CHO细胞初始接种密度对细胞毒性试验结果的影响

考察了CHO细胞初始接种密度对体外细胞毒性试验结果的影响。通过细胞倍增试验检测不同初始接种密度下CHO细胞倍增时间的差异,并分别采用中性红比色法及MTT比色法检测CHO细胞初始接种密度对细胞毒性试验结果的影响。结果表明,CHO细胞初始接种密度对细胞毒性试验的结果存在一定影响:以2×104～6×104个·mL-1为细胞初始接种密度,CHO细胞在48h内生长速度较为稳定;以4×104～6×104个·mL-1为细胞初始接种密度,中性红比色法毒性试验结果较为稳定;以2×104～4×104个·mL-1为细胞初始接种密度,MTT比色法细胞毒性试验结果较为稳定。在不同的细胞毒性试验中选择适合的细胞初始接种密度有助于提高细胞毒性试验结果的可重复性。     

体外微核试验重要影响因素研究

为了提高体外微核试验结果的可重复性和可比性，通过依据不同判定标准对同一受试物诱发细胞微核率进行统计、检测同一受试物对不同代次CHO细胞的微核率，研究了判定标准、细胞连续传代代次对体外微核试验结果的影响。结果表明．判定标准的不同对同一受试物诱发细胞微核率有显著影响；随细胞连续传代代次的升高．同一受试物对CHO细胞微核率呈上升趋势．连续传代9代以内细胞微核率较为稳定。判定标准、细胞连续传代代次是体外微核试验需要控制的重要因素。     

流感疫苗诱导Hela细胞凋亡与免疫调节效应

目的观察流感疫苗诱导Hela细胞凋亡与免疫调节效应。方法将流感疫苗作用于Hela细胞,采用MTT比色法和流式细胞仪检测疫苗对Hela细胞增殖、凋亡和细胞周期的影响;同时用MTT法检测疫苗对小鼠脾细胞增殖的影响;采用结晶紫、中性红染色及MTT法,分别检测脾细胞诱导上清中IFN-γ、IL-2和TNF-α的分泌情况。结果一定浓度流感疫苗能够抑制Hela细胞增殖,促进细胞凋亡,凋亡率可达58·37%;还可促进小鼠脾细胞增殖及Th1型细胞分泌IFN-γ。结论流感疫苗能够抑制Hela细胞增殖,此作用可能是通过诱导Hela细胞凋亡、调节免疫细胞增殖及IFN-γ的分泌而实现的。     

重组人粒细胞巨噬细胞集落刺激因子生物学活性测定TF-1细胞/MTT比色法的优化及其验证

目的对检测重组人粒细胞巨噬细胞集落刺激因子(recombinant human granulocyte macrophage colony stimulating factor,rh GM-CSF)生物学活性的TF-1细胞/MTT比色法进行优化及验证。方法以rh GM-CSF依赖细胞株TF-1为靶细胞,采用MTT比色法测定rh GM-CSF生物学活性,对比色法中裂解液种类、裂解时间、细胞浓度、MTT作用时间等进行优化,并对优化后的方法进行准确度和精密度验证。结果优化后的TF-1细胞/MTT比色法:将供试品及标准品稀释至18 IU/ml,做2倍系列稀释,共8个稀释度,50μl/孔;加入6×10~5个/ml TF-1细胞悬液,50μl/孔,37℃培养48~52 h;加入MTT溶液,20μl/孔,37℃培养5 h;加入15%SDS裂解液,150μl/孔,裂解过夜,检测A570值。3种不同浓度的rh GM-CSF标准品活性测定结果回收率为104%;rh GM-CSF标准品6次检测活性平均值为18.6 IU/ml,变异系数为5.37%;rh GM-CSF标准品3 d活性检测结果的平均变异系数为5.18%。结论采用优化后MTT比色法检测rh GM-CSF生物学活性,准确度和精密度均较高,可应用于rh GM-CSF活性的检测。     

