醋酸铅对大鼠胰岛瘤细胞INS-1自噬与凋亡的影响

为了研究环境中常见重金属污染物铅对大鼠胰岛瘤细胞INS-1自噬与凋亡的影响及其可能的分子机制,使用不同浓度醋酸铅暴露大鼠胰岛瘤细胞INS-1,利用磺酰罗丹明B(sulforhodamine B,SRB)法检测细胞存活率;Western blot法检测不同浓度醋酸铅对细胞中自噬与凋亡标志蛋白及哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)信号通路标志分子表达的影响;利用活性氧(reactive oxygen species,ROS)试剂盒检测细胞内ROS水平;用ROS清除剂N-乙酰-L-半胱氨酸(N-acetylcysteine,NAC)预处理细胞,检测醋酸铅引起的细胞自噬与凋亡是否受到影响。使用统计学软件SPSS 17.0对数据进行统计学分析后,与对照组相比,醋酸铅导致INS-1细胞的存活率下降(p0.05),且呈时间-剂量依赖性;随醋酸铅浓度增大,自噬和凋亡标志蛋白表达增加,mTOR信号途径标志分子没有明显变化;NAC预处理后醋酸铅引起的细胞自噬和凋亡减少。实验结果表明,醋酸铅可通过mTOR-非依赖途径诱导INS-1细胞的自噬与凋亡,其可能机制为刺激细胞内ROS的产生。     

甲醛对人支气管上皮细胞的毒性及N-乙酰半胱氨酸的保护作用

为研究甲醛对人支气管上皮细胞存活率的影响及N-乙酰半胱氨酸(N-acetylcysteine,NAC)的保护效应,以0、50、100、150、200、300和400μmol·L-1甲醛处理人支气管上皮BEAS-2B细胞24 h,200μmol·L-1甲醛处理BEAS-2B细胞0、6、24和48 h。以不同浓度(0、0.1、1和10 mmol·L-1)NAC预处理1 h或不同时间(预先3、1 h加入NAC、同时加入甲醛和NAC及加入200μmol·L-1甲醛1、3 h后)加入1 mmol·L-1NAC,再以200μmol·L-1甲醛处理BEAS-2B细胞(甲醛处理时间均为24 h),CCK-8(cell counting kit-8)实验和倒置相差显微镜观察甲醛对BEAS-2B细胞存活率的影响及NAC的保护作用。结果显示,甲醛以剂量依赖性方式引起BEAS-2B细胞死亡。200μmol·L-1甲醛处理BEAS-2B细胞6 h,细胞存活率下降,与对照组比较差异具有统计学意义(p0.05)。随甲醛处理时间的延长细胞存活率明显下降,存在时间效应关系。不同浓度和不同时间NAC处理可拮抗甲醛引起的细胞存活率下降,存在剂量效应关系,NAC不同时间处理组间细胞存活率未见明显差异。研究表明,甲醛以剂量和时间依赖性方式引起支气管上皮细胞存活率下降,NAC以剂量依赖性方式对甲醛引起的损伤具有保护作用。     

表没食子儿茶素没食子酸酯对四氯苯醌细胞毒性的保护作用研究

四氯苯醌(TCBQ)是高毒致癌化合物,而表没食子儿茶素没食子酸酯(EGCG)是茶叶中主要的茶多酚活性成分.利用人肝癌细胞系HepG2细胞,通过细胞存活率MTT毒性实验,探讨EGCG是否能解除TCBQ的毒性作用.实验结果表明,低浓度(5～40 μmol· L-1)的EGCG对TCBQ(200μmol·L-1)导致的细胞毒性有一定的缓解作用.此保护与EGCG和TCBQ之间的直接相互作用有关,紫外吸收光谱及高效液相色谱分析的实验结果表明EGCG降低TCBQ毒性的原因可能是其促使TCBQ还原为四氯氢醌TCHQ,并延缓了TCHQ的自氧化过程.     

