吸附作用,并能维持其正常形态、功能及活性,蚕丝素多孔支架是hUCMSCs三维立体培养时的良好天然支架。     

壳聚糖-明胶网络/羟基磷灰石复合材料支架的研究--成骨细胞培养

目的　研究大鼠颅骨成骨细胞在壳聚糖 -明胶网络 /羟基磷灰石 (CS- Gel/ HA)复合材料支架上的生长情况。方法　将原代培养大鼠颅骨成骨细胞第 3代 ,密度为 1.0 1× 10 6 / m l悬液 ,种植于孔隙率分别为85 .2 0 %、90 .4 0 %和 95 .80 %的 CS- Gel/ HA支架材料中 ,利用细胞计数法检测种植后 3天 ,1、2及 3周的细胞增殖曲线 ,采用 HE和 von Kossa染色方法观察细胞生长、骨样组织形成和矿化沉积情况。结果　大鼠颅骨成骨细胞在孔隙率为 85 .2 0 %的支架中增殖较慢 ,在孔隙率为 90 .4 0 %和 95 .80 %的 CS- Gel/ HA复合材料支架上生长良好 ,增殖较快 ,周围分泌有大量细胞外基质 ,3周时局部已出现骨样组织 ,且细胞 /支架结构物有利于钙质沉积。结论　CS- Gel/ HA复合材料支架有望成为培养自体成骨细胞的材料 ,以重建新的骨组织     

Esophagus Tissue Engineering: Hybrid Approach with Esophageal Epithelium and Unidirectional Smooth Muscle Tissue Component Generation In Vitro

Purpose  The aim of this study was to engineer the two main components of the esophagus in vitro: (a) esophageal epithelium and (b) smooth muscle tissue. Furthermore, (a) survivability of esophageal epithelial cells (EEC) on basement membrane matrix (BMM)-coated scaffolds and (b) oriented smooth muscle tissue formation on unidirectional BMM-coated collagen scaffolds was investigated. Methods  Both EEC and smooth muscle cells (SMC) were sourced from Sprague–Dawley rats. The EEC were maintained in vitro and seeded onto BMM-coated 2-D collagen scaffolds. Similarly, smooth muscle cells were obtained using an explants technique and seeded on unidirectional 3-D BMM-coated collagen scaffolds. Cell–polymer constructs for EEC and SMC were maintained in vitro for 8 weeks. Results  Protocols to obtain higher yield of EEC were established. EEC formed a layer of differentiated epithelium after 14 days. EEC survivability on polymers was observed up to 8 weeks. Unidirectional smooth muscle tissue strands were successfully engineered. Conclusion  Esophageal epithelium generation, survivability of EEC on BMM-coated scaffolds, and engineering of unidirectional smooth muscle strands were successful in vitro. The hybrid approach of assembling individual tissue components in vitro using BMM-coated scaffolds and later amalgamating them to form composite tissue holds promises in the tissue engineering of complex organ systems. This research is funded by the European Union within the 6th Framework Program (EuroSTEC; LSHC-CT-2006–037409). XXIst International Symposium on Pediatric Surgical Research, 2–4 October 2008, Leipzig, Germany     

用毛囊隆突细胞构建复合皮的实验观察

目的 以人毛囊隆突细胞为种子细胞体外构建组织工程复合皮，在体观察其功能性修复全层皮肤缺损的可行性。方法 胶原酶消化法体外分离培养人毛囊隆突细胞和毛乳头细胞，实验分为A、B两组。A组将毛囊隆突细胞与毛乳头细胞按1：2混合，接种于胶原包被的聚羟基乙酸纤维支架中；B组单纯接种相同数量的毛乳头细胞。而后覆盖角质形成细胞膜片，构成组织工程复合皮，移植于裸鼠全层皮肤缺损创面。观察创面愈合情况，分别于术后2、4、6周在光学显微镜下观察移植物组织学变化。结果 组织工程复合皮能够有效修复A、B两组裸鼠全层皮肤缺损。术后2周，A、B组创面均可见完整的表皮及真皮结构。术后4-6周，A组复合皮表皮层明显增厚并形成基膜的钉突，可见毛囊样结构；B组仅表皮层有所增厚但基膜平整，未见钉突和毛囊结构形成。结论 以聚羟基乙酸真皮基质为支架，用角质形成细胞、毛囊隆突细胞和毛乳头细胞共同构建的组织工程复合皮，可以有效修复裸鼠全层皮肤缺损。其中毛囊隆突细胞参与了创面解剖修复，同时可能引导组织结构和功能的修复。     

