长波紫外线对大鼠皮肤角朊细胞的损伤及茶多酚的保护作用

目的 探讨长波紫外线（ＵＶＡ）对原代培养的大鼠皮肤角朊细胞脂质过氧化和生长状况等影响，同时探讨一种植物多酚－－茶多酚（ＴＰＰ）在此过程中所起的作用。方法 在原代培养大鼠皮肤角朊细胞基础上，经ＵＶＡ照射后，测定角朊细胞浆酶－－乳酸脱氢酶（ＬＤＨ）释放情况，脂质过氧化产物丙二醛（ＭＤＡ）、谷胱甘肽过氧化物酶（ＧＳＨ－Ｐｘ）水平，并测定培养细胞的存活率和细胞周期动力学。结果 ＵＶＡ可以引起体外培养的细胞膜通透性增强，胞浆酶ＬＤＨ释放增加（从８２７．５５Ｕ／Ｌ增至１３１２．４７Ｕ／Ｌ）；脂质过氧化产物ＭＤＡ水平升高，抗氧化酶ＧＳＨ－Ｐｘ水平降低；细胞存活率下降，细胞周期动力学表现为细胞增殖抑制；增殖指数（ＰＩ）从３４．２４％降至１７．９８％。天然提取物ＴＰＰ（质量浓度为０．１％）可以比较明显地抑制ＵＶＡ引起的上述损害。     

3种中药有效成分抗氧化作用及对皮肤细胞内SOD活性的影响

采用化学发光法及皮肤角朊细胞原代培养技术，研究３种中药提取成分２０５６Ａ、２０５６Ｂ、２０５６Ｃ抗氧自由基作用，以及对皮肤角朊细胞内ＳＯＤ活性的影响。结果显示，２０５６Ａ（０．００１％￣０．５％）、２０５６Ｂ（０．００１％￣１％）、２０５６Ｃ（０．００１％￣３％）在各自实验浓度范围内均具有较好的抗氧自由基作用，且呈明显的剂量反应关系。其中，２０５６Ａ在０．０１￣１％浓度范围内，还可显著增强角朊细胞     

芥子气对皮肤细胞毒性与白细胞介素1—α表达关系的研究

培养４天的单层人表皮角朊细胞经１～１００μｍ芥子气染毒３０ｍｉｎ，继续培养３天后，测定细胞存活率、细胞内及培养液中白细胞介素１－α（ＩＬ－ｌα）含量。结果：角朊细胞存活率随芥子气染毒浓度而降低，而角朊细胞内和培养液中ＩＬ－ｌα含量均有不同程度的升高。３项指标与芥子气染毒剂量呈现剂量－反应关系（ｒ［细胞存活］＝０．９８２，Ｐ＜０．０１；ｒ［细胞ＩＬ－ｌα］＝０．９３７，Ｐ＜０．０１；ｒ［培养液ＩＬ－ｌα］＝０．９３２，Ｐ＜０．０１。细胞存活率与细胞ＩＬ－ｌα和培养液ＩＬ－ｌα含量之间具有明显的负相关性（ｒ（细胞存活与ＩＬ－ｌα）＝－０．９７２，Ｐ＜０．０１，ｒ（细胞存活与培养液ＩＬ－ｌα）＝－０．９８６，Ｐ＜０．０１。）研究结果提示了ＩＬ－ｌα用作评价芥子气对皮肤细胞毒性的评价指标的可能性。     

氧化型染发剂主要成分对大鼠皮肤角朊细胞DNA损伤作用的研究

应用大鼠皮肤角朊细胞的原代培养技术并结合单细胞凝胶电泳法检测氧化型染发剂的两种主要成分双氧水（Ｈ２Ｏ２）、对苯二胺（ＰＰＤ）及二者混合物致大鼠皮肤角朊细胞ＤＮＡ的单甸继裂作用。结果表明，染发剂及其组分均能使大鼠角朊细胞ＤＮＡ发生单链断裂，染毒剂量与慧尾长度呈剂量－反应关系（ｒＨ２Ｏ２＝０．９７８，ｒｐｐＤ＝０．９９３，ｒＨ２Ｏ２－ｐｐＤ＝０．９９６），说明ＤＮＡ单链断裂是氧化型染发剂对皮肤细胞产生     

