甘草次酸诱导U266细胞凋亡及对Survivin表达的影响

本研究旨在观察甘草次酸(glycyrrhetinic acid,GA)对人骨髓瘤细胞系U266增殖、凋亡及survivin表达的影响。用MTT法检测GA对U266细胞增殖活性的影响;流式细胞仪检测不同浓度GA作用于U266细胞后细胞凋亡,细胞周期的变化;扫描电子显微镜观察细胞凋亡的形态学变化;实时定量PCR检测GA对U266细胞survivin基因表达的影响。结果表明:GA对U266细胞有增殖抑制作用,其抑制作用呈现为时间和浓度依赖性;GA可以诱导U266细胞凋亡;扫描电子显微镜下可见核仁染色质边集,凝聚成块;GA可以诱导U266细胞周期阻滞于G0/G1期,表现为G0/G1期细胞比例升高,而G2/M及S期细胞比例下降。GA可以下调U266细胞survivin基因的表达,下调作用与浓度呈正相关。结论 :CA能抑制U266细胞增殖,呈浓度和时间依赖性,诱导其凋亡,其作用机理可能与细胞周期阻滞于G0/G1期和下调survivin基因表达有关。     

Genistein在调节肝癌HepG2细胞Fas基因表达及诱导细胞凋亡中的作用

目的: 探讨三磷酸肌醇( IP3) 和Fas基因表达变化在genistein诱导肝癌细胞凋亡中的作用。方法:以肝癌HepG2 细胞培养72h为对照,以20,40.60,80μmol/ L genistein作用于 HepG2 细胞72h和60μmol/L genistein 作用于 HepG2 细胞6h、12 h、24 h、48 h、72 h，应用同位素试剂盒IP3 - [3H] Birtrak检测细胞IP3 含量，RT-PCR分析Fas mRNA表达，Western blotting 分析细胞Fas蛋白表达，流式细胞仪检测细胞凋亡率。结果: 各浓度的genistein作用于肝癌HepG2 细胞72 h，IP3 含量显著高于对照组[（17.7±1.3）pmol/106cells、（11.2±0.9）pmol/106cells、（4.9±0.5）pmol/106cells、（4.8±0.3）pmol/106cells vs （29.4±0.5）pmol/106cells]，Fas mRNA表达显著高于对照组[RI（灰度与面积之积与β-actin的相对强度）0.25±0.002、0.30±0.01、0.28±0.04、0.30±0.03 vs 0.19±0.01]，Fas蛋白表达显著高于对照组[RI1.08±0.01、 1.11±0.02、1.05±0.06、1.03±0.01 vs 0.17±0.01]，细胞凋亡率显著高于对照组[（10.1±0.9）%、（18.7±1.6）%、（28.7±2.5）%、（27.9±2.0）% vs （2.6±0.1）%]；60 μmol/L genistein 作用于肝癌HepG2 细胞6h、12 h、24 h、48 h、72 h，6h后IP3 含量显著高于对照组[（22.6±0.9）pmol/ 106cells、 (12.0±1.4) pmol/ 106cells、(7.5 ±0.8) pmol/ 106cells、(5.6 ±0.5) pmol/ 106cells、(4.3 ±0.6) pmol/ 106cells vs (29.2 ±0.6) pmol/ 106cells。P < 0.01）；12h后Fas mRNA表达显著高于对照组[RI0.24±0.01、0.24±0.01、0.24±0.02、0.30±0.001 vs 0.20±0.01]，6h后Fas蛋白表达显著高于对照组[RI 0.55±0.08、 1.01±0.03、1.62±0.03、1.46±0.09 、1.56±0.04 vs 0.18±0.01]，24 h后各时相细胞凋亡率为显著高于对照组[(7.4 ±0.5) %、(20.5 ±2.0) %、(30.7 ±1.6) % vs (2.6 ±0.1) %。P < 0.01]。结论: Genistein能减少IP3 生成,上调Fas基因表达,诱导肝癌细胞凋亡。     

