附子多糖预防高胆固醇血症的作用及其对肝脏CYP7α-1表达的影响

目的: 探讨附子多糖(FPS)预防高胆固醇血症的作用及其对肝脏胆固醇7α-羟化酶(CYP7α-1)表达的影响。方法: SPF级雄性Wistar大鼠50只,体重100 g,随机分为正常组(control)、高胆固醇组(HC)和HC+附子多糖(HC+FPS)低、中、高3个剂量组,每组10只,分别给予正常、高胆固醇及高胆固醇加附子多糖(224、448和896mg·kg^-1·d^-1 )饮食,持续2周,检测各组的血脂水平;观察control组、HC组和HC+FPS(224 mg·kg^-1·d^-1)组大鼠的体重、进食量和粪便量的变化,实验结束后取3组大鼠的肝脏行HE染色;并检测3组大鼠肝脏羟甲基戊二酰辅酶A(HMG-CoA)还原酶mRNA水平、CYP7α-1 mRNA和蛋白水平以及粪便总胆汁酸含量等方面的改变。结果: 附子多糖能显著抑制高胆固醇血症大鼠血清中总胆固醇(TC)和低密度脂蛋白胆固醇(LDL-C)的水平(P<0.05);HC+FPS组大鼠肝细胞脂肪变性较HC组轻微;real-time PCR和Western blotting结果显示附子多糖能显著上调高胆固醇大鼠肝脏CYP7α-1 mRNA水平和蛋白表达并明显降低HMG-CoA还原酶的mRNA水平(P<0.01);HC组大鼠粪便中胆汁酸的含量增多而HC+FPS组进一步增加(P<0.05)。结论: 附子多糖具有明显的降血胆固醇作用,其机制与上调CYP7α-1 mRNA及蛋白水平和下调大鼠肝脏HMG-CoA还原酶mRNA水平有关。     

肥胖2型糖尿病患者与大鼠胃旁路术后血清总胆汁酸水平的变化

目的:观察胃旁路术对肥胖2型糖尿病患者及肥胖2型糖尿病模型大鼠血清总胆汁酸水平的影响,并探讨其分子机制。方法:收集并分析2011年6月~2016年6月暨南大学附属第一医院肥胖2型糖尿病患者共87例术后血糖恢复情况及血清总胆汁酸水平变化数据。动物实验选用SD大鼠,高脂喂养联合腹腔注射低剂量链脲佐菌素的方法制作肥胖2型糖尿病模型,分为正常对照(普通饲料喂养非手术)组、胃旁路手术组及假手术组,检测手术前后大鼠血糖及血清总胆汁酸水平,HE染色观察大鼠胰腺组织病理变化,ELISA方法检测大鼠肝组织胆固醇7α-羟化酶(CYP7A1)含量,real-time PCR和Western blot分别检测各组大鼠肝组织CYP7A1和小分子异源二聚体伴侣(SHP)mRNA和蛋白水平。结果:肥胖2型糖尿病患者及模型大鼠胃旁路术后空腹血糖降低,血清总胆汁酸水平升高,肝组织合成胆汁酸经典途径的限速酶CYP7A1含量降低,CYP7A1 mRNA和蛋白表达量均减少,肝组织胆汁酸合成的负性调节因子SHP mRNA和蛋白表达量均增加,与假手术组比较差异显著(P0.05)。结论:胃旁路手术后肥胖2型糖尿病患者及模型动物血清总胆汁酸水平升高,且该变化并非因经典途径合成胆汁酸增多。     

The impact of psychogenic stressors on oxidative stress markers and patterns of CYP2E1 expression in mice liver