氧化型染发剂对皮肤角朊细胞的毒性试验

应用大鼠皮肤原代细胞培养并结合ＭＴＴ法检测氧化型染发剂对皮肤细胞的毒性和增殖能力的影响，结果表明，对苯二胺经双氧水氧化后形成的化合物以及Ｇ牌染发剂均对大鼠角朊细胞的生长有抑制作用，随着染毒浓度的增高，ＯＤ值逐渐降低，即细胞线粒体代谢ＭＴＴ成ＭＴＴ甲月赞的能力降低，且具有剂量反应关系（ｒ对苯二胺和双氧水混合物＝－０６８７，ｒＧ牌染发剂＝－０９１３，ｎ＝３０，Ｐ＜００１）。除最低剂量组以外，其它４个浓度组的ＯＤ值均数与对照组相比均显著降低（ｔ检验，Ｐ＜００１）。对苯二胺和双氧水混合物及Ｇ牌染发剂的ＩＣ５０分别为０００３３％和００３９２ｍｇ／ｍｌ（９５％可信区间分别为０００２１％～０００５２％及００２０９～００７３５ｍｇ／ｍｌ）。结果显示对苯二胺与双氧水混合物以及Ｇ牌染发剂均具有较强的细胞毒性作用，能够抑制细胞增殖。氧化型染发剂的细胞毒性可能与其引起皮肤损伤的机制有关。     

儿茶素对LoVo细胞生长周期的影响和诱导凋亡的作用

目的 探讨表没食子儿茶素没食子酸酯（ＥＧＣＧ）、表没食子儿茶素（ＥＧＣ）、表儿茶素没食子酸酯（ＥＣＧ）和表儿茶素（ＥＣ）对大肠癌ＬｏＶｏ细胞生长周期的影响和它们诱导ＬｏＶｏ细胞凋亡作用及其差异性。方法 用ＭＴＴ法、琼脂糖凝胶电泳、透射电镜和流式细胞术观察４种儿茶素处理ＬｏＶｏ细胞后,它们对ＬｏＶｏ细胞的生长抑制作用、细胞生长周期的改变以及诱导其凋亡形态学和生化方面的改变。结果 ＥＧＣＧ和ＥＧＣ对Ｌ     

工频磁场对细胞缝隙连接通讯功能的影响

为了探讨极低频（ＥＬＦ）磁场可能存有的促癌作用或协同促癌作用，观察了５０Ｈｚ磁场对ＣＨＬ细胞间缝隙连接通讯（ＧＪＩＣ）功能的影响。利用离子电渗注射法将荧光染料引入细胞内，以５分钟后的荧光偶合细胞（ＤＣＣ）数作为ＧＪＩＣ功能的指标。研究了不同浓度的十四酰基咐拜醇酯（ＴＰＡ）、不同强度的工频磁场及工频磁场与ＴＰＡ（５ｎｇ／ｍｌ）共同作用对ＣＨＬ细胞ＧＪＩＣ的影响。结果表明，ＴＰＡ对ＧＪＩＣ的抑制具有浓度依赖关系，ＴＰＡ抑制ＣＨＬ细胞ＧＪＩＣ的阈浓度在１～５ｎｇ／ｍｌ之间；ＣＨＬ细胞经０.８０ｍＴ的工频磁场暴露２４小时后的ＤＣＣ数降至６．０８±１．５９，与空白对照组（９．８４±２．２７）比较，差异有显著性（Ｐ＜０．０５）；０．２０，０．４０，０．８０ｍＴ强度的工频磁场与５ｎｇ／ｍｌＴＰＡ共同作用后的ＤＣＣ数分别降至５．５２±１．５３，５．００±１．２２，４．００±１．２９，与单用５ｎｇ／ｍｌＴＰＡ组（６．３８±１．３９）比较，差异也有显著性（Ｐ＜０．０５）。说明一定强度的工频磁场具有抑制或协同抑制ＧＪＩＣ的作用，提示其可能存有促癌或协同促癌作用。     

