体外培养成骨细胞对自体骨髓间充质干细胞定向成骨分化的影响

目的观察体外培养成骨细胞对自体骨髓间充质干细胞（BMSC）增殖和定向成骨分化的影响．探讨此诱导方法作为骨组织工程种子细胞来源方法的可行性。方法应用密度梯度离心联合贴壁筛选法从兔股骨骨髓中分离、纯化BMSC．取第3代BMSC常规培养设为空白对照组,利用含有钙化诱导剂的DMEM培养基诱导培养第3代BMSC．设为钙化对照组。取第3代成骨细胞,1：1的比例和第3代BMSC共同培养．设为实验组。碱性磷酸酶（ALP）染色及钙结节染色鉴定诱导结果．ALP定量测定观察共同培养中成骨细胞对BMSC诱导影响。总蛋白定量测定观测诱导成骨细胞的分化活性．结果成骨细胞与BMSC共同培养24h后．在倒置光学显微镜下可见两种细胞形态混杂生长．共同培养5d后．细胞形态趋于一致,多呈长梭形。诱导培养5d后．实验组与钙化对照组ALP染色均为阳性。诱导培养21d．两组钙结节茜素红染色均呈阳性．而BMSC空白对照组并未见钙结节形成。ALP定量测定,实验组于3、5、7、9d均低于钙化对照组,且差异均具有统计学意义。实验组与空白对照组ALP定量测定,在4个时间段差异也均具有统计学意义。总蛋白定量测定显示实验组于第3天．A值高于钙化对照组,差异具有显著统计学意义（P〈0．01）,而第5天、第7天、第9天时却低于钙化对照组．差异具有显著统计学意义（P〈0．01）。实验组于各时间段均高于空白对照组．差异亦具有统计学意义。结论成骨细胞与BMSC共同培养应用于BMSC的成骨诱导．从诱导效率和诱导后成骨细胞的分化活性方面．都能证实该共同培养方法的有效性。但与钙化诱导方法相比．共同培养的诱导效果差于钙化诱导方法。     

3种组织来源的间充质干细胞体外成骨能力的比较

目的比较成人骨髓间充质干细胞(BMSCs)、人脐带间充质干细胞(UC-MSCs)和人胎盘间充质干细胞(P-MSCs)的成骨能力。方法用含10%胎牛血清的DMEM/Ham's F-12培养液培养3种MSCs,CCK8法检测增殖能力,流式细胞仪鉴定3种细胞。碱性磷酸酶(ALP)和茜素红染色观察细胞经成骨诱导后成骨分化蛋白-ALP的分泌和矿化钙结节的沉积。实时荧光定量PCR(RT-q PCR)法检测MSCs骨再生相关基因的表达。Western blot方法检测MSCs成骨再生相关基因的蛋白表达。结果 MSCs在第3天进入对数增殖期。3种细胞的表面标志物阳性率:CD44、CD90和CD105均高于98%。3种MSCs成骨诱导9 d时,3种MSCs的实验组均表达大量成骨分化蛋白-ALP,成骨诱导18 d时3种MSCs均呈现较好的矿化能力;3种MSCs成骨诱导9 d时,实验组RUNX2和ALP基因显著性高表达(P0.05),成骨诱导18 d时,实验组RUNX2和骨钙素(OCN)亦显著性高表达(P0.05);3种MSCs成骨诱导9 d时,实验组均检测到RUNX2和ALP的蛋白表达;成骨诱导18 d时,实验组细胞亦检测到RUNX2和OCN的蛋白表达。结论 UC-MSCs和P-MSCs具有良好的成骨分化能力,有望作为骨组织工程的种子细胞用于治疗骨缺损。     

新型壳聚糖基仿生支架材料生物相容性的评价

目的: 评价新型壳聚糖基仿生支架材料的生物相容性.方法: 采用仿生学方法,将壳聚糖、明胶、果胶按一定比例制成新型壳聚糖基仿生支架材料.体外培养骨髓间充质干细胞(MSCs)并与支架材料复合培养,通过倒置相差显微镜、H-E染色、扫描电镜、四甲基偶氮唑盐(MTT)法检测细胞的生物相容性.结果: 新型壳聚糖基仿生支架材料呈半透明薄膜状.MSCs接种在支架材料上,倒置相差显微镜观察到细胞在材料上贴附、生长良好、增殖旺盛;H-E染色显示细胞胞质丰富,核卵圆形,可见1～2个清晰的核仁;扫描电镜可见细胞伸出多个伪足样突起,互相连接,并分泌大量细胞外基质;MTT法检测细胞活性显示仿生材料组吸光度值与对照组比较差异无统计学意义.结论: 新型壳聚糖基仿生支架材料蕴涵丰富的生物信息,细胞毒性小,生物相容性好,是一种很好的组织工程支架材料.     

