The role of polymorphic cytochrome P450 gene(CYP2B6)in B-chronic lymphocytic leukemia(B-CLL)incidence and outcome among Egyptian patients

Cytochromes P450(CYPs)play a prominent role in catalyzing phase I xenobiotic biotransformation and account for about 75%of the total metabolism of commercially available drugs,including chemotherapeutics.The gene expression and enzyme activity of CYPs are variable between individuals,which subsequently leads to different patterns of susceptibility to carcinogenesis by genotoxic xenobiotics,as well as differences in the efficacy and toxicity of clinically used drugs.This research aimed to examine the presence of the CYP2B6*9 polymorphism and its possible association with the incidence of B-CLL in Egyptian patients,as well as the clinical outcome after receiving cyclophosphamide chemotherapy.DNA was isolated from whole blood samples of 100 de novo B-CLL cases and also from 100 sex-and age-matched healthy individuals.The presence of the CYP2B6*9(G516T)polymorphism was examined by PCR-based allele specific amplification(ASA).Patients were further indicated for receiving chemotherapy,and then they were followed up.The CYP2B6*9 variant indicated a statistically significant higher risk of B-CLL under different genetic models,comprising allelic(T-allele vs.G-allele,OR=4.8,p<0.001)and dominant(GT+TT vs.GG,OR=5.4,p<0.001)models.Following cyclophosphamide chemotherapy,we found that the patients with variant genotypes(GT+TT)were less likely to achieve remission compared to those with the wild-type genotype(GG),with a response percentage of(37.5%vs.83%,respectively).In conclusion,our findings showed that the CYP2B6*9(G516T)polymorphism is associated with B-CLL susceptibility among Egyptian patients.This variant greatly affected the clinical outcome and can serve as a good therapeutic marker in predicting response to cyclophosphamide treatment.

氯胺酮多次给药对大鼠肝微粒体内细胞色素P450_2B酶的诱导作用

目的考察氯胺酮对大鼠肝微粒体内细胞色素P450_2B酶活性的影响。方法以10mg.kg-1.d-1氯胺酮灌胃给予大鼠,连续给药10d。在第11d处死大鼠,以钙离子沉淀法制备肝微粒体。采用Omura和Sato方法测定细胞色素P450含量,采用7-戊氧基试卤灵-O-去烷基反应测定细胞色素P450_2B酶的活性。结果给药组和对照组细胞色素P450的总含量分别是(0.679±0.216)nmol·mg-1和(0.398±0.109)nmol·mg-1,细胞色素P450_2B酶的活性分别是(13.40±3.15)pmol·min-1.mg-1和(7.04±2.09)pmol·min-1.mg-1。结论氯胺酮能够增加大鼠肝微粒中细胞色素P450含量,并能显著诱导细胞色素P450_2B酶的活性。

Functionalized selenium nanoparticles ameliorated acetaminophen-induced hepatotoxicity through synergistically triggering PKCδ/Nrf2 signaling pathway and inhibiting CYP 2E1

Selenium nanoparticles(SeNPs)have been demonstrated potential for use in diseases associated with oxidative stress.Functionalized SeNPs with lower toxicity and higher biocompatibility could bring better therapeutic activity and clinical application value.Herein,this work was conducted to investigate the protective effect of Pleurotus tuber-regium polysaccharide-protein complex funtionnalized SeNPs(PTR-SeNPs)against acetaminophen(APAP)-induced oxidative injure in HepG2 cells and C57BL/6J mouse liver.Further elucidation of the underlying molecular mechanism,in particular their modulation of Nrf2 signaling pathway was also performed.The results showed that PTR-SeNPs could significantly ameliorate APAP-induced oxidative injury as evidenced by a range of biochemical analysis,histopathological examination and immunoblotting study.PTR-SeNPs could hosphorylate and activate PKCδ,depress Keap1,and increase nuclear accumulation of Nrf2,resulting in upregulation of GCLC,GCLM,HO-1 and NQO-1 expression.Besides,PTR-SeNPs suppressed the biotransformation of APAP to generate intracellular ROS through CYP 2E1 inhibition,restoring the mitochondrial morphology.Furthermore,the protective effect of PTR-SeNPs against APAP induced hepatotoxicity was weakened as Nrf2 was depleted in vivo,indicating the pivotal role of Nrf2 signaling pathway in PTR-SeNPs mediated hepatoprotective efficacy.Being a potential hepatic protectant,PTR-SeNPs could serve as a new source of selenium supplement for health-promoting and biomedical applications.

