黄芪甲苷与人参皂苷Rg1配伍对PC12细胞氧糖剥夺复糖复氧后细胞自噬和PI3K信号通路的影响

目的:探讨黄芪甲苷和人参皂苷Rg1配伍对PC12细胞氧糖剥夺后再复糖复氧(oxygen glucose deprivation/reoxygenation,OGD/R)诱导的细胞自噬的影响及作用机制。方法:以PC12细胞建立OGD/R自噬性损伤模型,观察黄芪甲苷与人参皂苷Rg1配伍对细胞自噬的影响,并通过PI3KⅠ/Akt/m TOR和PI3KⅢ/beclin-1/Bcl-2信号通路研究黄芪甲苷与人参皂苷Rg1配伍的作用机制。结果:氧糖剥夺2 h复糖复氧24 h后,PC12细胞内LC3-Ⅱ/LC3-Ⅰ蛋白比值增加。黄芪甲苷、人参皂苷Rg1及黄芪甲苷与人参皂苷Rg1配伍均能下调OGD/R后PC12细胞LC3-Ⅱ/LC3-Ⅰ蛋白比值,且配伍组的效应强于药物单用组。机制研究表明,人参皂苷Rg1单用及黄芪甲苷和人参皂苷Rg1配伍能升高PI3KⅠ、Akt、m TOR蛋白磷酸化水平,配伍的效应强于药物单用;黄芪甲苷单用及黄芪甲苷和人参皂苷Rg1配伍均能抑制PI3KⅢ、beclin-1蛋白表达,而配伍还能上调Bcl-2蛋白表达,且配伍的效应强于药物单用组。结论:PC12细胞在缺糖缺氧2 h再复糖复氧24 h后,细胞出现自噬;黄芪甲苷和人参皂苷Rg1均能减轻OGD/R诱导的PC12细胞自噬,且2者配伍对细胞自噬具有协同抑制作用,其机制可能与调节PI3KⅠ/Akt/m TOR和PI3KⅢ/beclin-1/Bcl-2信号通路有关。     

高浓度葡萄糖通过下调自噬增加体外培养雪旺细胞的凋亡

目的 观察高浓度葡萄糖对雪旺细胞自噬活性的影响以及自噬对高糖条件下雪旺细胞增殖活性及凋亡的影响.方法 体外培养RSC96细胞,Western blot和免疫荧光法检测beclinl和caspase-3蛋白表达,MTT检测细胞增殖活性.结果 高浓度葡萄糖组RSC96细胞beclin1的表达减少(P＜0.05),细胞增殖活性降低(P ＜0.05,P＜0.01).自噬被抑制后加剧了高糖对细胞增殖活性的削弱作用(P＜0.01),同时增加了高糖促进caspase-3的活化作用(P＜0.01).结论 高浓度葡萄糖通过下调自噬活性增加细胞凋亡.     

食管鳞状细胞癌中Beclin1、LC3和mTOR的表达及其临床意义

目的探讨Beclin1、LC3和m TOR在食管鳞状细胞癌中的表达,并分析其临床意义。方法采用免疫组化En Vision法检测食管30例正常黏膜、32例低级别上皮内瘤变、34例高级别上皮内瘤变、35例早期癌及126例进展期癌中Beclin1、LC3和m TOR的表达,并分析其相关性及其与临床病理特征的关系。结果 Beclin1在进展期癌组中的表达高于其他四组(P0.005)。LC3在食管进展期癌组的表达高于正常黏膜组、低级别上皮内瘤变及早期癌组(P0.005)。m TOR在进展期癌组中的表达高于正常黏膜组、低级别上皮内瘤变及高级别上皮内瘤变组(P0.005)。Beclin1、LC3、m TOR表达与肿瘤TNM分期、淋巴结转移具有显著相关性(P0.05)。Beclin1与LC3、Beclin1与m TOR在食管进展期癌中的表达均呈正相关(P0.05),m TOR与LC3在高级别上皮内瘤变组及进展期癌中的表达呈正相关(P0.05)。结论在食管癌的发生、发展中,Beclin1作为抑癌基因激活自噬,导致肿瘤细胞过度自我消耗死亡;m TOR通过抑制自噬及促进血管生成,促进肿瘤生长。联合检测Beclin1、LC3和m TOR在食管癌中的表达,有助于评估进展程度和预后判断。     