The increasing number of psychogenic stressors is a side effect of civilization. It results in the development of psychoemotional stresses and psychosomatic diseases. In this study we evaluated the effect of the chronic psychoemotional stress on the level of CYP2E1 expression in the liver of C57Bl/6 mice. Stress was induced by the immobilization of animals for 4h per day during 7 or 14 days. CYP2E1 expression level was evaluated on the 7th and 14th days of the experiment, respectively. We detected a twofold reduction in CYP2E1 protein expression level relatively to controls for both time points tested. This reduction was no longer significant when the effect of the stressor factor was terminated on the 14th day of the experiment and animals were analyzed one week later. Remarkably Cyp2e1 mRNA expression level was constant at any time point of the experiment. We also documented significant changes in the expression/activity of two oxidative stress markers examined in the liver of treated mice. The catalase activity decreased fivefold while malondialdehyde transiently increased threefold. These data suggest that oxidative stress can be involved in the reduction of hepatic CYP2E1 and catalase activity under the conditions of chronic emotional stress.     

Sustained upregulation of sodium taurocholate cotransporting polypeptide and bile salt export pump and downregulation of cholesterol 7α-hydroxylase in the liver of patients with end-stage primary biliary cirrhosis

To examine the mRNA expression of hepatobiliary transporters in primary biliary cirrhosis (PBC) patients and to compare bile acid absorption, synthesis, and efflux in patients with non-end-stage and end-stage PBC, we obtained liver samples from PBC patients by percutaneous needle biopsy. End-stage PBC was defined as follows: histological stage IV; cirrhosis; serum total bilirubin, ≥4.0 mg/dl; and Child-Pugh Class C. The mRNA expression levels of sodium taurocholate cotransporting polypeptide (NTCP), bile salt export pump (BSEP), and hepatic cholesterol 7α-hydroxylase (CYP7A1) were significantly higher in the PBC patients than in the controls (P < 0.01). The mRNA levels of NTCP and BSEP were significantly higher in the end-stage PBC patients than in the controls (P < 0.01). However, hepatic CYP7A1 mRNA expression decreased significantly (by 70%) in the patients with end-stage PBC as compared to the controls and the patients with non-end-stage PBC (P < 0.01). The hepatic expression of transporters mediating bile acid influx and efflux showed sustained elevation, whereas that of the rate-limiting enzyme for bile acid biosynthesis was attenuated in the end-stage PBC patients. Thus, mechanisms may be present preventing the accumulation of toxic bile acids in the hepatocytes of end-stage PBC patients.     

Hepatotoxicity and gene expression down-regulation of CYP isozymes caused by renal ischemia/reperfusion in the rat

Renal ischemia/reperfusion (I/R) occurs in many clinical scenarios, including trauma, elective surgery, and transplantation. Events initiated by this process can lead to inflammation in the kidneys, culminating in local injury as well as distant organ dysfunction. The objectives of this study were to investigate the changes in the functions of the liver and the regulation of gene expression of cytochrome P450 (CYP) isozymes after renal I/R. Hepatoxocity was assessed by serum alanine aminotransferase (sALT), serum aspartate aminotransferase (sAST) and liver glutathione-S-transferase (GST) activities, liver glutathione (GSH) level, and histopathological examination. Hepatic cytochrome P4503A1 (CYP3A1) and cytochrome P4502E1 (CYP2E1) activities were measured by erythromycin N-demethylase (ERD) and aniline hydroxylase (ANH) activities, respectively. CYP3A1 and CYP2E1 mRNA expression was determined by RT-PCR. Results showed that activities of sALT and sAST were significantly increased, while hepatic CYP3A1and CYP2E1 activities as well as their respective mRNA levels were significantly decreased after renal I/R. Moreover, hepatic tissue congestion, degeneration, and local necrosis were observed in rats after 1, 4, and 8 h renal reperfusion following 2 h renal ischemia. In conclusion, the present study suggests that renal I/R can cause hepatotoxicity and gene expression down-regulation of CYP isozymes in rats.     

