铁过载对人乳腺癌细胞c-MYC蛋白表达的影响

目的研究铁过载催化的氧化应激对乳腺癌细胞中癌前因子c-MYC影响。方法分别以0、50和500μmol/L硫酸亚铁溶液培养人乳腺癌MCF-7细胞系24 h后,以细胞荧光染色法检测ROS活性,Western blot检测IRP1、IRP2、c-MYC、p-ERK1/2、GSK和PP2A蛋白的表达。加入NADPH氧化酶抑制剂二苯基碘(DPI)后检测ROS活性和c-MYC蛋白表达。结果随着铁剂量的增加,MCF-7细胞内ROS活性和IRP2蛋白表达均显著增加(P0.05),IRP1无明显改变。铁过载还显著增加c-MYC蛋白表达,促进ERK1/2的磷酸化,降低GSK、PP2A蛋白表达(P0.05)。加入DPI后,铁诱导的ROS活性及c-MYC蛋白表达被显著抑制(P0.05)。结论铁过载可以通过诱导细胞内ROS活性的增强上调乳腺癌细胞c-MYC蛋白的表达。     

胰岛β细胞铁过载模型的建立及铁过载对胰岛β细胞损伤的研究

目的:通过枸橼酸铁铵(FAC)与大鼠胰岛素瘤细胞株INS-1共培养,构建铁过载INS-1细胞模型,并观察铁过载对胰岛细胞铁沉积、存活、胰岛素分泌、氧化应激以及线粒体损伤的影响。方法:体外培养INS-1细胞,不添加FAC作为对照组,加入不同浓度(5、10、20、40、80、160和320μmol/L)的FAC干预INS-1细胞,分别培养24 h、48 h和72 h,建立铁过载INS-1细胞模型,测定细胞内的不稳定铁池(LIP),CCK8法分析细胞活力的改变,筛选出后续实验组所用FAC浓度,ELISA法检测胰岛素分泌功能,活性氧簇(ROS)探针染色流式细胞术检测ROS的生成,JC-1试剂盒检测线粒体膜电位,透射电子显微观察线粒体的变化。结果:加入不同浓度FAC处理后,铁过载组INS-1细胞内的LIP水平明显高于对照组(P0.05)。随着FAC浓度的升高及干预时间的延长,INS-1细胞的活力逐渐降低(P0.05)。选取80、160和320μmol/L FAC作用48 h作为后续实验的铁过载组。胰岛素分泌随FAC浓度的增加出现先升高后降低,160和320μmol/L组与对照组相比差异具有统计学意义(P0.05)。INS-1细胞内ROS的水平较对照组均显著增加(P0.05)。线粒体膜电位随着铁浓度的增加而降低(P0.05)。铁过载后INS-1细胞的线粒体肿胀,内嵴扩张,失去正常结构,随着FAC浓度增加,线粒体结构破坏更加明显。结论:与FAC共培养48 h可成功建立INS-1细胞铁过载模型。铁过载可显著破坏线粒体结构和功能,增加细胞内ROS的水平。胰岛β细胞的存活对铁敏感,即使低剂量的铁也损伤胰岛β细胞,但只有细胞数量减少到一定程度,才会减少胰岛素的分泌。     

去铁胺通过抑制氧化应激反应促进小鼠深部组织压力性损伤创面愈合

目的:探讨去铁胺治疗小鼠深部组织压力性损伤(deep tissue pressure injury,DTPI)的效果和机制。方法:将去铁胺溶于无菌生理盐水中,通过CCK-8法检测不同浓度去铁胺对人永生化表皮细胞(HaCaT)活力的影响;利用活性氧(reactive oxygen species,ROS)检测试剂盒测定去铁胺对HaCaT细胞内ROS含量的影响。构建DTPI小鼠模型,分别利用电感耦合等离子体质谱仪和普鲁士蓝染色检测肌肉组织中铁离子的含量和铁沉积情况。实验随机分为假手术组、模型组及去铁胺(2 g/L和20 g/L)组,每组6只小鼠,通过伤口愈合率、HE染色、Masson染色、免疫组化染色和Western blot方法评价组织修复情况。结果:去铁胺的细胞相容性良好,对HaCaT细胞无显著毒性,并显著抑制细胞中ROS的产生,且呈浓度依赖性。DTPI肌肉组织中铁离子异常沉积,其铁含量较正常组显著升高(P0.05)。去铁胺有效促进DTPI的伤口愈合,其中20 g/L去铁胺组愈合速度最快,其新生血管密度和胶原沉积显著优于模型组,且炎症细胞的浸润显著减少(P0.01)。Western blot结果表明去铁胺能上调血管内皮生长因子α(vascular endothelial growth factor-α,VEGF-α)、低氧诱导因子1α(hypoxia-inducible factor-1α,HIF-1α)和基质细胞衍生因子1(stromal cell-derived factor-1,SDF-1)的表达,并抑制肿瘤坏死因子α(tumor necrosis factor-α,TNF-α)的表达(P0.01),且药物组之间无显著的差异性。结论:DTPI小鼠肌肉组织中铁离子异常沉积,存在铁超载现象,去铁胺通过抑制氧化应激反应促进DTPI伤口愈合。     