Prolonged L-alanine exposure induces changes in metabolism, Ca(2+) handling and desensitization of insulin secretion in clonal pancreatic beta-cells

Acute insulin-releasing actions of amino acids have been studied in detail, but comparatively little is known about the beta-cell effects of long-term exposure to amino acids. The present study examined the effects of prolonged exposure of beta-cells to the metabolizable amino acid L-alanine. Basal insulin release or cellular insulin content were not significantly altered by alanine culture, but acute alanine-induced insulin secretion was suppressed by 74% (P<0.001). Acute stimulation of insulin secretion with glucose, KCl or KIC (2-oxoisocaproic acid) following alanine culture was not affected. Acute alanine exposure evoked strong cellular depolarization after control culture, whereas AUC (area under the curve) analysis revealed significant (P<0.01) suppression of this action after culture with alanine. Compared with control cells, prior exposure to alanine also markedly decreased (P<0.01) the acute elevation of [Ca(2+)](i) (intracellular [Ca(2+)]) induced by acute alanine exposure. These diminished stimulatory responses were partially restored after 18 h of culture in the absence of alanine, indicating reversible amino-acid-induced desensitization. (13)C NMR spectra revealed that alanine culture increased glutamate labelling at position C4 (by 60%; P<0.01), as a result of an increase in the singlet peak, indicating increased flux through pyruvate dehydrogenase. Consistent with this, protein expression of the pyruvate dehydrogenase kinases PDK2 and PDK4 was significantly reduced. This was accompanied by a decrease in cellular ATP (P<0.05), consistent with diminished insulin-releasing actions of this amino acid. Collectively, these results illustrate the phenomenon of beta-cell desensitization by amino acids, indicating that prolonged exposure to alanine can induce reversible alterations to metabolic flux, Ca(2+) handling and insulin secretion.     

Programming of defective rat pancreatic beta-cell function in offspring from mothers fed a low-protein diet during gestation and the suckling periods

Poor fetal and infant nutrition has been linked to impaired glucose tolerance in later life. We studied the effect of protein deficiency during gestation and the suckling period in a rat model and found that poor nutrition 'programmes' pancreatic beta-cell GK (glucokinase; known as the glucose sensor) and glucose-stimulated insulin secretion response in newborn, suckling and adult rat offspring. Pregnant female rats were divided into three groups: a control group was kept on a normal protein (20%) diet, another group was fed a low-protein (LP) (6%) diet during gestation and suckling periods (LP-G + S group) and another was fed a LP diet during gestation then a normal protein diet during the suckling period (LP-G group). The pulsatile glucose-stimulated insulin secretion response was acutely disrupted and the peak insulin secretion was markedly decreased in newborn and 3-week-old offspring of the LP-G + S group compared with the control group. Also, there was an altered pulsatile secretory response in adults of the LP-G + S and 3-week-old and adult offspring of the LP-G groups compared with the control group. GK protein levels, detected by Western blotting, were decreased in newborn and 3-week-old offspring of both LP-G + S and LP-G groups compared with the control groups. The Km and Vmax of GK were altered. The prenatal and postnatal LP diet appeared to have a permanent effect in increasing the affinity of GK for glucose (indicated by decreased Km values) and decreasing the Vmax. This showed that the critical period of programming of the function of GK was after birth and during the postnatal weaning period, since the adult offspring of the LP-G + S group when fed a normal protein diet showed no reversal in the Km values of the enzyme. Similar experiments in adult offspring of the LP-G group showed normalization of the Km values of GK at 3 weeks of age. In conclusion, fetal and infantile nutrition 'programmes' pancreatic beta-cell function; poor nutrition during this period caused irreversible effects on glucose homoeostatic mechanisms in the offspring, which may predispose the offspring to diabetes in later life.     

