骨髓间充质干细胞的研究进展

骨髓间充质干细胞主要存在于全身结缔组织和器官间质中,具有多种生物学特性及分离、培养的方法,在适宜的微环境里具有多向分化潜能．本文就骨髓间充质干细胞的分离、培养及其诱导分化的最新进展做一综述．     

骨髓间充质干细胞与造血

骨髓间充质干细胞（MSC）是骨髓中不同于造血干细胞的另一类干细胞。MSC作为骨髓基质细胞的一部分,构成了造血微环境的主要细胞,在造血调控中发挥着重要的作用。研究MSC与造血作用的关系及其机理,在血液系统疾病的临床实践中具有广阔的应用前景。     

骨髓间充质干细胞诱导分化为神经细胞的研究进展

近年来研究认为骨髓中存在骨髓间充质干细胞,具有多项分化潜能,体内实验证明其不但能分化成骨、软骨、脂肪等中胚层起源的细胞,而且能分化为神经元和神经胶质细胞等外胚层起源细胞.本文将对骨髓间充质干细胞诱导分化为神经细胞的研究进展作一综述.     

骨髓间充质干细胞诱导分化为神经细胞的研究进展

近年来研究认为骨髓中存在骨髓间充质干细胞,具有多项分化潜能,体内实验证明其不但能分化成骨、软骨、脂肪等中胚层起源的细胞,而且能分化为神经元和神经胶质细胞等外胚层起源细胞.本文将对骨髓间充质干细胞诱导分化为神经细胞的研究进展作一综述.     

大鼠骨髓间充质干细胞的分离、培养及生物学鉴定

目的:探讨成体大鼠的间充质干细胞(MSCs)的分离、体外培养,为其应用提供理论依据.方法:用密度梯度离心结合贴壁培养法分离纯化大鼠骨髓MSCs,传代扩增,对分离的细胞进行碱性磷酸酶的检测.结果:取得较高纯度的成体大鼠骨髓MSCs,并保持细胞的活性;成体大鼠骨髓MSCs在体外培养中为贴壁生长的单个核球形细胞,培养3～4d后开始大量增殖,并形成形态均一的细胞增殖集群,对分离后所获得的细胞进行AKP染色为强阳性.结论:采用密度梯度离心结合贴壁培养法可获得较高纯度的MSCs,是实用、便捷和可行的方法.并且在体外培养条件下能大量增殖,形成形态均一的细胞集落,可以成为进一步进行细胞扩增或其他实际应用的基础.     

Bcl-2、Bax及Bid与细胞周期阻滞及凋亡调控的关系

Bcl-2家族是研究的最早与凋亡相关的因子,发挥抗凋亡或促凋亡的作用,是线粒体凋亡通路中最主要的调节因子。近年来对于Bcl-2家族的研究取得了很大的进展,个别Bcl-2家族成员不仅具有凋亡调节作用,与细胞增殖也密切相关,从而将细胞周期与细胞凋亡偶连。本文较全面地综述了Bcl-2家族中Bcl-2、Bax及Bid三个成员与细胞周期关系的研究新进展。     

EGFP基因转染骨髓间充质干细胞的实验研究

目的:探讨外源性EGFP基因转染修饰兔骨髓间充质干细胞(m esenchymal stem cells,MSCs)的可行性。方法:用增强型荧光绿色蛋白(enhanced green fluorescent protein,EGFP)作为报告基因,以脂质体法转染骨髓间充质干细胞,观察转染结果、表达情况及对靶细胞活力的影响。结果:经荧光显微镜下观察证实:成功地对骨髓间充质干细胞实现了基因转染。结论:兔骨髓间充质干细胞能够在体外适宜的条件下进行长期培养;骨髓间充质干细胞可直接作为基因靶细胞,建立稳定表达EGFP的骨髓间充质干细胞系具有可行性,为进一步做标记的MSCs细胞的移植研究奠定基础。     