柠檬酸铁铵通过活性氧途径影响人丙型肝炎病毒的蛋白翻译

目的研究铁对HCV IRES依赖的病毒蛋白翻译的影响,以及其与细胞ROS活性变化的关系。方法以脂质体细胞转染法,将双荧光素酶报告基因表达载体p CI-Rluc-HCV IRES-Fluc转染人肝癌细胞系Huh-7细胞。在0、50和300μmol/L浓度的柠檬酸铁铵(FAC)作用24 h后,双荧光素酶报告基因检测系统检测HCV IRES依赖的病毒蛋白翻译的变化。ROS荧光染色方法检测细胞ROS活性变化,Western blot法检测细胞中Nrf2蛋白表达的变化。加入100μmol/L的DPI后,检测300μmol/L FAC实验组中HCV蛋白翻译的变化和细胞ROS的变化。结果与对照组相比,FAC增加了Huh-7细胞HCV IRES依赖的病毒蛋白翻译、增加了ROS活性,并且可以引起核转录因子Nrf2表达增加(P0.05)。加入ROS抑制剂DPI后,可以显著抑制FAC诱导的HCV IRES依赖的病毒蛋白翻译及Nrf2蛋白的表达(P0.05)。结论 FAC可以诱导细胞HCV IRES依赖的病毒蛋白翻译增加,可能与FAC促进Huh-7细胞产生过多的ROS有关。     

XAV939抑制人肝癌HepG2细胞血管生成拟态的形成

目的初步研究XAV939对人肝癌Hep G2细胞血管生成拟态形成的影响及其可能的机制。方法实验分为对照组和实验组(0.5和1μmol/L XAV939分别处理Hep G2细胞48 h);体外成管实验检测各组细胞形成血管拟态的能力,RT-PCR检测ZEB1及MMP-7 mRNA的表达,Western blot检测β-catenin、ZEB1和MMP-7蛋白的表达。结果对照组与实验组形成管状结构数目分别为9.67±0.70,5.67±0.64(0.5μmol/L)和2.27±0.81(1μmol/L),体外形成管道结构的数目减少(P0.01);实验组ZEB1及MMP-7 mRNA表达和ZEB1、MMP-7及β-catenin蛋白表达均较对照组减少(P0.05)。结论 XAV939能有效抑制人肝癌Hep G2细胞血管生成拟态的形成。     