茶色素与重组人肿瘤坏死因子合用的抗肿瘤作用

应用四甲基偶氮唑盐 (MTT)光比色法 ,测定了茶色素及其与重组人肿瘤坏死因子合用对原发性肝癌细胞的细胞毒作用。结果表明 ,茶色素单用对肝癌细胞H740 2细胞无细胞毒作用 ,抑制作用不明显 ;rTNF单用对H740 2细胞的最大抑制率为 35 .1% ,两者合用对H740 2细胞的最大抑制率达 47.2 % ,茶色素能明显增强rTNF对H740 2细胞的细胞毒性作用。     

CHO细胞簇集试验在无细胞百日咳疫苗质量控制中的应用

目的探讨CHO细胞簇集试验在无细胞百日咳疫苗质量控制中的应用。方法采用CHO细胞簇集试验比较分析不同来源的CHO细胞对百日咳毒素(pertussis toxin,PT)簇集活性。将豚鼠随机分为进口疫苗Lot 1~3实验组、国产疫苗Lot 4实验组、参考疫苗对照组,同时设未免疫对照组。分别于第0和21天,经豚鼠腹部皮下注射0.5 ml疫苗。于初免后第28天,经心脏采血,分离血清,采用ELISA法检测PT抗体滴度,CHO细胞簇集试验检测中和抗体滴度。结果 PT对不同来源的CHO细胞簇集能力存在一定差异,其中以来自ATCC的CHO细胞的簇集最敏感。各无细胞百日咳疫苗在豚鼠动物模型上均能诱导较好的PT抗体免疫反应,进口疫苗与参考疫苗及国产疫苗相比,差异均无统计学意义(P0.05);两种方法的检测结果具有一定的相关性,Spearman相关系数为0.474。结论证实了CHO细胞簇集试验用于百日咳疫苗纯化过程中质量控制和PT免疫原性分析的适用性,为加强和完善我国无细胞百日咳疫苗的质量控制奠定了基础。     

人参皂苷代谢产物CK诱导卵巢癌细胞CAOV3的凋亡机制

目的探讨人参皂苷代谢产物CK对卵巢癌细胞CAOV3的增殖抑制作用,及其诱导细胞凋亡的机制。方法采用MTT比色法测定不同浓度(0、1.0、2.5、5.0、10.0、20.0、50.0μg/ml)CK对卵巢癌细胞CAOV3增殖的抑制作用。流式细胞术检测不同浓度(0、2.5、5.0μg/ml)CK诱导CAOV3细胞凋亡的情况;4′,6-二脒基-2-苯基吲哚(4′,6-diamidino-2-phenylindole,DAPI)染色观察细胞凋亡过程中形态变化;体外Caspase活力测定凋亡相关蛋白Caspase-3、Caspase-8和Caspase-9的激活情况;Western blot分析Caspase-3底物多聚(ADP-核糖)聚合酶[Poly(ADP-ribose)polymerase,PARP]的断裂情况。结果 CK可明显抑制卵巢癌细胞CAOV3的增殖,CK浓度与其对细胞的增殖抑制作用呈剂量-效应关系,IC50值为3.6μg/ml。随着CK浓度的增加,发生凋亡的细胞数增加,出现典型的凋亡形态特征的细胞逐渐增多。Caspase-3、Caspase-8和Caspase-9均被激活。随着CK浓度的增加,酶活性增加,Caspase-3底物PARP断裂的条带逐渐加深。结论 CK对卵巢癌细胞CAOV3有毒性作用,能够抑制细胞增殖,且CK浓度与这种抑制作用呈剂量-效应关系;CK抑制CAOV3细胞的增殖作用是通过促进细胞凋亡来实现的,且这种细胞凋亡涉及内源及外源型途径。     