Hepatoprotective effects of S-adenosyl-L-methionine against alcohol-and cytochrome P450 2E1-induced liver injury

S-adenosyl-L-methionine (SAM) acts as a methyl donor for methylation reactions and participates in the synthesis of glutathione. SAM is also a key metabolite that regulates hepatocyte growth, differentiation and death. Hepatic SAM levels are decreased in animal models of alcohol liver injury and in patients with alcohol liver disease or viral cirrhosis. This review describes the protection by SAM against alcohol and cytochrome P450 2E1-dependent cytotoxicity both in vitro and in vivo and evaluates mechanisms for this protection.

Cardioprotection of Shenfu preparata on cardiac myocytes through cytochrome P450 2J3

To evaluate whether Shenfu injection （SFI） protects against cardiac myocyte injury induced by Fupian injection （FPI） in vitro. METHODS： H9c2 cells were separately treated with FPI, Renshen injection （RSI） and SFI. Cell viability, lactate dehydrogenase （LDH） release, spontaneous beating rate of primative cardical cells, caspase-3/7 activity, cell apoptosis, and cytochrome P450 2J3 （CYP2J3） mRNA expression were analyzed. RESULTS： The viability of H9c2 cells treated with SFI （37 and 75 mg/mL） was significantly higher than that of H9c2 cells treated with FPI （25 and 50 mg/mL） （P〈0.05, P〈0.01, respectively）. LDH activity of H9c2 cells treated with SFI （75 mg/mL） was significantly decreased （P〈0.01） compared with that of H9c2 cells treated with FPI （50 mg/mL）. SFI （150 mg/mL） significantly attenuated FPI （100 mg/mL）-induced spontaneous beating rate decrease in primary myocardial cells after 4-hour treatment. Compared with FPI （12 and 25 mg/mL）, SFI （18 and 37 mg/mL） treatment could effectively reverse the change of caspase-3/7 activity （P〈0.01 and P〈0.01, respectively）. Compared with FPI （6 and 25 mg/mL）, apoptotic cells decreased significantly （P〈0.05, P〈0.01, respectively） when H9c2 cells were incubated with SFI （9 and 37 mg/mL）. The expression of CYP2J3 mRNA was down-regulated by FPI, while RSI and SFI could up-regulate the expression of CYP2J3 （P〈0.01）, which suggested the potential mechanism of protection of RSI against cardiac myocyte damage induced by FPI treatment. CONCLUSION： These observations indicate that SFI has the potential to exert cardioprotective effects against FPI toxicity. The effect was possibly correlated with the activation of CYP2J3.

Cytochrome P450 2E1 RsaI/PstI and DraI Polymorphisms Are Risk Factors for Lung Cancer in Mongolian and Han Population in Inner Mongolia

