EGF对大鼠深Ⅱ度烫伤创面成纤维细胞的影响

目的：探讨鼠表皮生长因子（epidermal growth factor,EGF)对大鼠深Ⅱ度汤伤创面成纤维细胞的影响。方法：采用流式细胞仪测定成纤维细胞的细胞周期，透射电镜观察成纤维细胞的形态，HE染色观察肉芽组织范围以了解成纤维细胞的功能变化。结果：应用EGF组和对照组大鼠分别于用药后第3，6d有成纤维细胞增殖活性的增加，后又迅速恢复近正常水平，电镜下可见用药组大成纤维细胞明显增生迹象，两组大鼠在肉芽组织范围及肉眼观察创面愈合天数上无明显不同。结论：按临床常规用药方法，EGF可在一定时相内增加成纤维细胞增殖活性，但对创面愈合并未产生明显影响。     

Modulation of type-IV procollagen and laminin production in A431 human squamous epidermoid carcinoma cells by 12-O-tetradecanoylphorbol-13-acetate (TPA) and epidermal growth factor (EGF)

Summary The effect of 12-O-tetradecanoylphorbol-13-acetate (TPA) and epidermal growth factor (EGF) on type-IV-procollagen (basement-membrane collagen) and laminin synthesis, turnover, and secretion was studied in human A431 squamous epidermoid carcinoma cells. Type-IV procollagen and laminin were biochemically and immunologically identified in the medium and cell extracts using immunoprecipitation followed by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis. EGF or TPA produced a sixfold increase in type-IV-procollagen and laminin secretion within 2 h; this was accompanied by a three-to fourfold increase in the levels of cell-associated type-IV procollagen and laminin, respectively. The level of type-IV-procollagen and laminin synthesis and secretion remained elevated for at least 16 h after the administration of either EGF or TPA. A combination of EGF and TPA was more effective than either agent alone in promoting the secretion of laminin but not of type-IV procollagen. EGF and/or TPA did not, however, produce a selective increase in the synthesis of collagen and laminin, since total protein synthesis was also increased to the same degree by these agents. As dtermined by labeling and chase studies, neither EGF nor TPA had any appreciable effect upon type-IV-procollagen or laminin degradation. These results indicate that the synthesis of components associated with the basement membrane in A431 cells (i.e., type-IV procollagen and laminin) can be rapidly modulated by EGF and a tumor promoter, i. e., TPA. The increase in extracellular-matrix-protein production precedes any effects of these agents on cell growth. However, changes in cell shape in response to either EGF or TPA may trigger the increase in the synthesis and secretion of type-IV procollagen and laminin.     

Detection of Epidermal Growth Factor Receptors and E-Cadherins in the Basolateral Membrane of A431 Cells by Laser Scanning Fluorescence Microscopy

We have examined the localization of epidermal growth factor (EGF) receptors and E-cadherins in cultured A431 cells, an epidermoid carcinoma cell line, using a laser scanning fluorescence microscope. The fluorescence signals generated by monoclonal antihodies against EGF receptor and E-cadherin were localized mainly in the cell-cell contact sites, about 3 μm in width. When these areas for cell adhesion were scanned perpendicularly, fluorescence was detected from a point 4μ from the cell base for a distance of 8 μm towards the cell surface (about 16 μm from the cell base). These data suggest the subcellular localization of EGF receptors and E-cadherins in the basolateral membrane of A431 cells.     

Effects of131I-EGF on cultured human glioma cells

Malignant glioma cells often have more epidermal growth factor (EGF) receptors than normal cells and targeting of toxic substances to the receptor might therefore be an attractive therapeutical approach. Radiation effects were analysed on human glioma cells growing as monolayers after exposure to¹³¹I-EGF. Unspecific effects were analysed with¹³¹I-BSA or after presaturation with nonradioactive EGF. The radiation effects were compared to the effects obtained by external⁶⁰Co gamma irradiation. Administration of the highest radioactive concentrations, 0.2–0.5 MBq/ml in the culture medium, corresponded, after 20 min incubation, to a binding of about 1.0–2.5 dpm/cell. Such an exposure to¹³¹I decays gave effects on cell survival corresponding to about 2.5 Gy of external gamma irradiation. Somewhat less than half of this effect came from the specific bound radioactivity and the rest from nonbound radioactivity. When administrating lower concentrations of radioactivity both the binding and the radiation effects were smaller. The observations showed that it is possible to inactivate cell-proliferation of glioma cells with specific bound¹³¹I-EGF. The possibilities to fractionate the treatments and of binding also other toxic agents than¹³¹I to the EGF receptor are discussed.     