Genotoxic and cytotoxic in vitro evaluation of ivermectin and its formulation ivomec® on Aedes albopictus larvae (CCL-126™) cells

Genotoxic effects of ivermectin (IVM) and its commercial formulation ivomec® (IVM 1.0%) were studied on Aedes albopictus larvae (CCL-126?) cells by sister chromatid exchange (SCE) and single cell gel electrophoresis (SCGE) while cytotoxicity was determined by cell-cycle progression (CCP), proliferative rate index (PRI), mitotic index (MI), 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and neutral red (NR) endpoints within a 1–250 µg mL^?1 concentration range. While IVM and ivomec® did not markedly affect SCE frequencies, these agents induced DNA-strand breaks enhancing both slightly damaged and damaged cells at 25–50 and 5–50 µg mL^?1 IVM and ivomec®, respectively. Both compounds exerted a delay in CCP and reduction of PRI at 10 µg mL^?1. Cytotoxicity was observed at concentrations higher than 25 µg mL^?1. A marked reduction of about 98% and 94% of MI compared to controls was noted with 25 µg mL^?1 of IVM and ivomec®, respectively. NR and MTT assays revealed that both compounds induced a cell growth inhibition within the 1–250 µg mL^?1 concentration range. Data indicated that IVM and ivomec® exert both genotoxicity and cytotoxicity in insect cells in vitro, at least in A. albopictus larvae CCL-126? cells.     

Early life environment and developmental immunotoxicity in inflammatory dysfunction and disease

Components of the innate immune system such as macrophages and dendritic cells are instrumental in determining the fate of immune responses and are, also, among the most sensitive targets of early life environmental alterations including developmental immunotoxicity (DIT). DIT can impede innate immune cell maturation, disrupt tissue microenvironment, alter immune responses to infectious challenges, and disrupt regulatory responses. Dysregulation of inflammation, such as that observed with DIT, has been linked with an increased risk of chronic inflammatory diseases in both children and adults. In this review, we discuss the relationship between early-life risk factors for innate immune modulation and promotion of dysregulated inflammation associated with chronic inflammatory disease. The health risks from DIT-associated inflammation may extend beyond primary immune dysfunction to include an elevated risk of several later-life, inflammatory-mediated diseases that target a wide range of physiological systems and organs. For this reason, determination of innate immune status should be an integral part of drug and chemical safety evaluation.     

Preconcentration of samarium with modified yeast cells for its determination by atomic emission spectroscopy

A chelating-modified biosorbent is produced by coupling of a dye, procion red, to yeast cells. The resulting modified cells have been characterized by Fourier transform infrared, elemental analysis and thermogravimetric analysis and studied for preconcentration and determination of trace Sm(III). The optimum pH value for sorption of the samarium ions is 6.2. The sorption capacity of functionalized modified yeast cells is 7.2 mg g^?1. Recovery was 99% when Sm(III) was eluted with an aqueous solution of 0.1 mol L^?1 ethylenediaminetetraacetic acid. Scatchard analysis suggested that binding sites were homogeneous. The equilibrium data were analyzed using Langmuir, Freundlich, Temkin, and Redlich–Peterson isotherm models, and the respective constants were determined as 1.0 (L mg^?1), 2.9 [(mg g^?1) (L mg^?1)^1/n], 2.4 × 10⁸ (L g^?1), and 30 (dm³ g^?1) at 20 °C. The method was applied for an Sm(III)-containing sample of ceramic industry effluent.     

Cytotoxicity of single-walled carbon nanotubes,multi-walled carbon nanotubes,and chrysotile to human lung epithelial cells

Carbon nanotubes (CNTs) have found numerous applications in various industries. Recently, adverse effects of these materials on human and animal cells in vitro have been reported. In the present study, the cytotoxicity of single-walled carbon nanotubes (SWCNTs), multi-walled carbon nanotubes (MWCNTs), and chrysotile asbestos in human lung epithelial cells has been studied using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. The cells were exposed for 6 h and 24 h to between 0.97 and 1500 μg mL^?1 of CNTs and chrysotile fibers prepared in two culture media containing 5% serum and 0.5% dimethylsulfoxide. Dose–response curves were obtained to determine the nonobservable adverse effect concentration and the half-maximum inhibitory concentration (IC₅₀). The way of dispersion affects the cytotoxicity of CNTs. For MWCNT, the toxicological indexes were lower than for SWCNT. Chrysotile fibers were even less cytotoxic than CNTs. Therefore, workplace control measures are recommended as priority for occupational and environmental conditions.     