Objective： To explore the relationship between cytochrome P450 2E1 （CYP2E1） RsaI/PstI and DraI polymorphism and lung cancer susceptibility in Mongolian and Han population in Inner Mongolia of China. Methods： CYP2E1 RsaI/PstI and DraI polymorphisms were detected by polymerase chain reaction-restriction fragment length polymorphism in 64 lung cancer patients, 150 healthy Mongolian and 150 healthy Han individuals. The distribution of genotype and allele frequencies of CYP2E1 RsaI/PstI and DraI polymorphisms were studied. Results： The risk of lung cancer was increased in individuals with CYP2E1 （cl/cl） and CYP2E1 （DD） with OR values of 2.431 （95%CI=1.082-5.460） and 2.778 （95%CI=1.358-5.683） respectively （P0.05）. When CYP2E1 RsaI/PstI and DraI polymorphisms were combined, the risk of lung cancer was reduced in individuals with CYP2E1 （cl/c2＋c2/c2 and DD＋CC） with OR values of 0.233 （95%CI=0.088-0.615, P0.05）. In smokers, the susceptibility to lung cancer was higher in the individuals with CYP2E1 （c1/c1） and CYP2E1 （DD） than in the individuals with c2 and C allele （P0.05, OR=2.643 and 4.308 respectively）. There was no significant difference in distribution of CYP2E1 genotype frequency between healthy Mongolian, Han population and lung cancer patients, healthy controls in Inner Mongolia. Conclusion： CYP2E1 （c1/c1） and CYP2E1 （DD） are predisposing factors of lung cancer in population in Inner Mongolia. CYP2E1 （c2﹢C） co-mutation may decrease the risk of lung cancer. Smoking exerts synergetic effect with CYP2E1 （c1/c1） and CYP2E1 （DD） on the occurrence of lung cancer.

Characteristics and roles of cytochrome b5 in cytochrome P450-mediated oxidative reactions in Locusta migratoria

Cytochrome b5(Cyt-b5)is a small heme protein and known to be involved in a wide range of biochemical transformations,in eluding cytochrome P450 monooxyge nase(CYP)-mediated metabolism of endoge nous and exogenous compo un ds.Studies on Cyt-b5 are more con centrated in mammals,but are relatively rare in in sects.The characteristics and functi on of Cyt-b5 from Locusta migratoria have not been described yet.We sequeneed the full-length cDNA sequenee of Cyt-b5 from L.migratoria(LmCyt-b5)by reverse transcription-PCR(RT-PCR)based on locust transcriptome database.The phylogenetic analysis showed that LmCyt-b5 was closely related to the Cyt-b5 from Blattodea.LmCyt-b5 was highly expressed in ovary,Malpighian tubules,midgut,gastric caeca,and fat bodies.Silencing of LmCyt-b5 had no effect on the susceptibility of L.migratoria to four different insecticides.Suppression of LmCyt-b5 or silencing of both LmCyt-b5 and LmCPR did not significantly change the total CYP activity toward the substrate 7-ethoxycoumarin(7-EC).However,coexpression of LmCYP6FD1 with LmCPR and LmCyt-b5 together in Sf9 cells by using Bac-to-Bac baculovirus expression system significantly increased the catalytic activity of LmCYP6FD1 toward 7-EC as compared with the coexpression of L.mCYP6FD1 with cytochrome P450 reductase(LmCPR)or LmCyt-b5 separately.These results suggest that LmCyt-b5 plays an important role in the catalytic reaction of LmCYP6FD1 toward 7-EC in our in vitro experiments.Further study is needed to clarify the role of LmCyt-b5 in CYP-mediated catalytic reactions in L.migratoria.

Cytotoxicity of acrylamide and its epoxide glycidamide in CHO cells expressing human cytochrome P450 2E1

Objective： To investigate whether CYP2E1 is responsible for the acrylamide metabolic activation in FIp-In CHO cell system. Methods： CYP2E1 cDNA was subcloned from the human liver full-length cDNA library and subsequently transfected into the FIp-In CHO cells to generate the stable transfectant of CYP2E1. The CYP2E1 mRNA expression was determined by RT-PCR. Acrylamide and its epoxide glycidamide induced cytotoxicity and cell cycle arrest in G2/M were conducted using MTS assay and flow cytometry, respectively. Results： In the CHO cell stably expressing CYP2E1 （CHO-2E1）, a -1.5 kb size of band was detected from the mRNA in the cells while no corresponding band in the CHO-vector cells, which indicated that CYP2E1 was successfully transfected in the CHO cells. Compared with the CHO-vector cells, acrylamide showed a concentration dependent loss of viability in the CHO-2E1 cells but no significant change of G2/M arrest was found. As expected, glycidamide induced similar profile of cytotoxicity in both of the cells, and G2/M arrest presented a concentration-dependent increased in the CHO-2E1 cells. Conclusion： The result suggested that CYP2E1 might be responsible for the acrylamide metabolism, and its metabolite glycidamide was a direct cytotoxic and genotoxic agent. It should be further considered whether acrylamide-induced toxicity is through its epoxide glycidamide in the presence of CYP2E1.