咪康唑与纤维蛋白协同促进神经球分化为成髓鞘样细胞

目的:探讨咪康唑与纤维蛋白能否协同促进神经球分化为成髓鞘样细胞。方法:培养并鉴定胎鼠神经球;通过MTT法确定不同浓度咪康唑对神经球存活的影响;将神经球按培养条件不同分为四组,对照组、咪康唑组(mico组)、纤维蛋白组(fibrin组)及纤维蛋白-咪康唑联用组(fibrin+mico组),培养两周后以免疫荧光染色比较髓磷脂碱性蛋白(MBP)的表达;Western Blot法比较MBP、2’3’环核苷酸磷酸二酯酶(CNPase)、整合素、细胞外调节蛋白激酶及其磷酸化(ERK、p-ERK)的表达。结果:(1)神经球阳性表达巢蛋白(nestin)和CD133:当咪康唑浓度低于或等于1.5μmol/L时,神经球存活在各组之间不存在统计学差异(P0.05),但2.5μmol/L组显著低于2μmol/L组和1.5μmol/L组(P0.05)。(2)免疫荧光结果显示:神经球分化所成的成髓鞘样细胞表达MBP阳性,呈多突起形态;fibrin组及mico组MBP相对荧光强度均高于对照组(P0.05),fibrin+mico组神经球分化为网络状的成髓鞘样细胞团,其相对荧光强度高于其他组(P0.05)。(3)Western Blot结果显示:fibrin+mico组MBP及CNPase表达显著高于mico组和fibrin组(P0.05),fibrin+mico组整合素表达及p-ERK/ERK显著高于mico组和fibrin组(P0.05),同时咪康唑及纤维蛋白对MBP、CNPase、整合素的表达及p-ERK/ERK的效应具有交互作用(P0.05)。结论:咪康唑与纤维蛋白能协同促进神经球分化为成髓鞘样细胞,其机制可能与ERK磷酸化有关。     

白藜芦醇对铁超载大鼠肝星状细胞凋亡的影响

目的：研究白藜芦醇（RES）对铁超载大鼠肝星状细胞凋亡的影响。方法：体外培养大鼠肝星状细胞细胞系HSC-T6，使用25μmol/L的柠檬酸铁铵（FAC）刺激24 h建立铁超载模型，将细胞分为对照组、铁超载模型组（25μmol/L FAC）、低剂量RES(L-RES)组（3.12μmol/L RES+25μmol/L FAC）、中剂量RES(M-RES)组（6.25μmol/L RES+25μmol/L FAC）、高剂量RES(H-RES)组（12.5μmol/L RES+25μmol/L FAC）和去铁铵（DFO）组（50μmol/L DFO+25μmol/L FAC）。采用CCK-8法测定HSC-T6细胞活力；采用免疫荧光法测定细胞凋亡及活性氧（ROS）水平；通过普鲁士蓝染色观察HSC-T6细胞中铁含量的变化；通过ELISA法测定各组HSC-T6细胞上清液中金属蛋白酶组织抑制剂1(TIMP-1)和基质金属蛋白酶13(MMP-13)的表达水平；Western blot法检测HSC-T6细胞中I型胶原蛋白（Col-I）、α-平滑肌肌动蛋白（α-SMA）、caspase-3及Bax蛋白的表...     

厚果崖豆藤提取物抑制NF-κB p65 的活化对三阴性乳腺癌细胞增殖、凋亡和转移的影响

目的:本研究探索厚果崖豆藤提取物MIL对MDA-MB-231乳腺癌细胞增殖、凋亡和转移的影响。方法:将MDA-MB-231细胞随机分为4组,分别在4组细胞的血清DMEM培养基中加入0、2、4、8μmol/L的MIL继续培养,用CCK8试剂盒检测处理细胞存活率;EDU染色检测细胞增殖状态;流式细胞术检测细胞凋亡;Transwell实验观察细胞侵袭的情况;RT-PCR检测E-cadherin、N-cadherin、Vimentin的表达;免疫印迹法检测NF-κB p65蛋白表达变化;免疫荧光检测p65的细胞核转位情况。结果:MIL对MDA-MB-231细胞有毒性作用,其毒性作用呈一定的剂量关系(P0.05)MIL浓度大于16μmol/L时,细胞存活率显著降低(P0.05);2、4、8μmol/L MIL三个处理组增殖抑制作用较0μmol/L MIL处理组明显(P0.05); 2、4、8μmol/L MIL三个处理组细胞凋亡率较0μmol/L MIL处理组明显升高,但差异无统计学意义;与对照组比较,MIL加药组显著抑制细胞增殖(P0.05);而对细胞凋亡率无显著影响;4μmol/L和8μmol/L两个浓度的MIL对MDA-MB-231细胞侵袭能力有显著的抑制作用(P0.05);与0μmol/L MIL处理组对照组比较,2μmol/L、4μmol/L和8μmol/L MIL处理MIL加药组组Vimentin mRNA的表达均显著降低(P0.05);4μmol/L和8μmol/L MIL两个处理组E-cadherin mRNA的表达均显著升高(P0.05),N-cadherin mRNA的表达均显著降低(P0.05);4μmol/L和8μmol/L MIL两个处理组p65磷酸化水平较0μmol/L MIL处理组显著降低(P0.05)。4μmol/L和8μmol/L两个浓度的MIL明显抑制p65的核转位(P0.05)。结论:MIL通过抑制NF-κB p65的活化有效抑制MDA-MB-231细胞增殖、侵袭能力并促进其发生凋亡,表明MIL对三阴性乳腺癌有缓解作用。     

