犬骨髓基质干细胞体外诱导分化为肌源性细胞的研究

目的 :探讨成年犬骨髓基质干细胞 (MSSCs)体外诱导分化为肌源性细胞的可行性。方法 :用贴壁法体外分离MSSCs ,实验组 5 氮胞苷诱导 ,对照组加入等量的培养基 ,用相差显微镜、免疫组织化学和电镜方法观察、鉴定培养细胞。结果 :实验组培养细胞诱导后 4周 ,多数培养细胞由梭形变为杆状 ,免疫组织化学检查结蛋白、平滑肌肌动蛋白和肌钙蛋白Ⅰ染色阳性 ;对照组多数培养细胞为梭形 ,免疫组织化学检查结蛋白染色弱阳性 ,平滑肌肌动蛋白染色弱阳性 ,肌钙蛋白Ⅰ染色阴性 ;电镜下实验组培养细胞内可见肌丝样结构 ,对照组培养细胞无明显肌丝样结构。结论 :成年犬MSSCs体外可诱导分化为肌源性细胞。     

细胞接触诱导骨髓间充质干细胞获得窦房结细胞表型的初步研究

目的 通过建立体外骨髓间充质干细胞(BMSCs)与纯化培养的乳鼠窦房结细胞共培养体系,探讨窦房结微环境对BMSCs分化的诱导作用.方法 自新生乳鼠的心脏分离窦房结细胞,并差速贴壁纯化培养,免疫荧光检测超极化激活环核苷酸门控阳离子通道基因4(HCN4)和缝隙连接蛋白45(Cx45)的表达.自成年大鼠的骨髓分离BMSCs,传2代后,用脂质体介导pEGFP-N1转染标记BMSCs,再与纯化培养的窦房结细胞以1:5比例进行直接接触共培养,并用窦房结细胞条件培养液对转染后的BMSCs进行培养作为对照.1周后应用免疫荧光检测BMSCs的HCN4和Cx45表达.结果 接触共培养组中,可见部分表达绿色荧光蛋白的BMSCs同时表达HCN4和Cx45,而条件液培养组中未见HCN4和Cx45的表达.结论 直接接触共培养体系可诱导BMSCs初步分化为窦房结样细胞.     

bFGF和PDGF-BB对内皮祖细胞分化的内皮样细胞和平滑肌样细胞增殖和迁移的影响

目的探讨内皮祖细胞分化的内皮样和平滑肌样细胞在碱性成纤维生长因子和血小板源生长因子BB作用下的增殖和迁移能力。方法将分离、培养及纯化的内皮祖细胞培养5天后进行分组:对照组、碱性成纤维生长因子组和血小板源长因子BB组。对照组使用20%胎牛血清的DMEM培养基;碱性成纤维生长因子组和血小板源生因子BB组在20%胎牛血清的DMEM培养基中分别添加碱性成纤维生长因子(30μg/L)和血小板源生长因子BB(40μg/L)。免疫荧光染色鉴定内皮祖细胞以及检测内皮祖细胞内皮方向分化标记物CD31和vWF,及平滑肌方向分化标记物α-SMA和Calponin。将分化的内皮样细胞和平滑肌样细胞用MTT法和Transwell小室分别检测其增殖活性和迁移能力。结果与对照组比较,内皮祖细胞经碱性成纤维生长因子或血小板源生长因子BB诱导后呈现较强的内皮细胞(CD31,vWF)或平滑肌细胞(α-SMA,Calponin)的荧光染色,被诱导细胞分别称为内皮样细胞和平滑肌样细胞;碱性成纤维生长因子促进内皮样细胞和血小板源生长因子BB促进平滑肌样细胞增殖的作用在一定范围内具有时间(0～48 h)和浓度(碱性成纤维生长因子:0～16μg/L;血小...     