大鼠组织因子基因克隆及其在C6细胞系中的表达

目的:克隆大鼠组织因子(tissue factor,TF)基因,构建真核表达载体pEGFP-N1-TF,转染C6大鼠神经胶质瘤细胞并检测转染细胞内TF表达水平.方法:采用RT-PCR法从Wistar大鼠肺组织中扩增TF基因,克隆到真核表达载体pEGFP-N1上.通过测序鉴定重组质粒中插入TF的完整性和可靠性.应用脂质体法将鉴定正确的重组质粒转入C6细胞中,荧光显微镜下观察EGFP报告基因的表达强度和转染效率,并对转染细胞的TF-eGFP融合蛋白进行Western blot检测.结果:成功构建pEGFP-N1-TF真核表达载体,转染C6细胞24 h后,在荧光显微镜下可以观测到荧光,并通过Western blot技术检测到TF-eGFP融合蛋白的表达.结论:重组真核表达载体pEGFP-N1-TF构建成功,转染C6细胞后获得了良好的瞬时表达.     

Tamoxifen inhibits proliferation and induces apoptosis in human hepatocellular carcinoma cell line HepG2 via down-regulation of survivin expression

Tamoxifen has been used in patients with hepatocellular carcinoma (HCC). However, its inhibitory mechanism remains unknown. In current study, we evaluated the effect of tamoxifen on the estrogen receptor-α-negative HCC cell proliferation, apoptosis and expression of survivin which had been known to play an important role in promotion of cellular proliferation as well as inhibition of apoptosis in cancer cells. HepG2 cells were incubated with tamoxifen (0.1, 1, 10, or 20 μM) for up to 72 h. Cell proliferation was assessed, flow cytometric analysis was performed, and survivin expression was detected. Our results are showed as follows. Ten or 20 μM tamoxifen induced a reduction of cell proliferation. Basically reduction of proliferation was related to an increase in the fraction of G0/1-phase. When tamoxifen was administrated at higher concentration (20 μM), the increase of the relative apoptosis appeared with a delay, augmenting the effect of tamoxifen on cell proliferation. When apoptosis was induced, a significant depression of survivin expression preceded. In conclusion, the tamoxifen decreasing cell proliferation and induction of apoptosis of HepG2 cells depends on drug concentration, which is due to cytostatic and cytocide effects, the latter may be mediated by a down-regulation of survivin expression.     

睡眠剥夺引起大鼠海马神经元凋亡及相关基因表达的变化

背景:睡眠剥夺是否引起细胞变性,其信号传导是否与某些基因调控有关。目的:探讨睡眠剥夺引起的神经元凋亡与相关基因表达的变化。设计:随机对照实验研究。地点和材料:实验地点:郑州大学医学院生理学实验室。成年健康SD大鼠,雌雄不限,体质量(200±20)g,由河南省实验动物中心提供。干预:采用TUNEL染色观察了快眼动睡眠剥夺大鼠海马神经元形态学变化,应用原位杂交检测了快眼动睡眠剥夺大鼠海马bcl-2,baxmRNA表达。主要观察指标:睡眠剥夺大鼠海马神经元形态学变化;海马bcl-2和baxmRNA表达。结果:快眼动睡眠剥夺大鼠海马CA1,CA3区神经元阳性凋亡细胞数增多,异相睡眠剥夺组海马CA1～CA4区细胞凋亡率分别为(6.60±2.24)%,(1.69±0.45)%,(6.87±1.32)%,(1.74±0.98)%。CA1,CA3区细胞凋亡率和CA2,CA4区相比较差异有显著性意义(t=5.26～6.95,P<0.05)。bcl-2mRNA阳性信号表达积分值较强,四个区之间差异无显著性意义,baxmRNA表达增强犤CA1为(211.12±59.85);CA3为(205.56±56.99)犦与CA2和CA4区犤(123.42±22.80),(124.21±20.47)犦比较差异有显著性意义(t=3.20～4.36,P<0.05)。结论:睡眠剥夺可引起大鼠海马神经元凋亡,与凋亡相关的bcl-2,baxmRNA基因表达的变化可能涉及神经元的凋亡机制。     

