苯对外周血人淋巴细胞周期阻滞及凋亡影响

目的 研究苯及其代谢产物氢醌对外周血人淋巴细胞周期阻滞与凋亡的影响,探讨苯的细胞毒性作用机制.方法 离体培养人淋巴细胞24h后加S9液,设置苯低、中、高浓度(0.25、3.5、50 μmol/L)和氢醌低、中、高浓度(50、150、450 μmol/L)的染毒组,另设空白对照组和溶剂对照组,采用四甲基偶氮唑蓝比色法检测细胞相对存活率,流式细胞术检测细胞周期和凋亡的分布状况,荧光检测细胞存活率的含量,单细胞凝胶电泳技术检测DNA断裂.结果 苯与氢醌剂量依赖性降低人淋巴细胞存活率,诱导人淋巴细胞阻滞于S+ G2/M期,并明显促凋亡且随着染毒浓度升高细胞内活性氧含量增加,与对照组比较,差异有统计学意义(P＜0.05),苯与氢醌高浓度组彗星尾长分别为(26.45±7.96)、(30.28 ±6.07)μm,均明显高于对照组(P＜0.01).结论 苯及其代谢物氢醌在体外可导致人淋巴细胞存活率降低,细胞周期紊乱,其机制与细胞内活性氧产生及DNA -蛋白质损伤有关.     

c-jun末端激酶在亚砷酸钠致人胚胎肝细胞损伤中的表达

目的探讨亚砷酸钠染毒对人胚胎肝(L-02)细胞中c-jun末端激酶(JNK)的变化。方法将处于对数生长期的L-02细胞分别暴露于终浓度为0(对照)、50、100、150μmol/L的亚砷酸钠溶液中培养24 h,采用四甲基偶氮唑蓝(MTT)法检测细胞生长情况,采用流式细胞术检测染毒24 h时的细胞周期及细胞凋亡率;采用蛋白杂交(Western-blot)法检测JNK及p-JNK的蛋白表达水平。结果与对照组相比,各浓度亚砷酸钠染毒组L-02细胞的存活率及G0-G1期构成比均较低,JNK、p-JNK的蛋白表达水平和S期构成比及凋亡率均较高;而G2-M期构成比在50μmol/L亚砷酸钠染毒组较低,在100、150μmol/L亚砷酸钠染毒组均较高,差异均有统计学意义(P0.05)。且随着亚砷酸钠染毒浓度的升高,L-02细胞凋亡率及JNK和p-JNK蛋白的表达水平均呈上升趋势,细胞存活率呈下降趋势。结论亚砷酸钠诱导L-02细胞凋亡可能与JNK及p-JNK表达的增加有关。     

Effect of Iodide Excess on Human Thyroid Cells ( Nthy-ori 3-1) Apoptosis

目的 探讨碘过量对人正常甲状腺细胞(Nthy-ori 3-1)的损伤作用及机制.方法 用0(对照)、1、10、50mmol/L的碘化钾(KI)作用于体外培养的Nthy-ori 3-1细胞24h后,分别采用噻唑蓝(MTT)法、乳酸脱氢酶(LDH)比色法检测细胞存活率和LDH漏出率,利用流式细胞术检测活性氧(ROS)水平、细胞周期构成比及凋亡率.结果 与对照组相比,50 mmol/L碘染毒组细胞存活率明显下降(P＜0.05),LDH漏出率明显上升(P＜0.05).各剂量组之间ROS产生水平差异无统计学意义.50 mmol/L碘染毒组G0/G1期细胞百分比明显增多(P＜0.05),但S期百分比明显减少(P＜0.05),且细胞凋亡率明显上升(P＜0.05).结论 一定剂量的碘能降低甲状腺细胞存活率,增加LDH漏出率,细胞G0/G1期阻滞和诱导细胞凋亡,碘对甲状腺的损伤作用可能与碘对细胞周期的影响有关.     

苯并[a]芘对小鼠睾丸支持细胞缝隙连接蛋白表达及细胞增殖的影响

[目的]探讨苯并[a]芘(BaP)在不引起小鼠睾丸支持细胞凋亡的情况下,对缝隙连接蛋白43(CX43)表达及细胞增殖的作用. [方法]取小鼠睾丸支持细胞系——TM4细胞,以二甲基亚砜为对照,0.5、10.0 μmol/L浓度的BaP同时染毒培养的TM4细胞,并于染毒的4h、72h后收集细胞,检测细胞的活力、增殖、凋亡情况,以及CX43的mRNA和蛋白的表达量. [结果]与对照组相比:BaP染毒4h时,两个染毒组细胞存活率、增殖、凋亡和CX43蛋白表达没有明显变化(P＞0.05),而CX43 mRNA的表达升高(P＜0.05);72h时,两个染毒组细胞凋亡无明显变化,而细胞存活率和增殖均下降(P＜0.05),CX43 mRNA和蛋白表达出现上升(P＜0.05). [结论]0.5、10.0 μmol/L浓度的BaP染毒小鼠睾丸支持细胞,可抑制细胞增殖,引起CX43 mRNA和蛋白表达升高.     