Expression of cytochrome P450 2A13 in human non-small cell lung cancer and its clinical significance

Lung cancer is one of the most important causes of cancer-related mortality worldwide. Human cytochrome P450 2A13 enzyme （CYP2A13） is predominantly expressed in the respiratory tract and could catalyze various carcinogens. In this study, we quantified CYP2A13 expression in non-small cell lung cancer （NSCLC） tissues and examined the relation between CYP2A13 and clinicopathologic factors. Thirty-five paired lung cancer and normal tissues were studied for the expression of the CYP2A13 gene by using real-time PCR and Western blot- ting assays. We also investigated the relationship between CYP2A13 expression and clinicopathologic factors such as age, gender, histology and lymph node status in tumor tissues. SPSS （17.0） statistical software was applied for data analysis. The real-time PCR results showed that there was no significant difference in the CYP2A13 mRNA transcript levels between tumor and paired normal tissues in the 35 samples and in 12 paired squamous cell car- cinomas. In adenocarcinoma, the expression of CYP2A13 mRNA in tumor tissues was 12.5% of that in adjacent tissues （P 〈 0.05） and it was not associated with age, gender, histology and lymph node status of the patients. The amounts of CYP2A13 proteins detected by Western blotting assays correlated well with those of the correspond- ing mRNAs. In conclusion, the expression of CYP2A13 was downregulated in lung adenocarcinoma. CYP2A13 may be involved in the development and progression of lung adenocarcinoma.

Influences of V5-epitope tag on the metabolic activation of AFB1 by human cytochrome P450 2A13

Objective： To explore the impact of V5-epitope tag inserted in the commercial pcDNA5/FRT/V5-His TOPO expression vector on the metabolic activation of AFB1 by human CYP2A13. Methods ： A C-terminal 6 × Histag was first introduced into CYP2A13 cDNA by PCR and subsequently transferred into the expressing vector pcDNA5/FRT. Another commercial pcDNA5/FRT/V5-His TOPO expression vector was used to develop the construct directly via PCR. Both of the constructs were then transfected into Flp-In CHO and allowed for the stable expression of CYP2A13. The mouse CYP2A5 and the vector alone were used as positive and negative control, respectively. The presence of CYP2A5 and CYP2A13 cDNA and their protein expression in the stable transfectant cells were deterrrfined by immunoblotting assay using a monoclonal antibody against 6 × Histag. The AFBl-induced cytotoxicity in these tranfected CHO cells were conducted by MTS assay and the IC50 of cell viability was used to compare the CYP enzyme metabolic activity in AFB1 metabolism among these cells. Results： In accordance with the Flp-In system working mechanism, all the transfectant cells presented same protein expression level. The CHO cells expressing CYP2A5 was more sensitive to AFB1 treatment than those cells expressing CYP2A13, there was about 30-fold ICs0 difference between the two cells （2.1 nmol/L vs 58 nmol/L）. Interestingly, CYP2A13 fused with V5-Histag had the lost of metabolic activity to AFB1 than that fused with Histag alone, the ICa, of the viability in CHO-2A13-His-V5 cells was about 20-fold less than CHO-2A13- His （〉 1 000 nmol/L vs 58 nmol/L）. However, there was no change between CYP2A5 fused with V5-Histag and Histag alone （2.4 nmol/L vs 2.1 nmol/L）. Conclusion： The results demonstrate that CYP2A13 fused with V5-epitope has a significant impact on its metabolic activation to AFB1, which indicated that it should be careful to select a new expressing vector for evaluating the enzyme activity in carcinogen metabolism.

