三种茶饮料对小鼠肠道首过效应及肝脏Cyp3a、Cyp2e1的影响

目的:研究市售罐装绿茶、冰红茶及茉莉清茶饮料对小鼠肠道首过效应和肝脏细胞色素氧化酶(cytochrome P450,CYP)Cyp3a、Cyp2e1的影响。方法:SPF级小鼠随机分为6组,其中绿茶组、冰红茶组、茉莉清茶组小鼠分别自由饮用绿茶、冰红茶、茉莉清茶7 d。用血中扑热息痛(ac-etaminophen,APAP)的浓度推断肠道首过效应。采用差速离心法分离肝/肠微粒体,以Bradford法定量蛋白,紫外分光光度法定量Cyp3a、Cyp2e1及血中APAP浓度。结果:绿茶组血中APAP浓度较空白组明显升高(P<0.01),而冰红茶组与空白组相比则显著降低(P<0.01);绿茶组和冰红茶组小肠Cyp3a酶活性较空白组显著升高(P<0.05或P<0.01)。各供试物组肝脏Cyp3a酶活性较空白组明显升高(P<0.01),各供试物组肝脏Cyp2e1酶活性较空白组显著降低(P<0.01)。结论:绿茶、冰红茶能显著改变肠道首过效应(绿茶抑制肠道P-gp,诱导肠道Cyp3a;冰红茶则诱导肠道P-gp及肠道Cyp3a;而茉莉清茶对肠道首过效应无影响)。各供试物均诱导肝脏Cyp3a的酶活性,抑制肝脏Cyp2e1的酶活性。故在服用经CYP3A、CYP2E1和P-gp代谢/转运的药物期间,大量或经常饮用上述茶可能影响这些药物的临床疗效和/或不良反应。     

川芎嗪诱导小鼠肝药酶Cyp3a11的作用及其机制研究

目的 考察川芎嗪对小鼠肝药物代谢酶Cyp3a11（CYP3A4同源基因）的作用及相关机制。方法 24只8周龄C57BL/6小鼠随机分为对照组和川芎嗪低、中、高剂量（25,50,100 mg·kg^-1）组,连续灌胃给药15 d。以RT-PCR法检测肝脏Cyp3a11 mRNA表达。采用差速离心法提取肝微粒体,以Cyp3a11经典底物咪达唑仑进行孵育,HPLC-MS/MS检测肝脏Cyp3a11活性。以双荧光报告基因法分析川芎嗪对CYP3A4转录活性的影响。结果 川芎嗪可诱导小鼠肝脏中Cyp3a11的mRNA表达,且诱导作用呈剂量依赖性增加。高剂量组可诱导Cyp3a11的代谢活性升高。川芎嗪可通过核受体PXR途径激活CYP3A4启动子转录活性。结论 川芎嗪对CYP3A4同源基因Cyp3a11的表达和活性具有一定的诱导作用,提示在临床使用过程中可能存在潜在的药物相互作用风险。     

阿托伐他汀诱导肝脏Cyp7a1和时钟基因的表达

<正>他汀类药物是羟甲戊二酰辅酶A(HMGCR)选择性抑制剂,是临床防治冠心病的重要药物~([1-2])。研究表明,阿托伐他汀能升高肝脏中胆固醇7羟化酶(Cyp7a1)的表达,改变体内胆汁酸代谢~([3]),并可能与其长期使用所致肝脏不良反应有关~([4])。Cyp7a1表达受时钟基因的调控,具有昼夜节律性~([5])。本研究采用长期给予临床剂量阿托伐他汀,观察其对小鼠肝Cyp7a1基因和时钟基因表达的影响。     

淫羊藿苷对小鼠肝微粒体细胞色素P450酶及其亚型CYP2E1活性的影响

目的 研究淫羊藿苷对小鼠肝脏微粒体细胞色素P450(CYP)总酶含量及其亚型CYP2E1、CYP3A和CYP1A1活性的影响.方法 给予小鼠ig淫羊藿苷(50、100、200 mg·kg-1·d-1),3d后钙沉淀法制备肝细胞微粒体,UV法测定肝微粒体CYP的含量及其亚型CYP2E1与CYP3A的活性;荧光分光光度法测定肝微粒体CYP1A1的活性.结果 高剂量淫羊藿苷可降低小鼠肝脏微粒体CYP的含量(约54%)、抑制CYP2E1的活性(抑制率为53.1%),对CYP3A和CYP1A1的活性无影响.结论 大剂量淫羊藿苷可降低小鼠肝脏微粒体CYP的总含量,并抑制其亚型CYP2E1的活性.     

西洋参总皂苷对大鼠肝微粒体CYP1A2活性的影响

目的考察西洋参总皂苷对大鼠肝微粒体CYP1A2活性的影响。方法将大鼠随机分为空白对照组(空白组)、西洋参总皂苷低剂量组[低剂量组,50 mg/(kg·d)]、西洋参总皂苷中剂量组[中剂量组,100 mg/(kg·d)]、西洋参总皂苷高剂量组[高剂量组,200 mg/(kg·d)]和β-萘黄酮阳性药对照组[阳性药组,80 mg/(kg·d)],预处理11 d后,观察大鼠肝微粒体CYP1A2酶活性、CYP1A2 mRNA表达和CYP1A2酶蛋白表达情况,研究CYP1A2特异性探针底物非那西丁在预处理大鼠体内的药动学变化。结果预处理后,大鼠肝微粒体CYP1A2活性、mRNA和蛋白表达随西洋参总皂苷剂量升高有增加趋势,非那西丁在预处理大鼠体内代谢速率加快。结论西洋参总皂苷对大鼠肝微粒体CYP1A2活性有一定诱导作用。     

