TIMP-2、MMP-2和MT1-MMP在活化肝星状细胞中的表达及对细胞外基质合成分泌的影响

目的 研究金属蛋白酶组织抑制剂-2(TIMP-2)、基质金属蛋白酶-2(MMP-2)和膜型基质金属蛋白酶-1(MT1-MMP)在活化肝星状细胞(HSCs)中的表达,观察其对细胞外基质(ECM)合成分泌的影响.方法 原代分离培养大鼠HSCs活化后,分别给予40～160 pmol化学合成经修饰抗TIMP-2 siRNA进行干预,检测培养细胞上清液透明质酸(HA)、Ⅲ型前胶原(PCⅢ)和羟脯氨酸(Hyp)的含量,采用荧光实时定量PCR法检测TIMP-2、MMP-2、MT1-MMP、MMP-13、COL Ⅰ和COL Ⅲ mRNA的表达,western印迹检测TIMP-2、MT1-MMP和MMP-13蛋白表达及明胶酶谱法检测MMP-2蛋白表达.结果 应用化学合成经修饰抗TIMP-2 siRNA后,TIMP-2、MMP-2、MT1-MMP、COL Ⅰ和COL Ⅲ的表达明显降低,而MMP-13的表达则明显增加,培养细胞上清液中HA、PCⅢ和Hyp的含量也明显减少.结论 TIMP-2通过MT1-MMP介导MMP-2的活化,抑制TIMP-2的表达,MT1-MMP和MMP-2的表达随之降低,而HSCs合成分泌ECM也相应减少.     

抗纤软肝颗粒对肝纤维化大鼠肝脏基质转换及肝窦毛细血管化的影响

目的:观察抗纤软肝颗粒对实验性肝纤维化时肝脏基质金属蛋白酶-1(MMP-1)、金属蛋白酶组织抑制因子-1(TIMP-1)以及肝窦毛细血管化的影响,探讨其防治肝纤维化的作用。方法:250ml/L CCl_4经大鼠皮下注射制备肝纤维化模型并同时给予秋水仙碱、小和大剂量抗纤软肝颗粒治疗,用光镜和电镜观察肝组织病理变化;免疫组织化学法检测肝组织Ⅰ、Ⅲ、Ⅳ型胶原、层粘蛋白(LM)原住杂交的方法检测MMP-1 mRNA、TIMP-1 mRNA。结果:抗纤软肝颗粒能促进MMP-1的表达(P<0.05),抑制TIMP-1的表达(P<0.01),促进Ⅰ、Ⅲ型胶原的降解(P<0.01);有效抑制Ⅳ型胶原、LM的生成和沉积(P<0.01),改善肝纤维化大鼠肝组织病理变化(P<0.01)。减轻肝窦毛细血管化程度。结论:抗纤软肝颗粒能促进MMP-1的表达,抑制TIMP-1的表达,促进胶原的降解,抑制肝窦毛细血管化的形成,从而产生抗肝纤维化的作用。     

抗纤方对肝星状细胞活化增殖、凋亡和基质金属蛋白酶-1及其抑制剂表达的影响

目的:观察抗纤方抗肝纤维化的药效学作用。方法:分离培养大鼠HSC,制备抗纤方大鼠药物血清,温育HSC。MTT比色法测定细胞增殖,流式细胞仪检测细胞凋亡。原位杂交法观察MMP-1、TIMP-1的表达。结果:抗纤方可抑制体外培养的HSC增殖,经抗纤方作用后,HSC的凋亡明显增多,并促进MMP-1表达。抑制TIMP-1的表达。结论:抗纤方抗肝纤维化可能机理为抑制HSC增殖,促进其凋亡,促进HSC表达MMP-1,抑制TIMP-1的表达。     