成年鼠骨髓单个核细胞在体外培养中分化为平滑肌祖细胞

目的:探讨大鼠骨髓单个核细胞在体外经条件培养基诱导定向分化成平滑肌祖细胞的可行性。方法:分离4～6周龄的大鼠胫骨、股骨,以4℃预冷的DMEM培养基冲出骨髓,密度梯度离心法分离骨髓单个核细胞,在血小板源生长因子-BB(PDGF-BB)和碱性成纤维细胞生长因子(b-FGF)作用下,培养8～12d形成贴壁的梭形细胞。采用CD34与α-SMA免疫荧光染色进行鉴定,RT-PCR法测定其α-SMAmRNA表达情况。结果:在PDGF-BB作用下,82%的骨髓单个核细胞α-SMA染色阳性,78%细胞CD34染色阳性,新鲜分离的骨髓单个核细胞不表达α-SMAmRNA,体外培养后表达α-SMAmRNA。结论:体外培养的骨髓单个核细胞能分化为平滑肌祖细胞,可作为研究平滑肌细胞分化和筛选抑制再狭窄药物的工具。     

犬骨髓间充质干细胞体外诱导分化为胰岛样细胞的研究

目的 研究犬骨髓间充质干细胞(MSC)体外诱导分化为胰岛样细胞的可能性.方法 分离纯化犬骨髓MSC,予EGF、bFGF和β细胞调节素、尼克酰胺、B27添加剂诱导.双硫腙染色、 Western blot、免疫荧光染色、胰岛素分泌量测定和葡萄糖刺激胰岛素释放试验鉴定诱导前后的细胞功能.结果 未诱导细胞呈长梭形贴壁生长,诱导第2周细胞逐渐变圆,聚集成团,双硫腙染色呈棕红色;Western blot检测诱导后细胞表达PDX-1;免疫荧光染色显示诱导后细胞表达胰岛素、胰升血糖素、生长抑素; ELISA结果表明诱导后细胞可分泌胰岛素,体外葡萄糖刺激胰岛素释放试验阳性.结论 犬骨髓MSC在体外能被诱导分化为胰岛样细胞.     

紫杉醇联合骨髓基质干细胞种植体外修复内皮及对血管平滑肌增生的影响

目的探讨紫杉醇联合骨髓基质干细胞种植体外修复内皮的可行性及对血管平滑肌细胞增生的影响。方法培养兔主动脉内皮、平滑肌和人骨髓基质干细胞,通过细胞共培养将内皮/骨髓基质干细胞接种于下室、平滑肌细胞接种于上室模拟血管内皮修复过程,分别用3H TdR掺入和Westernblot检测紫杉醇(1,10,100nmol/L)干预20min后第10天平滑肌DNA合成和PCNA蛋白表达,用免疫荧光细胞化学法观察与紫杉醇干预内皮共培养的骨髓基质干细胞vWF和Flk1蛋白表达。结果骨髓基质干细胞种植组平滑肌细胞3H TdR掺入和PCNA蛋白光密度相对值均高于融合内皮组(n=6,P<0.05),低于对数内皮组(n=6,P<0.05)。共培养前骨髓基质干细胞不表达vWF和Flk1蛋白,与紫杉醇干预内皮共培养10天时vWF染色阴性,但部分骨髓基质干细胞开始表达Flk1蛋白。结论骨髓基质干细胞种植能部分抑制紫杉醇引起的平滑肌细胞延迟增生,与紫杉醇干预内皮共培养的骨髓基质干细胞有向内皮分化的能力。     

肝脏细胞条件培养基诱导大鼠骨髓间质细胞分化为肝细胞的作用

目的:探讨肝脏细胞条件培养基诱导大鼠骨髓间质细胞分化为肝细胞的作用.方法:从大鼠骨髓中分离纯化培养间质细胞,诱导前24小时加1μg/L碱性成纤维生长因子(bFGF)入培养液中以促进细胞分裂,再以肝脏细胞条件培养基作诱导剂,分别在诱导培养0、7、14、21、28天时,留取细胞,观察细胞形态的变化,并采用免疫细胞化学方法检测肝细胞功能标志物(AFP、白蛋白、CK18)、用PAS法进行糖元染色试验,以验证诱导分化的结果.结果:诱导后3天间质细胞表现为肝细胞样,随着诱导时间的延长,肝细胞功能标志逐渐出现和成熟.AFP在7、14天时表达较高,21、28天时表达显著减少;白蛋白、CK18和糖元随着诱导时间的延长表达逐渐增多.结论:肝脏细胞条件培养基能诱导骨髓间质细胞分化为肝细胞.     

