hMSCs成骨诱导前后分泌免疫相关细胞因子的实验研究

目的:研究hMSCs、DOC(osteogenic cells differentiated from mesenchymal stem cells,成骨诱导后骨髓间充质干细胞)分泌免疫相关细胞因子的变化,从细胞因子角度探讨hMSCs、DOC形成免疫抑制微环境的可能机理。方法:hMSCs、DOC(成骨诱导18天),采用ELISA技术,分别检测IL-2、IL-4、IL-10和TGF-β1分泌水平的变化。结果:在MSCs、DOC中IL-2、IL-4h低表达或忽略表达,IL-10中度表达,TGF-β1高表达。对IL-2、IL-4、IL-10,hMSCs、DOC的表达水平有统计学差异(P<0.05)。结论:在体外实验中,hMSCs、DOC可能形成免疫抑制微环境并通过其维持免疫调节功能。     

CD24及其免疫调节与免疫耐受诱导作用

CD24是一种低分子量高度糖基化膜糖蛋白,主要表达在大多造血细胞和脑组织,发挥重要功能。最新研究显示,CD24协同刺激T细胞活化,促进其增殖,也参与自身免疫性疾病的发生。而且随着不同细胞型别和生物学环境的变化,CD24也起着诱导凋亡或促进树突状细胞的免疫耐受作用。     

羊肚菌免疫调节作用研究

观察DNFB诱导小鼠迟发型变态反应、血清溶血素测定（血凝法）、小鼠腹腔巨噬细胞吞噬鸡红细胞试验,结果表明,羊肚菌可以促进小鼠细胞免疫功能提高液免疫功能,促进小鼠体内抗体的产生,具有增强小鼠腹巨噬功能,是一种比较有效的免疫调节剂。     

灵芝孢子粉免疫调节作用研究

观察DNFB诱导小鼠迟发型变态反应、血清溶血素测定（血凝法）、小鼠腹腔巨噬细胞吞噬鸡红细胞试验,结果表明,灵芝了粉可以促进小鼠细胞免疫功能提高体液免疫功能,促进小鼠体内抗体的产生,具有增强小鼠腹腔巨噬细胞吞噬功能,是一种比较有效的免疫调节剂。     

甘草多糖免疫调节作用的研究

目的：研究甘草多糖对小鼠免疫系统功能的影响。方法：以体内给药方式,对实验动物进行碳粒廓清实验、淋巴细胞增殖实验、血清溶血素水平测定实验,研究甘草多糖对非特异性和特异性免疫系统的影响。结果：实验表明,与空白对照组进行比较,低、中、高剂量多糖给药组小鼠的免疫能力均有显著性提高（P〈0.05）,并呈现一定剂量依赖关系,且达到阳性对照药物组水平。结论：甘草多糖对正常小鼠的免疫能力有促进作用。     

水苏冲剂免疫调节作用的研究

目的研究以水苏糖为主要功能组分的水苏冲剂的免疫调节作用.方法通过实验鼠进行免疫调节实验,观察该微生态调节剂的作用.结果细胞免疫功能测定:小白鼠迟发型变态反应(DTH)结果为阳性;ConA诱导小白鼠脾淋巴细胞转化试验(MTT)结果为阳性.体液免疫功能测定:(1)抗体生成细胞检测(PFC)结果为阳性,(2)血清溶血素测定结果为阳性.单核-巨噬细胞功能测定:小白鼠碳粒廊清试验结果为阴性;小白鼠腹腔巨噬细胞吞噬鸡红细胞试验结果为阴性.脏/体比值测定结果为阴性.结论该次实验观察到"水苏牌水苏冲剂"对小白鼠细胞免疫和体液免疫功能试验结果均为阳性,故证明"水苏牌水苏冲剂"具有免疫调节作用.     

北方姬松茸免疫调节作用的研究

姬松茸(Ａｇａｒｉｃｕｓｂｌｇｅｉｍｕｒｒｉｌｌ)商品名巴西菇[1]。90年代初由日本引入我国,我所1995年从日本引种,经驯化试验已获栽培成功。姬松茸味道鲜美,营养丰富,且含有蛋白质、多糖、甾醇等多种活性物质其,具有显著的免疫调节作用和抑肿瘤作用[2]。我们以北方栽?..     