β－胡萝卜素对人体乳腺癌细胞株BCap－37生物学作用的研究

应用细胞培养技术，分子杂交的ＮｏｒｔｈｅｒｎＢｌｏｔ方法和图像细胞分析技术（ＩＣＭ）研究了β－胡萝卜素对体外培养的人乳腺癌细胞株ＢＣａｐ一３７的生物学作用。细胞生长曲线的结果显示，两个实验组（５×１０（－５）ｍｏｌ／Ｌ，１×１０（－４）ｍｏｌ／Ｌ）对细胞的生长有显著抑制作用并伴有明显的细胞形态学特征的改变。抑制率分别为３３．３３％和２８．２５％（Ｐ＜０．０１，Ｐ＜０．０５）。血浆生理浓度组（１×１０（－５）ｍｏｌ／Ｌ）对细胞的生长没有抑制作用（Ｐ＞０．０５）。基因表达的研究显示，β－胡萝卜素（１×１０（－５）ｍｏｌ／Ｌ，１×１０（－４）ｍｏｌ／Ｌ）对癌基因Ｃ一ｅｒｂＢ２ｍＲＮＡ的表达没有抑制作用，１×１０（－４）ｍｏｌ／Ｌ浓度组对癌相关基因ＥＧＦＲｍＲＮＡ的表达有抑制作用，应用ＩＣＭ技术测定四项指标，即ＤＮＡ指数（ＤＩ值），Ｓ期百分比（Ｓ％），总ＤＮＡ含量以及细胞核面积。结果显示，两实验组（１×１０（－５）ｍｏｌ／Ｌ，１×１０（－４）ｍｏｌ／Ｌ）ＤＩ值为１．８１和１．７４，反映细胞呈异倍体水平，为恶性细胞的特征。两组的Ｓ期百分比为３３．７０％和３０．３９％，核面积为１４３．０μＭ２和１２０．９０μＭ２，均低?     

茶色素防癌作用的实验研究

作者用一组体外短期检测试验,检验了茶色素在肿瘤的起动、促进、增殖阶段的作用并与茶多酚进行比较。选用基因正向突变和周期阻断法微核实验作为起动阶段指标,选用代谢协作和小鼠耳炎性水肿实验作为促癌阶段指标,选用Ｈｅｌａ 细胞存活率和软琼脂生长及小鼠Ｓ１８０实体瘤实验,检测对肿瘤细胞存活和增殖的影响。结果发现茶色素与茶多酚在肿瘤发生的起动、促进和增殖各阶段均显示出明显的保护作用;体外给予茶多酚、茶色素处理Ｈｅｐ Ｇ２肝肿瘤细胞,发现茶色素及其单体成分及茶多酚可诱导醌还原酶（ＱＲ）活性和谷胱甘肽硫转移酶（ＧＳＴ）活性;在用二乙基亚硝胺（ＤＥＮ）诱导的大鼠肝癌前病变,阳性对照组的ＧＳＴ水平有一定程度的降低;饮用０．１％ 茶多酚、茶色素可显著诱导大鼠肝ＧＳＴ活性,茶多酚的诱导率为２５％ ,茶色素的诱导率为１８％ ,而且ＧＳＴ１－１、１－２、３－３蛋白表达均有明显升高。结果表明茶色素与茶多酚同样具有抗肿瘤作用,茶色素对具有抗氧化作用和解毒作用的Ⅱ相代谢酶ＱＲ和ＧＳＴ 具有诱导作用,这可能是茶色素防癌作用的重要机制     