LXR激活对大鼠原代培养海马神经元胆固醇代谢关键酶基因表达的影响

为了探讨肝X受体(LXR)激活对海马神经元胆固醇代谢关键酶基因表达和胆固醇外流的影响,本研究取当天新生大鼠海马神经元行体外培养7d,随机分为TO组(培养液含2.0μmol/L的TO901317)和正常对照组(CON),继续培养48h。用胆固醇氧化酶-比色法检测TO组胆固醇的排出量;应用RT-PCR方法检测两组海马神经元ATP结合盒转运体A1(ABCA1)、HMG-CoA还原酶(HMGR)、胆固醇24-羟化酶(CYP46)、P450侧链裂解酶(P450scc)、固醇生成急性调节蛋白(StAR)和酰基辅酶A-胆固醇酰基转移酶1(ACAT1)等胆固醇代谢关键酶基因的mRNA的表达。结果显示:TO组mRNA表达上调的酶有HMGR、P450scc和StAR(P<0.01);表达下调的酶是ACAT1(P<0.01);表达不受影响的酶是CYP46。上述结果表明LXR激活、促进细胞内胆固醇外流时,海马神经元可能通过协调胆固醇代谢关键酶基因的表达,增加胆固醇的合成和向神经甾体的转化,抑制胆固醇的储备,而不影响胆固醇排出血脑屏障,从而维持细胞内胆固醇的动态平衡,保证神经元的正常生理功能。     

奥贝胆酸对非酒精性脂肪肝大鼠法尼醇X受体及细胞色素P450家族成员7A1基因表达的影响

目的探讨奥贝胆酸对非酒精性脂肪肝(NAFLD)大鼠法尼醇X受体(FXR)蛋白、细胞色素P450家族成员7A1(CYP 7A1)蛋白及其基因表达的影响,及保肝作用。方法雄性SD大鼠52只通过高脂饲料喂养建立大鼠非酒精性脂肪肝模型;设置对照组11只,模型组、奥低组、奥中组和奥高组共41只,给药4周后,取大鼠相同部位肝脏,免疫组织化学法测定FXR蛋白表达、RT-PCR检测FXR mRNA,Western blotting法检测CYP 7A1蛋白、RTPCR检测CYP 7A1 mRNA的表达水平;通过大鼠肝指数,外周血谷丙转氨酶(ALT)、谷草转氨酶(AST)和碱性磷酸酶(ALP)的浓度,及肝脏组织切片观察,评估肝功能。结果高脂饲料喂养10周后,大鼠具有典型的NAFLD特征,模型建立成功。模型组的FXR蛋白和FXR mRNA表达水平显著低于对照组(P<0.05),奥低组和奥中组的FXR蛋白和FXR mRNA表达水平与模型组相比,差异无统计学意义(P>0.05),奥高组的FXR蛋白和FXR mRNA表达水平显著高于模型组(P<0.05);模型组、奥低组和奥中组的吸光度值显著低于对照组(P<0.05),奥高组显著升高,与对照组差异无统计学意义(P>0.05)。模型组的CYP 7A1蛋白和CYP 7A1 mRNA表达水平显著高于对照组(P<0.05),奥低组和奥中组的CYP 7A1蛋白和CYP 7A1 mRNA的表达水平与模型组相比,差异无统计学意义(P>0.05),奥高组的CYP 7A1蛋白和CYP 7A1 mRNA表达水平显著低于模型组(P<0.05)。与对照组相比,模型组的肝指数(%)显著增大(P<0.05);奥低组和奥中组的肝指数(%)与模型组相比,差异无统计学意义(P>0.05),奥高组肝指数(%)显著低于模型组(P<0.05)。与对照组相比,模型组的ALT、AST和ALP的浓度显著升高(P<0.05);奥贝胆酸组的ALT、AST和ALP浓度显著低于模型组(P<0.05),且随着奥贝胆酸给药量的增加,ALT、AST和ALP的浓度逐渐降低;肝组织切片观察结果显示,奥贝胆酸呈剂量依赖性改善大鼠肝组织。结论奥贝胆酸高剂量能显著上调FXR蛋白及其基因的表达,并抑制CYP 7A1蛋白及其基因的表达,显著改善大鼠肝功能及肝组织病理状态。     