DNA fragmentation,apoptosis and cell cycle arrest induced by sodium arsenite in cultured murine Sertoli cells: prevention by curcumin

Arsenic is a significant environmental concern worldwide, primarily due to geo physiochemical contamination of drinking water, and a major public health hazard in both developing and developed countries. The present study was aimed to investigate ameliorative effects of curcumin (Cur) against sodium arsenite (SA)-induced toxicity in cultured murine Sertoli cells. The cells were treated with SA (5 μM) and Cur (5 μg/ml and 10 μg/ml) alone or in combination for 12 hr. The SA treatment decreased cell viability, produced oxidative stress, and induced apoptosis as reflected by reactive oxygen species (ROS) generation, loss of mitochondrial transmembrane potential, DNA fragmentation, and apoptotic cells. Moreover, the SA-induced cell cycle arrest in the cells is characterized by a rise in the number of cells in the sub G1 phase of the cell cycle. The Cur was found to be effective in reversing all these arsenic (As)-induced cellular events. Data suggest that Cur modulates As-mediated oxidative stress, apoptosis, DNA fragmentation, and cell cycle arrest through suppression of excessive ROS generation. Evidence indicates that Cur may emerge as a useful protective agent against As-induced Sertoli cells toxicity by inhibiting As-induced damage in testes.     

Cytotoxicity of benalaxyl,metalaxyl, and triadimefon on Chinese hamster ovary cells

The cytotoxicity of the fungicides benalaxyl, metalaxyl, and triadimefon was evaluated in vitro using the Chinese hamster ovary (CHO-K1) cell line. The midpoint cytotoxicity values of neutral red (NR) incorporation (NRI₅₀), total cellular protein content (TCP₅₀), and the methyl tetrazolium assay (MTT₅₀) were estimated. Benalaxyl was the most cytotoxic fungicide, followed by metalaxyl and triadimefon. Fetal calf serum (10%) caused a reduction in benalaxyl, metalaxyl, and triadimefon cytotoxicity by factors of 1.8, 1.3, and 1.3. The effects of sublethal concentrations (NRI₂₅) of the three fungicides on the glutathione redox cycle components glutathione S-transferase, glutathione reductase, glutathione peroxidase, and total glutathione content were studied. The ameliorative effects of extracellular glutathione (1 mmol L^?1), vitamin C (70 µmol L^?1), and vitamin E (30 µmol L^?1) were also investigated. The three antioxidants led to significant effects on the glutathione redox cycle components.     

Manufactured silver and gold nanoparticles-induced apoptosis by caspase-pathway in human cell lines

Abstract

Metallic nanoparticles have emerged as an important class of nanomaterials for a wide range of industrial and medical applications. Because of the intensive commercial applications, risk assessment of these nanoparticles is of great importance. In the present study, the human hepatoma and leukemia cells were used to characterize the apoptotic effects of silver nanoparticles (4.7 and 42?nm) and gold nanoparticles (30?nm). Apoptotic cells were identified by chromatin condensation and flow cytometry analysis, using Annexin V/PI, TUNEL and caspase activation assays. Flow cytometry analysis showed that the three metallic nanoparticles induced apoptotic cell death in a concentration and time dependent-manner. Moreover, the three nanoparticles induced activation of caspase-3 and -7 in hepatoma and leukemia cells. Apoptotic effects were stronger after exposure of both cell lines with 4.7?nm silver nanoparticles than those obtained with 42?nm silver and 30?nm gold nanoparticles. In conclusion, silver (4.7 and 42?nm) and gold (30?nm) nanoparticles induced apoptosis in hepatoma and leukemia cells via the caspase dependent pathway. The smaller silver nanoparticles (4.7?nm) had a greater ability to induce apoptosis in both cell lines.