电场对细胞影响的研究进展

概述了近年国内外在电场对细胞影响领域的研究成果,阐述了由电场引起的细胞定位,特性运动,向电生长等电特性的机理及其在生物细胞工程中的应用。     

电场对生物细胞的作用及其实际应用

电场对细胞作用的研究是细胞生物物理学的传统领域之一。近年来由于引入了新的技术和方法,使电场在生物与医学的实际应用方面开辟了广阔的途径。在所应用的电场中,无论是高电压强脉冲或是弱的交变场电脉冲都能对生物细胞的活动产生作用,并伴随许多后续的影响(见表1)     

电场对细胞影响的研究进展*

概述了近年国内外在电场对细胞影响领域的研究成果 ,阐述了由电场引起的细胞定位、特性运动、向电生长等电特性的机理及其在生物细胞工程中的应用。     

低频脉冲电场对PC12细胞突起生长和NGF受体分布的影响

以PC12细胞为实验材料,研究低频脉冲电场(f=50Hz,τ=20ms,Epp=1V／m)对神经细胞突起生长及膜受体聚簇的影响。结果显示,该电场能促进NGF受体的聚簇。电场处理15min使PC12细胞表面的NGF受体发生明显的聚簇,30min组次之,5min组聚簇效果较弱。这表明细胞膜受体可能是电磁场与细胞相互作用的位点之一。运用细胞突起图形处理软件,追踪测定经电场处理后PC12细胞的突起数量和长度,发现该电场能显著促进细胞突起的生长,但对突起数量没有明显的影响。     

外加直流电场对血管平滑肌细胞形态及迁移行为的影响

在外加直流电场(electricalfields,EFs)作用下血管平滑肌细胞(VSMCs)膜表面细胞生长因子受体表达发生明显的变化,并影响细胞形态、迁移的特性。通过EFs干预装置干预体外培养的大鼠主动脉VSMCs,记录和分析细胞图像,研究不同强度电场、不同作用时间下VSMCs迁移和细胞形态的变化,并用免疫细胞化学或免疫荧光染色方法检测与VSMCs迁移相关的血小板衍化生长因子受体(PDGFR)、血管紧张素II1型受体(AT1R)和2型受体(AT2R)等受体的表达情况,研究EFs影响VSMCs形态及迁移的机制。研究结果提示,在EFs干预作用下,VSMCs膜PDGFR表达增加,部分细胞呈不对称分布,在EFs阴极面较集中;细胞中AT1R表达亦增加,但无明显不对称分布现象;AT2R表达没有改变;EFs长时间作用下,培养的VSMCs有明显的电场趋化性,细胞向阴极迁移的距离明显高于无EFs作用对照组,细胞膜向阴极方向伸展,发生形状改变,定向迁移依赖于EFs强度。EFs作用下,部分细胞生长因子受体的表达上调和重分布,可能与细胞定向迁移的启动和维持有关。     

Src蛋白对细胞行为的调控

病毒癌基因ｖ ｓｒｃ具有致癌性 ,与其同源的ｃ ｓｒｃ基因是人或动物细胞中的正常基因 ,蛋白质产物由Ｎ端豆蔻酰化序列、ＳＨ2域、ＳＨ3域、激酶域 (含正调节自磷酸化位点Ｙ4 16 )和Ｃ端调节域 (含负调节磷酸化位点Ｙ5 2 7)组成 .ＳＨ2域和激酶域为细胞信号转导所必需 ,ＳＨ3域则对细胞骨架的重组装具有重要意义 .Ｓｒｃ蛋白在调控细胞的生长、运动和胞内信号转导等方面扮演重要角色 .细胞运动 :用温敏ＲＳＶ突变体转化成纤维细胞 ,发现在特定温度范围以外 ,ｔｓｖ Ｓｒｃ蛋白能解除自身抑制 ,借助ＳＨ3域与肌动蛋白应力纤维的结合 ,从核周…     

不同的基质表面形貌对细胞生长行为的影响

在细胞体外培养中,基质的表面形貌特征是影响细胞行为的一个重要因素。在微米尺度范围内本文研究了几种不同几何轮廓的脊／沟状形貌结构和不同间距的柱状体对鼠C6神经胶质瘤细胞生长的影响。脊／沟状形貌结构诱导细胞趋向生长,不同的几何轮廓对细胞行为的影响存在差异。柱状体间距影响细胞的贴壁和铺展,进而影响细胞的生长行为;大的间距不利于细胞生长,当间距很小时,柱状体截面的几何轮廓影响细胞的行为。     

外源性核酸对机体作用的研究进展

人们曾一度认为核酸不是人体的必需营养成分,但近些年来大量研究资料表明,核酸（包括DNA、RNA、核苷酸和核苷）对维持机体的正常功能有重要作用,是特定生理条件下不可缺少的营养成分。作者主要对外源性核酸在机体营养、免疫调节和疾病防治等方面的功能做一简要综述。     