不同诱导条件对人骨髓基质干细胞向内皮分化的影响

目的探讨不同诱导条件对人骨髓基质干细胞向内皮分化的影响。方法采用密度梯度离心法分离培养人骨髓基质干细胞,用荧光激活细胞分选法分析骨髓基质干细胞CD34、CD105和CD166的表达率;用免疫荧光细胞化学法观察骨髓基质干细胞在细胞因子(50μgL血管内皮细胞生长因子、5μgL碱性成纤维细胞生长因子、100mgL内皮细胞生长补充因子)、内皮条件培养基或与成熟兔主动脉内皮共培养5天时vWF或和Flk1蛋白的表达。结果分离培养的骨髓基质干细胞CD34表达率为4.16%±0.16%,与阴性对照(4.06%±0.23%)相比无统计学差异,CD105表达率为90.20%±2.35%,CD166表达率为82.30%±3.22%,均明显高于阴性对照(P<0.05)。诱导前骨髓基质干细胞不表达vWF和Flk1蛋白,经血管内皮细胞生长因子、碱性成纤维细胞生长因子和内皮细胞生长补充因子等细胞因子联合诱导5天时,33.42%骨髓基质干细胞开始表达vWF蛋白;与成熟内皮共培养5天时,vWF染色仍为阴性,但25.71%骨髓基质干细胞开始表达Flk1;用内皮条件培养基培养5天时,骨髓基质干细胞vWF和Flk1染色均为阴性。结论细胞因子和成熟内皮细胞均能诱导骨髓基质干细胞向内皮分化,而内皮条件培养基不能诱导骨髓基质干细胞向内皮分化。     

大鼠胸主动脉平滑肌细胞的培养与鉴定

目的探讨平滑肌细胞培养方法,了解生长特性。方法用组织贴块法培养大鼠胸主动脉平滑肌细胞,用相差显微镜观察其生长情况,用免疫荧光染色分析其抗原的表达。结果培养3日可见组织块周边有细胞长出,2周达亚融合,传代后细胞“谷峰”生长明显。SM-α-肌动蛋白和Calponin抗体免疫荧光染色呈阳性。结论组织贴块法是简单、经济、高效的平滑肌细胞培养方法,为心血管疾病发病机制的研究提供了理想的细胞模型。     

骨髓间充质干细胞体外诱导分化为神经细胞的实验研究

目的　体外分离培养SD大鼠骨髓间充质干细胞 (rMSC)并诱导分化为神经细胞。方法　取 4周龄健康SD大鼠骨髓 ,以percoll淋巴细胞分离液分离rMSC ,以DMEM +15 %胎牛血清 (FBS)培养 ,以 1mmol Lβ巯基乙醇 (BME)及无血清DMEM培养液处理细胞 ,免疫细胞化学鉴定诱导后细胞。结果　rMSC可以在体外大量培养扩增 ,以BME诱导后大部分rMSC分化为神经元样细胞 ,免疫组织化学染色神经元特异性烯醇化酶 (NSE)呈阳性 ,诱导后细胞可在体外生存 2周。结论　rMSC可在体外诱导分化为神经细胞并在体外存活。     

Cell-to-cell contact induces mesenchymal stem cell to differentiate into cardiomyocyte and smooth muscle cell

BACKGROUND: Recent evidences have suggested that stem cell can differentiate into cardiomyocyte and smooth muscle cell (SMC) in vivo or in vitro. But the mechanism on how stem cell differentiates is still unknown. We investigated whether intercellular interaction or soluble chemical factors would induce mesenchymal stem cells (MSCs) to acquire the phenotypical characteristics of cardiomyocytes or SMC. METHODS: MSCs were isolated from rat bone marrow with density gradient centrifugation and amplified in vitro. Flow cytometry was used to monitor the expression of surface antigen profile. After labeled by GFP (green fluorescent protein) transfection, rat MSCs were used to culture with adult rat cardiomyocytes and rat aortic SMCs in direct co-culture, indirect co-culture and conditioned culture, respectively. One week later, immunofluorescence staining against alpha-actin, desmin, and cardiac troponin T (cTnT) for cardiomyocyte, smooth muscle calponin and SM-alpha-actin for SMC were performed. RESULTS: Immunofluorescence staining was positive against alpha-actin, desmin, and cTnT on MSCs in co-culture group with adult cardiomyocytes, positive against smooth muscle calponin and SM-alpha-actin on MSCs in co-culture group with SMCs. In contrast, no alpha-actin, desmin, and cTnT expression was observed in the indirect co-culture group and conditioned culture group; no smooth muscle calponin and SM-alpha-actin in the indirect co-culture group and conditioned culture group. CONCLUSIONS: Direct cell-to-cell contact between MSC and adult cardiomyocyte or SMC, but not the soluble signaling molecules is obligatory in the differentiation of MSC into cardiomyocytes or SMC.     