MMP-1、TIMP-1与实验性肝纤维化形成过程中基质转换的关系及抗纤软肝颗粒的干预作用

目的：动态观察肝纤维化形成过程中肝组织MMP-1、TIMP-1 mRNA及Ⅰ、Ⅲ型胶原的表达，以探讨MMP-1、TIMP-1与基质转换的关系，以及抗纤软肝颗粒对它们的影响。方法：将大鼠随机分为正常对照组、CCl4模型组与治疗组。采用250ml／L CCl4在大鼠皮下注射制备肝纤维化模型，并同时给与抗纤软肝颗粒治疗，各组分别于第3、5、7、9、11周分批处死大鼠，取肝脏标本。采用免疫组织化学法检测肝组织Ⅰ、Ⅲ型胶原，原位杂交的方法检测MMP-1 mRNA、TIMP-1 mRNA。结果：在肝纤维化形成过程中：①胶原持续增高，治疗组较同期模型组比较有不同程度的降低。②MMP-1 mRNA的表达先逐渐增强，后期有所下降；治疗组较同期模型组比较有不同程度的增强。③TIMP-1 mRNA的表达持续增强，治疗组较同期模型组比较有不同程度的减弱。TIMP-1 mRNA与Ⅰ、Ⅲ型胶原的表达呈显著正相关（P〈0．01）。结论：在肝纤维化过程中TIMP-1通过对MMP-1活性的抑制，导致ECM在肝脏内的过度沉积；抗纤软肝颗粒能促进MMP-1的表达，抑制TIMP-1的表达。促进肢原降解而产生抗肝纤维化作用。     

Ca2+/钙调蛋白依赖性蛋白激酶Ⅱ在PDGF诱导肝星状细胞胶原合成中的作用

目的观察Ca2+/钙调蛋白依赖性蛋白激酶Ⅱ(CaMKⅡ)对PDGF诱导下人肝星状细胞(hepatic stellate cell,HSC)colla-genα1(Ⅰ)合成的影响。方法 CaMKⅡαsiRNA转染对HSC内CaMKⅡα进行干扰,real-time PCR法检测HSC collagenα1(Ⅰ)及TIMP-1 mRNA的表达,Western blot法检测collagenα1(Ⅰ)及MMP-2、TIMP-1表达的变化,ELISA法检测HSC collagenα1(Ⅰ)分泌的变化。结果 CaMKⅡαsiRNA可显著抑制PDGF诱导下HSC collagenα1(Ⅰ)及MMP-2、TIMP-1的转录、蛋白表达以及collagenα1(Ⅰ)的分泌,差异均有统计学意义(P<0.05)。结论 CaMKⅡα信号参与了PDGF诱导下HSC collagenα1(Ⅰ)的产生与分泌,同时通过抑制MMP-2、促进TIMP-1的表达而阻止胶原的降解,是肝纤维化发展过程中PDGF信号的重要调控分子和肝纤维化的潜在治疗靶点。     

秋水仙碱对肝纤维化大鼠肝脏基质金属蛋白酶-1及其抑制因子-1表达的影响

目的 观察秋水仙碱对纤维化肝脏基质金属蛋白酶-1(MMP-1)、基质金属蛋白酶组织抑制因子-1(TIMP-1)表达的影响,从胶原降解的角度探讨秋水仙碱对肝纤维化有无逆转作用及可能存在的机制.方法 制备免疫性大鼠肝纤维化模型,并给予秋水仙碱治疗;通过RT-PCR检测MMP-1、TIMP-1的表达,并作Ⅰ、Ⅲ型胶原的免疫组化以及Masson胶原染色.结果 发现秋水仙碱对肝纤维化大鼠MMP-1的表达无明显影响(P>0.05),但可以抑制TIMP-1的表达(P<0.05),促进Ⅰ、Ⅲ型胶原的降解(P<0.05);然而在病理形态学的观察中,未发现秋水仙碱治疗组与肝纤维化模型组之间存在的显著性差异(P>0.05).结论 秋水仙碱可以抑制纤维化肝脏TIMP-1的表达,从而增强间质胶原酶的活性,促进Ⅰ、Ⅲ型胶原的降解,产生抗肝纤维化的作用,但其作用有限.     

软肝缩脾丸对肝纤维化大鼠TIMP-1、2及工、Ⅲ型胶原mRNA及蛋白表达的影响

目的观察软肝缩脾丸对纤维化大鼠肝脏基质金属蛋白酶组织抑制因子-1、2(TIMP-1、TIMP-2)及Ⅰ、Ⅲ型胶原mRNA及蛋白表达的影响,从胶原降解的角度探索中药抗肝纤维化的可能机理.方法制备大鼠肝纤维化模型,并给予软肝缩脾丸治疗;用原位杂交和免疫组化的方法分别测定TIMP-1、TIMP-2及Ⅰ、Ⅲ型胶原的mRNA和蛋白表达.结果CC14模型组TIMP1、TIMP-2,Ⅰ、Ⅲ型胶原mRNA及蛋白水平明显高于治疗组.正常组大鼠肝组织无一例阳性.结论TIMP-1、TIMP-2与肝纤维化形成密切相关,软肝缩脾丸可以抑制纤维化肝脏TIMP-1、TIMP-2的表达,从而增强间质胶原酶的活性,促进Ⅰ、Ⅲ型胶原的降解,产生抗肝纤维化作用.     

