人参总皂苷防治原发性骨质疏松

目的观察人参总皂苷对碱性磷酸酶(ALP)、骨形成蛋白(BMP)和Smad1的调控作用,探讨人参总皂苷在原发性骨质疏松疾病中的作用机制。方法建立大鼠老年性骨质疏松模型,分别给予人参总皂苷高(60 mg/kg)、中(40 mg/kg)和低剂量(20 mg/kg)治疗;利用X-射线扫描技术检大鼠骨密度(BMD);应用qRT-PCR技术和Western印迹技术检测、分析ALP、BMP、Smad1mRNA和蛋白表达情况。结果治疗90 d后与空白组比较,模型组BMD显著降低(P0. 01),造模成功;与模型组比较,阳性组、人参总皂苷高、中剂量组BMD均显著升高(P0. 01,P0. 05)。与空白组比较,模型组ALP、BMP、Smad1 mRNA表达均显著降低(均P0. 01);与模型组比较,阳性组及人参总皂苷高剂量组ALP、BMP、Smad1 mRNA及中剂量组BMP mRNA表达明显升高(P0. 01,P0. 05)。与空白组比较,模型组ALP、BMP、Smad1蛋白表达显著降低(P0. 01);与模型组比较,阳性组、人参总皂苷高、中剂量组ALP、BMP、Smad1蛋白表达显著升高(P 0. 01,P 0. 05)。结论人参总皂苷能上调ALP、BMP、Smad1三者的表达,可能是通过BMP/Smad1信号通路发挥调节骨代谢的作用,对原发性骨质疏松有一定的防治作用。     

丁苯酞通过上调Nrf-2增强抗氧化保护大鼠脑缺血再灌注损伤

目的 探讨丁苯酞对脑缺血再灌注大鼠Nrf2信号通路的影响和神经保护作用.方法 采用线栓法制作大鼠大脑中动脉缺血再灌注损伤模型,随机分为假手术组、缺血再灌注组以及丁苯酞小剂量组(100 mg/kg)和大剂量组(400mg/kg),在再灌注后24 h进行神经功能缺损评分,采用蛋白质印迹法检测缺血脑组织Nrf2蛋白表达水平以及超氧化物歧化酶和丙二醛含量,TUNEL法检测神经细胞凋亡情况,免疫组化染色法检测cleaved-caspase-3表达情况.结果 与模型组相比,丁苯酞以剂量依赖性方式显著上调Nrf2蛋白表达(P＜0.05),提高超氧化物歧化酶活性(P＜0.05),降低丙二醛含量(P＜0.05),并且减少cleaved-caspase-3阳性细胞和凋亡细胞数量(P＜0.05).结论 丁苯酞可在大鼠脑缺血再灌注损伤中发挥显著的神经保护作用,其作用可能与上调Nrf2信号通路和增强抗氧化有关.     

环氧合酶-1和前列腺素E2在多潘立酮对大鼠胃黏膜保护中的作用

目的　研究多潘立酮对大鼠胃黏膜损伤是否具有保护作用 ,并探讨胃黏膜细胞中环氧合酶 1(COX 1)及前列腺素 (PG)E2是否参与其中。方法　研究分为对照组和实验组。后者分别用多潘立酮 0 .5mg/kg、1mg/kg和 2mg/kg灌胃 ,3次 /d ,连续 3d。各组大鼠灌入无水乙醇后 ,肉眼观察胃黏膜损伤指数 (LI) ,光镜下观察黏膜缺损深度 ,并计算黏膜缺损深度与胃壁全层厚度百分比。放射免疫法测定各组胃黏膜PGE2的水平。免疫组织化学方法检测COX 1和COX 2蛋白表达水平并以平均吸光度值表示其强度。RT PCR检测胃黏膜COX 1和COX 2mRNA表达变化。结果　多潘立酮 1mg/kg组的LI及黏膜缺损深度与胃壁全层厚度百分比显著低于对照组 (P <0 .0 5 ) ,0 .5mg/kg组和 2mg/kg的组LI亦显著低于对照组 (P <0 .0 5 )。多潘立酮 1mg/kg组大鼠胃黏膜COX 1蛋白表达水平及PGE2水平显著高于空白对照组 (P <0 .0 1)。各实验组和对照组在胃黏膜细胞内均无COX 2蛋白表达。三个实验组COX 1mRNA表达量与对照组比较差异均有显著性 (P <0 .0 1)。各组均未检测到COX 2mRNA表达。结论　多潘立酮对胃黏膜损伤具有保护作用 ,其机制之一可能与其增加胃黏膜COX 1mRNA和COX 1蛋白表达及促进胃黏膜PGE2分泌有关。     