全身放射损伤对皮肤伤口成纤维细胞参与组织修复能力的影响

合并全身放射损伤的创伤（放创复合伤）是一种重要而有代表性的难愈性创伤,其难愈机制尚未完全阐明,成纤维细胞是最为重要的组织修复细胞,其辐射敏感性较低,为了明确放创复合伤时合并的放射损伤是否对伤口成纤维细胞有直接损伤作用,以及这些损伤作用对创伤愈合的影响,实验检测了分离,培养的放创复合伤和单纯创伤大鼠皮肤伤口成纤维细胞的增殖,凋亡及其他反映其参与组织修复能力的指标变化,结果发现,在去除全身因素和局部因素,特别是创伤局部细胞因子和细胞外基质对成纤维细胞的反馈作用后,放创复合伤组伤口成纤维细胞增殖力,贴壁力和粘附力均显著弱于单纯创伤组,而成纤维细胞的凋亡率则显著增加,这些细胞表明,全身放射损伤对伤口成纤维细胞有直接损伤作用,使其参与组织修复能力显著受抑,这是合并全身放射损伤时创伤难愈的重要原因。     

胰岛再生源蛋白(Reg)在组织修复中的功能和调控机制

胰岛再生源蛋白(regenerating islet-derived protein,Reg)是一个多功能分子,在多种生理、病理活动中发挥重要作用。该文主要综述Reg蛋白在组织损伤后促进细胞增殖、抑制炎症因子过表达、调控细胞凋亡和抑制病原微生物生长和扩散的功能及调控机制,为治疗组织损伤提供新思路和新途径。     

Epithelial Cell Repopulation and Preparation of Rodent Extracellular Matrix Scaffolds for Renal Tissue Development

This protocol details the generation of acellular, yet biofunctional, renal extracellular matrix (ECM) scaffolds that are useful as small-scale model substrates for organ-scale tissue development. Sprague Dawley rat kidneys are cannulated by inserting a catheter into the renal artery and perfused with a series of low-concentration detergents (Triton X-100 and sodium dodecyl sulfate (SDS)) over 26 hr to derive intact, whole-kidney scaffolds with intact perfusable vasculature, glomeruli, and renal tubules. Following decellularization, the renal scaffold is placed inside a custom-designed perfusion bioreactor vessel, and the catheterized renal artery is connected to a perfusion circuit consisting of: a peristaltic pump; tubing; and optional probes for pH, dissolved oxygen, and pressure. After sterilizing the scaffold with peracetic acid and ethanol, and balancing the pH (7.4), the kidney scaffold is prepared for seeding via perfusion of culture medium within a large-capacity incubator maintained at 37 °C and 5% CO₂. Forty million renal cortical tubular epithelial (RCTE) cells are injected through the renal artery, and rapidly perfused through the scaffold under high flow (25 ml/min) and pressure (~230 mmHg) for 15 min before reducing the flow to a physiological rate (4 ml/min). RCTE cells primarily populate the tubular ECM niche within the renal cortex, proliferate, and form tubular epithelial structures over seven days of perfusion culture. A 44 µM resazurin solution in culture medium is perfused through the kidney for 1 hr during medium exchanges to provide a fluorometric, redox-based metabolic assessment of cell viability and proliferation during tubulogenesis. The kidney perfusion bioreactor permits non-invasive sampling of medium for biochemical assessment, and multiple inlet ports allow alternative retrograde seeding through the renal vein or ureter. These protocols can be used to recellularize kidney scaffolds with a variety of cell types, including vascular endothelial, tubular epithelial, and stromal fibroblasts, for rapid evaluation within this system.     

Electrical Interactions via the Extracellular Potential Near Cell Bodies

Ephaptic interactions between a neuron and axons or dendrites passing by its cell body can be, in principle, more significant than ephaptic interactions among axons in a fiber tract. Extracellular action potentials outside axons are small in amplitude and spatially spread out, while they are larger in amplitude and much more spatially confined near cell bodies. We estimated the extracellular potentials associated with an action potential in a cortical pyramidal cell using standard one-dimensional cable theory and volume conductor theory. Their spatial and temporal pattern reveal much about the location and timing of currents in the cell, especially in combination with a known morphology, and simple experiments could resolve questions about spike initiation. From the extracellular potential we compute the ephaptically induced polarization in a nearby passive cable. The magnitude of this induced voltage can be several mV, does not spread electrotonically, and depends only weakly on the passive properties of the cable. We discuss their possible functional relevance.     