Relation of cytochrome P450 2C19 gene 681G>A single nucleotide polynmrphism to clopidogrel resistance after PCI in Chinese

Objectives Clopidogrel is a prodrug that has to be converted to an active metabolite by hepatic cytochrome P450(CYP) isoenzymes to inhibit platelet aggregation.Individualvariability of platelet inhibition by clopidogrel suggests a possibility for genetic factors having a significant influence on clopidogrel responsiveness.In this study,we sought to determine the association between the single nucleotide polymorphism of CYP 2C19 681G】A and the occurrence of clopidogrel resistance(CR) in Chinese.Methods The study enrolled 614 hospitalized patients who underwentsuccessful percutaneouscoronary intervention with drug-eluting stents were received the treatmentwith dual antiplatelet regimen(aspirin plus clopidogrel).All patients received loading doses of 600 mg clopidogrel and 300 mg aspirin.20μmol/L ADP-induced platelet aggregation ratio(PAR ) was assessed 24 h after clopi- dogrel administration.The maximum residual PAR≥70%was defined as CR.Genomic DNA was extracted from whole blood samples according to standard protocols,the single nucleotide polymorphism of the CYP2C19 681G】A was genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) in all the patients.Results CR was found in 126 patients(20.5%).There was CYP2C19 681G】A polymorphism in the study population.The frequencies of the three kinds of genotypes(GG,GA,A A) in CR group and non-CR (NCR)group were 32.5%,47.6%,19.8%and 48.0%, 45.0%,7.0%,respectively.The frequency of AA genotype was significantly higher in NCR group than that in CR group (OR =3.03,95%CI:1.889～5.784,P=0.003).The A allele carriers were more likely to develop clopidogrel resistance compared with that of G allele carriers(OR=1.85,95%CI: 1.392～2.459,P=0.002).Conclusions CYP2C19 681G/A polymorphism is associated with the risk of CR,and the A allele carriers may be a possible genetic susceptibility factor for patients with CR.

百令胶囊上调miR-145-5p逆转TGF-β_(1)/Smad3通路机制初探

目的探讨百令胶囊(BLC)对慢性阻塞性肺疾病(COPD)模型大鼠肺损伤的改善作用,以及对香烟烟雾提取物(CSE)作用下人支气管上皮细胞BEAS-2B生长的影响。方法将60只SD大鼠随机分为正常对照组(A组,灌胃生理盐水2 mL),模型组(B组,灌胃生理盐水2 mL),BLC组(C组,灌胃BLC 5.5 mg/kg),miR-145-5p inhibitorNC组(D组,灌胃BLC 5.5 mg/kg+尾静脉注射miR-145-5p inhibitorNC 6μL),miR-145-5p inhibitor组(E组,灌胃BLC 5.5 mg/kg+尾静脉注射miR-145-5p inhibitor 6μL),各12只。以香烟烟雾吸入法复制大鼠COPD模型。建模成功后灌胃相应药物或生理盐水(每日1次),尾静脉注射相应药物(每周1次),连续8周。以0(空白对照),3%,5%,10%,20%CSE,以及加5%,10%,20%,40%的BLC药物血清(BLC-S)孵育细胞48 h。检测大鼠潮气量(TV)、呼气峰流量(PEF)、分钟通气量(MV)、用力肺活量(FVC)和第0.3秒用力呼气容积(FEV_(0.3));观察肺组织病理形态;免疫组化法检测Smad3表达水平,用酶联免疫吸附试验(ELISA)法测定转化生长因子(TGF)-β_(1)表达水平,采用实时荧光定量聚合酶链反应(RT-qPCR)法检测miR-145-5p mRNA表达水平。采用CCK-8法检测细胞活力。结果与B组比较,C组及D组大鼠TV,PEF,MV,FVC,FEV0.3均显著升高;与D组比较,E组大鼠上述指标均显著降低(P<0.05)。与B组比较,C组及D组大鼠肺组织病理形态显著改善,平均肺泡数显著增加,肺泡直径显著减小;与D组比较,E组大鼠肺组织病理形态未改善,且平均肺泡数显著减少,肺泡直径显著增长(P<0.05)。与5%CSE条件比较,5%CSE+20%BLC-S条件下的细胞活力显著增强(P<0.05)。与B组比较,C组及D组大鼠肺组织中Smad3,TGF-β_(1)的表达水平均显著降低,miR-145-5p mRNA表达水平显著升高(P<0.05);与D组比较,E组大鼠肺组织中Smad3,TGF-β_(1)的表达水平均显著升高,miR-145-5p mRNA表达水平显著降低(P<0.05)。与5%CSE条件比较,5%CSE+20%BLC-S条件下细胞Smad3和TGF-β_(1)的表达水平均显著降低,miR-145-5p mRNA表达水平显著升高(P<0.05);与5%CSE+20%BLC-S+inhibitor NC条件比较,同水平inhibitor条件下细胞Smad3及TGF-β_(1)表达水平均显著升高(P<0.05)。结论BLC在体内和体外均显示出对香烟诱导COPD的保护作用,其机制可能与上调miR-145-5p水平逆转香烟暴露激活的TGF-β_(1)/Smad3信号通路有关。