溶酶体在2,2’,4,4’-四溴联苯醚诱导HepG2细胞凋亡中的作用

[目的]探讨2,2’,4,4’-四溴联苯醚(BDE 47)致人肝癌HepG2细胞凋亡机制. [方法]不同浓度BDE 47(0.00、6.25、12.50、25.00、50.00、100.00 μmol/L)染毒HepG2细胞24h,采用四氮唑盐比色法(MTT法)检测细胞存活率;用2’,7’-二氢二氯荧光素(DCFH-DA)探针检测活性氧水平;用吖啶橙(AO)探针及罗丹明(Rh123)荧光探针分别检测溶酶体膜通透性和线粒体膜电势,并通过溶酶体组织蛋白酶B特异性抑制剂环氧酶琥珀酰肽甲基酯(CA-074)验证溶酶体在BDE 47细胞毒性的作用. [结果]与对照组比较,50.00、100.00 μmol/L BDE 47染毒组HepG2细胞存活率明显降低(P＜0.01);各BDE47染毒组HepG2细胞凋亡率明显升高(P＜0.01),呈现剂量-效应关系(R2=0.981);各BDE47染毒组HepG2细胞活性氧含量明显升高(P＜0.01),≥12.50μmol/L BDE 47染毒组HepG2细胞内溶酶体膜通透性明显升高(P＜0.05; P＜0.01),各BDE47染毒组HepG2细胞内线粒体膜电势明显降低(P＜0.01),上述3项指标与染毒浓度均呈剂量-效应关系(R2=0.918,R2=0.636,R2=0.678).25 μmol/L CA-074能够明显干预50 μmol/L BDE 47对细胞的毒性作用使细胞存活率升高,细胞调亡减少(均P＜0.05). [结论]BDE47可能通过溶酶体介导线粒体途径诱导HepG2细胞凋亡.     

叔丁基过氧化氢体外模拟噪声引起的耳蜗毛细胞氧化损伤模型的建立

目的 研究有机氧化剂叔丁基过氧化氢(t-BHP)体外模拟噪声对耳蜗毛细胞的氧化损伤.方法 用t-BHP染毒,设置从30～4000 μmol/L8个染毒浓度对耳蜗毛细胞(HEI-OC1)细胞染毒12h,绘制100 μmol/L浓度组染毒时间(1～96 h)与耳蜗毛细胞存活率曲线;采用台盼蓝染色法检测细胞存活率,噻唑蓝(MTT)试验检测细胞增殖能力的改变,2’-7’-二氯荧光黄双乙酯(DCFH-DA)探针法检测胞内活性氧(ROS)水平.结果 不同浓度的t-BHP对耳蜗毛细胞染毒12h后,100μmol/L以上浓度组细胞存活率开始出现有统计学意义的下降,其中200～2000μmol/L浓度组细胞存活率呈直线下降.100 μmol/L浓度组t-BHP染毒时间-细胞存活率曲线较为平缓.MTT试验提示,30μmol/L的t-BHP染毒可以促进耳蜗毛细胞增殖,200μmol/L以上各浓度组则抑制细胞增殖.DCFH-DA探针法显示,无染毒细胞镜下无荧光(-),阳性对照为强荧光(+),30和50 μmol/L浓度组则有弱荧光(-+),100μmol/L染毒组为强明亮荧光(++),200～1000μmol/L各组荧光均较强,但随着存活率的迅速降低视野下细胞稀疏.结论 100 μmol/L的t-BHP对HEI-OC1细胞染毒12h可以在不影响细胞外形、增殖能力的前提下提高耳蜗毛细胞内ROS水平,模拟噪声引起的氧化应激.     