联合抑制PI3K和MEK的活性可协同抑制顺铂耐药卵巢癌细胞的增殖

目的研究磷脂酰肌醇3激酶(PI3K)特异性抑制剂LY294002联合丝裂原活化蛋白激酶激酶(MEK)特异性抑制剂AZD6244对顺铂耐药卵巢癌细胞株(SKOV3/DDP)增殖的影响。方法 (5、10、20、40、80)μmol/L LY294002、(1、2、4、8、16)μmol/L AZD6244单独及联合作用于SKOV3/DDP细胞,MTT法检测对细胞增殖的影响,计算半数抑制浓度(IC50)及合用指数(CI);根据结果确定联合用药的浓度,将实验分为对照组、LY294002组(5μmol/L)、AZD6244组(7μmol/L)及联合组(LY294002 5μmol/L+AZD6244 7μmol/L);作用48 h后,采用MTT法确定细胞生长曲线,计算细胞倍增时间;平板克隆检测集落形成能力;annexinⅤ-PE/7-ADD染色结合流式细胞术(FCM)检测细胞凋亡率,并测定细胞周期;Western blot法检测细胞外信号调节激酶1/2(ERK1/2)、磷酸化的ERK1/2(p-ERK1/2)、AKT、磷酸化的AKT(p-AKT)、细胞周期蛋白D1(cyclin D1)及激活型caspase-3蛋白的水平。结果 LY294002及AZD6244均可抑制SKOV3/DDP细胞增殖,两药联合作用IC50明显降低,此时CI1,具有协同作用;联合组细胞的生长速度较单独作用组及对照组慢;倍增时间延长;集落形成数减少(P0.01);FCM显示联合组凋亡率增高,阻滞于G1期的细胞增多,S期明显减少(P0.05);Western blot结果显示,AKT、ERK1/2蛋白表达水平在各组间无明显差异(P0.05);LY294002组p-AKT水平降低,p-ERK水平增高;AZD6244组p-ERK水平降低,p-AKT水平增高;联合组p-AKT、p-ERK水平均降低,cyclin D1表达较其余各组低,激活型caspase-3较其余各组高。结论 PI3K抑制剂LY294002联合MEK抑制剂AZD6244通过促进细胞凋亡及阻滞细胞周期进展协同抑制SKOV3/DDP细胞生长。     

白藜芦醇对神经母细胞瘤SH-SY5Y增殖的影响

目的:探讨白藜芦醇(Resveratrol,Res)对人神经母细胞瘤SH-SY5Y增殖变化规律和生长状况的影响。方法:通过不同浓度(0.15～500)μmol/LRes作用于SH-SY5Y,检测药物作用5d后各组细胞增殖率和细胞生长状态,同时通过增殖率曲线获得其半数生长抑制浓度(IC50)和杀伤浓度,并对各组细胞进行Hochest染色,检测其细胞凋亡情况。结果:Res5μmol/L组细胞增殖率为(117.00±15.30)%显著高于空白对照组(P0.05),15μmol/L组细胞增殖率为(31.33±2.89)%,50、150、500μmol/L组,细胞出现负增长。Res对SH-SY5Y的IC50为12.78μmol/L,细胞杀伤浓度(即增殖率为0%)为19.88μmol/L。Res50～500μmol/L各组内,部分细胞皱缩,突起减少或消失,并出现凋亡细胞。结论:Res在0.15～500μmol/L浓度范围内对SH-SY5Y的增殖影响存在浓度依赖性,并依次表现为促进增殖、抑制增殖和杀伤细胞三个方面效应。其中杀伤细胞效应与促进SH-SY5Y的凋亡启动相关。     

Development in in vitro toxicology

There are three principal pressures driving the development of in vitro toxicology: (1) the need for more efficient testing systems to cope with the large number of xenobiotics currently being developed; (2) public pressure to reduce animal experimentation; and (3) a need for a better understanding of the mechanisms of toxicity. Within this, in vitro toxicology is focused on local, systemic, and target-organ toxicity. It is becoming increasingly apparent that a step or decision-tree approach using input of a variety of experimental data (physicochemical properties, biokinetics, cytotoxicity) provides the most efficient system for predicting toxicity. Examples of the use of in vitro toxicity systems for prediction of systemic toxicity and target-organ (liver) toxicity are presented.Originally presented at ECCP 93.     