体外培养经皮移植自体骨髓间充质干细胞治疗四肢骨不连

目的:探讨体外培养经皮移植自体骨髓间充质干细胞(MSCs)治疗四肢骨折骨不连的效果。方法:12例四肢骨折骨不连患者采用体外培养经皮移植自体MSCs治疗。结果:9例获得了骨性愈合,骨折愈合平均时间为5个月(4~7月),X线显示骨折线消失,骨痂形成。骨折愈合率为75%(9/12)。结论:体外培养经皮移植自体MSCs治疗四肢骨折骨不连创伤小、安全、并发症少,临床效果满意。     

帕金森病大鼠模型的骨髓间充质干细胞移植疗效的磁共振波谱探讨

目的利用1.5T质子磁共振波谱（^1H-MRS）监测活体帕金森病大鼠模型骨髓间充质干细胞（mesenchymal stem cells,MSCs）移植治疗前后纹状体区的神经代谢变化,以探讨1．5T磁共振波谱分析在评价MSCs移植术疗效中的应用价值。方法30只正常大鼠,以6-羟基多巴胺（6-OHDA）单侧（右侧）损毁制备偏侧帕金森病模型。在活体状态下,分别于造模后3周、MSEs移植后4周及8周应用Philips1．5T临床型磁共振仪扫描,对双侧纹状体区进行^1H—MRS采集,分析该区N-乙酰天门冬氨酸／肌酸（NAA／Cr）、胆碱／肌酸（Cho／Cr）比值变化,同时对大鼠进行行为学检测。利用黑质酪氨酸羟化酶免疫组织化学染色对黑质致密部（SNc）神经元进行定量分析。结果MSCs移植后8周组（C组）大鼠损毁侧（右侧）NAA／Cr比值与未处理组（A组）和MSCs移植后4周组（B组）相比明显升高（P〈0．05）;B,C组损毁侧Cho／Cr比值较A组明显降低（P〈0．05）,且分别明显低于其对侧（P均〈0．05）。B,C组旋转圈数分别较A组低（P均〈0．05）正组旋转圈数较B组显著降低（p〈0．05）。三组损毁侧SNCTH阳性细胞生存率无显著差异（P均〉0．05）。结论1．5T磁共振波谱可以作为一种活体无创性检测方法,对帕金森病大鼠模型纹状体区MSCs细胞移植疗效进行动态监测而作出有价值的评价。     

间充质干细胞的研究进展。

间充质干细胞（Mesenchymal stem cells,MSCs）具有低免疫原性、免疫调节作用及多向分化潜能,并且来源充足、可避免伦理学争议的优点,使其有望成为种子细胞,应用于临床干细胞移植治疗．目前通过体内外诱导等方法已能实现MSCs的扩增和定向分化,本文对MSCs的研究进展作一综述,希望对今后MSCs的相关研究与临床应用提供参考．     

大鼠实验性胃溃疡自愈期间胃黏膜组织凋亡相关因子Bax，Bcl-2的表达变化

目的:探讨大鼠实验性胃溃疡自愈期间促凋亡蛋白Bax与抗凋亡蛋白Bcl-2在胃黏膜组织中表达的变化.方法:胃前壁黏膜下注射冰乙酸制备大鼠胃溃疡模型,免疫组织化学法检测正常组、溃疡组、盐水组大鼠胃黏膜组织Bax和Bcl-2表达变化,并应用图像分析系统软件进行积分光密度值(IOD)分析.结果:Bax阳性细胞在胃溃疡组1d即增多,表达强度强,显著高于正常组与相应盐水组(P<0.01);之后随术后时间延长,阳性细胞逐渐减少,表达强度渐弱,至术后23d,溃疡组Bax IOD与对照组相比差异无统计学意义(P>0.05).Bcl-2阳性细胞随术后时间延长表达逐渐增多,至胃溃疡损伤后的第6天Bcl-2阳性细胞数量最多,表达强度最强,胃溃疡损伤后10d及14d Bcl-2 IOD略低于溃疡后6d,但仍维持于较高水平,至胃溃疡损伤后23d,Bcl-2 IOD显著降低,与正常组、盐水组相比差异无统计学意义(P>0.05).结论:大鼠胃溃疡自愈期间Bax与Bcl-2共同参与了胃黏膜的损伤修复.在胃溃疡损伤早期以促凋亡因素为主,抗凋亡因素对溃疡胃黏膜的保护及修复作用主要是在损伤后的6～14d.     