DNA依赖蛋白激酶抑制剂对1,4-苯醌诱导的非p53依赖的HL60细胞凋亡的影响

目的 探讨DNA依赖蛋白激酶(DNA-PK)抑制剂NU7026和渥曼青霉素(Wortmannin)对1,4-苯醌(1,4-BQ)诱导的人早幼粒白血病细胞(HL60)细胞凋亡的影响.方法 HL60细胞分为染毒组(0、5、10、25和50μmol/L1,4-BQ染毒24 h)和NU7026 、Wortmannin预处理组(10μmol/L NU7026、25μmol/L Wortmannin分别预处理1h后以0、5、10、25和50 μmol/L 1,4-BQ染毒24 h),用流式细胞仪Annexin V/PI双染法和DNA Ladder法分析检测细胞凋亡水平.将HL60细胞分为空白对照组、NU7026处理组(10 μmol/L)、Wortmannin处理组(25 μmol/L)、1,4-BQ染毒组(10 μmol/L)、NU7026+1,4-BQ组(10μmol/L NU7026预处理1h,以10 μmol/L 1,4-BQ染毒24 h),25 μmol/L Wortmannin+1,4-BQ组(25μmol/L Wortmannin预处理1h,以10 μmol/L 1,4-BQ染毒24 h),用real-time PCR法检测Bax mRNA基因表达;蛋白免疫印迹法(Western blot)检测HL60细胞的p53蛋白表达.结果 流式细胞仪Annexin V/PI双染法结果显示,NU7026+10 μmol/L 1,4-BQ处理组细胞凋亡率为17.6％±1.19％,Wortmannin+ 10μmol/L 1,4-BQ处理组细胞凋亡率为15.2％±1.22％,两组细胞凋亡率均高于10 μmol/L 1,4-BQ染毒组(6.3％±1.04％);NU7026+25tμmol/L1,4-BQ处理组细胞凋亡率为46.2％±3.55％,Wortmannin+25 μmol/L1,4-BQ处理组细胞凋亡率为26.9％±2.62％,两组细胞凋亡率均明显高于25 μmol/L 1,4-BQ染毒组(14.1％±1.54％);NU7026+50 μmol/L1,4-BQ处理组细胞凋亡率为61.8％±1.78％,明显高于50 μmol/L1,4-BQ染毒组(35.9％±4.51％),以上各组的差异均有统计学意义(P＜0.05).DNA Ladder法结果与流式细胞仪检测数据基本一致.与NU7026组和1,4-BQ染毒组比较,NU7026+1,4-BQ组Bax mRNA表达水平升高;与Wortmannin组和1,4-BQ组比较,Wortmannin+1,4-BQ组Bax mRNA表达水平升高,差异均有统计学意义(P＜0.05).Western blot检测HL60细胞不表达p53蛋白.结论 DNA-PK抑制剂NU7026和Wortmannin促进1,4-BQ诱导的非p53依赖的HL60细胞凋亡.     

三甲基氯化锡诱导PC12细胞凋亡的机制

目的 在体外条件下,研究三甲基氯化锡(trimethyltin chloride,TMT)对PC12细胞增殖、细胞凋亡及细胞氧化损伤的作用,并探讨TMT对NF-kB表达的影响.方法 (1)不同浓度TMT(0、0.3125、0.6250、1.2500、2.500、5.000、10.000、20.000 μmol/L)处理PC12细胞24、48 h,噻唑蓝(MTT)法测定细胞存活率;(2)1.25、2.50、5.00、10.00 μmol/L TMT分别染毒PC12细胞12、24h后,流式细胞仪检测检测细胞凋亡率;(3)1.25、2.50、5.00、10.00 μmol/L剂量的TMT染毒PC12细胞6h后,测定活性氯(ROS)和谷胱甘肽(GSH)含量的变化;(4)1.25、2.50、5.00、10.00 μmol/L剂量的TMT染毒PC12细胞12h后免疫印迹法(Western blot)检测核蛋白NF-kB的水平.结果 与溶剂对照组比较,染毒24 h,2.5000、5.0000、10.0000、20.0000 μmol/L TMT剂量组细胞存活率明显下降;染毒48 h,1.2500、2.5000、5.0000、10.0000、20.0000 μmol/L剂量组细胞存活率明显下降,差异均有统计学意义(P＜0.05).1.25、2.50、5.00、10.00 μmol/L TMT染毒细胞12h,凋亡率分别为15.30％±0.75％、18.90％±0.61％、22.00％±0.60％、36.50％±0.66％,染毒24 h凋亡率分别为28.60％±0.40％、43.54％±2.00％、65.73％±0.71％、74.67％±0.40％,明显高于对照组[12 h:(12.80％±1.00％)、24 h:(16.83％±0.25％)],差异均有统计学意义(P＜0.05).1.25、2.50、5.00、10.00 μmol/L剂量组的ROS荧光强度值分别为对照组的1.42、1.71、1.78、1.89倍,差异有统计学意义(P＜0.05).2.50、5.00、10.00 μmol/L组GSH含量分别为(0.17±0.0)、(0.20±0.04)、(0.07±0.03)μmol/μg pro,明显低于对照组(0.30±0.01) μmol/L pro,差异有统计学意义(P＜0.05).2.50、5.00、10.00 μmol/L剂量组NF-kB p65表达的蛋白条带灰度值明显高于对照组,差异有统计学意义(P＜0.05).结论 在本实验条件下,TMT对PC12细胞具有明显抑制增殖和诱导凋亡的作用,其作用可能与氧化应激以及NF-kB信号通路的激活有关.     