Seasonal variations in acute toxoplasmosis in pregnant women in Slovenia

Between December 1999 and December 2004, 40 081 pregnant women were examined for toxoplasmosis with Toxo-IgG, Toxo-IgM enzyme immunoassay. Women with positive results were then retested with the Toxo-IgG avidity assay for recent toxoplasmosis. Recent acute toxoplasmosis in pregnant women was found to be significantly more frequent (p < 0.01) during winter than summer. The incidence of acute toxoplasmosis during winter-spring was also significantly more frequent (p < 0.025) than summer-autumn. This phenomenon should be taken into account when formulating preventive measures for toxoplasmosis, especially for pregnant women.     

休克过程中肾上腺髓质素变化的研究进展

Adrenomedullin (AM) is a new peptidergic regulator of vascular function. AM serves as a hormone, which has many biological properties, plays an important role in the many pathophysiological processes, especially shock. This review will highlight the structure, biological properties of AM and the relationship between AM and shock.     

Age-related changes in polyamines in memory-associated brain structures in rats

Polyamines putrescine, spermidine and spermine are positively charged aliphatic amines and have important roles in maintaining normal cellular function, regulating neurotransmitter receptors and modulating learning and memory. Recent evidence suggests a role of putrescine in hippocampal neurogenesis, that is significantly impaired during aging. The present study measured the polyamine levels in memory-related brain structures in 24- (aged), 12- (middle-aged) and 4- (young) month-old rats using liquid chromatography/mass spectrometry and high performance liquid chromatography. In the hippocampus, the putrescine levels were significantly decreased in the CA1 and dentate gyrus, and increased in the CA2/3 with age. Significant age-related increases in the spermidine levels were found in the CA1 and CA2/3. There was no difference between groups in spermine in any sub-regions examined. In the parahippocampal region, increased putrescine level with age was observed in the entorhinal cortex, and age did not alter the spermidine levels. The spermine level was significantly decreased in the perirhinal cortex and increased in the postrhinal cortex with age. In the prefrontal cortex, there was age-related decrease in putrescine, and the spermidine and spermine levels were significantly increased with age. This study, for the first time, demonstrates age-related region-specific changes in polyamines in memory-associated structures, suggesting that polyamine system dysfunction may potentially contribute to aged-related impairments in hippocampal neurogenesis and learning and memory.     

Secular change in menarche in women in Madrid

The age at menarche was estimated by recollection in 1617 women between the ages of 18 and 60 in Madrid and a nearby suburb, Pinto. The population of Pinto is working-class and the Madrid group, taken from residential neighbourhoods , belongs to the upper middle class. In both groups we found a diminution in average age at menarche, from 14.04 to 13.02 years in Madrid and from 14.55 to 13.16 years from about 1935 to about 1965 in Pinto. These changes have been more intense in the group which is less well-off economically, where living conditions have varied much more drastically.     

The cyclic-AMP concentration in plasma and in muscle in response to exercise and beta-blockade in man

At rest the cAMP concentration in (muscle samples of) the quadriceps femoris ranged from 1.55 to 3.00 μmol per kg dry muscle and in plasma from 15.3 to 32.3 nmol per 1. Blockade of the beta adrenoreceptors with propranolol resulted in a significant decrease in the concentration in muscle at rest, the magnitude of the fall being related to the inital level. Similarly in plasma there was a trend towards lower levels of cAMP in those with the highest pretreatment levels, but the overall change was not statistically significant. There was no relation between the concentrations in muscle and plasma, before or after beta-blockade. Maximum dynamic exercise for 4–8 min resulted in an approximate doubling in the cAMP concentration in both muscle and blood. The increase in plasma was closely related to that in muscle. Beta-blockade inhibited totally the rise in cAMP in muscle during exercise but was marginally less effective in preventing the increase in blood. No increase in plasma or muscle cAMP levels during 40–70 s isometric contraction were observed.