大鼠脂肪源性干细胞来源的施万细胞特性分析

目的 探讨脂肪源性干细胞（ADSCs）及其分化的施万细胞（SCs）在形态、活性和标志物表达上的区别。方法 取SD大鼠腹股沟处脂肪制备ADSCs，用流式细胞术检测细胞表面标志；钙钴金属盐沉淀法检测碱性磷酸酶（ALP），茜素红染色观察矿化结节；油红O染色观察脂滴；随机分对照组和诱导组，加入条件培养基向SCs诱导分化；MTT法检测诱导后第2、4、6和8 d各时间点的细胞活性；扫描电镜及免疫染色观察S100的表达。结果 光镜下可见ADSCs呈梭形贴壁生长；ADSCs表达抗原分化簇90(CD90)和抗原分化簇105(CD105)，不表达抗原分化簇45(CD45)；成骨诱导后可见ALP呈强阳性表达，茜素红染色可见橘红色矿化结节，油红O染色可见胞内红染脂滴聚集；向SCs诱导后第4 d，可见多数细胞呈纺锤形，第8 d纺锤状细胞增多；MTT检测显示第4 d诱导组的吸光度明显低于对照组，差异有统计学意义（P<0.05）；组内相比，诱导组和对照组的吸光度均随着时间的延长而逐渐增大，差异有统计学意义（P<0.05）；第6、第8 d诱导组与对照组吸光度差异无统计学意义（P>0.05）；扫描电镜...     

维甲酸对成纤维细胞及脂肪源干细胞成骨诱导的影响

目的　探究维甲酸（RA）对乳鼠真皮成纤维细胞（DFB）及脂肪源干细胞（ADSCs）成骨诱导分化的影响。 方法　分别离体培养5~7 d龄乳鼠DFB及ADSCs。对DFB进行波形蛋白的免疫荧光鉴定,对ADSCs进行成骨、成脂肪诱导并做表面标记物鉴定。用RA及传统成骨诱导液分别对两类细胞进行成骨诱导2周,茜素红染色检测细胞内钙结节的形成,酶标仪检测细胞诱导后ALP 的OD值。 结果　两类细胞在常规成骨诱导及RA诱导成骨后,均有钙结节形成。传统成骨诱导与RA成骨诱导组与各自对照组相比,ALP活性均升高。在DFB组中,RA诱导的ALP活性比传统成骨诱导高,而在ADSCs组中,结果相反。 结论　RA可以促进DFB及ADSCs的成骨分化,并且因细胞种类不同而显著效果不同。     

骨化三醇通过PI3K/AKT促进BMP9诱导的间充质干细胞成骨分化作用

目的研究骨化三醇(calcitriol)对骨形态发生蛋白9(bone morphogenetic protein 9,BMP9)诱导的间充质干细胞(mesenchymal stem cells,MSCs)成骨分化作用的影响。方法实验分为4组:对照组、calcitriol组、BMP9组、calcitriol联合BMP9组。通过PNPP法检测各组碱性磷酸酶(alkaline phosphatase,ALP)活性;通过RT-PCR和Western blotting方法检测成骨分化标记物骨钙蛋白(osteocalcin,OCN)和骨桥蛋白(osteopontin,OPN)表达变化,同时检测AKT和β-catenin磷酸化水平以及和ALP活性水平;茜素红染色检测矿化结节形成。此外,用原子力显微镜测试MSCs成骨分化过程中细胞形态及细胞弹性模量改变。结果 calcitriol单独作用对MSCs成骨分化过程无明显作用,但是calcitriol可以增强BMP9诱导MSCs的ALP、OCN、OPN表达和矿化结节形成。同时,calcitriol和BMP9作用均不影响细胞弹性模量数值。BMP9和calcitriol联合作用可以增强AKT和β-catenin磷酸化水平,而PI3K抑制剂应用以后可以抑制这种磷酸化变化,并抑制联合作用后的ALP活性。calcitriol作用以后不影响BMP9诱导的BMP/Smad信号通路。结论 calcitriol通过激活PI3K/AKT信号通路从而协同BMP9促进MSCs成骨分化。研究不同调控因子对MSCs成骨分化的作用及机制对于骨质疏松等疾病的治疗和骨组织工程的发展有一定意义。     