脓毒症大鼠心脏组织基因表达变化的研究

目的 应用基因芯片技术初步分析脓毒症大鼠心脏组织细胞基因表达谱的变化.方法 雄性Wistar大鼠30只被随机分为脓毒症组和对照组,每组15只.采用盲肠结扎穿孔术(CLP)制备大鼠脓毒症模型,以透射电镜下心脏组织检查鉴定模型.应用含有22 523个大鼠基因cDNA克隆的表达谱基因芯片进行检测,以Cy3和Cy5两种荧光信号强度结果 比值均>2.0或<0.5的基因为脓毒症表达差异基因,用计算机软件筛选并分析脓毒症大鼠心脏组织术后24 h的基因表达变化,并初步分析表达差异基因与脓毒症之间的关系.结果 与对照组比较,脓毒症组大鼠心脏组织共筛选出418个出现差异表达的基因,占基因芯片总点数的1.86%,其中表达上调者200个,表达下调者218个.在已知功能基因中表达上调者84个,下调者74个,与应激反应、细胞信号转导、糖皮质激素受体、免疫反应、胰岛素样生长因子、细胞物质能量代谢等方面的相关基因功能有关.结论 脓毒症大鼠心脏组织出现一系列基因表达异常,用基因芯片检测技术可快速分析.     

脓毒症大鼠肝脏组织基因表达变化的研究

目的 应用基因芯片技术初步分析脓毒症大鼠肝脏组织细胞基因表达谱的变化.方法 按随机数字表法将30只Wistar大鼠分为对照组和脓毒症组,每组15只.采用盲肠结扎穿孔术(CLP)制备大鼠脓毒症模型.应用含有22 523个大鼠基因cDNA克隆的表达谱基因芯片进行检测,以Cy3和Cy5两种荧光信号强度结果比值＞2.0或＜0.5的基因为脓毒症表达差异基因,用计算机软件筛选并分析脓毒症大鼠肝脏组织术后24h的基因表达变化,并初步分析表达差异基因与脓毒症之间的关系.结果 与对照组比较,脓毒症组大鼠肝脏组织共筛选出285个出现差异表达的基因,占基因芯片总点数的1.27％,其中表达上调者150个,表达下调者135个.在已知功能基因中表达上调者74个,下调者63个,与细胞物质能量代谢、信号转导、调控转录、物质转运、炎症反应、免疫反应、氧化反应、细胞生长调节、细胞凋亡等方面的相关基因功能有关.结论 脓毒症大鼠肝脏组织出现一系列基因表达异常,脓毒性肝损伤的防治应从多方面、多层次入手.     

CD28 and T cell antigen receptor signal transduction coordinately regulate interleukin 2 gene expression in response to superantigen stimulation

Activation of an immune response requires intercellular contact between T lymphocytes and antigen-presenting cells (APC). Interaction of the T cell antigen receptor (TCR) with antigen in the context of major histocompatibility molecules mediates signal transduction, but T cell activation appears to require the induction of a second costimulatory signal transduction pathway. Recent studies suggest that interaction of CD28 with B7 on APC might deliver such a costimulatory signal. To investigate the role of CD28 signal transduction during APC-dependent T cell activation, we have used Staphylococcal enterotoxins (SEs) presented by a B7-positive APC. We used anti-B7 monoclonal antibodies and a mutant interleukin 2 (IL-2) promoter construct, unresponsive to CD28-generated signals, in transient transfection assays to examine the contribution of the CD28-B7 interaction to IL-2 gene activation. These studies indicate that the CD28-regulated signal transduction pathway is activated during SE stimulation of T cells and plays an important role in SE induction of IL-2 gene expression through its influence upon the CD28-responsive element contained within the IL-2 gene promoter. This effect is particularly profound in the activation of the IL-2 gene in peripheral blood T cells.     