双歧杆菌的免疫调节作用研究现状与展望

自1899年法国巴斯德研究院的TISSIER发现双歧杆菌以来,人们对双歧杆菌进行了广泛的研究,各方面的研究结果证实：双歧杆菌是人体中很重要的益生菌,是健康人肠道内定植且数量占优势的一种细菌,具有免疫调节、抗肿瘤、抗感染、抗衰老、降血脂、营养保健等一系列特殊生理功能。但双歧杆菌的免疫调节作用一直以来都是研究的热点,双歧杆菌通过竞争作用机制粘附到肠黏膜上皮,其菌体成分或其分泌至菌体外的可溶性物质如生物素、抗菌物质和菌体外多糖（EPS）等能通过M细胞进入集合淋巴结,激活T细胞和B细胞,从而调节和增强机体的免疫能力。近几年来各国学者在此领域取得了丰硕的成果,现将该方面的研究现状综述如下。     

胎盘免疫调节因子研究新进展

胎盘免疫调节因子（placental factor,PF）的研究首起我国。由刘月新（1985）首先报道,胎盘免疫调节因子是从健康产妇的胎盘中提取的生物活性成分,经过生物实验及临床观察,初步证明胎盘免疫调节因子对病毒性疾病、免疫缺陷性疾病及恶性肿瘤等多种疾病均有较好的临床效果。作为一种新的免疫调节剂,近年来引起了广泛的关注和研究。     

miR-143通过抑制PTN促进人骨髓间充质干细胞成脂分化

目的：研究miR-143调控人骨髓问充质干细胞（hMSCs）成脂分化的新机理。方法：将NC、miR-143、siPTN、miR-143i转入hMSCs中,诱导成脂分化,检测miR-143对成脂分化的影响。经miRNA靶点分析软件Findtar预测出miR-143在人多效生长因子（hPTN）的3＇-UTR端有靶点。RT-PCR、westernblot研究mjR-143与hPTN的关系。构建hPTN3＇-UTR靶位点荧光检测质粒prltk-PTN及其突变质粒prltk-m,验证miR-143是否在人PTN3＇-UTR上有靶点。结果：miR-143促进hMSCs成脂分化,抑制hPTN的mRNA和蛋白表达水平。荧光报告实验证实miR-143在人PTN的3＇-UTR上有靶点。结论：miR-143通过与hPTN3I-UTR上的靶点相结合而抑制hPTN的表达,从而促进了hMSCs成脂分化进程。     

miR-143 通过抑制PTN 促进人骨髓间充质干细胞成脂分化

目的:研究miR-143调控人骨髓间充质干细胞(hMSCs)成脂分化的新机理。方法:将NC、miR-143、siPTN、miR-143i转入hMSCs中,诱导成脂分化,检测miR-143对成脂分化的影响。经miRNA靶点分析软件Findtar预测出miR-143在人多效生长因子(hPTN)的3’-UTR端有靶点。RT-PCR、western blot研究miR-143与hPTN的关系。构建hPTN 3’-UTR靶位点荧光检测质粒prltk-PTN及其突变质粒prltk-m,验证miR-143是否在人PTN 3’-UTR上有靶点。结果:miR-143促进hMSCs成脂分化,抑制hPTN的mRNA和蛋白表达水平。荧光报告实验证实miR-143在人PTN的3’-UTR上有靶点。结论:miR-143通过与hPTN3’-UTR上的靶点相结合而抑制hPTN的表达,从而促进了hMSCs成脂分化进程。     

Thickness sensing of hMSCs on collagen gel directs stem cell fate

Mechanically compliant substrate provides crucial biomechanical cues for multipotent stem cells to regulate cellular fates such as differentiation, proliferation and maintenance of their phenotype. Effective modulus of which cells sense is not only determined by intrinsic mechanical properties of the substrate, but also the thickness of substrate. From our study, it was found that interference from underlying rigid support at hundreds of microns away could induce significant cellular response. Human mesenchymal stem cells (hMSCs) were cultured on compliant biological gel, collagen type I, of different thickness but identical ECM composition and local stiffness. The cells sensed the thin gel (130 μm) as having a higher effective modulus than the thick gel (1440 μm) and this was reflected in their changes in morphology, actin fibers structure, proliferation and tissue specific gene expression. Commitment into neuronal lineage was observed on the thin gel only. Conversely, the thick gel (1440 μm) was found to act like a substrate with lower effective modulus that inhibited actin fiber polymerization. Stem cells on the thick substrate did not express tissue specific genes and remained at their quiescent state. This study highlighted the need to consider not only the local modulus but also the thickness of biopolymer gel coating during modulation of cellular responses.     