SIRT1信号通路在白藜芦醇保护脑缺血再灌注损伤中的作用机制

目的探讨白藜芦醇(Res)对大脑缺血再灌注损伤后大鼠神经元凋亡的影响及其作用机制。方法采用线栓法制作短暂性大脑中动脉栓塞(MCAO)模型。将60只SD大鼠随机分为假手术组(Sham组)、脑缺血再灌注模型组(MCAO组)、白藜芦醇低剂量(10 mg/kg)组(Res 10组)、白藜芦醇高剂量(30 mg/kg)组(Res 30组)。栓塞缺血2 h、再灌注24 h后对各组大鼠进行神经功能损伤评分、脑组织含水量及脑梗死体积评估,TUNEL染色检测细胞凋亡,同时测定缺血再灌注损伤缺血测脑组织中SIRT1、Bax、Caspase-3 mRNA表达水平。结果脑缺血再灌注后24 h,MCAO组脑梗死体积大于Sham组(P0.01),神经功能损伤评分、脑组织含水量、TUNEL(+)细胞数及Bax mRNA、Caspase-3 mRNA表达量均明显高于Sham组(P0.01),而SIRT1 mRNA表达量较Sham组明显降低(P0.01)。与MCAO组比较,Res 10组、Res 30组脑梗死体积明显缩小(P0.01),神经功能损伤评分、脑组织含水量、TUNEL(+)细胞数以及脑组织中Bax mRNA、Caspase-3 mRNA表达量明显降低(P0.01),SIRT1 mRNA表达明显增加(P0.01)。结论白藜芦醇可通过减轻缺血脑组织神经元凋亡对大鼠脑缺血再灌注损伤发挥神经保护作用,其可能通过激活SIRT1信号通路从而抑制或逆转脑缺血再灌注神经损伤的发生。     

白藜芦醇通过抑制TNF-α表达保护大鼠脑缺血再灌注损伤

目的探讨不同浓度白藜芦醇对缺血再灌注大鼠神经功能损伤及肿瘤坏死因子α(TNF-α)表达的影响。方法将150只健康成年雄性SD大鼠随机分成5组:假手术组、模型组(I/R组)、小剂量白藜芦醇(2.5mg/kg)组、中剂量白藜芦醇(5 mg/kg)组、大剂量白藜芦醇(10 mg/kg)组,每组30只。模型组和白藜芦醇组在制作脑缺血再灌注损伤模型20 min前分别给予生理盐水或不同浓度白藜芦醇腹腔注射,术后6 h、24 h、48 h、72 h、7天时间节点分别评定神经功能缺损评分。应用四氮唑红染色(TTC)脑组织后计算脑梗死病灶体积并比较5组的差异;分别应用免疫组织化学检测缺血脑组织周边区组织的TNF-α表达量并比较5组的差异。结果 (1)模型组大鼠在缺血再灌注后各时间点均有神经功能缺损,白藜芦醇可改善神经功能缺损,剂量越大,改善越明显。(2)白藜芦醇干预各组大鼠的脑梗死体积显著减少(P0.05),呈显著剂量依赖性。(3)在各个时间点,各组大鼠缺血周边区脑组织的TNF-α阳性细胞数为:模型组小剂量白藜芦醇组中剂量白藜芦醇组大剂量白藜芦醇组假手术组(P0.05)。结论 (1)缺血再灌注脑损伤过程中,白藜芦醇能有效的保护大鼠脑神经细胞,减少脑梗死体积,改善神经功能缺损评分,这一作用可能是通过抑制TNF-α表达来完成的。(2)白藜芦醇对脑缺血再灌注损伤的保护作用与剂量相关,并且呈现显著剂量依赖性。     