siRNA沉默HLA-A2基因表达对人脐带间充质干细胞诱导成骨的影响

目的探讨RNAi技术下调人脐带间充质干细胞(human umbilical cord mesenchymal stem cells,hUCMSCs)HLA-A2基因表达后,对HLA-A2基因诱导成骨的影响。方法利用HLA-A2靶向小分子干扰RNA(small interfering RNA,siRNA)转染hUCMSCs,实验组为转染的细胞,对照组为未转染细胞。免疫细胞化学染色、Western Blot法检测两组细胞HLA-A2的表达;用诱导剂(0.1μmol/L地塞米松、10mmol/Lβ-甘油磷酸钠、50mg/L维生素C)行成骨诱导分化,茜素红矿化结节染色计数;碱性磷酸酶(ALP)染色以及比色法检测ALP活性。结果免疫细胞化学染色显示,实验组HLA-A2表达为弱阳性,对照组HLA-A2表达为阳性;Western Blot法检测HLA-A2蛋白的表达量对照组明显高于实验组。茜素红矿化结节染色显示:两组细胞均出现红色结节的阳性染色,但无差异(P0.05);两组ALP染色细胞胞浆均呈蓝色阳性反应,ALP活性检测结果显示两组无差异(P0.05)。结论应用RNAi技术下调HLA-A2基因表达后,不影响人脐带间充质干细胞的成骨诱导。     

不同浓度细胞松弛素D对人脂肪源干细胞分化能力的影响

目的　观察不同浓度细胞松弛素D（Cyto D）对人脂肪源干细胞（hASC）成骨分化和成脂分化能力的影响。 方法　在生长培养基、成脂诱导培养基及成骨诱导培养基中分别加入0.05、0.1、0.2 μg/ml的Cyto D处理hASC,干扰肌动蛋白的延长,并在处理的第1、4、7 d时分别进行油红O染色、ALP染色及CCK8等实验检测细胞性能的改变。 结果　7 d时实验组0.2 μg/ml的存活率相比于对照组下降了1/3。Cyto D能抑制hASCs的存活和增殖,且浓度越大细胞的存活率越低。单纯的Cyto D既能促使hASC胞内脂滴形成,又能改变细胞内成骨的基础状态。Cyto D与成脂诱导液联合使用后能极大的促进成脂,且不同的浓度具有不同的成脂效果,低浓度使脂滴数量增加,高浓度促进脂滴成熟;与成骨诱导液联合使用后Cyto D用药浓度和成骨效果成反比。 结论　细胞松弛素D能增强成骨或成脂诱导液效果,且低浓度细胞松弛素D能够促进成骨,低浓度和高浓度细胞松弛素D都能促进成脂。本实验探究了细胞松弛素D引起的肌动蛋白解聚对脂肪源干细胞的分化能力影响,为研究脂肪源干细胞的分化机制提供了重要生物学信息。     

脂肪源性干细胞向成纤维细胞的分化

目的 探讨脂肪源性干细胞（ADSCs）向成纤维细胞分化的可能,为解决皮肤组织工程种子细胞提供有效途径。方法 取健康成年SD大鼠10只,体重280～320 g,雌雄不限,麻醉、脱毛、消毒,于腹股沟处获取脂肪后进行ADSCs的体外分离、培养和传代,观察原代细胞的生长特点;取第3代细胞,成骨诱导后第16天行碱性磷酸酶（ALP）检测,成骨诱导后第23天行茜素红染色,成脂诱导后第12天行油红O染色;流式细胞术检测细胞表面标志;加入条件培养基向成纤维细胞诱导分化,于诱导后第2天、第4天、第6天、第8天摄片记录细胞形态变化过程,MTT检测各时相点的细胞活性;诱导后第6天和第8天行扫描电子显微镜检测;诱导后第8天行免疫细胞化学染色,检测成纤维细胞主要标志物波形蛋白（vimentin）的表达。结果 原代ADSCs呈长梭形贴壁生长,成骨诱导后可见ALP强阳性表达,茜素红染色可见红色矿化结节;成脂诱导后可见胞内红染脂滴聚集;流式细胞术检测显示,间充质干细胞相关标志物CD90阳性表达,造血干细胞标记物CD45呈阴性表达;ADSCs向成纤维细胞诱导后第2天可见形态开始改变,部分细胞漂浮;诱导后第4天细胞呈水滴形或短棒状;诱导后第6天细胞呈有突起的多边形或三角形混杂;诱导后第8天细胞拥挤并铺满瓶底,呈细长纤维状; MTT检测表明,诱导后第2天的细胞活性要显著低于对照组（P<0.01）;诱导后第4天、第6天和第8天细胞活性与对照组均无明显差异（P>0.05）;扫描电子显微镜检测可见,诱导后第6天细胞呈三角形,表面纤毛较多;诱导后第8天细胞呈细长纤维状,有小突起,表面纤毛密集;诱导后第8天绝大多数细胞vimentin呈阳性表达。结论 ADSCs在体外经诱导分化后可以具备成纤维细胞的形态特征;能表达成纤维细胞的标志蛋白。     