神经生长因子撤退诱导神经元样PC12细胞凋亡及HRK/MCL-1基因表达变化

目的:探讨神经生长因子(NGF)撤退对已分化神经元样PC12细胞的影响.方法:建立NGF诱导PC12细胞交感神经元样分化模型,观察NGF撤退后,神经元样PC12细胞形态学及超微结构的变化情况,检测凋亡相关基因HRK/MCL-1的表达变化情况.结果:神经元样PC12细胞在NGF撤退后,可观察到显著的细胞凋亡样特征性改变,并随着NGF撒退时间的延长,凋亡率不断增加,同时随着NGF撤退时间的延长,促凋亡基因HRK的表达不断增高.而抑凋亡基因MCL-1在撤退24 h内表达水平下降明显,撤退24 h后变化不显著.结论:NGF撒退确实能诱导已分化的神经元样PC12细胞出现典型的神经元细胞凋亡现象,该现象与凋亡相关基因HRK/MCL-1的表达变化有密切关系.     

Rebamipide protects small intestinal mucosal injuries caused by indomethacin by modulating intestinal microbiota and the gene expression in intestinal mucosa in a rat model

The effect of rebamipide, a mucosal protective drug, on small intestinal mucosal injury caused by indomethacin was examined using a rat model. Indomethacin administration (10 mg/kg, p.o.) induced intestinal mucosal injury was accompanied by an increase in the numbers of intestinal bacteria particularly Enterobacteriaceae in the jejunum and ileum. Rebamipide (30 and 100 mg/kg, p.o., given 5 times) was shown to inhibit the indomethacin-induced small intestinal mucosal injury and decreased the number of Enterococcaceae and Enterobacteriaceae in the jejunal mucosa to normal levels. It was also shown that the detection rate of segmented filamentous bacteria was increased by rebamipide. PCR array analysis of genes related to inflammation, oxidative stress and wound healing showed that indomethacin induced upregulation and downregulation of 14 and 3 genes, respectively in the rat jejunal mucosa by more than 5-fold compared to that of normal rats. Rebamipide suppressed the upregulated gene expression of TNFα and Duox2 in a dose-dependent manner. In conclusion, our study confirmed that disturbance of intestinal microbiota plays a crucial role in indomethacin-induced small intestinal mucosal injury, and suggests that rebamipide could be used as prophylaxis against non-steroidal anti-inflammatory drugs -induced gastrointestinal mucosal injury, by modulating microbiota and suppressing mucosal inflammation in the small intestine.     

体外培养大鼠海马神经元癫痫模型中神经元凋亡及半胱氨酸天冬氨酸蛋白酶3基因的表达

背景：颞叶癫痫的发病与海马神经元丢失死亡有关，但其海马神经元丢失的具体方式和详尽机制还不清楚，难以确定海马神经元癫痫样放电与半胱氨酸天冬氨酸蛋白酶3（cysteine-containing ASPartate—specific protease，Caspase-3）激活及神经元凋亡的必然联系。 目的：观察体外培养大鼠海马神经元癫痫模型中神经元凋亡及Caspase-3基因的表达情况。 设计：开放性实验。 单位：解放军第二军医大学长海医院神经外科，解放军第二军医大学长征医院神经外科。 材料：实验于2002-06／2003—06在解放军第二军医大学神经外科实验室完成。选取出生24h内的SD大鼠10只，雌雄不拘。Caspase-3流式检测试剂盒购自美国BD公司，PCR引物由上海皓嘉公司合成。 方法：①将24h内新生SD大鼠断头取脑，解剖出双侧海马，制备海马神经元癫痫样放电细胞模型。通过全细胞膜片钳对细胞模型放电情况进行检测。以培养8d并经无镁处理的神经元细胞作为癫痫样放电模型组，以培养8d但未经无镁处理的神经元细胞作为空白对照组，记录电位变化。②采用反转录-聚合酶链法克隆大鼠全长caspase-3 cDNA．并加以标记；采用原位杂交和流式细胞术检测caspase-3基因表达和神经元凋亡情况。 主要观察指标：①Caspase-3基因cDNA的克隆结果。②Caspase-3原位杂交检测结果。③细胞凋亡检测结果。 结果：①反转录-聚合酶链反应扩增的产物经12g/L琼脂糖凝胶电泳显示约800bp DNA片段区带，与预期值一致。DNA序列测定显示所得克隆的开放阅读框架长843bp。②杂交显示空白对照组海马阳性染色神经元少于10％，神经元突起饱满，形成广泛的突触联系。癫痫样放电模型组无镁处理3h后，染色阳性细胞明显增多；无镁处理12h后，有较多强阳性染色神经元，基本保持有神经元突起，但突起变得菲薄。③流式细胞分析显示。无镁处理6h后凋亡细胞开始明显增加，单位时间内凋亡细胞数不尽一致。 结论：癫痫样放电可以启动caspase-3表达，继而介导神经元凋亡。     