聚羟基烷酸酯与绵羊骨髓基质干细胞相容性的研究

目的评价聚羟基烷酸酯(PHBV)作为组织工程支架与绵羊骨髓基质干细胞(BMSCs)的生物相容性。方法原代培养绵羊BMSCs,传至2～3代后,接种至PHBV膜和泡沫样三维支架上,光镜和扫描电镜观察细胞形态,计数1、2、6 h时的细胞黏附率;并以接种至培养板上细胞为对照组,每日细胞计数,绘制生长曲线;按培养液量与支架体积10 mL／cm3为标准浓度制备浸提液,并制备标准浓度1／16～16倍的浸提液,以MTT法检测细胞毒性;流式细胞仪分析接种到材料上的细胞周期,计算增殖指数;BMSCs接种于PHBV三维支架上4、8、12 d,以Hoechst33258荧光法定量测定细胞内DNA含量, BCA法测定蛋白质含量。结果第3代BMSCs接种至PHBV膜上2 h后即大部黏附,黏附率75．6％,与对照组相比差异无统计学意义,绘制生长曲线见细胞生长与对照组无差异;MTT法检测见9个浓度梯度的浸提液毒性均为0级;光镜和扫描电镜观察见细胞接种于PHBV膜上2 h后大部分黏附,3 d后伸展良好,呈纺锤形或梭形,在三维支架的孔隙内立体生长,1周开始细胞间连接,3周广泛连接,分泌大量基质;流式细胞分析见接种于材料上的细胞周期无变化;接种至PHBV三维支架上的细胞内DNA、蛋白质浓度与对照组比较无差异。结论PHBV作为BMSCs的组织工程支架材料,具有良好的生物相容性。     

Mesenchymal stem cell-based tissue engineering of small-diameter blood vessels

The aim of the study was to construct small-diameter vascular grafts using canine mesenchymal stem cells (cMSCs) and a pulsatile flow bioreactor. cMSCs were isolated from canine bone marrow and expanded ex vivo. cMSCs were then seeded onto the luminal surface of decellularized arterial matrices, which were further cultured in a pulsatile flow bioreactor for four days. Immunohistochemical staining and scanning electron microscopy was performed to characterize the tissue-engineered blood vessels. cMSCs were successfully seeded onto the luminal surface of porcine decellularized matrices. After four-day culture in the pulsatile flow bioreactor, the cells were highly elongated and oriented to the flow direction. Immunohistochemistry demonstrated that the cells cultured under pulsatile flow expressed Von Willebrand factor, an endothelial cell marker. In conclusion, cMSCs seeded onto decellularized arterial matrices could differentiate into endothelial lineage after culturing in a pulsatile flow bioreactor, which provides a novel approach for tissue engineering of small-diameter blood vessels.     

利用灌注式生物反应器体外构建大段组织工程化骨的实验研究

目的 研究体外利用灌注式生物反应器构建大段组织工程化骨的可行性. 方法把在体外培养扩增的第三代人骨髓基质干细胞与大段多孔β-磷酸三钙(β-TCP)支架复合.将细胞/支架复合体放入灌注式生物反应器中,进行连续灌注培养.28 d后,检测细胞的增殖及碱性磷酸酶(ALP)活性,同时对培养后的细胞/支架复合体进行组织学检测及形态学计量,用以评价体外组织工程化骨的构建.以静态培养作为对照组. 结果培养28 d后,灌注培养组的细胞活性明显高于静态培养组.灌注培养组细胞的ALP活性显著高于静态培养组.静态培养组细胞仅在多孔β-TCP支架周缘增殖,形成的新骨量较少.灌注培养组细胞在整个β-TCP支架内增殖,形成的新骨量较多. 结论利用灌注式生物反应器的灌注培养,可以使人骨髓基质干细胞在大段β-TCP载体内增殖并形成新骨,使体外大段组织工程化骨的构建成为可能.     