亚砷酸钠对人正常肝细胞凋亡及Bax和Bcl-2 mRNA和蛋白表达的影响

目的探讨亚砷酸钠对人正常肝(L-02)细胞凋亡及Bax、Bcl-2 m RNA和蛋白表达的影响。方法将L-02肝细胞分别暴露于含0(对照)、50、100、150μmol/L亚砷酸钠的培养基中暴露24 h。采用MTT法检测L-02肝细胞的存活率,采用流式细胞术检测L-02肝细胞凋亡率,采用RT-PCR的方法检测Bax、Bcl-2 m RNA相对表达情况,采用Westernblotting方法检测L-02肝细胞中Bax、Bcl-2蛋白的表达情况。结果与对照组相比,各浓度亚砷酸钠染毒组L-02细胞的存活率均较低,凋亡率均较高,差异均有统计学意义(P0.05);且随着亚砷酸钠染毒浓度的升高,L-02细胞的存活率呈下降趋势,而凋亡率上升趋势。与对照组相比,各浓度亚砷酸钠染毒组L-02细胞中Bcl-2、Bax m RNA和蛋白的表达水平均较高,100μmol/L亚砷酸钠染毒组Bcl-2 m RNA/Bax m RNA值也较高,而150μmol/L亚砷酸钠染毒组Bcl-2 m RNA/Bax m RNA值及50、150μmol/L亚砷酸钠染毒组Bcl-2蛋白/Bax蛋白值均较低,差异均有统计学意义(P0.05)。结论亚砷酸钠可抑制L-02肝细胞的生长,诱导细胞凋亡的发生;其机制可能与Bcl-2家族的激活有关。     

亚砷酸钠对Chang肝细胞增殖与凋亡的影响

目的 探讨亚砷酸钠对正常人Chang肝细胞体外增殖及凋亡的影响.方法 采用0(对照)～100 μmol/L亚砷酸钠分别处理细胞24、48、72、96 h.采用MTT比色法检测细胞活力;采用流式细胞术检测染毒48 h时的细胞凋亡率.结果 仅0.2μmol/L亚砷酸钠染毒24 h的细胞活力略高于对照组,但差异无统计学意义;且随着亚砷酸钠染毒浓度的升高和染毒时间的延长,Chang肝细胞存活率均呈下降趋势,并具有剂量-效应和时间-效应关系.与对照组相比较,5～100 μmol/L亚砷酸钠染毒组Chang肝细胞凋亡率均显著升高,差异有统计学意义(P＜0.05);且随着亚砷酸钠染毒浓度的升高,Chang肝细胞的凋亡率呈显著升高趋势,并具有剂量-效应关系.结论 亚砷酸钠有明显的细胞毒性,能抑制Chang肝细胞的增殖,这可能与其诱导细胞凋亡有关.     

Alcohol, injury, and cellular immunity.

It is widely accepted that alcohol exposure is a causative factor in the occurrence of burn or other traumatic injury. It is less well known that individuals who have consumed alcohol before sustaining an injury suffer from increased morbidity and mortality compared with the morbidity and mortality of non-alcohol-consuming subjects with similar injuries. Complications due to bacterial infection are the most common burn sequelae in injured patients and are frequently associated with depressed immunity. Independently, alcohol exposure and injury have been shown to influence cellular immunity negatively. These changes in immunity are closely linked to injury- or alcohol-induced alterations in the cytokine milieu in both clinical studies and animal models. Not surprisingly, the combination of insult of alcohol exposure and burn injury results in immune suppression that is greater in magnitude and duration compared with either insult alone. The combined effects of alcohol and injury on immunity have been examined in a limited number of studies. However, results of these studies support the suggestion that altered cytokine production is an integral part of the immune dysregulation and increased mortality that is observed. In particular, the increased presence of macrophage-derived mediators observed after burn or alcohol exposure alone seems to be synergistically increased in a combined injury model. Although more research is needed, it is likely that therapeutic modalities that include manipulation of cytokine networks to boost cellular immunity may improve outcome for patients who sustain injuries subsequent to consuming alcohol.     