应用CHO细胞法检测百日咳疫苗中的残余毒性

根据百日咳毒素（PT）能特异地使中华地鼠卵巢细胞（CHO）聚集的性质，采用CHO细胞分析法检测了18批全细胞百白破疫苗（DTPw）和12批无细胞百白破疫苗（DTPa）。存放于4℃的两种疫苗中，DTPw聚集CHO细胞滴度的几何均值（GMT）是30.79±2．316,DTPa不产生聚集、两种疫苗在37℃存放4周后，DTPw聚集滴度的GMT是948．09±1．598．DTPa是205．67±1．392。实验结果表明，百日咳疫苗存在明显的毒性逆转现象，与动物试验不一致。因此建议采用CHO方法检测百日咳疫苗中PT的毒性。     

流行性乙型脑炎减毒活疫苗生产毒株(SA_(14)-14-2)的稳定性研究

流行性乙型脑炎病毒弱毒株经原代地鼠肾细胞连续传至17代后,毒株蚀斑形态与低代次毒株相似,均为一致的小斑,直径为1mm士,边缘整齐;高代次毒株对成龄小鼠的神经内和神经外毒力未发现增高现象;乳鼠脑内返传一代和返祖试验均未发现高代次较低代次毒力明显升高;不同抗原性的单克隆抗体在与低代和高代次弱毒株的免疫荧光反应中未发现抗原位点变化。     

APS作为重组(CHO细胞)乙型肝炎疫苗佐剂的安全性及免疫效果

目的 探讨黄芪多糖（APS）作为重组（CHO细胞）乙肝疫苗免疫佐剂的可行性。方法APS与重组（CHO细胞）乙肝病毒表面抗原（HBsAg）混合制成疫苗,进行了动物毒性试验、过敏试验及效力试验。结果 该佐剂毒性轻微,无过敏反应,同一剂量组动物血清抗-HBs阳转率高于Al（OH）3对照组。结论APS是一种很有潜力的疫苗佐剂。     

Investigation of the cytotoxicity of CCVD carbon nanotubes towards human umbilical vein endothelial cells

The cytotoxicity of different samples of carbon nanotubes synthesised by catalytic chemical vapour deposition was investigated towards human umbilical vein endothelial cells, using two cytotoxicity standard assays (neutral red assay for the cell viability and MTT assay—tetrazolinium salt—for the cell metabolic activity). No cytotoxicity was found for any sample.     

靶向性重组PF4裸质粒抗血管生成活性的研究

构建重组真核表达载体pcDNA3.1（+）-PF4^47-70-RGD,并检测靶向性重组血小板因子四（PF4）在真核细胞内的表达水平,探讨其体外抗血管生成活性。设计构建了靶向性重组PF4真核表达载体pcDNA3.1（+）-PF4^47-70-RGD,用脂质体法将其转染至中华仓鼠卵巢细胞系（CHO）,用G418筛选稳系,采用RT-PCR和Western blot检测表达产物,MTT法测定CHO稳转体系培养上清对脐静脉内皮细胞（HUVEC）增殖的影响。成功构建出重组真核表达载体pcDNA3.1（+）-PF4^47-70-RGD,并获得稳转CHO细胞系,从基因水平和蛋白水平均可检测到目的基因的表达。MTT法显示,CHO稳系培养上清对HUVEC生长抑制率是50.8%,与对照组比,血管内皮细胞的增殖能力显著减小。靶向性重组PF4具有较强的体外抑制血管生成活性,该重组肽能够抑制HUVEC增殖。     

体外连续传代培养对生物工程细胞CHO凋亡的影响

采用Annexin V-FITC/PI双染法检测磷脂酰丝氨酸外翻、JC-1染色法检测线粒体膜电位、底物切割法检测Caspase-3及Caspase-8酶活性等4个指标来评估连续传代培养的中国仓鼠卵巢(CHO)细胞的凋亡情况。结果表明,随着连续传代培养代次的增加,CHO细胞发生内部凋亡途径介导的凋亡,同时对凋亡诱导剂的反应更为敏感。因此,可以采用凋亡指标来监测细胞状态,从而提高基因工程蛋白的生产效率及化学品毒理学评价的准确性。     