生石膏对大鼠胃酸分泌及胃粘膜屏障的影响

目的:探讨寒性药物生石膏对大鼠胃粘膜屏障损伤的机制。方法:30只雄性SD大鼠随机分为空白对照组、生石膏灌胃组和生理盐水灌胃组。实验结束后利用激光多普勒血流仪测定胃黏膜血流量,测定动物的胃结合粘液、空腹胃液量和胃液酸度,并取各组动物的胃粘膜组织测定表皮生长因子(epi-dermal growth factor,EGF)和一氧化氮(nitric oxide,NO)含量。结果:生石膏组与对照组比较,大鼠的胃黏膜血流量及胃结合粘液量明显减少,而空腹胃液量和胃液酸度均明显增加,且胃组织内NO和EGF含量明显减少;而生理盐水组与对照组之间差异无统计学意义。结论:生石膏伤胃与其破坏胃粘膜屏障作用有关。     

Development of a human corneal epithelium model utilizing a collagen vitrigel membrane and the changes of its barrier function induced by exposing eye irritant chemicals

The brief TEER (trans-epithelial electrical resistance) assay after exposing chemicals to corneal epithelium in vivo is known as a suitable method for evaluating corneal irritancy and permeability quantitatively and continuously. A collagen vitrigel membrane we previously developed is a thin (about 20 μm thick) and transparent membrane composed of high density collagen fibrils equivalent to connective tissues in vivo, e.g. corneal Bowman’s membrane. To develop such a TEER assay system in vitro utilizing a human corneal epithelial model, HCE-T cells (a human corneal epithelial cell line) were cultured on the collagen vitrigel membrane substratum prepared in a Millicell chamber suitable for TEER measurement. Human corneal epithelium model possessing 5-6 cell layers sufficient for TEER assay was successfully reconstructed on the substratum in the Millicell chamber by culturing the cells in monolayer for 2 days and subsequently in air-liquid interface for 7 days. The exposure of chemicals to the model induced the time-dependent relative changes of TEER in response to the characteristic of each chemical within a few minutes. These results suggest that the TEER assay using the human corneal epithelial model is very useful for an ocular irritancy evaluation as an alternative to the Draize eye irritation test.     

生物蛋白胶联合金因肽在肝创面中的应用价值

目的评价医用生物蛋白胶与金因肽联合应用于肝脏创面预防出血和胆瘘的效果。方法取32例肝脏手术后肝组织创面渗血病人作为实验组,将金因肽及医用生物蛋白胶局部联合应用于肝脏创面;取同期21例病人做对照组,对比观察其创面愈合效果。结果实验组32例病人术中出血量较对照组减少[（350.3±12.52）ml VS（572.5±18.75）ml,P〈0.05];术后第一天引流量较对照组减少[（93.2±11.15）ml VS（162.6±25.39）ml,P〈0.05];实验组术后拔除引流管时间较对照组短（2.0±1.50天VS 5.0±4.09天,P〈0.05）。结论医用生物蛋白胶与金因肽联合应用具有良好的防止肝脏创面出血及胆瘘的发生,促进创面愈合,无不良反应发生。     

大鼠乙酸胃溃疡愈合过程中EGF和VEGF对胃黏膜组织形态的影响

目的探讨表皮生长因子（epidermal growth factor,EGF）和血管内皮生长因子（vascular endothelial growth factor,VEGF）对再生胃黏膜形态的影响。方法采用大鼠乙酸溃疡模型,用免疫组化方法观察了EGF和VEGF在溃疡3天、8天、25天时的表达,同时测定了再生黏膜厚度、腺体扩张数、胃黏液量,并分析了EGF和VEGF对再生黏膜厚度、腺体扩张数、胃黏液量的影响。结果25天组的EGF积分光密度高于8天组（P〈0．01）,8天组的积分光密度高于3天组（P〈0．05）;25天组的VEGF积分光密度高于8天组（P〈0．01）,8天组的积分光密度高于3天组（P〈0．01）;25天组的再生黏膜厚度高于8天组（P〈0．01）,8天组的再生黏膜厚度高于3天组（P〈0．01）;25天组的腺体扩张数低于8天组（P〈0．01）,8天组的腺体扩张数低于3天组（P〈0．01）;25天组的胃黏液含量高于8天组（P〈0．01）,8天组的胃黏液含量高于3天组（P〈0．01）。结论随着溃疡的愈合,EGF和VEGF促进了再生的异常胃黏膜向正常胃黏膜转化,并促进了再生胃黏膜功能的恢复。     

HMGA2 induces transcription factor Slug expression to promote epithelial-to-mesenchymal transition and contributes to colon cancer progression

Epithelial-to-mesenchymal transition (EMT) is considered to play an essential role in progression and metastasis. This study aims to investigate the expression and underlying molecular targets of high-mobility group AT-hook 2 (HMGA2) in the progression of colon cancer. The expression of HMGA2 is upregulated by both active extracellular signal-regulated kinase (ERK)1/2 and TGF-β signaling in colon cancer cells through a series of lentiviral infection and pharmacological assays. HMGA2 knockdown by specific shRNAs attenuates proliferation, motility and invasion of colon cancer cells in vitro and in vivo. Besides, exogenous HMGA2 expression caused EMT in colon cancer cells, which was confirmed by the downregulation of the epithelial markers and the upregulation of the mesenchymal markers. Moreover, HMGA2 positively regulates the Slug expression by directly binding to the regulatory region in Slug promoter. Importantly, the knockdown of Slug could reverse the HMGA2-induced EMT and decrease the migration and invasion ability of colon cancer cells. Taken together, our results reveal a critical role for HMGA2 in promoting EMT, migration, invasion, and proliferation of colon cancer cells, suggesting HMGA2 as a potential molecular target to prevent colon cancer progression.