Major acute-phase reactant synthesis during chronic inflammation in amyloid-susceptible and -resistant mouse strains

Hepatic levels of mRNA specific for total serum amyloid A (SAA), the SAA1 and SAA2 isotypes, serum amyloid P (SAP), C-reactive protein (CRP), and fibronectin, as well as the plasma concentrations of SAA and SAP were examined in amyloid-resistant (A/J) and amyloid-susceptible (CBA/J) mice during azocaseininduced chronic inflammation. In both strains hepatic SAA and SAP mRNA levels and plasma SAA and SAP protein concentrations increased dramatically during the early stages of inflammation; this was followed by a decrease to concentrations that were maintained at levels considerably higher than background. The ratios of SAA1 and SAA2 mRNA and plasma protein were 1 1 throughout. This indicated that there was no preferential accumulation of mRNA specifying a particular isotype and no preferential synthesis or clearance of a particular isotype during chronic inflammation and the early stages of amyloidogenesis in either strain. Similarly, hepatic SAP mRNA levels in both strains increased dramatically during the early stages of inflammation and were subsequently maintained at elevated levels. Plasma SAP concentrations increased rapidly during the first three days of the study in both A/J and CBA/J mice; however, during the later stages of inflammation, A/J plasma SAP levels decreased to a steady-state concentration that was approximately half that observed in CBA/J mice. Our results identify differences in the hepatic mRNA and plasma protein levels of the major mouse acute-phase reactants (APR) in the amyloid-resistant A/J and amyloid-susceptible CBA/J mouse strains. These findings are consistent with circulating inflammatory APR concentrations contributing, together with other factors, to the onset and pathogenesis of secondary amyloidosis.     

Evidence for steroidogenic potential in human prostate cell lines and tissues

Malignant prostate cancer (PCa) is usually treated with androgen deprivation therapies (ADTs). Recurrent PCa is resistant to ADT. This research investigated whether PCa can potentially produce androgens de novo, making them androgen self-sufficient. Steroidogenic enzymes required for androgen synthesis from cholesterol (CYP11A1, CYP17A1, HSD3β, HSD17β3) were investigated in human primary PCa (n = 90), lymph node metastases (LNMs; n = 8), and benign prostatic hyperplasia (BPH; n = 6) with the use of IHC. Six prostate cell lines were investigated for mRNA and protein for steroidogenic enzymes and for endogenous synthesis of testosterone and 5α-dihydrotestosterone. All enzymes were identified in PCa, LNMs, BPH, and cell lines. CYP11A1 (rate-limiting enzyme) was expressed in cancerous and noncancerous prostate glands. CYP11A1, CYP17A1, HSD3β, and HSD17β3 were identified, respectively, in 78%, 52%, 16%, and 82% of human BPH and PCa samples. Approximately 10% of primary PCa, LNMs, and BPH expressed all four enzymes simultaneously. CYP11A1 expression was stable, CYP17A1 increased, and HSD3β and HSD17β3 decreased with disease progression. CYP17A1 expression was significantly correlated with CYP11A1 (P = 0.0009), HSD3β (P = 0.0297), and HSD17β3 (P = 0.0090) in vivo, suggesting CYP17A1 has a key role in prostatic steroidogenesis similar to testis and adrenal roles. In vitro, all cell lines expressed mRNA for all enzymes. Protein was not always detectable; however, all cell lines synthesized androgen from cholesterol. The results indicate that monitoring steroidogenic metabolites in patients with PCa may provide useful information for therapy intervention.     