重组IL-12对人乳腺癌细胞自噬的研究

目的 探讨重组人IL-12（rIL-12）对乳腺癌细胞自噬的影响。方法 两株乳腺癌细胞（MDA-MB-231和MCF7）分别用rIL-12处理,经免疫蛋白印迹技术和细胞免疫荧光技术检测其自噬微管相关蛋白轻链3（LC3）的变化,以观察自噬情况;另外,用透射电镜观察rIL-12处理乳腺癌细胞前后自噬小体的变化。分别用胰岛素样生长因子1（IGF-1）激活磷脂酰肌醇-3激酶/蛋白激酶B（PI3K/Akt）通路,再加入rIL-12处理后,蛋白免疫印迹法检测相关通路蛋白PI3K/Akt, 哺乳动物雷帕霉素靶点（TOR）磷酸化变化及LC3的表达。结果 与空白组相比,rIL-12组细胞的自噬标志蛋白LC3表达增高,差异有统计学意义（P＜0.05）,且增加程度呈时间和浓度依赖性;荧光显微镜观察自噬体形成的结果显示,与空白组相比,rIL-12处理组的细胞核周点状聚集的绿色荧光增多;使用电镜观察到rIL-12处理组明显有自噬小体形成。与rIL-12组相比,IGF-1+rIL-12组的LC3Ⅱ表达减少,差异有统计学意义（P＜0.05）。结论 rIL-12可以激活乳腺癌细胞自噬,并通过抑制PI3K/Akt信号通路的机制,促进自噬标志蛋白LC3,特别是LC3Ⅱ的表达。     

自噬在晚期糖基化终产物诱导的内皮细胞凋亡中的作用

目的: 研究晚期糖基化终产物(AGEs)对人脐静脉内皮细胞(HUVECs)自噬水平的影响并探讨自噬在AGEs诱导的内皮细胞凋亡中的作用。方法: 用AGEs处理HUVECs,相同条件牛血清白蛋白处理为对照组,Western blotting检测相应蛋白表达的变化,电镜观察细胞自噬体的出现,流式细胞术检测细胞凋亡,MTT比色法测定细胞活性。结果: AGEs处理HUVECs后,自噬相关蛋白LC3-Ⅱ的表达显著上调并呈时间和浓度依赖性,电镜观察到细胞胞浆内自噬体数量增加;与对照组比较,AGEs处理组内皮细胞凋亡率增加,活性下降,自噬抑制剂3-甲基腺嘌呤预处理的AGEs组细胞活性较AGEs组进一步下降,凋亡率继续增加。AGEs处理HUVECs后,蛋白激酶B(Akt)和哺乳动物雷帕霉素靶蛋白(mTOR)的磷酸化水平也明显下调, Akt激活剂胰岛素样生长因子1预处理后,Akt的磷酸化水平增加,自噬相关蛋白LC3-Ⅱ的增高表达被抑制。结论: AGEs通过PI3K/Akt/mTOR介导的信号通路诱导HUVECs自噬水平升高。自噬在AGEs诱导的内皮细胞凋亡中对细胞起保护作用。     

RIPK2介导自噬对高糖诱导的小鼠肾系膜细胞ROS、caspase-1及IL-1β表达的激活作用

目的观察受体结合丝氨酸/苏氨酸激酶2(RIPK2)介导自噬对高糖诱导的肾系膜细胞(GMCs)ROS、caspase-1及IL-1β表达的调控。方法体外培养正常小鼠GMCs,高糖作为刺激因子,设计siRNA靶向沉默RIPK2表达并构建自噬双荧光(mRFP-GFP-LC3)标记体系,激光共聚焦显微镜观察自噬流变化;DCFH-DA荧光探针检测细胞内ROS水平;Western blot及RT-PCR检测RIPK2、LC3Ⅱ/Ⅰ、caspase-1、IL-1β蛋白及mRNA表达;ELISA检测IL-1β的分泌。结果 1)高糖呈时间-浓度依赖性增加细胞内ROS水平,诱导caspase-1和IL-1β表达(P0.05)。2)短期(0~12 h)高糖刺激可诱导RIPK2和LC3Ⅱ/Ⅰ表达(P0.05),超过12 h后RIPK2和LC3Ⅱ/Ⅰ表达下调(P0.05)。3)siRNA靶向沉默RIPK2下调LC3Ⅱ/Ⅰ表达和细胞自噬流形成,上调细胞内ROS、caspase-1及IL-1β表达(P0.05)。结论 RIPK2介导自噬负性调控高糖诱导的ROS、caspase-1及IL-1β表达,可能是防治糖尿病肾脏疾病(DKD)的新思路。     