中药双甲五灵冲剂对免疫性肝纤维化大鼠抗肝纤维化的分子机制研究

目的探讨中药双甲五灵冲剂对免疫诱导型肝纤维化大鼠的治疗作用及机制。方法90只雌性Wistar大鼠。10只大鼠为正常对照组,80只大鼠予尾静脉注射人血白蛋白,建立免疫损伤性肝纤维化大鼠模型,分为5组：预防组、治疗1组、治疗2组、秋水仙碱组、观察组。用光镜观察肝脏HE染色、VanGieson（VG）胶原染色,采用原位杂交及免疫组织化学染色技术检测大鼠肝脏组织中TIMP-1、TIMP-2、Ⅰ型胶原、Ⅲ型胶原mRNA及蛋白的表达强度;用电镜观察肝脏超微结构的变化。结果免疫诱导型肝纤维化大鼠在造模结束后肝组织学改变呈进行性加重,以造模结束后3个月为著;TIMP-1、TIMP-2、Ⅰ型胶原、Ⅲ型胶原mRNA及蛋白呈强阳性表达,电镜见观察组有较多激活的HSC及大量胶原纤维沉积在肝窦间隙及肝细胞间,经双甲五灵冲剂治疗后的大鼠与观察组大鼠相比,肝组织结构明显好转,纤维组织减少,未见到激活的HSC、TIMP-1和TIMP-2mRNA及蛋白表达与观察组相比均明显降低,Ⅰ、Ⅲ型胶原蛋白及基因表达明显降低（P〈0．05）,并且其效果为预防组效果最好,治疗1组较治疗2组效果好,三组均明显优于秋水仙碱组。结论双甲五灵冲剂可以逆转肝纤维化,抗肝纤维化机制可能是：①抑制肝星状细胞活化,减少ECM的生成及TIMP分泌;②直接抑制TIMP—1、TIMP-2mRNA及蛋白的表达;二者共同作用使得TIMP分泌减少,从而降低对MMPs的抑制,有利于MMPs对ECM的降解;③具有加速Ⅰ、Ⅲ型胶原的降解,抑制其生成及沉积的作用。     

实验性肝纤维化时MMP-1、TIMP-1的表达与Ⅰ、Ⅲ型胶原含量变化的关系

为了观察实验性肝纤维化时MMP-1、TIMP-1的表达与Ⅰ、Ⅲ型胶原含量变化之间的关系,本文制备了免疫性大鼠肝纤维化模型,运用定量RT-PCR检测肝脏内MMP-1、TIMP-1的表达,通过免疫组化检测肝组织中Ⅰ、Ⅲ型胶原的含量.运用相关理论作统计学分析.结果发现在肝纤维化发生时,Ⅰ型胶原和Ⅲ型胶原含量的变化有显著相关性;MMP-1的表达在肝纤维化组与正常对照组之间未见显著差异,与Ⅰ、Ⅲ型胶原的含量变化之间也未见有相关性;TIMP-1的表达在肝纤维化发生时显著增高,与Ⅰ、Ⅲ型胶原的变化也有显著相关性.结果表明肝纤维化发生时MMP-1的表达未见明显改变,而TIMP-1的表达显著增高,且与Ⅰ、Ⅲ型胶原含量的增高呈显著相关,提示TIMP-1的表达增高在肝纤维化的发生、发展中具有重要作用.     

维生素E对肝脏星状细胞Ⅰ型胶原、TGFβ1和TIMP2表达的影响

目的　探讨维生素E对肝脏星状细胞 (HSC)Ⅰ型胶原、转化生长因子 β1(TGFβ1)和基质金属蛋白酶组织抑制剂 2 (TIMP2 )表达的影响。方法　体外培养的HSC ,经 1mg/L维生素E作用后 ,用免疫组织化学法检测Ⅰ型胶原表达 ;原位杂交技术检测TGFβ1和TIMP2 mRNA表达。结果　实验组中维生素E能使HSCⅠ型胶原表达明显少于对照组 (P <0 .0 1) ,但对TGFβ1及TIMP2 mRNA表达无影响。结论　维生素E抗肝纤维化作用可以通过抑制Ⅰ型胶原表达实现。     

1-Naphthyl isocyanate and 1-naphthylamine as metabolites of 1-naphthylisothiocyanate