Mesenchymal stem cells participating in ex vivo endothelium repair and its effect on vascular smooth muscle cells growth

BACKGROUND: Previous studies have shown that mesenchymal stem cells (MSCs) transplantation can promote neovascularization and regenerate damaged myocardium. However, it remains unknown whether MSCs seeding can be used to repair injured cellular components in vascular diseases. In this study we explored the feasibility of applying MSCs to endothelium repair in endothelial damage and vasoproliferative disorders. METHODS: Ex vivo model of endothelium repair was developed in which rabbit vascular smooth muscle cells (SMCs) were inoculated into the upper chamber and rabbit endothelial cells (ECs)/human MSCs into the lower chamber of a co-culture system. 3H-TdR incorporation and PCNA protein expression were assayed and migrated number of SMCs was calculated to evaluate the effect of MSCs seeding on SMCs growth. Flk-1 and vWF protein expressions were observed to analyze the plasticity of the seeded MSCs along endothelial lineage. RESULTS: In this co-culture system, no vWF protein but Flk-1 protein was observed in the 25.71% of MSCs after having been co-cultured with mature rabbit ECs for 5 days. Compared with the control group, the proliferation and migration of SMCs was significantly increased by proliferative ECs but decreased by confluent ECs (n=6, P<0.01). MSCs seeding decreased the proliferation and migration of SMCs compatible with the effect of proliferative ECs (n=6, P<0.001). However, no inhibition on SMCs growth was observed with MSCs seeding in comparison to the effect of confluent ECs. CONCLUSIONS: MSCs seeding can inhibit the proliferation and migration of SMCs. MSCs co-cultured with mature ECs have the ability to undergo milieu-dependent differentiation toward ECs.     

骨髓基质干细胞种植体外修复内皮及对血管平滑肌细胞增生的影响

目的探讨骨髓基质干细胞(MSCs)种植体外修复内皮的可行性及对血管平滑肌细胞增生的影响。方法培养兔血管内皮、平滑肌和人MSCs,通过细胞共培养模拟血管内皮修复过程,用流式细胞仪分析MSCs分子表型特征,免疫荧光细胞化学法观察与内皮共培养的MSCsFlk1和vWF蛋白表达,根据下室内皮生长状态及是否接种MSCs将其分为对照组、单纯MSCs组、融合内皮组、对数内皮组和MSCs种植组。氚胸腺嘧啶脱氧核苷(3HTdR)掺入检测平滑肌细胞DNA合成,Westernblot检测平滑肌细胞中增殖细胞核抗原蛋白表达。结果分离的MSCs表达基质细胞标志CD105和CD166,不表达造血干祖细胞和内皮细胞标志CD34、Flk1、vWF;与内皮共培养5天时,vWF染色仍为阴性,但约25.71%MSCs开始表达Flk1;MSCs种植组平滑肌细胞3HTdR掺入虽高于融合内皮组,但与对数内皮组比较显著降低;MSCs种植组平滑肌细胞PCNA蛋白吸光度相对值虽高于融合内皮组,但与对数内皮组比较明显减少。结论MSCs种植能抑制平滑肌细胞增生,种植在成熟内皮中的MSCs具有微环境依赖向内皮分化的能力。     

人脐动脉内皮细胞和平滑肌细胞体外培养鉴定及缝隙连接通讯功能测定

目的:应用双光子激光扫描共聚焦显微镜鉴定体外培养的脐动脉内皮细胞(ECs)和平滑肌细胞(SMCs),应用荧光光漂白恢复技术(FRAP)测定血管ECs、SMCs之间的缝隙连接通讯(GJIC)功能。方法:人脐动脉ECs、SMCs分离培养,Ⅷ因子和SMα-actin相关抗原鉴定ECs和SMCs,应用FRAP技术测定血管内皮细胞、平滑肌细胞之间的GJIC功能,记录实时成像结果,应用动态比(M)计算漂白区域内标记荧光的分子中动态分子的比例。结果:第一组ECs和SMCs单独培养,选择漂白细胞与周围至少3个同种细胞相连接,SMCs被漂白后平均M值为31.79±5.69;ECs被漂白后平均M值为23.43±2.11;第二组ECs和SMCs混合培养,选择ECs和SMCs独立相连的2个细胞,SMCs被漂白后平均M值为14.47±3.28,ECs被漂白后平均M值为6.41±0.80。结论:FRAP实时动态恢复曲线可直接观察荧光恢复强度及速度,参照FRAP恢复曲线,M值可做为组间GJIC比较相对定量的可靠指标,通过检测证实ECs和SMCs之间存在GJIC,且荧光由ECs向SMCs方向的传递大于由SMCs向ECs方向的传递。     