Cholesterol enriched diet suppresses ATF6 and PERK and upregulates the IRE1 pathways of the unfolded protein response in spontaneously hypertensive rats: Relevance to pathophysiology of atherosclerosis in the setting of hypertension

Many studies have been dedicated to hypertension and hypercholesterolemia, as they are the primary conditions that influence the unfolded protein response (UPR). However, the concurrent effects of these two factors are unknown. Our research used spontaneously hypertensive rats (SHR) fed a cholesterol enriched diet (CED) as model of atherosclerosis formation to discover what effect the simultaneous actions of hypertension and hypercholesterolemia have on the UPR. The combination of hypertension and consumption of a CED (not the CED alone) caused the formation of early atherosclerotic features. Both increased expression of the CCAAT-enhancer-binding protein (CHOP) and the insulin induced gene 1 (INSIG1), which is the target gene of the sterol regulatory element-binding protein 1-c (SREBP1-c), and decreased expression of the spliced x-box binding protein1 (sXBP1) mRNA were observed in the SHR fed a CED. Cholesterol overload strongly suppressed glucose regulated protein 78 (GRP78), glucose regulated protein 94 (GRP 94), and the expression of CHOP and INSIG1 mRNA in both normotensive and hypertensive rats. Unlike other UPR factors, the sXBP1 mRNA expression was strongly downregulated in SHR fed a normal diet but upregulated in those fed a CED. The changes to UPR in the SHR fed a CED were associated with improvement of the initially impaired heart function of the rats.     

活血降脂方对小鼠脂肪肝的防治作用

目的:探讨活血降脂方对小鼠脂肪肝的防治作用及机制。方法:高脂饲料喂养小鼠,分别用不同剂量的活血降脂方(由人参、三七、天麻组成,命名为GST)给小鼠灌胃2周,检测血脂、肝组织甘油三酯(TG)含量,并观察肝指数和肝脏病理变化,筛选出药物的最佳用药剂量。此外,小鼠分为正常对照(NC)组,喂基础饲料;模型组喂高脂饲料。12周后将模型小鼠随机分为高脂(HF)组,正常饮食(ND)组和GST组。除HF组饲高脂饲料外,其余各组饲基础饲料;GST组给予GST灌胃2周,其余各组以同等容积蒸馏水灌胃。检测血清总胆固醇(TC)、TG、高密度脂蛋白胆固醇(HDL-C)、低密度脂蛋白胆固醇(LDL-C)及肝组织TC、TG含量,观察肝指数、肝组织超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量,肝组织病理变化及过氧化物酶体增殖物激活受体α(PPARα)、细胞色素P450 2E1(CYP2E1)的mRNA表达。结果:GST可显著降低血脂、肝脂和MDA水平,增加SOD活性,明显降低肝指数并改善肝组织脂肪变性,增加肝组织PPARαmRNA表达、抑制CYP2E1 mRNA的表达。结论:GST具有有效防治脂肪肝的作用,其机制可能与上调肝组织PPARαmRNA的表达、降低血清和肝组织TG含量、下调CYP2E1 mRNA的表达以及抗脂质过氧化反应有关。     