Abstract: The importance of the bioactivation of 1-naphthylisothiocyanate was studied. Forty minutes after 1-naphthylisothiocyanate administration to rats, bile was collected over a 2.5-h period; the liver was then excised and homogenized. 1-naphthylisothiocyanate and its metabolites in bile and liver of rats were identified and quantified using coupled gas chromatography-mass spectrometry. Three main compounds were found in all 1-naphthylisothiocyanate-treated animals. They were identified as 1-naphthyl isocyanate, 1-naphthylamine and the parent compound, 1-naphthylisothiocyanate. When rats were given cycloheximide, which attenuates 1-naphthylisothiocyanate toxicity, 30 min before 1-naphthylisothiocyanate (300 mg/kg), 1-naphthyl isocyanate concentration was significantly lower than in rats receiving only 1-naphthylisothiocyanate. The appearance of 1-naphthylamine was also inhibited by cycloheximide, although not to the same extent as 1-naphthyl isocyanate. On the other hand, phenobarbital, which potentiates 1-naphthylisothiocyanate hepatotoxicity, enhanced 1-naphthyl isocyanate and 1-naphthylamine formation. It is suggested that 1-naphthyl isocyanate, 1-naphthylamine and the highly reactive sulfur released from 1-naphthylisothiocyanate might be involved in the hepatotoxic effect of 1-naphthylisothiocyanate.     

Inhibition of procarcinogen-bioactivating human CYP1A1, CYP1A2 and CYP1B1 enzymes by melatonin

Abstract:  Administration of melatonin to rodents decreases the incidence of tumorigenesis initiated by benzo[ a ]pyrene or 7,12-dimethylbenz[ a ]anthracene, which requires bioactivation by cytochrome P450 enzymes, such as CYP1A1, CYP1A2 and CYP1B1, to produce carcinogenic metabolites. The present study tested the hypothesis that melatonin is a modulator of human CYP1 catalytic activity and gene expression. As a comparison, we also investigated the effect of melatonin on the catalytic activity of CYP2A6, which is also a procarcinogen-bioactivating enzyme. Melatonin (3–300 μ m ) decreased 7-ethoxyresorufin O -dealkylation catalyzed by human hepatic microsomes and recombinant CYP1A1, CYP1A2 and CYP1B1, whereas it did not affect coumarin 7-hydroxylation catalyzed by hepatic microsomes or recombinant CYP2A6. Melatonin inhibited CYP1 enzymes by mixed inhibition, with apparent K _i values (mean ± S.E.M.) of 59 ± 1 (CYP1A1), 12 ± 1 (CYP1A2), 14 ± 2 (CYP1B1) and 46 ± 8 μ m (hepatic microsomes). Additional experiments indicated that melatonin decreased benzo[ a ]pyrene hydroxylation catalyzed by hepatic microsomes and CYP1A2 but not by CYP1A1 or CYP1B1. Treatment of MCF-10A human mammary epithelial cells with melatonin (up to 300 μ m ) did not affect basal or benzo[ a ]pyrene-inducible CYP1A1 or CYP1B1 gene expression. Consistent with this finding, melatonin did not influence reporter activity in aryl hydrocarbon receptor-dependent pGudluc6.1-transfected MCF-10A cells treated with or without benzo[ a ]pyrene, as assessed in an in vitro cell-based luciferase reporter gene assay. Overall, melatonin is an in vitro inhibitor of human CYP1 catalytic activity, and it may be useful to develop potent analogues of melatonin as potential cancer chemopreventive agents that block CYP1-mediated chemical carcinogenesis.     

The target of ezetimibe is Niemann-Pick C1-Like 1 (NPC1L1)

Ezetimibe is a potent inhibitor of cholesterol absorption that has been approved for the treatment of hypercholesterolemia, but its molecular target has been elusive. Using a genetic approach, we recently identified Niemann-Pick C1-Like 1 (NPC1L1) as a critical mediator of cholesterol absorption and an essential component of the ezetimibe-sensitive pathway. To determine whether NPC1L1 is the direct molecular target of ezetimibe, we have developed a binding assay and shown that labeled ezetimibe glucuronide binds specifically to a single site in brush border membranes and to human embryonic kidney 293 cells expressing NPC1L1. Moreover, the binding affinities of ezetimibe and several key analogs to recombinant NPC1L1 are virtually identical to those observed for native enterocyte membranes. KD values of ezetimibe glucuronide for mouse, rat, rhesus monkey, and human NPC1L1 are 12,000, 540, 40, and 220 nM, respectively. Last, ezetimibe no longer binds to membranes from NPC1L1 knockout mice. These results unequivocally establish NPC1L1 as the direct target of ezetimibe and should facilitate efforts to identify the molecular mechanism of cholesterol transport.     