Cytochrome P450 CitCYP97B modulates carotenoid accumulation diversity by hydroxylating β-cryptoxanthin in Citrus

Carotenoids in plant foods provide health benefits by functioning as provitamin A.One ofthe vital provitamin A carotenoids,β-cryptoxanthin,is typically plentiful in citrus fruit.However,little is known about the genetic basis of β-cryptoxanthin accumulation in citrus.Here,we performed a widely targeted metabolomic analysis of 65 major carotenoids and carotenoid derivatives to characterize carotenoid accumulation in Citrus and determine the taxonomic profile of b-cryptoxanthin.We used data from 81 newly sequenced representative accessions and 69 previously sequenced Citrus cultivars to reveal the genetic basis of β-cryptoxanthin accumulation through a genome-wide association study.We identified a causal gene,CitCYP97B,which encodes a cytochrome P450 protein whose substrate and metabolic pathways in land plants were undetermined.We subsequently demonstrated that CitCYP97B functions as a novel monooxygenase that specifically hydroxylates the β-ring of β-cryptoxanthin in a heterologous expression system.In planta experiments provided further evidence that CitCYP97B negatively regulates b-cryptoxanthin content.Using the sequenced Citrus accessions,we found that two critical structural cis-element variations contribute to increased expression of CitCYP97B,thereby altering β-cryptoxanthin accumulation in fruit.Hybridization/introgression appear to have contributed to the prevalence of two cis-element variations in different Citrus types during citrus evolution.Overall,these findings extend our understanding of the regulation and diversity of carotenoid metabolism in fruit crops and provide a genetic target for production of β-cryptoxanthin-biofortified products.

CYP1A1和NAT2基因多态性与肾癌易感性关系的病例对照研究

目的:探讨致癌物CYP1A1和NAT2基因多态性对肾癌易感性的影响。方法:利用限制性片段长度多态性-聚合酶链反应(RFLP-PCR)方法,检测病例和对照组细胞色素P450酶基因CYP1A1 MspⅠ位点和N-乙酰基转移酶2(NAT2)基因的多态性情况。结果:与对照组相比,病例组CYP1A1(W/M)及NAT2(intermediate)基因型分布差异均存在统计学意义(P<0.05)。携带CYP1A1(W/M)或NAT2(intermediate)基因型的个体患肾癌的危险度升高,比值比(OR)分别达到2.487(1.493～4.142)和1.970(1.128～3.442)。多因素分析结果显示携带CYP1A1(W/M)及NAT2(intermediate)基因型的吸烟个体具有肾癌易感性。结论:CYP1A1(W/M)和NAT2(intermediate)基因型均是肾癌的危险因素,两者存在交互作用,且均与吸烟有协同作用。