Scaffold seeded with cells is essential in urothelium regeneration and tissue remodeling in vivo after bladder augmentation using in vitro engineered graft

OBJECTIVE: Tissue-engineering methods using synthetic biodegradable scaffolds seeded with cells have potential to induce regeneration to a functional bladder wall. The aim of the study was to induce in vivo urothelial growth on implanted scaffolds previously seeded with stromal cells as compared with matrices implanted without cells for rat cystoplasty augmentation. MATERIALS AND METHODS: 3T3 mouse fibroblasts were multiplied up to total of 10(8) cells. Cells were grown on Dulbecco's modified essential medium supplemented with 10% of fetal bovine serum and antibiotics in CO(2) chambers. Cells were seeded on biodegradable polyglycolic acid (PGA) scaffolds in eight rats: four bladders were augmented with cell-seeded grafts and the other four with acellular scaffolds. Rats were sacrificed after 4 months in preparation for hematoxylin and eosin staining. RESULTS: One death in the acellular cystoplasty group was observed after 3 weeks. No epithelial layer was observed in the central part of the acellular graft. The cell-seeded grafts showed good visible multilayered epithelium with at least five layers of epithelial cells in the central part. The epithelium resembled rat native urothelium. The cell-seeded grafts showed a high degree of implanted 3T3 cells infiltration with good degradation of PGA fibers. CONCLUSIONS: Our data indicated that urothelial proliferation on PGA grafts was intensified using a "feeder layer" of fibroblasts.     

尿道移行上皮细胞与生物可降解尿道支架体外复合培养的研究

目的:研究体外培养的兔尿道上皮细胞在生物可降解性网状尿道支架上的贴附和生长增殖情况,观察其对尿道上皮细胞形态和功能的影响,利用组织工程技术培养种植细胞的尿道内支架.方法:应用机械分离与酶消化法分离培养兔尿道移行上皮细胞,并在体外行原代培养与扩增后制成细胞悬液,接种在网状尿道支架上,形成尿道移行上皮细胞-支架复合物.应用免疫组织化学、荧光染色法鉴定尿道上皮细胞及其活性,并用倒置显微镜、扫描电镜观察尿道上皮细胞在支架表面吸附与生长状态.结果:网状尿道支架具有良好的生物相容性,能使尿道移行上皮细胞增殖,不影响其活性.尿道移行上皮细胞在尿道支架上贴附生长良好,1～2天后完全贴壁,3～7天细胞生长增殖活跃,支架网眼内充满上皮细胞;长期培养仍保持尿道移行上皮细胞特性,扫描电镜可见上皮细胞与网状支架紧密贴附,适度伸展并有基质分泌.结论:网状尿道支架适合尿道移行上皮细胞黏附生长,可作为尿道组织工程的细胞载体,利用组织工程方法可获得适于移植尿道细胞的组织工程化尿道.     

壳聚糖作为组织工程软骨支架的实验研究

目的 探索壳聚糖作为组织工程技术中软骨细胞培养支架的可行性。方法 消化分离猪耳郭软骨细胞，接种于自制壳聚糖、壳聚糖-胶原复合多孔支架上培养，从光镜和扫描电镜观察其亲水性和对细胞吸附力，MTT检测软骨细胞在壳聚糖、壳聚糖-胶原上的黏附率及壳聚糖、壳聚糖-胶原复合多孔支架对细胞的增殖、功能的影响。结果 软骨细胞能够在壳聚糖、壳聚糖-胶原支架上黏附、伸展、增殖和发挥正常功能，MTT测得细胞黏附率分别为81.25%和87.50%，MTT测得软骨细胞在壳聚糖-胶原支架中的增殖能力较强。结论 壳聚糖、壳聚糖-胶原复合多孔支架与软骨细胞具有较好的相容性，壳聚糖-胶原复合多孔支架更适合作为软骨组织工程中的细胞培养支架。     