法尼酯X受体在肝硬化大鼠肝切除术后肝再生中的作用

目的 探讨法尼酯X受体(FXR)在肝硬化大鼠肝切除术后肝再生中的作用.方法 30只肝硬化大鼠肝切除术后按完全随机法分为对照组、胆酸组和消胆胺组饲养1周,每组10只.对照组给以标准饲料饲养,胆酸组给以含0.2%胆酸的饲料饲养,消胆胺组以含2%消胆胺的饲料饲养.1周后检测各组大鼠胆汁分泌速度及总胆汁酸(TBA)含量,检测肝功能、有丝分裂指数(MI)、增殖细胞核抗原(PCNA)标记指数和细胞核DNA含量,并应用RT-PCR和Western免疫印迹分别检测肝组织FXR、胆固醇7α羟化酶(CYP7A1)两者mRNA和蛋白的表达.结果 胆酸组胆汁分泌速度、TBA含量、血清白蛋白(ALB)含量、MI、PCNA标记指数、细胞核DNA含量均高于对照组(P<0.05),血清谷草转氨酶(AST)、谷丙转氨酶(ALT)均低于对照组(P<0.05).而消胆胺组胆汁分泌速度、胆汁TBA含量、血清ALB含量、MI、PCNA标记指数、细胞核DNA含量均低于对照组和胆酸组(P<0.05),血清谷草转氨酶(AST)、谷丙转氨酶(ALT)均高于对照组和胆酸组(P<0.05).胆酸组肝组织FXR mRNA和蛋白表达均高于对照组(mRNA:0.671±0.027比0.528±0.017,蛋白:0.702±0.039比0.566±0.020,P<0.05).肝组织CYP7A1mRNA和蛋白表达含量均低于对照组(mRNA:0.237±0.020比0.325±0.076,蛋白:0.264±0.015比0.325±0.084,P<0.05).而消胆胺组肝组织FXR mRNA(0.468±0.023)和蛋白表达(0.502±0.021)均低于对照组和胆酸组(P<0.05),肝组织CYP7A1 mRNA(0.411±0.021)和蛋白表达(0.476±0.018)则高于对照组和胆酸组(P<0.05).结论 胆汁酸与其受体FXR结合激活细胞内信号转导对肝硬化大鼠肝切除术后肝再生起重要作用,升高胆汁酸水平促进肝再生,降低胆汁酸水平则抑制肝再生.     

gp73在小鼠肝纤维化肝组织中的表达及机制

目的在小鼠肝组织中探讨高尔基体跨膜糖蛋白73(gp73)在肝纤维化进程中的变化及机制。方法腹腔注射CCl4构建C57BL/6J小鼠肝纤维化模型;用ELISA检测小鼠血清中gp73的水平;用免疫组织化学染色检测肝组织内gp73的表达;用密度梯度离心法分离肝星状细胞(HSC)并检测其中gp73的表达;用免疫组织化学染色法检测肝组织中胰岛素样生长因子2 mRNA结合蛋白3(IGF2BP3)的表达;接下来分别转染IGF2BP3过表达与敲低的质粒,用RT-PCR检测GP73蛋白的编码基因GOLM1的表达变化;流式细胞计量术检测基因敲除鼠肝纤维化模型中HSC内gp73的表达。结果在肝纤维化模型的小鼠血清(P<0.01)、肝组织(P<0.05)及原代HSC(P<0.001)中gp73蛋白表达水平均升高,同时组织中的IGF2BP3蛋白表达也升高(P<0.05)。细胞系中转入IGF2BP3的过表达及敲低质粒后,成功过表达IGF2BP3(P<0.001)和敲低(P<0.01),GOLM1的表达也随之上调(P<0.001)和下调(P<0.01)。随后在IGF2BP3敲除鼠的肝纤维化模型的HSC中检测发现gp73表达降低(P<0.01)。结论在CCl4诱导的小鼠肝纤维化模型中,由HSC表达的gp73蛋白水平升高,而RNA结合蛋白IGF2BP3是促进其表达的潜在调控因素。     

Mutation frequency in the lacI gene of liver DNA from lambda/lacI transgenic mice following the interaction of PCBs with iron causing hepatic cancer and porphyria

The synergistic interaction of iron overload, AHR: genotype and exposure to a mixture of polychlorinated biphenyls (PCBs) (Aroclor 1254) in mice leads to hepatic porphyria, oxidative DNA damage and cancer. In humans, hepatocellular cancer is associated with iron overload and hepatic porphyria. Neither the mechanism of hepatic carcinogenesis induced by PCBs in rodents nor hepatocellular cancer induced by iron and porphyria in humans are understood. To test the hypothesis that chronic interaction of iron and PCBs may induce mutagenesis in liver DNA, lambda /lacI transgenic C57BL/6 mice were given iron dextran (600 mg iron/kg) and then administered Aroclor 1254 in the diet (0.01%) for 7 weeks. Hepatic iron, CYP1A activity and CYP1A1/1A2 protein were elevated >20-fold as a result of iron or Aroclor treatments, respectively, but porphyria with associated histological changes only developed in the combined iron/Aroclor treatment group. lambda/lacI shuttle vectors were isolated from liver genomic DNA and the mutational frequency (MF) in the lacI gene determined. Both iron and Aroclor treatments alone caused significant small increases in MF (1.5- and 1.4-fold, respectively), however, the MF following the combined iron and Aroclor treatment (1. 6-fold) was not greater than the additive effects. In contrast, the MF was significantly elevated (4.7-fold) in liver DNA of mice 2 weeks following five daily doses of N-nitrosodimethylamine (4 mg/kg). These studies demonstrate that neither PCBs nor iron overload caused marked point mutations even in a combination regime that leads to oxidative damage and cancer. There was also no strong evidence either that porphyrins or chronic CYP1A1 expression induced by the PCBs after this period caused marked point mutagens or simple deletions. Hence, to understand the PCBs-iron synergism more complex scenarios than point mutations or simple deletions must be invoked.     