术前静脉营养支持在胃癌治疗中的意义——蛋白质代谢、免疫功能与肿瘤细胞动力学变化

肿瘤病人应用静脉营养支持的利弊众说不一。本文就我院外科１９８４～１９９０年间围绕术前营养支持——蛋白质代谢——免疫功能——肿瘤生长所作的一系列前瞻性研究作一综合与分析。研究分二部分，对象均为伴有营养不良的进展期胃癌病人（共３３例），除医院内饮食外，术前给予１周肠外营养支持（ＰＮＳ）。通过血浆转铁蛋白和前白蛋白、氮平衡、整体蛋白质更新率、ＮＫＣ和Ｔ淋巴细胞亚群及细胞周期动力学五个方面的检测，结果提示：①术前ＰＮＳ可促进整体蛋白质的更新率，并以合成率的增加为主；②改善免疫功能；③ＰＮＳ后，肿瘤细胞周期中Ｇ０／Ｇ１％显著下降（Ｐ＜０．０１），而增殖期，即Ｓ＋Ｇ２＋Ｍ％则明显增加（Ｐ＜０．０２５）。正常胃粘膜细胞未见类似变化。作者认为术前ＰＮＳ虽可能刺激肿瘤生长，但ＰＮＳ后病人营养状况和免疫功能的改善确是事实。     

茶多酚和茶色素对肝癌细胞株HepG2细胞周期的影响

为探讨茶对肝癌细胞周期的影响 ,体外培养人肝癌细胞株HepG2 ,加入终浓度为 50mg L和 1 0 0mg L茶多酚和茶色素作用 48h后 ,流式细胞仪分析DNA含量 ,Westernblot观察对细胞周期蛋白P2 1 WAF1 CIP1 和细胞周期素D1 (cyclinD1 ) ,RT PCR检测细胞周期素依赖激酶 4 (Cdk4)在mRNA水平上的表达情况。结果表明 ,茶多酚和茶色素引起了细胞周期G1 期阻滞 (G1 arrest) ,抑制了cyclinD1蛋白的表达 ,诱导了P2 1 WAF1 CIP1 蛋白的表达增加 ,并且显著抑制了Cdk4在mRNA水平上的表达。因此 ,诱导细胞周期阻滞可能是茶预防肿瘤的一个重要机制     

Apoptosis Inducing Effects of Kuding Tea Polyphenols in Human Buccal Squamous Cell Carcinoma Cell Line BcaCD885

Tea polyphenols are functional substances present in tea. Kuding tea as a traditional drink also contains these compounds. After 25, 50 and 100 μg/mL of Kuding tea polyphenol treatment for 48 h, cell proliferation of human buccal squamous cell carcinoma cell line BcaCD885 was inhibited, and the 100 μg/mL of Kuding tea polyphenol showed the highest inhibitory rate at 72.3%. Compared to the lower concentration, the 100 μg/mL of Kuding tea polyphenols significantly (p < 0.05) induced apoptosis as determined by flow cytometry analysis, the content of sub-G1 cancer cells was 32.7%. By RT-PCR and western blot assays, Kuding tea polyphenol significantly induced apoptosis in BcaCD885 cancer cells (p < 0.05) by upregulating caspase-3, caspase-8, caspase-9, Fas/FasL, Bax, p53, p21, E2F1, p73 and downregulating Bcl-2, Bcl-xL, HIAP-1, and HIAP-2 mRNA and protein expressions. Kuding tea polyphenols thus present apoptosis inducing effects in vitro.     

姜黄素对人肺成纤维细胞凋亡及细胞周期的影响

目的研究姜黄素对人肺成纤维细胞(human lung fibroblasts,HLFs)体外生长、细胞周期及凋亡的影响。方法应用CCK-8、Annexin-V/PI、PI流式细胞分析术、免疫印迹法,检测姜黄素对细胞的增殖、凋亡、细胞周期和Bax蛋白表达的影响。结果姜黄素对HLFs的增殖有抑制作用,可促进HLFs的早期凋亡,对细胞周期可产生G2/M期阻滞,增加HLFs的Bax蛋白的表达。结论姜黄素可抑制HLFs的增殖并能诱导其凋亡,其机制可能与细胞的G2/M期阻滞及凋亡相关蛋白的表达增强有关。     