PI3K/Akt信号通路在脓毒症肾脏损伤诱导的自噬中的调节作用*

 目的：研究脓毒症造成肾脏损伤时的自噬情况以及磷脂酰肌醇3-激酶（PI3K）/蛋白激酶B(Akt)信号通路的调节作用。方法：对大鼠盲肠进行结扎与穿刺（CLP）,对肾脏组织切片进行HE染色,并测定血清尿素氮和肌酐。通过Western blotting定量分析CLP大鼠肾脏损伤发生后不同时点自噬相关分子微管相关蛋白轻链3（LC3）Ⅰ/Ⅱ、beclin-1和Akt蛋白磷酸化的表达情况;体外用LPS诱导人近端肾小管上皮细胞株HK-2发生自噬,检测不同浓度LPS和不同刺激时间自噬相关分子LC3Ⅰ/Ⅱ和Akt蛋白磷酸化的表达情况;进一步使用PI3K抑制剂、Akt抑制剂和LPS刺激HK-2细胞观察自噬相关蛋白的表达情况及细胞的凋亡水平。结果：同对照组相比,CLP大鼠显微镜下可见肾损伤的典型病理改变,血清尿素氮和肌酐均有上升。CLP肾脏损伤发生后,自噬相关蛋白LC3Ⅰ/Ⅱ、beclin-1含量及Akt磷酸化水平均有上升。LPS刺激HK-2细胞后,随着刺激浓度的增加,p-Akt(308)表达量逐渐提高,而LC3Ⅰ/Ⅱ及p-Akt(472)的表达量在10 mg/L LPS刺激组最高。随着刺激时间的延长,p-Akt(308)表达量逐渐提高;LC3Ⅰ/Ⅱ表达量同p-Akt(472)在刺激8 h时最高;使用PI3K抑制剂及Akt抑制剂后,LPS诱导的LC3表达显著下调,HK-2细胞凋亡明显增加。结论：CLP肾脏损伤发生时可以诱导自噬发生, PI3K／Akt信号通路在其中发挥重要调节作用。     

双氢青蒿素通过调控细胞自噬性死亡增强宫颈癌细胞的化疗敏感性

目的:探究双氢青蒿素(DHA)对宫颈癌HeLa细胞化疗敏感性的影响及作用机制。方法:用5、10、20μmol/L的DHA处理细胞,CCK8检测细胞存活率;顺铂联合不同浓度DHA处理细胞并检测细胞活性;将细胞分为Control、DHA(20μmol/L)、Cisplatin(10μg/ml)和DHA+Cisplatin组,分别用溶媒、DHA(20μmol/L)、顺铂(10 mg/L)和DHA联合顺铂处理细胞24 h,CCK8检测细胞增殖,流式检测细胞凋亡,免疫荧光检测LC3表达,免疫印迹检测Ki67、Cleaved Caspase-3、Beclin1、LC3、P62、雷帕霉素靶蛋白(m TOR)、p-mTOR、p-Ulk1和Ulk1的表达。结果:DHA处理细胞4 d后,细胞增殖倍数明显降低;DHA (10,20μmol/L)联合顺铂处理细胞后,细胞活性显著降低,并具有量效关系;与Control组比较,DHA(20μmol/L)组Ki67表达水平明显降低,细胞凋亡率和Cleaved Caspase-3的表达水平明显升高;与Cisplatin组比较,DHA+Cisplatin组Ki67表达水平明显降低,凋亡率和Cleaved Caspase-3的表达水平显著降低;同时,DHA(20μmol/L)组自噬相关蛋白Beclin1的表达水平、LC3Ⅱ/LC3Ⅰ及LC3在细胞质的表达率均显著低于Control组,P62的表达水平明显升高; DHA+Cisplatin组细胞Beclin1的表达水平、LC3Ⅱ/LC3Ⅰ及LC3在细胞质的表达率与Cisplatin组比较均显著降低,P62的表达水平升高;此外,DHA还能明显升高降低He La细胞p-mTOR/m TOR和p-Ulk1/Ulk1的比值。DHA能显著减弱顺铂下调p-mTOR/m TOR和p-Ulk1/Ulk1的作用。结论:DHA能通过激活m TOR/Ulk1信号通路抑制自噬增强宫颈癌He La细胞的化疗敏感性。     