3Gyγ射线照射和丝裂霉素C对大鼠肝脏细胞色素P450含量及其同工酶CYP2B1、CYP2E1活性的影响

为研究3Gyγ射线全身照射和丝裂霉素C(MitomycinC,MMC)对雄性(Sprague-Dawley,SD)大鼠肝脏细胞色素P450含量、CYP2B1、CYP2E1活性的影响,分别给大鼠腹腔注射1mg/kgd的MMC(分1d,连续3d及6d用药三组),3mg/kg的MMC1d,3Gyγ射线全身照射,3Gyγ射线全身照射加1d3mg/kgMMC,另设空白对照和溶剂对照。各组处理结束后24h,处死大鼠取肝脏,制备微粒体,测P450含量、CYP2B1、CYP2E1活性。实验结果表明,给MMC1mg/kgd,1d后P450含量、CYP2B1活性变化无统计学差异(p>0.05),CYP2E1活性明显上升(p<0.01);连续3d或6d后,P450含量、CYP2B1、CYP2E1活性均无明显变化(p>0.05)。给3mg/kg的MMC1d,对P450含量、CYP2B1活性影响无统计学差异(p>0.05),CYP2E1活性上升明显(p<0.01);3Gyγ射线全身照射后,P450含量、CYP2B1活性无明显变化(p>0.05),CYP2E1活性下降(p<0.05);分析发现,3mg/kgMMC与3Gyγ射线之间没有交互作用。结果提示,γ射线可以抑制雄性SD大鼠肝脏CYP2E1活性,MMC对CYP2E1活性有诱导作用,但多次刺激使其耐受,P450含量、CYP2B1活性对γ射线、MMC不敏感。

原发性高血压患者醛固酮合酶基因-344T/C多态性与心房颤动的相关性研究

目的探讨中国河南豫北地区原发性高血压人群醛固酮合酶（CYP11B2）基因-344T／C多态性与心房颤动（房颤）的关系。方法运用病例对照法，选择803例原发性高血压患者，运用PCR—RFLP技术对405例伴房颤者（房颤组）和398例窦性心律者（窦律组）的CYP11B2基因-344T／C多态性进行基因分型，并进行分析。结果2组T和C等位基因分布，差异无统计学意义（x2=1．32，P=0．25）；房颤组CC基因频率明显高于窦律组（x2=21．29，P〈0．05）。与携带TT或TC基因型者比较，携带CC基因型高血压患者患房颤的风险增加（OR=1．96，95％CI：1．23～2．67），携带CC基因型的高血压合并房颤患者左心房内径明显增高（P〈0．05）。结论CYP11B2基因-344T／C多态性与原发性高血压患者房颤的发生相关。

肝硬化模型大鼠CYP2B6和CYP3A酶活性变化

目的研究CYP2B6和CYP3A酶活性在肝硬化模型大鼠体内的变化。方法雄性SD大鼠分别采用每周2次ip给予30%CCl4连续7周、饮用含0.03%-0.04%硫代乙酰胺（TAA）液连续10周、复合法（sc给予用花生油配制的40%CCl4＋高脂饲料＋15%乙醇,共6周）及免疫法（sc给予牛血清白蛋白20-40 mg·kg-1,共11周）制备肝硬化模型后,联合ig给予安非他酮15 mg·kg-1和咪达唑仑10 mg·kg-1。测定给药前及给药后0.083,0.25,0.5,1,1.5,2,2.5,3,4,6,8,12和24 h的血药浓度。结果与正常对照组相比,四氯化碳组和TAA组的2个探针药曲线下面积（AUC）均显著性升高（P〈0.05）,峰浓度c max显著性升高（P〈0.01）,清除率Cl/F均显著性下降（P〈0.05）;复合法组2个探针药c max均显著性下降（P〈0.05）;免疫组2个探针药的药代参数均无统计学意义。结论 CCl4和TAA诱导的肝硬化模型大鼠体内CYP2B6和CYP3A酶活性降低。