软骨细胞外基质源性取向支架与骨髓基质干细胞体外软骨组织工程的初步研究

目的 制备关节软骨细胞外基质源性取向支架,观察其对体外培养的骨髓基质干细胞分布排列的影响,探索其用于修复关节软骨缺损的可行性.方法 收集天然猪关节软骨,在PBS溶液中超微湿法粉碎关节软骨,利用差速离心收集细胞外基质悬液;低温超速离心收集沉淀,制备成2%～3%悬液;采用定向结晶与冷冻干燥技术制备取向支架,应用紫外交联及碳化二亚胺交联.光学显微镜及扫描电镜观察支架的形态结构,冰冻切片后组织化学染色对支架进行定性分析;生物力学方法检测支架的力学特性.分离培养兔骨髓基质干细胞,PKH26标记,接种到支架上体外软骨诱导培养,倒置荧光显微镜及扫描电镜观察培养3 d内种子细胞在支架内的黏附、分布及排列方式.结果 制备的支架材料具有垂直取向排列的孔道结构,软骨细胞外基质特异性染色阳性,纵向压缩弹性模量为(2.02±0.02)MPa,横向压缩弹性模量为(0.264±0.16)MPa,具有各向异性的力学特点.体外培养显示骨髓基质干细胞广泛均匀地分布在支架内部,并且在支架材料表层呈平行排列,深层呈柱状排列,类似于天然软骨组织中细胞的排列方式.结论 以关节软骨细胞外基质材料制备的取向性组织工程支架,在生化组成和结构上仿生天然关节软骨细胞外基质,是一种较为理想的软骨组织工程支架.     

利用不同复合技术体外构建三维尿道组织的比较研究

目的 探讨优化体外构建三维立体尿道组织的复合技术.方法 高速振荡脱细胞法制备猪尿道海绵体脱细胞(ACSM)支架,碘消毒法进行复合前消毒,酶消化法分离及扩增兔舌黏膜上皮细胞和海绵体平滑肌细胞.采用3种复合技术进行细胞与ACSM的复合.A组(三明治复合组):于ACSM尿道面及海绵体面分别静态接种两种细胞.B组(注射复合组):将平滑肌细胞注射入ACSM内部并在尿道面静态接种舌黏膜上皮细胞.C组(动态复合组):采用振荡法将平滑肌细胞接种于ACSM内部并在尿道面静态接种舌黏膜上皮细胞.体外培养14 d以后行HE染色以检查复合效果. 结果振荡脱细胞处理后ACSM的结构较脱细胞前更为疏松;碘消毒法在彻底消毒的同时能够最大限度的保留脱细胞支架的原有结构.复合支架体外培养14 d后HE染色均可见有完整的上皮细胞层形成于支架表面.A组复合后平滑肌细胞仅在支架大间隙中可见,未见向深部浸润趋势.B组复合后平滑肌细胞成团分布于支架内,并受周围支架组织约束成局限化表现,仅5%～10%的细胞有向外生长倾向.C组HE染色可见平滑肌细胞均匀分布于支架内部,15%～20%的区域可见平滑肌成束生长.同时平滑肌层与支架表面的上皮细胞层分界清晰. 结论高速振荡法制备的支架组织具有理想的三维空间结构,结合动态细胞复合技术可构建拥有良好立体结构的尿道组织.

Abstract：

Objective To investigate and assess the best seeding method for constructing three dimensional urethral tissue in vitro. Methods High speed agitation decellular method was used for preparing the porcine acellular corporous spongiosum matrix (ACSM). Before seeding, the matrix was sterilized via soaking compound iodine solution. Rabbit tongue epithelial cells and cavernosal smooth muscle cells were isolated and cultured. Three different groups of seeding method was used in this study. Group A (sandwich seeding group): The smooth muscle cells and epithelial cells were seeded onto the different side of ACSM by static method. Group B (injection seeding group): The smooth muscle cells were injected into the scaffold. Then, epithelial cells were seeded onto the urethral surface of ACSM by static method. Group C (agitation seeding group): The smooth muscle cells were seeded into the scaffold by agitation method. Then, epithelial cells were seeded onto the urethral surface of ACSM by static method. After being seeded, all matrixes were cultured in vitro for 14 d. HE and immunoassay staining were used to examine the results of seeding. Results Looser matrix was obtained after using high speed agitation decellular method. Compound iodine solution could not only sterilize efficiently but also reserve the original structure of biomaterial. An intact epithelial cellular layer onto the surface of scaffold could be observed in HE staining section after 14 d culturing in vitro.Few smooth muscle cells could be found in big space of biomaterial in group A. In group B, smooth muscle cells were restrained in some regions of the matrix. Smooth muscle cells were well distributed into the scaffold in group C. Conclusions After using high speed agitation decellular method, an ideal matrix with three dimensional structure can be obtained. Combined with agitated seeding method, three dimensional urethral tissue can be constructed.     