熊果酸抑制神经细胞凋亡降低局灶性脑缺血再灌注损伤的实验研究

目的探讨熊果酸不同剂量对脑缺血再灌注损伤的保护作用及其机制。方法采用线栓法复制局灶性脑缺血再灌注大鼠模型,随机分为假手术组、模型组及熊果酸低剂量组(20 mg/kg)、中剂量组(40 mg/kg)、高剂量组(80 mg/kg),每组20只再灌注前30min腹腔注射给药,24 h后行盲法神经功能评分,测定各组脑组织含水量和脑梗死体积;观察神经细胞凋亡并计算凋亡指数(AI),检测脑组织中bcl-2 mRNA、Bax mRNA表达及caspase-3、核转录因子-κB(NF-κB)蛋白表达。结果熊果酸中、高剂量组大鼠神经功能评分较模型组降低,神经功能症状明显改善,脑组织含水量和梗死体积均降低,差异有统计学意义(P0.05或P0.01);熊果酸各剂量组神经细胞凋亡状况呈不同程度好转,中、高剂量组AI降低(P0.05或P0.01);熊果酸中、高剂量组脑组织Bax mRNA表达下调、bcl-2 mRNA上调、bcl-2/Bax比值升高,caspase-3、NF-κB蛋白表达下调,差异有统计学意义(P0.05或P0.01)。结论熊果酸中、高剂量可能通过抑制神经细胞凋亡而起到降低局灶性脑缺血再灌注损伤的作用。     

基于TLR4/MyD88/NF-κB信号通路探讨毒消肝清丸对肝硬化内毒素血症大鼠肝组织炎症反应的影响

目的通过CCl4复合造模制备肝硬化内毒素血症模型,探讨毒消肝清丸对大鼠肝脏炎性损伤的保护机制。方法:66只大鼠造模过程中有17只死亡,取3只大鼠检测内毒素和观察肝脏结构,确定造模成功,剩余随机分成正常组(n=6),模型组(n=8)、乳果糖组(n=8)、毒消肝清丸高、中、低剂量组(223. 4 mg/kg、111. 7 mg/kg、58. 9 mg/kg,n=8)。采用CCl4复合造模法造模8周,制备肝硬化内毒素血症动物模型。正常组和模型组给予蒸馏水,乳果糖组予乳果糖,毒消肝清丸药物组按上述剂量每天给药1次,连续8周。测定内毒素含量变化、HE染色观察肝脏组织变化情况、采用ELISA检测肝脏组织TNFα、IL-1β、IL-6的含量;Western Blot和RT-PCR技术检测TLR4、MyD88、NF-κB蛋白及其mRNA的表达。计量资料多组间比较采用单因素方差分析,进一步两两比较采用LSD-t法。结果各组间大鼠血浆内毒素水平差异有统计学意义(F=26. 011,P 0. 001);模型组内毒素水平较正常组显著升高(P 0. 01);给药后乳果糖组、毒消肝清丸不同剂量组大鼠血清内毒素含量较模型组均显著降低(P值均0. 01)。各组间大鼠血清IL-6、IL-1β以及TNFα水平差异均有统计学意义(F值分别为35. 390、38. 271、40. 241,P值分别为0. 002、0. 001、0. 001);与正常组比较,模型组大鼠血清IL-1β、IL-6以及TNFα显著升高(P值均0. 01);给药后乳果糖组及毒消肝清丸不同剂量药物组大鼠血清IL-1β、IL-6以及TNFα水平较模型组均显著降低(P值均0. 01)。各组间大鼠肝组织TLR4、MyD88、NF-κB mRNA及其蛋白表达差异均有统计学意义(F值分别为24. 483、29. 547、19. 242、18. 752、22. 146、15. 834,P值均0. 01);与正常组大鼠相比,模型组大鼠肝脏TLR4、MyD88、NF-κB mRNA及其蛋白相对表达量均显著升高(P值均0. 01);乳果糖和毒消肝清丸不同剂量治疗后大鼠肝组织TLR4、MyD88、NF-κB mRNA及其蛋白相对表达量较模型组均显著下降(P值均0. 01)。与低剂量治疗组比较,中高剂量组大鼠肝脏TLR4、MyD88、NF-κB mRNA及其蛋白相对表达量下降尤为显著(P值均0. 01)。结论药物组可能通过下调肝脏组织TLR4/MyD88/NF-κB信号通路来抑制炎症信号的转导,减少了细胞因子TNFα、IL-1β、IL-6的表达,进而缓解内毒素血症并对肝脏组织起到保护作用。     