Cordycepin induces apoptosis by enhancing JNK and p38 kinase activity and increasing the protein expression of Bcl-2 pro-apoptotic molecules

Objective  

To explore the molecular mechanism by which cordycepin inhibits cell proliferation and induces apoptosis of human colorectal cancer cells.     

Bcl-2基因家族及子宫内膜增生、癌变研究综述

目前已发现数个Bcl-2基因家族成员。主要有Bcl-2、Bax等，它们调节子宫内膜细胞的凋亡，与子宫内膜增生、癌变有密切联系。     

Epstein-Barr virus interactions with the Bcl-2 protein family and apoptosis in human tumor cells

Epstein-Barr virus(EBV),a human gammaherpesvirus carried by more than 90% of the world’s population,is associated with malignant tumors such as Burkitt’s lymphoma(BL),Hodgkin lymphoma,post-transplant lymphoma,extra-nodal natural killer/T cell lymphoma,and nasopharyngeal and gastric carcinomas in immune-compromised patients.In the process of infection,EBV faces challenges:the host cell environment is harsh,and the survival and apoptosis of host cells are precisely regulated.Only when host cells receive sufficient survival signals may they immortalize.To establish efficiently a lytic or long-term latent infection,EBV must escape the host cell immunologic mechanism and resist host cell apoptosis by interfering with multiple signaling pathways.This review details the apoptotic pathway disrupted by EBV in EBV-infected cells and describes the interactions of EBV gene products with host cellular factors as well as the function of these factors,which decide the fate of the host cell.The relationships between other EBV-encoded genes and proteins of the B-cell leukemia/lymphoma(Bcl) family are unknown.Still,EBV seems to contribute to establishing its own latency and the formation of tumors by modifying events that impact cell survival and proliferation as well as the immune response of the infected host.We discuss potential therapeutic drugs to provide a foundation for further studies of tumor pathogenesis aimed at exploiting novel therapeutic strategies for EBV-associated diseases.     

Optimal time for mesenchymal stem cell transplantation in rats with myocardial infarction

Background:Bone marrow mesenehymal stem cell(MSC)transplantation is a promising strategy in the treatment of myocardial infarction(MI).However,the time for transplanting cells remains controversial.The aim of this study was to find an optimal time point for cell transplantation.Methods:MSCs were isolated and cultured from Sprague-Dawley(SD) rats.MI model was set up in SD rats by permanent ligation of left anterior descending coronary artery.MSCs were directly injected into the infarct berder zone at 1 h,1 week and 2 weeks after MI,respectively.Sham-operated and MI centrel groups received equal volume of phosphate buffered saline(PBS).At 4 weeks after MI,cardiac function Was assessed by echocardiography;vessel density Was analyzed on hematoxylin-eosin stained slides by light microscopy;the apoptosis of cardiomyocytes Was evaluated by terminal deoxynucleotidy1 transferase-mediated dUTP nick end-labeling(TUNEL) assay;the expressions of proteins were analyzed by Western blot.Results:MSC transplantation improved cardiac function.reduced the apoptosis of cardiomyocytes and increased vessel density.These benefits were more obvious in l-week group than in 1-h and 2-week groups.There are more obvious increases in the ratio of bc1-2/bax and the expression of vascular endothelial growth factor(VEGF)and more obvious decreases in the expression of cleaved-caspase-3 in 1-week group than those in other two groups.Conclusion:MSC transplantation was beneficial for the recovery of cardiac function.MSC transplantation at l week post-MI exerted the best effects on increases of cardiac function,anti-apoptosis and angiogenesis.     