沉默c-myc基因对Raji细胞自噬活性的影响

为了研究沉默c-myc基因后Raji细胞自噬活性的变化及其机制,采用脂质体转染SiRNA法沉默c-myc基因,在透射电镜下观察细胞自噬体的形成情况,采用western blot法测定LC3-Ⅰ、LC3-Ⅱ、Beclin-1、磷酸化P70、磷酸化AKT蛋白的表达。研究发现沉默c-myc基因后,电镜下观察到Raji细胞自噬活性随时间而增强,LC3-Ⅰ、LC3-Ⅱ蛋白表达、LC3-Ⅱ/LC3-Ⅰ比值随时间而增高;Beclin-1表达增高,磷酸化P70表达降低,磷酸化AKT表达无明显变化。结果提示沉默c-myc基因使Raji细胞自噬活性明显增强,其机制是通过上调Beclin-1表达和抑制mTOR的活性来实现的。     

氟西汀调控CUMS抑郁大鼠海马突触重塑

目的:探究氟西汀(fluoxetine)对慢性不可预见性温和刺激(chronic unpredictable mild stress,CUMS)抑郁大鼠海马突触重塑的m TOR和细胞自噬信号调控作用。方法:60只雄性Sprague-Dawley大鼠随机分成正常对照(control)组、CUMS组和氟西汀组。采用CUMS结合孤养法构建CUMS抑郁模型,期间给予氟西汀(20 mg·kg-1·d-1)灌胃治疗。通过体重变化、糖水测试水平及行为学实验验证模型建立,采用RT-PCR和Western blotting等生化方法测定突触重塑相关蛋白胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)、突触泡蛋白(synaptophysin,SYP),细胞凋亡相关蛋白Bcl-2、cleaved caspase-3,m TOR信号通路相关蛋白m TOR、4EBP1,自噬相关蛋白beclin 1、LC3 mRNA及蛋白表达水平的变化。结果:与control组相比,CUMS大鼠的体重、糖水摄取量、旷场实验总路程和中间停留时间均下降,差异具有统计学显著性。RT-PCR和Western blotting实验结果显示,与control组相比,CUMS组SYP和GFAP的mRNA和蛋白水平显著下调,Bcl-2表达下调,cleaved caspases-3上调,m TOR及下游靶分子4EBP1磷酸化水平下调,细胞自噬关键基因beclin1和LC3在mRNA和蛋白水平显著上调。氟西汀可以减缓以上结果中的上调或下调趋势,差异具有统计学显著性。结论:氟西汀可能通过下调细胞凋亡和自噬信号通路以及上调m TOR信号通路调节海马突触重塑并缓解抑郁症状。     

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.     

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.     

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.     

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.     

Uteroglobin in the developing rabbit conceptus in vivo and in vitro

Summary Uteroglobin (UGL) was measured in day- 4 to day-10 rabbit conceptuses by a competitive ELISA. Levels in blastocyst fluid, tissues, coverings and in the early fetus were determined separately. The total amount of UGL increased from 18.4 ng to 6.8 g per conceptus. The UGL content of individual day-6 blastocysts was studied in vitro. Culturing was carried out up to 60 h in Ham's F10 medium with polyvinylpyrrolidone as macromolecular component, with and without progesterone, and with progesterone plus estradiol. UGL was determined in the blastocyst fluids, tissues with coverings and in the culture media. After labelling with [³⁵S]-methionine, protein patterns of total blastocysts and of culture media were analysed by two-dimensional gel electrophoresis and fluorography. The morphology of cultured blastocysts was examined by electron microscopy. During 60 h of culture, the blastocysts expanded in diameter by 84%, and released 19% of their initial UGL content into the medium, independent of the hormonal substitution. Neither de novo synthesis, nor degradation of UGL was found: the protein remained unlabelled in fluorography, and its total quantity was not significantly different from that of non-cultured controls. Trophoblast, endoderm and embryoblast cells showed well preserved cell organelles and intercellular junctions, while the morphological differentiation of the germ layer was inhibited.