大豆苷原对体外培养人胃癌细胞增殖和细胞周期的影响

目的:了解二羟异黄酮对胃癌细胞有无促增殖与诱导凋亡作用。方法:以不同浓度的二羟异黄酮处理人胃癌细胞系MGC-803细胞。然后分别用MTT法测定细胞增殖情况、流式细胞仪和琼脂糖凝胶电泳测定细胞周期和细胞凋亡等。结果:MTT 结果显示:二羟异黄酮对胃癌细胞具有促进和抑制增殖的双相作用-在低浓度(0.1-1 μmol/L)时促进细胞生长,在较高浓度(10-100 μmol/L)时对细胞生长则有抑制作用。流式细胞术结果显示:癌细胞群阻滞在G1期,没有明显凋亡峰的出现;凝胶电泳也末检测到明显的DNA阶梯状条带。结论:二羟异黄酮对体外培养的胃癌细胞的生长有双相作用,较高浓度可抑制胃癌细胞的生长并使细胞阻滞在G1期,而无诱导细胞凋亡的作用。     

苦参碱诱导人喉癌细胞Hep-2凋亡的实验研究

目的 研究苦参碱对人喉癌细胞Hep-2的生长抑制作用及凋亡机制.结果 四甲基噻唑蓝(MTT)法测定苦参碱对细胞的抑制作用,荧光显微镜、DNA琼脂糖凝胶电泳、流式细胞仪技术(FCM)观察细胞周期及凋亡.结果 不同浓度苦参碱对Hep-2细胞有明显抑制作用,且呈时间依赖性及剂量依赖性;FCM检测结果 显示:S期细胞比例及凋亡率增高,G2/M期细胞比例下降,且呈剂量依赖性;形态学发现Hep-2细胞染色质凝聚,核碎裂,凋亡小体形成;DNA琼脂糖凝胶电泳显示典型的梯形条带.结论 苦参碱可能是通过将人喉癌细胞周期阻滞在S期,诱导喉癌细胞凋亡,抑制其增殖,发挥其抗癌功能.     

Reduced thymocyte proliferation but not increased apoptosis as a possible cause of thymus atrophy in iron-deficient mice

Iron deficiency induces thymus atrophy in laboratory animals and very likely in humans by unknown mechanisms. The atrophy is associated with impaired cell-mediated immunity. In this study, we tested the hypothesis that thymus atrophy is a result of increased apoptosis and reduced thymocyte proliferation. Thymocytes were obtained from twenty-seven control, twenty-seven pairfed, twenty-seven iron-deficient (ID) mice; twelve and fourteen ID mice that received the control diet (0.9 mmol/kg versus 0.09 mmol/kg for the ID diet) for 1 d (repletion, R1) and 3 d (R3), respectively. Cell cycle analysis and apoptosis were studied by flow cytometry using propidium iodide staining and terminal deoxyuridine nick end labeling of DNA breaks assay respectively. When mice were killed, haemoglobin, haematocrit, and liver iron stores of ID, R1, and R3 mice were 25-40 % of those of control and pairfed mice Absolute and relative thymus weights and thymocyte numbers were 19 to 68 % lower in ID, R1, and R3 than in control and pairfed groups We found no significant difference among groups in the percentage of cells undergoing apoptosis. A higher percentage of thymocytes from ID and R1 mice than those of control, pairfed, and R3 mice were in the resting phase of the normal cell cycle Conversely, a lower percentage of thymocytes from ID and R1 mice than those from control, pairfed, and R3 mice were in the DNA synthesis phase and late phase of DNA synthesis and onset of mitosis (G2-M) Indicators of iron status positively correlated (r 0.3 to 0.56) with the percentage of thymocytes in the G2-M phase Results suggest that reduced cell proliferation but not increased apoptosis is the cause of thymus atrophy associated with iron deficiency.     