甲型H1N1与季节性H1N1流感病毒血凝素基因比较分析

目的分析泰安市2008～2009年度季节性流感与2009年度甲型H1N1流感病原学检测结果 ,比较季节性H1N1与甲型H1N1血凝素基因变异情况。方法选择国家级流感监测哨点医院以及暴发疫情的疫点,采集流感样病例的鼻咽拭子标本,通过RealtimePCR进行病毒检测,用MDCK细胞进行病毒分离,通过RT-PCR扩增血凝素HA1片段的基因并测序,利用生物信息学进行序列分析。结果 2008～2009年共检测鼻咽拭子标本283份,分离出流感病毒33株,分离阳性率为11.67%,其中季节性H1N1亚型31株。2009年5月1日～12月31日,检测鼻咽拭子标本996份,流感核酸检测阳性417份,阳性率为41.86%,其中甲型H1N1337份,季节性H1N1亚型1份。6株季节性H1N1病毒均在多个氨基酸位点上发生变异,与疫苗株A/Brisbane/59/2007(H1N1)比较,有11个位点发生了突变,其中5个位点位于抗原决定簇上;测序成功的6株甲型H1N1病毒在多个氨基酸位点发生变异,与疫苗株A/California/07/2009(H1N1)比较,有6个位点发生突变,其中1个位点位于抗原决定簇的B区。结论 2008～2009年度季节性H1N1为优势株,甲流暴发后,甲型H1N1成为绝对优势毒株。季节性H1N1分离株有多处氨基酸替换,抗原决定簇B区变异频繁;甲型H1N1病毒分离株的基因有变异,但关键位点第222位仍为D(天冬氨酸),与疫苗株相比抗原决定簇的关键位点变化不大。     

Characterization of MTHFR,GSTM1, GSTT1, GSTP1, and CYP1A1 genotypes in childhood acute leukemia

The role of methylenetetrahydrofolate reductase (MTHFR C677T), glutathione S-transferases (GSTM1 and GSTT1 null, GSTP1 Ile105Val), and cytochromes p450 (CYP1A1*2A) genotypes in the etiology of childhood leukemia was simultaneously investigated. 144 Turkish children with acute lymphoblastic leukemia (ALL) and 33 with acute nonlymphoblastic leukemia (ANLL) were studied and compared with 185 healthy pediatric controls. The frequency of MTHFR genotype was insignificantly higher in ALL (7.7%) and ANLL (6.3%) than in controls (4.4%). Equal distribution of the GSTM1 null genotype was detected between ALL patients and controls (55%), while its incidence was slightly higher in ANLL patients (61.3%). Although GSTT1 null genotype was insignificantly lower in ALL patients (20.9%) than controls (22.7%), it was significantly underrepresented in ANLL patients (6.5%) (P = 0.05, OR 0.24, 95% CI 0.05-1.03). The homozygous frequency of GSTP1 genotype did not differ significantly between groups of ALL (3.7%), ANLL patients (9.1%) and controls (4.9%). Homozygous CYP1A1*2A genotype was underrepresented in ALL patients (1%) as compared to control (4.8%) but the differences did not reach to statistical significance (OR 0.21; 95% CI 0.03-1.72). Homozygosity for this genotype was not detected in ANLL patients. No particular association was noted between different combinations of combined genotypes and risk of development of childhood ALL and ANLL. These results suggested that there are no significant associations between the studied genotypes and the risk of developing either form of acute leukemia except GSTT1 null and homozygosity for CYP1A1 genotypes that may play protective roles in the development of ANLL in Turkish children.     

Cytochrome 1A1 and 1B1 gene diversity in the Zanzibar islands

Amodiaquine (AQ) is a 4‐aminoquinoline widely used in the treatment of malaria as part of the artemisinin combination therapy (ACT). AQ is metabolised towards its main metabolite desethylamodiaquine mainly by cytochrome P450 2C8 (CYP2C8). CYP1A1 and CYP1B1 play a minor role in the metabolism but they seem to be significantly involved in the formation of the short‐lived quinine‐imine. To complete the genetic variation picture of the main genes involved in AQ metabolism in the Zanzibar population, previously characterised for CYP2C8, we analysed in this study CYP1A1 and CYP1B1 main genetic polymorphisms. The results obtained show a low frequency of the CYP1A1*2B/C allele (2.4%) and a high frequency of CYP1B1*6 (approximately 42%) followed by CYP1B1*2 (approximately 27%) in Zanzibar islands. Genotype data for CYP1A1 and CYP1B1 show a low incidence of fast metabolisers, revealing a relatively safe genetic background in Zanzibar’s population regarding the appearance of adverse effects.