大鼠BMSCs成骨诱导及复合支架材料构建组织工程骨组织的研究*

目的利用诱导成骨分化的骨髓间充质干细胞(bone marrowmesenchymal stem cells,BMSCs)复合生物支架材料构建组织工程骨组织。方法采用密度梯度离心法获取大鼠骨髓间充质干细胞,原代培养扩增后,条件培养基诱导成骨分化作为实验组,并设非条件培养基培养为对照组。诱导培养后,通过碱性磷酸酶、钙结节染色;I型胶原、骨钙素检测鉴定成骨性。将诱导的BMSCs利用滴加法种入自制组织工程生物支架复合培养,采取扫描电镜、HE切片染色观察培养8天时细胞在支架内部的生长情况。结果密度梯度离心法获取培养的原代骨髓间充质干细胞呈梭形或三角形贴壁生长,以梭形为主;经成骨诱导剂诱导后细胞呈多角形贴壁生长,碱性磷酸酶染色呈阳性、茜素红染色出现阳性的钙化结节;Western blotting检测Ⅰ型胶原蛋白表达较对照组明显增加(<0.05);ELISA法检测骨钙素结果较对照组明显升高(<0.01)。HE切片染色可见支架内部有细胞长入,细胞呈圆形或椭圆形。扫描电镜可见支架内部有大量细胞长入,细胞粘附、生长良好,呈现完全伸展状态,细胞-支架-细胞之间有基质连接。结论本实验获取的原代细胞为骨髓间充质干细胞,诱导剂诱导后成功分化为成骨细胞。采用经诱导成骨后的细胞作为组织工程骨构建的种子细胞,与三维支架材料复合后共培养,使构建的组织复合物更接近骨组织,为临床大段骨缺损的修复增加可能性。     

Modulation of mesenchymal stem cells behaviors by chitosan/gelatin/pectin network films

In this article, the chitosan/gelatin/pectin (CGP) network films were prepared to build appropriate physicochemical and mechanical microenvironment for attachment, proliferation, and differentiation of mesenchymal stem cells (MSCs). Results suggested that the hydrophilicity and mechanical character of CGP composites films could be modulated via adjusting the pectin content in the composites. The investigations of attachment and proliferation behaviors of mesenchymal stem cells (MSCs) on the CGP films were carried out. The morphology of cells was observed with hematoxylin/eosin staining (HE) and scanning electron microscope (SEM). The osteogenic differentiation of MSCs was investigated via ALP and polymerase chain reaction (PCR). Results suggested that the CGP films have excellent biocompatibility. MSCs seeded on CGP (0.1) film show higher proliferation capacity compared with other samples. Moreover, osteogenic differentiation of MSCs also depends on the properties of the substrate. The MSCs seeded on CGP (0.5) expressed the highest ALP activity, osteogenic gene expression and mineral formation capacity. These results suggest that the composition of the CGP network films could effectively modulate their physicochemical and mechanical properties and further regulate the cell behaviors of MSCs.     