Accelerated adipogenic differentiation of hMSCs in a microfluidic shear stimulation platform

The use of transplanted adipose tissue to repair crucial defects is clinically interesting for surgical reconstruction. Terminally differentiated adipocytes are utilized to promote the healthy regeneration of defective tissue. Use of differentiated mesenchymal stem cells, capable of differentiation into adipocytes, is advantageous because of their regenerative properties. Conventionally, the differentiation of hMSCs toward adipocytes occurs through chemical stimulation. We designed a microfluidic system, consisting of plastic tubing and a syringe pump, to create an environment of shear to accelerate this differentiation process. This system employed a flow rate equivalent to the accelerated flow rates found within the arterial system in order to promote and activate intracellular and extracellular proteins associated with the adipogenic lineage. Confirmation of sustained viability following shear exposure was obtained using a fluorescent live‐dead assay. Visualization of intracellular lipid accumulation was achieved via Oil Red O staining. When placed into culture, shear stimulated hMSCs were further induced toward brown adipose tissue, as evidenced by a greater quantity of lipid triglycerides, relative to unstimulated hMSCs. qRT‐PCR analysis validated the phenotypic changes observed when the hMSCs were later cultured in adipogenic differentiation media. Additionally, increased fold change for adipogenic markers such as LPL1, CFL1, and SSP1 were observed as a result of shear stimulation. The significance of this work lies in the demonstration that transient fluid shear exposure of hMSCs in suspension can influence differentiation into adipocytes. © 2015 American Institute of Chemical Engineers Biotechnol. Prog., 32:440–446, 2016     

Influence of hydrology and seasonality on DOC exports from three contrasting upland catchments

Variation in dissolved organic carbon (DOC) concentrations of surface waters is a consequence of process changes in the surrounding terrestrial environment, both within annual cycles and over the longer term. Long-term records (1987–2006) of DOC concentrations at six catchments (0.44–10.0 km²) across a climatic transect in Scotland were investigated for intra-annual relationships to evaluate potential long-term seasonal patterns. The intra-annual mode of DOC export contrasted markedly between catchments and appeared dependent on their hydrological characteristics. Catchments in wetter Central Scotland with high rainfall–runoff ratios, short transit times and well-connected responsive soils show a distinct annual periodicity in DOC concentrations throughout the long-term datasets. Increased DOC concentrations occurred between June and November with correspondingly lower DOC concentrations from December to May. This appears unrelated to discharge, and is dependent mainly on higher temperatures driving biological activity, increasing decomposition of available organic matter and solubility of DOC. The drier eastern catchments have lower rainfall–runoff ratios, longer transit times and annual drying–wetting regimes linked to changing connectivity of soils. These are characterised by seasonal DOC concentration–discharge relationships with an autumnal flush of DOC. Temperature influences the availability of organic matter for DOC transport producing a high DOC concentration–discharge relationship in summer/autumn and low DOC concentration–discharge relationship in winter/spring. These two distinct modes of seasonal DOC transport have important implications for understanding changes in DOC concentrations and export brought about by climate change (temperature and precipitation) and modelling of aquatic carbon losses from soil-types under different hydrological regimes.     