Molecular, cellular and clinical aspects of myocardial ischemia

The authors summarize the fundamentals and actualities of the molecular and cellular background of myocardial ischaemia-reperfusion for the clinician. Metabolic changes following acute and chronic ischaemia and the role of free radicals, white blood cells, the endothelium, the heat shock proteins are reviewed. "New ischaemic syndromes" are important intrinsic adaptation mechanisms. Stunning is a transient contractile dysfunction following short periods of coronary occlusion in spite of restored perfusion. Hibernating myocardium is resulted after progressive chronic ischaemia including reversible contractile dysfunction, reduced metabolism and cellular dedifferentiation. Preconditioning means concomitant development of a protected state against lethal ischaemia after mild noxious stimuli. Several strategies are considered for myocardial cytoprotection based on the complex physiopathology of ischaemia-induced injury.     

Evaluation of oocyte quality: morphological, cellular and molecular predictors

Mounting evidence that oocyte quality profoundly affects fertilisation an d subsequent embryo development drives the continued search for reliable predictors of oocyte developmental competence. In the present review, we provide an overall summary and analysis of potential criteria that can be used to evaluate oocyte quality. These criteria are specifically classified as morphological and cellular/molecular predictors. Traditional methods for the evaluation of oocyte quality are based on morphological classification of thefollicle, cumulus-oocytecomplex, polar body and/or meiotic spindle. Although the use of morphological characteristics as predictors of oocyte quality is controversial, such a grading system can provide valuable information for the preselection of oocytes with higher developmental competence and, therefore, may maximise embryo developmental outcome. Several intrinsic markers (such as mitochondrial status and glucose-6-phosphate dehydrogenase 1 activity) and extrinsic markers (such as apoptosis of follicular cells and levels of the transforming growth factor-beta superfamily in follicular fluid or serum) have also been reported as useful indicators of oocyte competence and embryo quality. Compared with the morphological parameters, these cellular and molecular predictors of oocyte quality may prove to be more precise and objective, although further studies and refinement of techniques are needed.     

小头畸形的临床诊断与细胞和分子生物学诊断的研究进展

小头畸形是儿科常见的神经系统畸形,尤其在智力低下的儿童中更常见。迄今为止国内对小头畸形的相关研究报道较少,本文通过复习国外相关文献,对小头畸形的临床诊断与细胞和分子生物学诊断进行综述,旨在为小头畸形的临床诊治及进一步研究提供参考。     

Purification, properties, and developmental changes of cellular retinol-binding protein, type II, in chicken intestine

Two distinct cellular retinol-binding proteins were detected in chicken small intestine. A predominant form was purified to homogeneity. The apparent molecular weight of this protein was estimated to be 17,200. This form was larger than a second minor form partially purified (molecular weight of 15,000). The absorption and fluorescence spectra of the bound retinol to the purified proteins were typical for the known cellular retinol-binding proteins. The results suggest that the purified binding protein corresponds to CRBP(II), previously identified in small intestine of rats and humans. To gain an insight into the possible role of CRBP(II) in chicken small intestine, the CRBP(II) contents in cytosols of small intestine of embryonic and post-hatch chicks were determined by enzyme-linked immunosorbent assay. The amount of CRBP(II) per unit DNA in small intestine was low at 15- and 17-day embryonic stage, but rapidly increased around the period of hatching. The increased level was still maintained in 6-week-old chicks, which accounted for 0.9% of total proteins in duodenum. The developmental pattern and the presence of abundant amount of CRBP(II) in chicken small intestine supports the hypothesis that CRBP(II) might play some role in the intestinal absorption of retinoids. Thus the involvement of a tissue-specific cellular retinol-binding protein in the intestinal absorption of retinoids appears to be common in mammalian and avian species.     

Regulation of cellular differentiation and cellular function by phosphatidylinositol 3-kinase

Phosphatidylinositol 3-kinases (PI3Ks) generate lipids that are implicated in receptor-stimulated signalling and in the regulation of cell growth/differentiation and cellular function. Several pathways have been recently identified and this article summarizes current knowledge about them. Depending on cell type the PI3K pathway has been involved in positive or negative regulation of differentiation. Products of PI3Ks and other signalling intermediates are shared between the G protein-coupled receptors and receptor tyrosine kinases, suggesting that control of differentiation and growth is equally dependent on these two distinct classes of receptors. Thus, the role of PI3Ks in the regulation of differentiation is clearly a very complex process implicating integration between different receptor systems and cell type-specific responses.