心肌缺血对左室心肌细胞凋亡和凋亡相关基因表达的影响及其分子机制

目的:研究缺血对左室心肌细胞凋亡和凋亡相关基因表达的影响,探讨心肌细胞凋亡的分子机制。方法:采用结扎冠脉左前降支(LAD)法制作大鼠心肌缺血模型;运用DNA琼脂糖凝胶电泳技术鉴定基因组DNA的断裂情况;使用Northern Blot检测缺血心肌细胞p53、c-myc及bcl-2的表达活性。结果;a.缺血能够诱导左室心肌细胞凋亡;b.缺血明显上调p53基因的转录;c.缺血的左室心肌细胞c-myc mRNA含量显著增加;d.缺血减弱了bcl-2基因的转录。结论:内源性促凋亡基因p53、c-myc及抗凋亡基因bcl-2表达活性的改变介导了缺血诱导的心肌细胞凋亡,凋亡是心肌缺血时心肌细胞缺失的一个重要原因。     

Heat shock protein 90 protects rat mesenchymal stem cells against hypoxia and serum deprivation-induced apoptosis via the PI3K/Akt and ERK1/2 pathways

Mesenchymal stem cell(MSC)transplantation has shown a therapeutic potential to repair the ischemic and infracted myocardium,but the effects are limited by the apoptosis and loss of donor cells in host cardiac microenvironment.The aim of this study is to explore the cytoprotection of heat shock protein 90(Hsp90)against hypoxia and serum deprivation-induced apoptosis and the possible mechanisms in rat MSCs.Cell viability was determined by3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide(MTT)assay.Apoptosis was assessed by Hoechst 33258nuclear staining and flow cytometric analysis with annexin V/PI staining.The gene expression of Toll-like receptor-4(TLR-4)and V-erb-b2 erythroblastic leukemia viral oncogene homolog 2(ErbB2)was detected by real-time polymerase chain reaction(PCR).The protein levels of cleaved caspase-3,Bcl-2,Bcl-xL,Bax,total-ERK,phospho-ERK,totaI-Akt,phospho-Akt,and Hsp90 were detected by Western blot.The production of nitric oxide was measured by spectrophotometric assay.Hsp90 improves MSC viability and protects MSCs against apoptosis induced by serum deprivation and hypoxia.The protective role of Hsp90 not only elevates Bcl-2/Bax and Bcl-xL/Bax expression and attenuates cleaved caspase-3 expression via down-regulating membrane TLR-4 and ErbB2 receptors and then activating their downstream PI3K/Akt and ERK1/2 pathways,but also enhances the paracrine effect of MSCs.These findings demonstrated a novel and effective treatment strategy against MSC apoptosis in cell transplantation.     

Chlorella vulgaris triggers apoptosis in hepatocarcinogenesis-induced rats

Chlorella vulgaris (CV) has been reported to have antioxidant and anticancer properties. We evaluated the effect of CV on apoptotic regulator protein expression in liver cancer-induced rats. Male Wistar rats (200-250 g) were divided into eight groups: control group (normal diet), CDE group (choline deficient diet supplemented with ethionine in drinking water to induce hepatocarcinogenesis), CV groups with three different doses of CV (50, 150, and 300 mg/kg body weight), and CDE groups treated with different doses of CV (50, 150, and 300 mg/kg body weight). Rats were sacrificed at various weeks and liver tissues were embedded in paraffin blocks for immunohistochemistry studies. CV, at increasing doses, decreased the expression of anti-apoptotic protein, Bcl-2, but increased the expression of pro-apoptotic protein, caspase 8, in CDE rats, which was correlated with decreased hepatoctyes proliferation and increased apoptosis as determined by bromodeoxy-uridine (BrdU) labeling and terminal deoxynucleotidyl transferase mediated dUTP nick-end labeling (TUNEL) assay, respectively. Our study shows that CV has definite chemopreventive effect by inducing apoptosis via decreasing the expression of Bcl-2 and increasing the expression of caspase 8 in hepatocarcinogenesis-induced rats.