五种国产活性炭吸附饮用水中有机污染物的比较

采用细胞生长抑制率、用MTT比色法测定细胞的增殖毒辣性和用流式细胞光度计测量细胞的凋亡率三项细胞毒性指标，评价了5种国产活性炭处理饮用水3a后的使用效果。实验表明4号活性炭仍具有一定的吸附功能，其他4种活性炭已经失去吸附过滤作用。此外还对5种国产活性炭使用效果的时间效应进行了简要的分析。     

Teucrium plant species as natural sources of novel anticancer compounds: antiproliferative, proapoptotic and antioxidant properties

This study deals with total phenolic content, antiproliferative and proapoptotic activity of methanolic extracts from different Teucrium species and the effect on the prooxidant/antioxidant status in HCT-116 cells. The total phenolic content of the extracts was measured spectrophotometricaly and the obtained results ranged from 56.62 mg/g to 172.50 mg GA/g. The antiproliferative activity of methanolic extracts from different Teucrium species was determined using MTT cell viability assay, where IC(50) value was used as a parameter for cytotoxicity. The type of cell death was explored by fluorescence microscopy using the acridin orange/ethidium bromide method. MTT assay showed that all extracts significantly reduced cell viability in a dose-dependent manner, with very low IC(50) values. The highest content of phenolic compounds and the best cytotoxic activity on HCT-116 cells after 24 h of exposure was in T. chamaedrys extract, with IC(50) values of 5.48 × 10(-9) μg/mL. After 72 h, methanolic extract of T. arduini appeared to have the best cytotoxic activity on HCT-116, with IC(50) values of 0.37 μg/mL. Treatments caused typical apoptotic morphological changes in HCT-116 cells and showed a high percentage of apoptotic cells. The results of the presented research indicate that some Teucrium extracts are a very rich source of phenols, which may directly contribute to high antiproliferative and proapoptotic activity.     

Fabrication and Properties of Gelatin/Chitosan Composite Hydrogel

Gelatin/chitosan hydrogels were prepared by using glutaraldehyde as crosslinker. The porous structure was confirmed by scanning electron microscope (SEM). Swelling ratios of the hydrogels with various ratio of gelatin to chitosan and crosslinker reagent dosage were studied in phosphate-buffered saline (PBS). In addition, in-vitro cytotoxicity was assessed via MTT assay with fibroblastic cell cultured in hydrogel extractions. It was found that by increasing glutaraldehyde dosage and chitosan content, the swelling ratio of the hydrogels decreased in buffer solutions. The MTT test showed that the gelatin/chitosan hydrogel clearly presented adequate cell viability, non-toxicity, and suitable properties. Therefore, these developed blends, based on gelatin and chitosan has broadened the number of choices of biomaterials to be potentially used in biomedical applications such as biomaterial, drug delivery vehicles and skin tissue engineering.     

The MTT Assay: Utility,Limitations, Pitfalls,and Interpretation in Bulk and Single-Cell Analysis

The MTT assay for cellular metabolic activity is almost ubiquitous to studies of cell toxicity; however, it is commonly applied and interpreted erroneously. We investigated the applicability and limitations of the MTT assay in representing treatment toxicity, cell viability, and metabolic activity. We evaluated the effect of potential confounding variables on the MTT assay measurements on a prostate cancer cell line (PC-3) including cell seeding number, MTT concentration, MTT incubation time, serum starvation, cell culture media composition, released intracellular contents (cell lysate and secretome), and extrusion of formazan to the extracellular space. We also assessed the confounding effect of polyethylene glycol (PEG)-coated gold nanoparticles (Au-NPs) as a tested treatment in PC-3 cells on the assay measurements. We additionally evaluated the applicability of microscopic image cytometry as a tool for measuring intracellular MTT reduction at the single-cell level. Our findings show that the assay measurements are a result of a complicated process dependant on many of the above-mentioned factors, and therefore, optimization of the assay and rational interpretation of the data is necessary to prevent misleading conclusions on variables such as cell viability, treatment toxicity, and/or cell metabolism. We conclude, with recommendations on how to apply the assay and a perspective on where the utility of the assay is a powerful tool, but likewise where it has limitations.