共同培养诱导骨髓基质干细胞向肝细胞分化的研究

目的 探索大鼠骨髓皋质干细胞（MsCS）向肝细胞分化的能力，及肝细胞生长的微环境埘其诱导分化的作用。方法 采用梯度离心法，获取大鼠骨髓基质干细胞；改良的两步法获取大鼠肝细胞。将鉴定的MsCS和肝细胞以半透膜相隔共同培养，以单独培养的MSCs作对照。在第1、3、7．14．21、28天，分别以逆转录聚合酶链反应（RT-PCR）和免疫细胞化学分析检测甲胎蛋白（AFP）、白蛋白、细胞角蛋白l8（CK-l8）的基因和蛋白表达。结果在MSCs与肝细胞共同培养过程中，MSCs出现明显的细胞形态、体积和数量变化，可见双核或多核细胞，细胞轮廓较清晰。RT-PCR检测：共同培养的MSCs第7天即出现AFP基因表达，第14天表达增强，第21天表达减弱；第14天开始出现白蛋白、CK-18基因表达，并持续表达。单独培养的MSCs均无表达。共同培养的MSCs，于第7天进行免疫细胞化学检测，AFP即呈阳性；第14天白蛋白和CK-18也呈阳性；单独培养的MSCs未见AFP、白蛋白及CK-18表达。结论 大鼠骨髓基质干细胞与肝细胞共同培养，可被诱导分化为肝细胞。     

Differential regulation of smooth muscle markers in human bone marrow-derived mesenchymal stem cells

OBJECTIVE: To study smooth-muscle differentiation and de-differentiation of human bone marrow-derived mesenchymal stem cells (MSCs), which have been shown to enter the circulation and to contribute to vascular repair and atherosclerosis. DESIGN: Human MSCs from bone marrow were cultured with 20% fetal calf serum (FCS) or with 10% FCS and various concentrations of dimethyl sulfoxide (DMSO). Expression of smooth muscle markers was determined by Western blot analysis and immunofluorescence. For signalling studies, involvement of the mammalian target of rapamycin (mTOR) pathway was tested by treatment with rapamycin. RESULTS: MSCs cultured with 20% FCS acquired a smooth muscle-like appearance and expressed the smooth muscle (sm) markers sm-alpha-actin, desmin, sm-calponin and myosin light chain kinase (MLCK). DMSO induced a spindle-like morphology with marked reduction of stress fibers. As judged by Western blot analysis, treatment with 2.5% DMSO strongly downregulated expression of sm-calponin (-85%), short MLCK (-98%) and sm-alpha-actin expression (-51%). Reduced calponin expression was detected by day 2 of treatment with 0.5-2.5% DMSO. After withdrawal of DMSO, MSCs regained high expression of sm-calponin. Treatment with 6 nmol/l rapamycin partly antagonized the effect of DMSO, indicating the involvement of mTOR in regulation of the smooth muscle phenotype of MSCs. CONCLUSIONS: DMSO strongly downregulates the smooth muscle markers sm-calponin, short MLCK and sm-alpha-actin in human MSCs, indicating a transition from a smooth muscle-like phenotype to an undifferentiated state by an mTOR-dependent mechanism. Regulating the phenotype of human MSCs may be of relevance for novel therapeutic approaches in atherosclerosis and intimal hyperplasia after vascular injury.     