白蛋白治疗对大鼠脑缺血后海马血管内皮生长因子及其受体1的影响

目的探讨人血白蛋白治疗对大鼠脑缺血早期海马血管内皮生长因子(VEGF)及fam样酪氨酸激酶受体1(flt-1)表达的影响。方法雄性SD大鼠40只,采用大脑中动脉线栓法制备大鼠局灶性脑缺血再灌注模型,随机分为假手术组10只、生理盐水组15只和白蛋白组15只。采用溴甲酚绿法测定血清白蛋白水平,RT-PCR检测脑缺血再灌注后6、24、48h大鼠海马VEGF和flt-1mRNA表达,免疫组织化学和Western blot法检测脑缺血再灌注24h海马VEGF蛋白表达。结果与生理盐水组比较,白蛋白组大鼠神经功能缺损评分于脑缺血再灌注后24、48h明显降低(P<0.05),海马VEGF mRNA和flt-1mRNA表达于脑缺血再灌注后6、24h明显降低(P<0.05,P<0.01),海马VEGF蛋白表达于脑缺血再灌注后24h明显降低(P<0.05)。结论白蛋白治疗可下调脑缺血早期海马VEGF和flt-1mRNA表达,降低海马VEGF蛋白表达水平,改善神经功能缺损。     

锦鸡儿总黄酮对大鼠脑缺血再灌注损伤后半暗带区GFAP表达的影响

目的研究锦鸡儿总黄酮(TFC)对大鼠局灶性脑缺血再灌注损伤后缺血周边区星形胶质细胞胶质纤维酸性蛋白(GFAP)生长的影响。方法将大鼠随机分为假手术组、模型组、TFC高、中、低剂量(60、30、15 mg/kg)组,采用线栓法制作大鼠局灶性脑缺血再灌注损伤模型,脑缺血1.5 h再灌注3 h后,TFC高、中、低剂量组分别给予TFC 60、30、15 mg/kg灌胃治疗,假手术组及模型组给予等体积生理盐水,每日1次,连续治疗14 d,观察各组大鼠在脑缺血后24 h和治疗第14天后神经功能缺损综合评分,苏木素-伊红(HE)染色观察缺血周边区脑组织形态结构的变化,荧光免疫组织化学染色及Western印迹法检测各组脑缺血边缘区GFAP表达水平。结果脑缺血24 h后,与模型组比较,TFC高、中、低剂量组神经功能缺损评分差异无统计学意义(P0.05);脑缺血14 d后,与模型组比较,TFC高、中、低剂量组神经功能缺损评分均显著降低(P0.05,P0.01),TFC高、中、低剂量组均明显促进脑缺血边缘区神经细胞的修复;模型组和TFC高、中、低剂量组GFAP阳性细胞数及蛋白表达量均显著高于假手术组(P0.01),TFC高、中剂量组GFAP阳性细胞数及蛋白表达量显著少于模型组(P0.05,P0.01),细胞生长形态规则。结论 TFC能改善脑缺血后神经功能缺损症状,可促进神经细胞恢复,其机制可能与抑制缺血半暗带区GFAP的过度生长有关。     