Photodegradation of DOC in a shallow prairie wetland: evidence from seasonal changes in DOC optical properties and chemical characteristics

Wetlands across the Canadian prairies are typically shallow (<1.0 m) and exhibit high dissolved organic carbon (DOC) concentrations (>10 mg l^–1). Studies have shown that DOC in such shallow wetlands is not as reliable an indicator of ultraviolet radiation (UVR) attenuation as it is in clearwater. Changes in DOC character and composition as a result of sunlight exposure might provide a reasonable explanation for this observation. To test this, we investigated seasonal changes in DOC optical and chemical properties in a shallow prairie wetland over a 2-year period. Although DOC concentration increased at least two-fold from spring until fall, DOC specific absorption (at 350 nm) and fluorescence decreased by 30 and 32%, respectively, for the same period. In both years, seasonal decreases in DOC molecular weight and size (from measurements of tangential filtration and mass electrospray mass spectrometry) were reflected in concomitant increases in spectral slope. ¹³C NMR analysis of DOC isolated on XAD-8 resins revealed a 49% decrease in aromatic moieties when spring values were compared to those in the fall. As well, ¹³C signatures of this isolated DOC became heavier seasonally. In a short term photodegradation experiment (6 days) we noted a 47% decline in DOC specific absorption coefficients at 350 nm and a 15% increase in spectral slope when water exposed to the total light spectrum was compared to that of a dark control. Taken together, all of these observations were consistent with the occurrence of seasonal DOC photodegradation in shallow prairie wetlands and underlined the importance of this process in shaping DOC character and composition in these hydrologically dynamic systems. Our data also indicates that constant mixing and shallow depths in these wetlands were factors which enhanced DOC photodegradation. Although the high DOC concentrations of prairie wetlands should theoretically offer protection for their biota, seasonal photodegradation of DOC means that these systems may not be as protected as their high DOC concentrations suggest.     

An electron microscope autoradiographic study of DOC conversion to corticosterone in the rat adrenal cortex

Summary Seven thymuses from children between 1 and 12 years were examined by electron microscopy. Biopsies had been taken during surgical correction of congenital heart defects.In all cases we found interdigitating reticulum cells (IRC) in the medulla and inner cortex. These cells resembled the IRC which have been described previously in the thymus-dependent regions of the spleen and lymph node. They were characterized by an irregularly shaped nucleus, narrow cisterns of rough endoplasmic reticulum, and widespread interdigitation and invagination of the cell membrane. The surfaces of the IRC were in close contact with those of small lymphocytes, sometimes polysomal lymphatic cells, epithelial cells, and occasionally with those of lymphatic cells containing ergastoplasm.The IRC is apparently a specific cell of thymus-dependent regions. It may be that the IRC in the thymus, lymph node, and spleen contribute to the microenvironment needed for the differentiation of T-cells.Supported by the Deutsche Forschungsgemeinschaft, SFB 111/CII and III.—We wish to thank Miss M. Neubert and Mrs. R. Köpke for their technical assistance and Mrs. M. Soehring for her help with the translation.     

不同干湿交替频率对土壤速效养分、水溶性有机碳的影响

为了探究不同干湿交替频率对速效养分、DOC的影响机理,选择北京褐土(表层0—10cm土壤)为研究对象,采用室内模拟控制实验法,控制其他变量,设计一系列不同频率的干湿交替实验,在58d内设置了10d土壤培育期和48d试验期,其中48d试验期设置0、1、2、3、4次干湿交替,试验结束(第58天)进行速效养分、水溶性有机碳(DOC,Dissolved organic carbon)等主要土壤速效养分指标测定。采用单因素方差分析与LSD多重比较法进行数据分析,研究结果显示:恒湿组的速效钾、硝态氮含量比干湿交替组高;低频率的干湿交替使得土壤速效钾含量减少,高频率可能在后期出现释钾现象,速效钾含量随着干湿交替频率增加可能会有所增加,趋近恒湿组速效钾水平,4次干湿交替频率是出现速效钾回升的临界次数;硝态氮含量随着频率增加也有增加趋势,低频率的1次干湿交替(DW1,1 drying-rewetting cycle)硝态氮含量最低,高频率的4次干湿交替(DW4,4 dryingrewetting cycles)最高,干湿交替频率增加更频繁的打破平衡,促进矿化,干湿交替组也趋近恒湿组的硝态氮水平。经过干湿交替,土壤中速效钾、铵态氮、DOC的含量下降,硝态氮含量增加,速效磷、pH的变化不明显。在固定时间内(48d),随着干湿交替的频率增加(从1次到2、3、4次),周期变短(从48d到24、16、12d),干燥与湿润的持续时间变短(从24d到12、8、6d),干湿交替组的速效钾、硝态氮含量分别趋于恒湿组的速效钾、硝态氮水平。