Epigallocatechin Gallate (EGCG) Is the Most Effective Cancer Chemopreventive Polyphenol in Green Tea

Green tea is a popular drink consumed daily by millions of people around the world. Previous studies have shown that some polyphenol compounds from green tea possess anticancer activities. However, systemic evaluation was limited. In this study, we determined the cancer chemopreventive potentials of 10 representative polyphenols (caffeic acid, CA; gallic acid, GA; catechin, C; epicatechin, EC; gallocatechin, GC; catechin gallate, CG; gallocatechin gallate, GCG; epicatechin gallate, ECG; epigallocatechin, EGC; and epigallocatechin gallate, EGCG), and explored their structure-activity relationship. The effect of the 10 polyphenol compounds on the proliferation of HCT-116 and SW-480 human colorectal cancer cells was evaluated using an MTS assay. Cell cycle distribution and apoptotic effects were analyzed by flow cytometry after staining with propidium iodide (PI)/RNase or annexin V/PI. Among the 10 polyphenols, EGCG showed the most potent antiproliferative effects, and significantly induced cell cycle arrest in the G1 phase and cell apoptosis. When the relationship between chemical structure and anticancer activity was examined, C and EC did not show antiproliferative effects, and GA showed some antiproliferative effects. When C and EC esterified with GA to produce CG and ECG, the antiproliferative effects were increased significantly. A similar relationship was found between EGC and EGCG. The gallic acid group significantly enhanced catechin’s anticancer potential. This property could be utilized in future semi-synthesis of flavonoid derivatives to develop novel anticancer agents.     

蛋白激酶C信号通路在温石棉致肺成纤维细胞的细胞周期和凋亡改变中的作用

目的 探讨蛋白激酶C（PKC）信号通路与温石棉致人胚肺成纤维细胞（HEPF）的细胞周期及细胞凋亡改变的联系。方法 流式细胞技术测定PKC的抑制剂或激活剂对温石棉处理兔肺泡巨噬细胞（AM）的培养上清液致HEPF的细胞周期和凋亡改变的影响。同时设立空白对照、正常对照（不加粉尘的AM）、阴性对照（标准TiO2)和阳性对照（标准SiO2）。结果 温石棉处理AM的上清液刺激HEPF增殖时,HEPF的G／M期细胞百分比为7．2％,高于各对照组,而细胞凋亡百分率为3．5％,低于各对照组,差异均有显著性（P＜0．01）。PRKC抑制剂C25H24N4O2使温石棉所致HEPF增殖时的S期细胞百分比由37．8％减少到27．3％,凋亡百分率由3．5％增加到22．7％,差异均有显著性（P＜0．01）,而PKC激活剂PMA能使此S期细胞百分比增加。结论 温石棉所致HEPF增殖时的细胞周期变化与其上游PKC信号通路有关,PKC抑制剂和激活剂主要是作用 于S期DNA的合成和诱导细胞凋亡。     

Mechanisms of cancer prevention by tea constituents

Consumption of tea (Camellia sinensis) has been suggested to prevent cancer, heart disease and other diseases. Animal studies have shown that tea and tea constituents inhibit carcinogenesis of the skin, lung, oral cavity, esophagus, stomach, liver, prostate and other organs. In some studies, the inhibition correlated with an increase in tumor cell apoptosis and a decrease in cell proliferation. Studies with human cancer cell lines have demonstrated that epigallocatechin-3-gallate (EGCG), a major tea polyphenol, inhibits mitogen-activated protein kinases, cyclin-dependent kinases, growth factor-related cell signaling, activation of activator protein 1 (AP-1) and nuclear factor kappaB (NFkappaB), topoisomerase I and matrix metalloproteinases as well as other potential targets. Although some studies report effects of EGCG at submicromolar levels, most experiments require concentrations of >10 or 20 micromol/L to demonstrate the effect. In humans, tea polyphenols undergo glucuronidation, sulfation, methylation, and ring fission. The peak plasma concentration of EGCG is approximately 1 micromol/L. The possible relevance of each of the proposed mechanisms to human cancer prevention is discussed in light of current bioavailability data for tea polyphenols and the potential limitations of animal models of carcinogenesis. Such discussion, it is hoped, will clarify some misunderstandings of cancer prevention by tea and stimulate new research efforts.