三七皂苷Rg1对肺纤维化大鼠信号传导蛋白3和胰岛素样生长因子-1 mRNA表达的影响

目的探讨三七皂苷Rg1对博来霉素诱导的肺纤维化组织中胰岛素样生长因子(IGF)-1和信号传导蛋白Smad3mRNA表达的影响。方法雄性SD大鼠随机分为6组:假手术组、模型组、模型+阳性对照组、模型+三七皂苷Rg1低剂量组(18 mg/kg)、模型+三七皂苷Rg1中剂量组(36 mg/kg)和模型+三七皂苷Rg1高剂量组(72 mg/kg)。采用Masson染色和酶联免疫吸附(ELISA)法分别检测肺纤维化评分和肺组织中羟脯氨酸(Hyp)的含量,定量聚合酶链反应(qP CR)测定大鼠肺组织中IGF-1和Smad3 mRNA水平。结果三七皂苷Rg1可剂量依赖性地降低肺纤维化大鼠肺纤维化评分和肺组织中羟脯Hyp含量,可显著减少IGF-1和Smad3 mRNA表达,与模型组差异有统计学意义(P0. 05或P0. 01);三七皂苷Rg1高剂量组给药28 d的作用与阳性对照药比较,作用较优。结论三七皂苷Rg1良好的抗肺纤维化作用与其下调肺纤维化大鼠肺组织IGF-1和Smad3 mRNA表达有关。     

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。     

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.     

CYP1A1 , GSTM1 , GSTT1 and NQO1 polymorphisms and colorectal adenomas in Japanese men

AIM: To investigate the role of functional genetic poly-morphisms of metabolic enzymes of tobacco carcinogens in the development of colorectal adenomas. METHODS: The study subjects were 455 patients with colorectal adenomas and 1052 controls with no polyps who underwent total colonoscopy in a preretirement health examination at two Self Defense Forces hospitals. The genetic polymorphisms studied wereCYP1A1*2A (rs 4646903), CYP1A1*2C (rs 1048943), GSTM1 (null or non-null genotype), GSTT1 (null or non-null genotype) and NQO1 C609T (rs 1800566). Genotypes were determined by the polymerase chain reaction (PCR)-restriction fragment length polymorphism or PCR method using genomic DNA extracted from the buffy coat. Cigarette smoking and other life-style factors were ascertained by a self-administered questionnaire. The associations of the polymorphisms with colorectal adenomas were examined by means of OR and 95%CI, which were derived from logistic regression analysis. Statistical adjustment was made for smoking, alcohol use, body mass index and other factors. The gene-gene interaction and effect modification of smoking were evaluated by the likelihood ratio test. RESULTS: None of the five polymorphisms showed a significant association with colorectal adenomas, nor was the combination of GSTM1 and GSTT1 . A borderline significant interaction was observed for the combination of CYP1A1*2C and NQO1 (P = 0.051). The OR associated with CYP1A1*2C was significantly lower than unity among individuals with the NQO1 609CC genotype. The adjusted OR for the combination of the CYP1A1*2C allele and NQO1 609CC genotype was 0.61 (95%CI: 0.42-0.91). Although the interaction was not statistically significant (P = 0.24), the OR for individuals carrying the CYP1A1*2C allele and GSTT1 null genotype decreased significantly compared with those who had neither CYP1A1*2C allele nor GSTT1 null genotype (adjusted OR: 0.69, 95%CI: 0.49-0.97). Smoking did not modify the associations of the individual polymorphisms with colorectal adenomas. There w     

Polymorphisms of CYP1A1 and GSTM1 and laryngeal cancer risk: evidence-based meta-analyses