Increased prooxidant production and enhanced susceptibility to glutathione depletion in HepG2 cells co-expressing HCV core protein and CYP2E1

Hepatitis C virus (HCV) and HCV core protein are hypothesized to induce hepatic oxidative stress and exacerbate injury caused by other toxins such as ethanol that induce the cytochrome P450 enzyme, CYP2E1. In the current study, the effects of HCV core protein [sequence genotype 1b, (nt 342-915)] on parameters indicative of oxidative stress were evaluated in HepG2 cells stably over expressing CYP2E1 (E47), or vector controls (C34). Stable (>10 passages) expression of HCV core protein and CYP2E1 was confirmed in clonal cell lines at the level of mRNA and immunoreactive protein. Prooxidant production, as determined by cellular oxidation of dichlorodihydrofluorescin and dihydroethidium (HE), was increased by expression of HCV core protein in the presence or absence of CYP2E1. Depletion of glutathione (GSH) with buthionine sulfoximine (BSO) enhanced prooxidant production in both C34 and E47 cells. In addition, prooxidant production was greater in BSO-treated cells expressing HCV core protein, and this effect was further enhanced in cells expressing both HCV core and CYP2E1. The CYP2E1 inhibitor, 4-methylpyrazole, could suppress increased prooxidant production in E47 cells. Finally, cells co-expressing both CYP2E1 and HCV core protein showed significantly decreased viability following GSH depletion. These studies show simultaneous expression of HCV core protein and CYP2E1 increases parameters indicative of oxidative stress as well as sensitization to cell injury induced by GSH depletion. These results support the hypothesis that enhanced injury in hepatocytes over expressing both HCV core protein and CYP2E1 is mediated by increases in oxidative stress.     

Cytochrome P450 and antioxidant activity in interleukin-6 knockout mice after induction of the acute-phase response.

Hepatic cytochrome P450 (CYP) expression and antioxidant activity have been shown to decrease following endotoxin (lipopolysaccharide [LPS]) or proinflammatory cytokine administration. Using mice deficient in interleukin-6 (IL-6), the role of IL-6 in the regulation of hepatic CYP activity, glutathione (GSH) metabolism, and catalase (CAT) activity was analyzed after LPS administration. Administration of LPS produced comparable decreases in hepatic CYP3A activity in WT B6x129 (WT) mice and IL-6 knockout mice. No decrease was observed for CYP2D9 activity after LPS administration in either WT or IL-6 knockout mice. LPS administration significantly increased hepatic and renal CYP2E1 and CYP4A activity in WT mice, with no effect in IL-6 knockout mice. CYP2A12 activity increased in IL-6 knockout, mice with no change in WT mice after LPS administration. LPS administration had no significant effect on hepatic GSH reductase, GST peroxidase, GSH-S-transferase (GST), or total GSH in either WT or IL-6 knockout. However, hepatic CAT activity was significantly reduced in WT mice after LPS administration, with no effect in IL-6 knockout mice. These results support IL-6 as a critical mediator of the effects of LPS on specific hepatic and renal CYP activities and hepatic CAT activity.