Responses of mesenchymal stem cell to chitosan-coralline composites microstructured using coralline as gas forming agent

Macroporous composites made of coralline:chitosan with new microstructural features were studied for their scaffolding potential in in vitro bone regeneration. By using different ratios of natural coralline powder, as in situ gas forming agent and reinforcing phase, followed by freeze-drying, scaffolds with controlled porosity and pore structure were prepared and cultured with mesenchymal stem cells (MSCs). Their supportive activity of cellular attachment, proliferation and differentiation were assessed through cell morphology studies, DNA content, alkaline phosphatase (ALP) activity and osteocalcin (OC) release. The coralline scaffolds showed by far the highest evaluation of cell number and ALP activity over all the other chitosan-based scaffolds. They were the only material on which the OC protein was released throughout the study. When used as a component of the chitosan composite scaffolds, these coralline's favourable properties seemed to improve the overall performance of the chitosan. Distinct cell morphology and osteoblastic phenotype expression were observed depending on the coralline-to-chitosan ratios composing the scaffolds. The coralline-chitosan composite scaffolds containing high coralline ratios generally showed higher total cell number, ALP activity and OC protein expression comparing to chitosan scaffolds. The results of this study strongly suggest that coralline:chitosan composite, especially those having a high coralline content, may enhance adhesion, proliferation and osteogenic differentiation of MSCs in comparison with pure chitosan. Coralline:chitosan composites could therefore be used as attractive scaffolds for developing new strategies for in vitro tissue engineering.     

Modulation of In Vitro Attachment,Proliferation and Osteogenic Differentiation of Rat Bone-Marrow-Derived Stem Cells Using Different Molecular Mass Chitosans and Their Blends with Gelatin

We systematically investigated the behaviors of rat bone-marrow-derived stem cells (MSCs) on films prepared from high-molecular-mass chitosan (CH), low-molecular-mass chitooligosaccharide (COS) and their blends with gelatin (G) at various weight blending ratios. On the first day after seeding, the spreading areas of MSCs attached on the blended G/CH and G/COS films were larger than those attached on pure gelatin and COS films. Round-shaped MSCs on pure CH film were observed. The number of proliferated MSCs was also dominant in the case of blended films, at some certain blending ratios which correlated to suitably positive charge of the blended films obtained from zeta potential measurement. Among pure materials, attachment and proliferation of MSCs on COS film were comparable to those on gelatin film while CH film was toxic. The difference in toxicity of CH and COS was also confirmed by Annexin V-FITC/PI apoptosis test. After a 7-day culture under osteogenic induction, the blended films were also found to be more preferable materials for in vitro osteogenic differentiation of MSCs, as confirmed by alkaline phosphatase (ALP) activities, calcium contents and Von Kossa staining. It was proved from this study that attachment, proliferation and osteogenic differentiation of MSCs strongly depended on molecular mass of CHs and the ratio of their blends with gelatin.     

Klotho对大鼠骨髓间充质干细胞增殖和分化的影响

目的 探讨延缓衰老基因Klotho对骨髓间充质干细胞（BMSCs）增殖和分化的影响。 方法 体外条件下培养大鼠骨髓间充质干细胞,构建分泌型Klotho(sKL)过表达的BMSCs。Western blotting检测细胞及培养基中sKL的表达;MTT法检测细胞增殖能力;Western blotting检测衰老标志物P53、P21蛋白的表达。利用成骨诱导液定向诱导BMSCs向成骨细胞分化,应用碱性磷酸酶(ALP)染色鉴定成骨效果;利用成脂诱导液定向诱导BMSCs向脂肪细胞分化,应用油红O染色鉴定成脂效果。 结果 Western blotting结果显示,sKL组细胞和培养基中sKL蛋白表达显著上调（P<0.05）,P53、P21表达显著下调（P<0.05）;MTT结果显示,各组细胞吸光度值（A值）差别无显著性（P>0.05）,sKL组成骨及成脂能力明显强于对照组（P<0.05）。 结论 sKL增强了大鼠BMSCs的延缓衰老能力,对BMSCs的成骨分化和成脂分化产生一定的促进作用,而对BMSCs的增殖无显著影响。     