心肌细胞裂解液对骨髓间充质干细胞向心肌细胞分化诱导作用的研究

目的通过向骨髓间充质干细胞(MSCs)培养体系中添加心肌细胞裂解液的方法,体外模拟心肌微环境,观察MSCs向心肌细胞分化的诱导作用,并与诱导分化剂5-氮杂胞苷(5-aza)比较。方法分离新生乳鼠的心肌细胞并制成心肌细胞裂解液,自成年大鼠骨髓中分离MSCs,用含有心肌细胞裂解液的培养基(A组)、含有5-aza的培养基(B组)、含有5-aza和心肌细胞裂解液的培养基(c组)以及普通培养基(对照组)培养。观察细胞形态的改变,并通过免疫组化分析分化后细胞表达α-肌动蛋白、心脏特异性肌钙蛋白T(cTnT)、连接蛋白43及CD31的情况。结果A、B组的MSCs在培养1周后均形成肌细胞形态,并且均表达α-肌动蛋白和cTnT;A组MSCs分化的肌样细胞所含的肌纤维较B组更丰实,细胞生长趋势也优于B组,并且可以表达CD31;B组MSCs分化的肌样细胞不表达CD31;对照组细胞仅表达α-肌动蛋白。结论心肌细胞裂解液是体外诱导MSCs分化为心肌样细胞的理想条件,优于传统的5-aza,在心肌细胞移植技术中可以用于体外模拟心肌细胞微环境。     

Comparison of human amniotic fluid-derived and umbilical cord Wharton's Jelly-derived mesenchymal stromal cells: Characterization and myocardial differentiation capacity

Objective To compare the characterization and myocardial differentiation capacity of amniotic fluid-derived mesenchymal stromal cells (AF MSCs) and umbilical cord Wharton's Jelly-derived mesenchymal stromal cells (WJ MSCs). Methods The human AF MSCs were cultured from amniotic fluid samples obtained by amniocentesis. The umbilical cord WJ MSCs were obtained from Wharton's Jelly of umbilical cords of infants delivered full-term by normal labor. The morphology, growth curves, and analyses by flow cytometry of cell surface markers were compared between the two types of cells. Myocardial genes (GATA-4, c-TnT, α-actin, and Cx43) were detected by real-time PCR and the corresponding protein expressions were detected by Western blot analysis after myocardial induced in AF MSCs and WJ MSCs. Results Our findings revealed AF MSCs and WJ MSCs shared similar morphological characteristics of the fibroblastoid shape. The AF MSCs were easily obtained than the WJ MSCs and had a shorter time to reach adherence of 2.7 ± 1.6 days to WJ MSCs of 6.5 ± 1.8 days. The growth curves by MTT cytotoxic assay showed the AF MSCs had a similar proliferative capacity at passage 5 and passage 10. However, the proliferative capacities of WJ MSCs were decreased at 5 passage relative to 10 passage. Both AF stem cells and WJ stem cells had the characteristics of mesenchymal stromal cells with some characteristics of embryonic stem cells. They express CD29 and CD105, but not CD34. They were positive for Class I major histocompatibility (MHC I) antigens (HLA-ABC), and were negative, or mildly positive, for MHC Class II (HLA-DR) antigen. Oct-4 was positive in all the two cells types. Both AF MSCs and WJ MSCs could differentiate along myocardium. The differentiation capacities were detected by the expression of GATA-4, c-TnT, α-actin, Cx43 after myocardial induction. Conclusions Both AF MSCs and WJ MSCs have the potential clinical application for myogenesis in cardiac regenerative therapy.     

间接接触共培养下骨髓间充质干细胞分化为心肌样细胞及相关调控基因的时序表达

目的:研究间接接触共培养条件下骨髓间充质干细胞(mesenchymal stem cells,MSCs)向心肌细胞(myocadium-lkce cells,CMs)的分化及相关调控基因的时序表达;筛选MSCs定向分化为CMs的重要调控基因。方法:将MSCs与CMs按1∶5的比例进行间接接触共培养,连续观察两周,在相差显微镜下观察MSCs的形态变化。采用免疫荧光染色法检测心肌特征性肌动蛋白α(α-actin)和心脏肌钙蛋白T(cTnT)的表达。应用半定量RT-PCR分析TGF-β、Nkx-2.5、GATA-4、MEF-2C及TEF-1等相关调控基因在分化过程中的时序表达。结果:共培养后,MSCs的体积增大,其梭形形态逐渐变短变粗近似棒状或椭圆形,细胞之间形成连接,排列方向趋于一致。共培养两周时,α-actin及cTnT阳性细胞的比例分别为29.63%和27.38%。TGF-β、Nkx-2.5、GATA-4和MEF-2C基因在共培养后1 d表达开始增强,诱导后7 d达高峰,以后虽有所下降但仍维持在较高水平;TEF-1基因在诱导过程中表达无明显变化。结论:间接接触共培养条件下,MSCs可分化为心肌细胞。在此过程中,TGF-β、Nkx-2.5、GATA-4和MEF-2C基因可能是调控MSCs定向分化为心肌样细胞的重要调控基因。