In vitro differentiation of chick embryo bone marrow stromal cells into cartilaginous and bone-like tissues

Bone marrow stromal cells, progenitor cells involved in repair of bone and cartilage, can potentially provide a source for autologous skeletal tissue engineering. We investigated which factors were required to induce in vitro differentiation of avian bone marrow stromal cells into three-dimensional cartilaginous and bone-like tissues. Bone marrow stromal cells from embryonic chicks were expanded in monolayers, seeded onto biodegradable polyglycolic acid scaffolds, and cultured for 4 weeks in orbitally mixed Petri dishes. Cell-polymer constructs developed an organized extracellular matrix containing glycosaminoglycans and collagen, whereas control bone marrow stromal cell pellet cultures were smaller and consisted predominantly of fibrous tissue. Bone marrow stromal cells expanded with fibroblast growth factor-2 and seeded onto polymer scaffolds formed highly homogeneous three-dimensional tissues that contained cartilage-specific molecular markers and had biochemical compositions comparable with avian epiphyseal cartilage. When cell-polymer constructs were cultured in the presence of beta-glycerophosphate and dexamethasone, the extracellular matrix mineralized and bone-specific proteins were expressed. Our work shows that cell expansion in the presence of fibroblast growth factor-2 and cultivation on a three-dimensional polymer scaffold allows differentiation of chick bone marrow stromal cells into three-dimensional cartilaginous tissues. In the in vitro system studied, the same population could be selectively induced to regenerate either cartilaginous or bonelike tissue.     

Tissue engineering with chondrocytes

Tissue engineering of cartilage, using chondrocytes based on the use of synthetic biodegradable polymer cell delivery vehicles (scaffolds), is an alternate treatment modality for replacing missing cartilage. Cartilage tissue engineering has an important role to play in the generation of graft material for head and neck reconstruction. It is an approach to fabricate cartilage constructs in vitro, which could be used in reconstructive surgery. Methods involve (1) harvesting septal cartilage during septoplasty, (2) isolating chondrocytes through enzymatic digestion of the septal cartilage, (3) expanding the cell number in a two-dimensional monolayer culture, using serum-free media, (4) seeding the cells onto a biodegradable polymer scaffold, and (5) cultivating the seeded scaffolds in a rotating bioreactor. In this article we briefly outline the methodology and clinical applications of cartilage grown ex vivo.     

旋转系统下三维培养成纤维细胞-PGA复合物的实验研究

目的　观察微重力旋转培养系统对细胞种植于支架和细胞 支架复合物体外培养的影响。　方法　分离培养兔皮肤成纤维细胞 ,实验用第 2代细胞。 ( 1)分别用静止接种和动态接种方式 ,以 2× 10 6/cm3 的细胞密度接种于PGA网架 ,静止接种即滴加细胞悬液于PGA网架上 ,动态接种是把细胞悬液与PGA网架置于旋转细胞培养系统旋转接种 ,分别于 2、4、8、12、2 4h消化下网架上细胞后计数 ,通过计算细胞吸附率了解细胞吸附情况 ;( 2 )将相同细胞密度静止接种的细胞—PGA复合物分别置于旋转和静止条件下培养 ,于 1、3、5、7、14、2 1dMTT法检测细胞增殖 ;用倒置相差显微镜和扫描电镜观察细胞生长、基质形成及其细胞与PGA纤维结合状况的变化。　结果　细胞吸附量随时间延长而逐渐升高 ,动态组在接种后 8、12、2 4h细胞吸附率显著高于静止接种组 ,分别为 ( 46 70 %±2 16 %)比 ( 31 5 0 %± 3 5 4%) ;( 5 6 36 %± 3 18%)比 ( 34 2 8%± 3 16 %) ;和 ( 6 6 32 %± 4 6 0 %)比( 37 38%± 4 6 6 %)。在 3周培养中旋转培养组细胞增殖快于静止组 ,而且细胞在网架中分布比静止组均匀 ,并伴有活跃的细胞基质分泌。　结论　旋转培养系统具有促进细胞吸附增殖分化和在支架内均匀分布的特点 ,是培养细胞支架复合物进行组织工