羌活鱼研粉物、水提及酸提物含药血清对骨髓间充质干细胞增殖及向成骨分化的影响

背景：羌活鱼经大量的临床观察和报道有促进骨折愈合的作用,其具体的作用机制及其有效成分的研究报道尚少。 目的：分析羌活鱼研粉物、水提及酸提物含药血清对体外培养骨髓间充质干细胞增殖与成骨性分化的影响。 方法：制备羌活鱼研粉、水提物、酸提物,分别采用高、中、低剂量灌服大鼠制得羌活鱼研粉物、水提及酸提物含药血清,以灌服等体积生理盐水制得对照血清;采用贴壁筛选法培养大鼠骨髓间充质干细胞,通过MTT法检测细胞增殖;于干预后的不同时间点分别测定细胞碱性磷酸酶活性、钙盐沉积量、成骨性分化基因表达以及钙化结节数、并比较各组间差异。 结果与结论：羌活鱼研粉物及水提物含药血清具有刺激骨髓间充质干细胞增殖活性及促进其成骨性分化的能力,其中尤其以研粉物中剂量组最为明显,而酸提物含药血清并无此功效。主要表现在细胞增殖、碱性磷酸酶活性、钙盐沉积量、成骨性分化基因和钙化结节数显著高于空白对照组(P < 0.05)。     

microRNA-373参与调控人脂肪来源间充质干细胞成骨分化

目的用microRNA-373(miR-373)的模拟物转染人脂肪来源Flk1+间充质干细胞(MSC),探讨microRNA-373对Flk1+MSC成骨分化的影响。方法利用脂质体作为载体,用miR-373模拟物瞬时转染Flk1+MSCs,然后对其进行成骨诱导,碱性磷酸酶(ALP)染色和茜素红染色观察成骨情况,real-time PCR技术检测成骨标志性基因的表达。结果 ALP染色和茜素红可见明显差异;real-time PCR检测结果显示,实验组(miR-373组)成骨标志基因runt相关转录因子2(RUNX2)(0.543±0.021)、ALP(0.556±0.024)和骨钙蛋白(OC)(0.499±0.017)的表达都明显低于对照组(NC组)(P<0.05)。结论 miR-373参与调控Flk1+MSC向骨细胞分化。     

Evaluation of human mesenchymal stem cells response to biomimetic bioglass-collagen-hyaluronic acid-phosphatidylserine composite scaffolds for bone tissue engineering

The aim of this study was to examine in vitro the response of human mesenchymal stem cells (hMSCs) on the novel biomimetic bioglass-collagen-hyaluronic acid-phosphatidylserine (BG-COL-HYA-PS) composite scaffold for potential use in bone tissue engineering. The initial attachment, the proliferation, migration and differentiation behavior of the cells on the BG-COL-HYA-PS composites were assessed in comparison with those on pure 58sBG, BG-COL, and BG-COL-HYA composites in either growth medium (L-DMEM supplemented with 10% fetal bovine serum) or osteogenic medium (growth medium supplemented with 0.1 microM dexamethasone, 10 mM beta-glycerophosphate, and 50 microM ascorbic acid). HMSCs attached, and subsequently proliferated and migrated on the BG-COL-HYA-PS composites to a significantly higher degree. The alkaline phosphatase (ALP) staining, ALP activity and the expression of the bone associated gene ALP, osteocalcin (OC), and osteopontin (OPN) was also significantly higher in the hMSCs on the BG-COL-HYA-PS scaffolds than those on the BG-COL, BG-COL-HYA composites and the pure 58sBG. These findings suggest that the BG-COL-HYA-PS composite porous scaffolds have high potential for use as scaffolds in bone tissue engineering and repair.     

Osteogenic differentiation of bone marrow mesenchymal stem cells of ovariectomized and non-ovariectomized female rats with thyroid dysfunction

The objective of this study was to verify the osteogenic potential of the bone marrow mesenchymal stem cells (MSCs) of ovariectomized and non-ovariectomized female rats with hypo- and hyperthyroidism. Sixty two-month-old female rats were assigned to the following groups: (1) control (sham-operated), (2) ovariectomized (OVX’d), (3) hypothyroid sham-operated (Hypo-), (4) hypothyroid OVX’d, (5) hyperthyroid sham-operated (Hyper-) and (6) hyperthyroid OVX’d. After 135 days of treatment, the female rats were euthanized. We collected plasma to measure the levels of free T4, and the femur for extraction of MSCs. At 7 and 21 days of osteogenic differentiation of MSCs, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) conversion, alkaline phosphatase activity, mineralized nodule number and gene expression for collagen I, osteocalcin, bone sialoprotein and osteopontin were analyzed. The hypothyroid group presented a significant reduction in the osteogenic differentiation of MSCs. The hyperthyroid group did not present changes in the synthesis of mineralized nodules for MSCs at day 21 of differentiation. However, in ovariectomized rats, hyperthyroidism increased the osteogenic differentiation of MSCs characterized by the increase of the alkaline phosphatase activity, the number of mineralized nodules and the expression of osteocalcin, sialoprotein and osteopontin. Our results demonstrated that the hypothyroidism reduces the osteogenic differentiation of MSCs only in non-ovariectomized rats and that the hyperthyroidism increases the osteogenic differentiation of MSCs only in ovariectomized rats.     