体外培养大鼠海马神经元癫痫模型中神经元凋亡及半胱氨酸天冬氨酸蛋白酶3基因的表达

背景:颞叶癫痫的发病与海马神经元丢失死亡有关,但其海马神经元丢失的具体方式和详尽机制还不清楚,难以确定海马神经元癫痫样放电与半胱氨酸天冬氨酸蛋白酶3(cysteine-containingASPartate-specificprotease,Caspase-3)激活及神经元凋亡的必然联系。目的:观察体外培养大鼠海马神经元癫痫模型中神经元凋亡及Caspase-3基因的表达情况。设计:开放性实验。单位:解放军第二军医大学长海医院神经外科,解放军第二军医大学长征医院神经外科。材料:实验于2002-06/2003-06在解放军第二军医大学神经外科实验室完成。选取出生24h内的SD大鼠10只,雌雄不拘。Caspase-3流式检测试剂盒购自美国BD公司,PCR引物由上海皓嘉公司合成。方法:①将24h内新生SD大鼠断头取脑,解剖出双侧海马,制备海马神经元癫痫样放电细胞模型。通过全细胞膜片钳对细胞模型放电情况进行检测。以培养8d并经无镁处理的神经元细胞作为癫痫样放电模型组,以培养8d但未经无镁处理的神经元细胞作为空白对照组,记录电位变化。②采用反转录-聚合酶链法克隆大鼠全长caspase-3cDNA,并加以标记;采用原位杂交和流式细胞术检测caspase-3基因表达和神经元凋亡情况。主要观察指标:①Caspase-3基因cDNA的克隆结果。②Caspase-3原位杂交检测结果。③细胞凋亡检测结果。结果:①反转录-聚合酶链反应扩增的产物经12g/L琼脂糖凝胶电泳显示约800bpDNA片段区带,与预期值一致。DNA序列测定显示所得克隆的开放阅读框架长843bp。②杂交显示空白对照组海马阳性染色神经元少于10%,神经元突起饱满,形成广泛的突触联系。癫痫样放电模型组无镁处理3h后,染色阳性细胞明显增多;无镁处理12h后,有较多强阳性染色神经元,基本保持有神经元突起,但突起变得菲薄。③流式细胞分析显示,无镁处理6h后凋亡细胞开始明显增加,单位时间内凋亡细胞数不尽一致。结论:癫痫样放电可以启动caspase-3表达,继而介导神经元凋亡。     

胶质细胞源性神经营养因子对新生大鼠窒息后纹状体中Par-4基因表达的影响及其相关信号转导机制

目的研究胶质细胞源性神经营养因子对新生大鼠窒息后纹状体中促凋亡基因Par4表达的影响及其相关信号转导机制。方法制备新生大鼠缺氧缺血性脑病的动物模型,侧脑室给予胶质细胞源性神经营养因子(0.1、1.0、5.0μg/μl)。Westernblot测定Par4蛋白表达水平。结果新生大鼠窒息后纹状体中Par4蛋白表达上调、(P<0.01)。胶质细胞源性神经营养因子呈剂量依赖性地抑制缺氧缺血诱导的Par4蛋白表达上调(P<0.01)。给予200μmol L的P42/P44MAPK活性阻断剂PD98059预处理,胶质细胞源性神经营养因子对Par4表达的抑制作用由43%下调至22%(P<0.01)。结论胶质细胞源性神经营养因子抑制新生大鼠窒息后纹状体中促凋亡基因Par4的表达,其机制可能与P42/P44MAPK的活化有关。     