美洲大蠊提取物促组织修复作用机制研究进展

基础研究和临床实验都已证实康复新液等美洲大蠊Periplaneta americana提取物对烧伤、外伤、溃疡和术后创面修复等具有良好的治疗效果。本文综述了美洲大蠊提取物促组织修复作用机制,主要包括降低炎症反应、提高免疫和抗氧化活性、调节细胞生长因子表达、调控创面愈合相关信号通路等,为阐明美洲大蠊促修复作用的分子机制及其开发利用提供了科学参考。     

Pulsed Electromagnetic Fields Improved Peripheral Nerve Regeneration After Delayed Repair of One Month

The goal of this study was to determine if postoperative pulsed electromagnetic fields (PEMFs) could improve the neuromuscular rehabilitation after delayed repair of peripheral nerve injuries. Thirty-six Sprague–Dawley rats were randomly divided into sham group, control group, and PEMFs group. The sciatic nerves were transected except for the control group. One month later, the nerve ends of the former two groups were reconnected. PEMFs group of rats was subjected to PEMFs thereafter. Control group and sham group received no treatment. Four and 8 weeks later, morphological and functional changes were measured. Four and eight weeks postoperatively, compared to sham group, the sciatic functional indices (SFIs) of PEMFs group were higher. More axons regenerated distally in PEMFs group. The fiber diameters of PEMFs group were larger. However, the axon diameters and myelin thicknesses were not different between these two groups. The brain-derived neurotrophic factor and vascular endothelial growth factor expressions were higher in PEMFs group after 8 weeks. Semi-quantitative IOD analysis for the intensity of positive staining indicated that there were more BDNF, VEGF, and NF200 in PEMFs group. It's concluded that PEMFs have effect on the axonal regeneration after delayed nerve repair of one month. The upregulated expressions of BDNF and VEGF may play roles in this process. © 2023 Bioelectromagnetics Society.     

Fabrication and Application of Rose Bengal-chitosan Films in Laser Tissue Repair

Photochemical tissue bonding (PTB) is a sutureless technique for tissue repair, which is achieved by applying a solution of rose bengal (RB) between two tissue edges^1,2. These are then irradiated by a laser that is selectively absorbed by the RB. The resulting photochemical reactions supposedly crosslink the collagen fibers in the tissue with minimal heat production³. In this report, RB has been incorporated in thin chitosan films to fabricate a novel tissue adhesive that is laser-activated. Adhesive films, based on chitosan and containing ~0.1 wt% RB, are fabricated and bonded to calf intestine and rat tibial nerves by a solid state laser (λ=532 nm, Fluence~110 J/cm², spot size~0.5 cm). A single-column tensiometer, interfaced with a personal computer, is used to test the bonding strength. The RB-chitosan adhesive bonds firmly to the intestine with a strength of 15 ± 6 kPa, (n=30). The adhesion strength drops to 2 ± 2 kPa (n=30) when the laser is not applied to the adhesive. The anastomosis of tibial nerves can be also completed without the use of sutures. A novel chitosan adhesive has been fabricated that bonds photochemically to tissue and does not require sutures.     

联合细胞培养在组织工程血管化中的应用

自从1987年正式提出组织工程这一概念来以来,培养具有生物学活性组织器官替代物始终是组织工程学的发展方向。目前,虽然一些工程化组织如皮肤、软骨等已被成功构建,并应用于临床,但其他工程化组织如心脏、骨骼肌、肝脏等体积大、功能复杂,移植后难以及时建立血液供应。而及时建立的血管网络对组织器官的存活与功能实现至关重要。为此,国内外一些实验室采用联合细胞培养的方法,观察不同细胞间的相互作用对血管形成的影响。结果表明,联合细胞培养在血管的形成、稳定和成熟方面起着重要作用。     

Induction of Cell Differentiation of Isolated Cells in Dictyostelium discoideum by Low Extracellular pH

In Dictyostelium discoideum , the formation of multicellular masses is necessary for cell differentiation. However, the present study shows that amoebae of strain V12M2 efficiently differentiate to prespore or stalk cells under submerged incubation in a simple medium containing cAMP and salts without cell contact, only if the pH of the medium is maintained at acidic values; differentiation scarcely occurs in the neutral pH range. The optimum pH values for prespore and stalk cell differentiation are 5.1 and 4.5, respectively. In addition to the extracellular pH, Mg ions and the concentration of cAMP also affect the choice of the differentiation pathway. The time courses of differentiation of both cell types under optimum conditions are also presented.     

石竹科植物组织培养与细胞工程

近年来,植物组织培养与细胞工程研究在石竹科植物上取得了一定进展。现从组织培养、原生质体培养和体细胞杂交、单倍体育种、试管开花、转基因等5个方面对其进行综述,并展望了石竹科植物在组织培养和细胞工程研究方面的发展前景。