Effects of the Surface Characteristics of Nano-Crystalline and Micro-Particle Calcium Phosphate/Chitosan Composite Films on the Behavior of Human Mesenchymal Stem Cells In Vitro

Calcium phosphate (CaP) compounds, the main inorganic constituent of mammalian bone tissues, are believed to support bone precursor cell growth and osteogenic differentiation. Chitosan, a deacetylated derivative of chitin, is a versatile biopolymer to offer broad possibilities for cell-based tissue engineering. In the present study, different scales of CaP crystals on chitosan membranes were prepared for culture of human mesenchymal stem cells (hMSCs) in vitro. A series of aqueous CaP suspensions with different concentrations were mixed with chitosan solution and chitosan/calcium phosphate (C/CaP) films were fabricated by the solvent-casting method. With different weight ratios of CaP in chitosan solution, the various surface characteristics of nano-amorphous (C/CaP 0.1), nano-crystalline (C/CaP 0.5) and micro-particle (C/CaP 2) CaP compounds were examined by scanning electron microscopy and electron dispersion spectroscopy. X-ray diffraction on micro-particles of CaP indicated the formation of crystalline hydroxyapatite. The behavior of hMSCs, including proliferation, cell spreading and osteogenic differentiation, was studied on the C/CaP films. In basal culture medium, the incorporation of CaP into chitosan films could promote the proliferation of hMSCs. The C/CaP 0.5 film with connected CaP nano-crystals had better cellular viability. The fluorescence microscope images at 14 days of culture revealed extensive networks of F-actin filaments of hMSCs on chitosan, C/CaP 0.1 and C/CaP 0.5 films. The cellular morphology on C/CaP 2 film with discrete CaP micro-particles was partly restrained. In osteogenic medium, the alkaline phosphatase (ALP) activity of hMSCs increased and showed the process of osteogenic differentiation. The ALP levels on C/CaP 2 film were higher than those on C/CaP 0.1 and C/CaP 0.5 films. These results demonstrated that the crystallinity and topography of CaP on chitosan membranes could modulate the behaviors of cultured hMSCs in vitro.     

ERK信号通路在檞皮素促大鼠MSCs成骨分化中的作用

目的:观察细胞外信号调节激酶(ERK)信号通路在檞皮素(QUE)促进SD大鼠骨髓间充质干细胞(MSCs)成骨分化过程中的作用。方法:(1)用0.01μmol/L、0.1μmol/L、1μmol/L、10μmol/L和100μmol/LQUE干预MSCs,MTT法检测各浓度QUE对MSCs增殖的影响,碱性磷酸酶(ALP)测定试剂盒检测各浓度QUE对MSCsALP表达的影响;(2)用ERK1/2抑制剂干预后,加入QUE,用ALP测定试剂盒检测ALP的表达,ELISA法检测Ⅰ型胶原(ColⅠ)和骨钙素(BGP)的表达,Westernblotting检测ERK1/2的表达,荧光定量PCR检测转化生长因子β₁(TGF-β₁)mRNA、骨形成蛋白2(BMP-2)mRNA和核心结合因子α1(Cbfα1)mRNA表达。结果:(1)0.1μmol/L、1μmol/L和10μmol/LQUE剂量依赖性地促进MSCsALP的表达,同时能促进MSCs的增殖;(2)与空白组相比,QUE组ALP、BGP和ColⅠ表达均增加(P<0.01),加入ERK1/2抑制剂后,磷酸化的ERK1/2表达减少(P<0.05),同时ALP、BGP和ColⅠ表达降低(P<0.01);(3)与空白组比较,QUE组TGF-β₁mRNA、BMP-2mRNA和Cbfα1mRNA的表达均增加(P<0.05),加入ERK1/2抑制剂后这3个基因的表达都下降(P<0.05)。结论:一定浓度的QUE能促进MSCs的增殖和成骨分化,ERK通路的激活在此过程中起到了重要的作用。