肿瘤坏死因子与甲状腺细胞凋亡及相关蛋白的检测和表达的意义

目的　探讨肿瘤坏死因子 a(TNF a)诱导Graves病甲状腺细胞凋亡与相关蛋白表达在Graves病 (GD)发病关系中的意义。方法　采用免疫组织化学S P方法检测 5 0例Graves病患者TNF a,并检测对照组对Fas表达的影响。采用原代细胞培养方法进行细胞培养 ,细胞培养液中的sFas含量采用ELISA法检测。Fas/sFasmRNA检测采用半定量RT PCR法。结果　含有TNF aGD组细胞凋亡率为 92 6 % ,显著高于对照组的凋亡率 (36 0 % ) (P <0 0 1)。其含有TNF aGD组甲状腺细胞sFas、Fas/sFasmRNA含量与对照组比较差异有显著意义 (P <0 0 1)。结论　TNF a诱导Graves病甲状腺细胞凋亡及凋亡相关蛋白sFas、Fas/sFasmRNA有一定水平的表达 ,这些改变可能是TNF a破坏甲状腺细胞的重要机制之一。     

地塞米松对三氧化二砷诱导淋巴瘤细胞凋亡与NF-κB活化及相关基因表达的影响

目的　研究三氧化二砷(As2O3 )诱导淋巴瘤细胞凋亡与核因子κB(NF κB)活化以及血管内皮生长因子(VEGF)、基质金属蛋白酶9(MMP9)表达的关系,并观察地塞米松(Dex)抑制NF κB活化对As2O3诱导淋巴瘤细胞凋亡及VEGF、MMP9表达的影响。方法　采用流式细胞仪AnnexinⅤFITC法检测Raji细胞凋亡;采用免疫组织化学方法半定量分析Raji细胞NF κB、VEGF、MMP9表达的动态变化。结果　As2O3同时具有诱导Raji细胞凋亡[凋亡率为(39. 2±1. 3)% ]和NF κB活化的作用; 1. 0μmol/LDex能显著增加1 . 0μmol/LAs2O3诱导Raji细胞凋亡(增加率为77. 5%,P<0. 05)和抑制As2O3诱导Raji细胞NF κB活化(抑制率为28. 0%,P<0. 05)的作用,VEGF、MMP9变化与NF κB一致。结论　As2O3诱导Raji细胞凋亡的同时活化NF κB,VEGF、MMP9表达亦随之增强;Dex在抑制As2O3诱导Raji细胞NF κB活化的同时增强其诱导细胞凋亡的作用,VEGF、MMP9的表达也相应下降。     

Noninvasive, quantitative imaging in living animals of a mutant dopamine D2 receptor reporter gene in which ligand binding is uncoupled from signal transduction

The dopamine D2 receptor (D2R) has been used in adenoviral delivery systems and in tumor cell xenografts as an in vivo reporter gene. D2R reporter gene expression has been non-invasively, repetitively and quantitatively imaged by positron emission tomography (PET), following systemic injection of a positron-labeled ligand (3-(2'-[18F]-fluoroethyl)-spiperone; FESP) and subsequent D2R-dependent sequestration. However, dopamine binding to the D2R can modulate cyclic AMP levels. For optimal utilization of D2R as a reporter gene, it is important to uncouple ligand-binding from Gi-protein-mediated inhibition of cAMP production. Mutation of Asp80 or Ser194 produces D2Rs that still bind [3H]spiperone in transfected cells. The D2R80A mutation completely eliminates the ability of the D2R to suppress forskolin-stimulated cAMP accumulation in response to dopamine, in cells transfected with a D2R80A expression plasmid and in cells infected with replication-defective adenovirus expressing D2R80A. The D2R194A mutation substantially reduces, but does not completely eliminate, dopamine modulation of cAMP levels. Cultured cells infected with adenoviruses expressing D2R and D2R80A demonstrated equivalent [3H]spiperone binding activity. Moreover, hepatic FESP sequestration is equivalent, following intravenous injection of adenoviruses expressing D2R and D2R80A. The D2R80A mutant, which can no longer modulate cAMP levels following ligand binding, has full capability as a PET reporter gene.