Purpose  Previous evidence implicates CYP1A1 and GSTM1 polymorphisms as risk factors for various cancers. A number of studies have been devoted to the association of CYP1A1 or GSTM1 polymorphism with susceptibility to laryngeal carcinoma, with the results inconsistent and inconclusive. The aim of the present study was to assess the possible associations of laryngeal cancer risk with CYP1A1 genetic variation and GSTM1 null genotype respectively. Methods  The associated literature was acquired through deliberate searching and selected based on the established inclusion criteria for publications, then the extracted data were further analyzed using systematic meta-analyses. Results  The results showed that the overall odds ratio (OR) was 1.32 (95% CI = 1.08–1.61) for CYP1A1 Mspl polymorphism. Using subgroup analysis, the pooled ORs were 1.38 (95% CI = 0.98–1.95) in Asians and 1.29 (95% CI = 1.01–1.65) in Caucasians. For CYP1A1 exon7 polymorphism, the overall OR was 1.38 (95% CI = 0.98–1.95). The overall OR was 1.24 (95% CI = 1.03–1.49) for GSTM1 polymorphism and the pooled ORs were 1.36 (95% CI = 0.75–2.48) in Asians, 1.16 (95% CI = 0.94–1.44) in Caucasians and 1.52 (95% CI = 1.05–2.19) in Turkey population. Conclusions  The data suggest CPY1A1 MspI polymorphism as a risk factor for laryngeal cancer in Caucasians but not in Asians. However, the results suggest a marked correlation of GSTM1 polymorphism with laryngeal cancer risk in Turkey population but not Caucasians and Asians. The author Xian-Lu Zhuo works at Guiyang Medical College.     

SIRT1和E2F1的研究进展

随着人类对肿瘤的了解和认识不断加深,人类对肿瘤的基因方面的研究应运而生。SIRT是一种具有烟碱腺嘌呤二核苷酸依赖性的蛋白脱乙酰化酶,参与细胞增殖、衰老、凋亡、分化等生理活动。迄今为止,人类细胞内发现了7种不同类型的SIRT蛋白,分别命名为SIRT1～7。其中SIRT1是目前关于肿瘤相关性研究较多的一个,在抑制凋亡、延缓衰老、延长寿命中发挥着重要作用。E2F家族是一组能够编码转录调节因子的基因,是细胞周期进程的重要调控因子。其中E2F1是细胞周期的重要正向调控因子,在细胞从G0/G1期进入S期的进程中发挥着关键作用,即促进进入S期的细胞明显增多。众多研究表明,转录因子SIRT1和E2F1在细胞周期,细胞凋亡和肿瘤发生、发展过程中都具有重要的作用。相信随着对这两个基因研究的日益深入,其与细胞凋亡、细胞周期以及肿瘤的关系将逐渐明确,必定会为肿瘤的诊断和治疗提供更多有价值的思路。     

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.     

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.     

8-溴-环磷酸腺苷对单核细胞株THP1中ABCA1及细胞间黏附分子的影响

目的 观察8-Br-cAMP刺激下,单核细胞株THP1中ABCA1、细胞间黏附分子-1(ICAM-1)及 白介素-1β(IL-1β)mRNA和蛋白质表达的变化,阐明ABCA1基因在动脉粥样硬化(AS)形成中的可能机制.方法 复苏培养THP1单核细胞,加入8-Br-cAMP(0.5 mmol/L)刺激3、6、12、24 h,设未加刺激同时孵育24 h的细胞为阴性对照组;以荧光定量RT-PCR和Western印迹法及ELISA法检测ABCA1、ICAM-1及IL-1β mRNA和蛋白质表达量;用ABCA1的反义寡核苷酸(100 nmol/L)转染THP1细胞,给予8-Br-cAMP刺激,同样的方法观察上述指标的改变.结果 予8-Br-cAMP刺激后,THP1细胞中ABCA1、ICAM-1 mRNA和蛋白质及IL-1β蛋白质表达均增高,给予反义寡核苷酸转染后氧化低密度脂蛋白(Ox-LDL)刺激3、6 h上述指标的mRNA表达降低 (P<0.01),12、24 h蛋白质表达降低 (P<0.01).结论 THP1单核细胞中,8-Br-cAMP激活ABCA1不仅可增加细胞内胆固醇外运,还具有增加炎症因子表达的作用,在AS的发生中发挥双重作用.