银杏内酯B对CYP2C9底物双氯芬酸在大鼠体内药动学和药效学的影响

目的:在大鼠体内,以双氯芬酸为工具药,研究银杏内酯B对双氯芬酸药动学和药效学的影响,阐明银杏内酯B对大鼠肝细胞色素P450 2C9(CYP 2C9)是否有抑制或诱导作用。方法:通过观察大鼠连续给予银杏内酯B(剂量为12 mg·kg^(-1),ip,bid,连续7 d)前后对单次给予临床等效量的双氯芬酸(15 mg·kg^(-1),iv)的药时曲线及药动学参数的改变,评价其对双氯芬酸药动学的影响,并评价银杏内酯B连续给药后对单次给予双氯芬酸抗足跖肿胀作用药效学的影响。结果:连续给予银杏内酯B后,与用药前比较,双氯芬酸及其主要代谢物4-羟基双氯芬酸的血药浓度及其药动学参数未见显著性改变;双氯芬酸抗足跖肿胀作用亦未见显著性改变。结论:多剂量给予银杏内酯B对临床等效量双氯芬酸在大鼠体内药动学和药效学无显著影响;银杏内酯B对大鼠肝CYP 2C9无明显的抑制或诱导作用。

心肌缺血再灌注损伤对大鼠肝细胞色素P450酶代谢的影响

目的探讨心肌缺血再灌注状态下,大鼠肝代谢功能和相关的氧化/抗氧化能力变化。方法雄性SD大鼠随机分为5组,除假手术组外,制备在体心肌缺血再灌注模型,并于缺血40min、再灌注15,60和180min分别处死大鼠,检测血浆丙氨酸转氨酶(ALT)和天冬氨酸转氨酶(AST)活性,肝匀浆丙二醛(MDA)含量、超氧化物歧化酶(SOD)活性;以红霉素N-脱甲基酶、五氧基异噁唑O-脱乙基酶和苯胺羟化酶法为探针测定肝细胞色素P450(CYP)3A,CYP2B1和CYP2E1催化功能;RT-PCR法检测肝Ⅰ相药物代谢酶CYP3A1,CYP2B1/2,CYP2E1,以及Ⅱ相解毒酶NAD(P)H醌氧化还原酶(NQO1)及其上游因子NF-E2相关因子(Nrf2)mRNA水平。结果再灌注60 min,肝匀浆MDA含量升高(P<0.05),SOD活力下降(P<0.01);再灌注180 min时,血浆ALT和AST活性升高(P<0.05)。Nrf2基因于再灌注60 min时显著激活(P<0.05),下游因子NQO1 mRNA于再灌注180 min时明显上调(P<0.05)。CYP3A催化功能和mRNA水平分别于再灌注60和180 min开始明显降低(P<0.05);CYP2B1/2 mRNA和催化功能水平分别于再灌注15和180 min开始明显降低(P<0.05);CYP2E1催化功能无明显改变。结论大鼠心肌缺血再灌注可引起肝组织氧化应激及并导致功能损伤。在再灌注早期,具有抗氧化功能的NQO1在转录水平显著上调,其机制可能与上游因子Nrf2被激活相关;CYP3A和CYP2B催化功能在转录和(或)转录后水平明显下调。

氧化代谢酶DNA甲基化研究进展

DNA甲基化是表观遗传修饰过程之一,能导致基因表达异常。细胞色素P450酶、环氧合酶、脂氧合酶和单胺氧化酶是人体内介导内外源化学物氧化代谢的酶类,这些酶基因在正常组织与病理组织中的甲基化模式存在差异,异常的甲基化模式会导致酶表达和功能发生改变,进而影响疾病的发生和发展。本文就上述4种氧化代谢酶基因甲基化状态在一些疾病组织中的特征性变化、对化学物的代谢活性的影响以及对机体的作用变化进行综述,为疾病的诊断以及化学物毒作用机制提供新的理论依据。