薯蓣皂苷激活PERK-Nrf2-HO-1通路改善糖尿病小鼠胰岛素抵抗的机制探究

目的 基于蛋白激酶R样内质网激酶(PERK)/核转录因子E2相关因子2(Nrf2)/血红素加氧酶-1(HO-1)通路的抗氧化作用,研究薯蓣皂苷改善糖尿病小鼠胰岛素抵抗(IR)的作用机制。方法 将小鼠随机分成对照组,糖尿病组(建模),薯蓣皂苷低剂量组(建模+25 mg/kg薯蓣皂苷)、薯蓣皂苷中剂量组(建模+50 mg/kg薯蓣皂苷)、薯蓣皂苷高剂量组(建模+100 mg/kg薯蓣皂苷)和二甲双胍组(建模+100 mg/kg二甲双胍),各组小鼠9只。药物处理30 d后,对各组小鼠空腹血糖(FBG)、空腹胰岛素(FINS)、胰岛素抵抗指数(HOMA-IR)和体重进行检测;通过HE染色检测小鼠肝脏组织病理学情况;通过试剂盒检测肝脏组织超氧化物歧化酶(SOD)活性、丙二醛(MDA)和活性氧自由基(ROS)水平及肝脏细胞凋亡指数(AI);通过Western blot检测肝脏组织中PERK、Nrf2、HO-1及凋亡相关蛋白Bax、cleaved caspase-6的表达情况。结果 与对照组相比,糖尿病组小鼠FBG、FINS、MDA、ROS、AI及Bax、cleaved caspase-6蛋白表达水...     

多氯联苯对大鼠脾脏EROD的诱导作用

本文报告用多氯联苯(PCB)200mg/kg对大鼠连续腹腔注射三日染毒,除可诱导肝脏微粒体乙氧基异吩噁唑脱乙基酶(EROD)活性增高外,在脾脏微粒体内也检出EROD活性(4.9pmol/min·mg蛋白质)。当PCB剂量为400mg/kg时,大鼠脾脏S_9组分中EROD活性为对照组的3.3倍。结果说明尽管脾脏本底的细胞色素P-448活性极低,但仍可被化学致癌物PCB诱导。     

对乙酰氨基酚诱导小鼠急性肝损伤中p62-keap1-Nrf2信号通路变化

目的检测对乙酰氨基酚(acetaminophen,APAP)诱导小鼠急性肝损伤中p62-keap1-Nrf2抗氧化信号通路变化。方法 40只C57/BL6小鼠建立急性肝损伤剂量-反应模型,随机分为4组:对照组、APAP低剂量组(180 mg/kg)、APAP中剂量组(300 mg/kg)和APAP高剂量组(500 mg/kg),每组10只。禁食12 h后,腹腔注射0.9%氯化钠溶液或APAP溶液,24 h后摘眼球取血。另取60只小鼠建立时间-反应模型,对照组给0.9%氯化钠溶液,染毒组腹腔注射300 mg/kg APAP后,分别于3、6、12、24和48 h各取10只小鼠摘眼球取血测生化指标。以上小鼠均剪取肝同一部位做病理切片,HE染色检测病理损伤。并匀浆肝组织提取蛋白,利用Western blot检测p62-keap1-Nrf2信号通路相关蛋白的表达水平,荧光定量PCR技术检测抗氧化基因的相对表达。结果剂量-反应模型中,APAP处理组与对照组相比,肝脏系数明显增大(P0.05);ALT、AST水平显著升高(P0.05);肝病理切片显示APAP处理组出现不同程度肝细胞坏死;p62-keap1-Nrf2通路相关蛋白p62、p-p62、Keap1、Nrf2胞浆及胞核蛋白表达增加;而抗氧化基因HO-1、GCLC相对表达量下降。时间-反应模型中,APAP处理组小鼠ALT、AST水平明显高于对照组,呈时间反应趋势,24 h达到峰值;抗氧化基因HO-1、GCLC在3和6 h表达明显增加(P0.05),12、24和48 h急剧下降至较低水平。结论对乙酰氨基酚诱导的小鼠急性肝损伤中,p62-keap1-Nrf2信号通路激活,Nrf2可能在APAP肝损伤早期通过激活抗氧化相关基因表达发挥作用。     

丙烯腈染毒对大鼠肝脏钙稳态某些指标的影响

本研究观察了丙烯腈对大鼠肝脏 Ca2 - ATPase、Mg2 - ATPase、Na / K - ATPase和磷酸化酶 a( P- a)活性的影响 ,探讨其对大鼠肝脏钙稳态的影响。结果表明 ,随着染毒剂量的增大和染毒时间的延长 ,各 ATPase活性均逐渐降低 ,而 P- a的活性却逐渐升高 ( P<0 .0 1) ,其中高剂量( 5 0 mg/ kg)组的各观察时段和染毒 42天时各染毒组酶活性的变化均具有显著性意义 ( P<0 .0 5 ) ,并具有较好的剂量 -反应关系 ( P<0 .0 1)。结果提示 ,丙烯腈可影响大鼠肝脏钙稳态某些指标变化 ,并可能导致肝脏钙稳态的失调     

柴胡提取物及其所含皂苷 a和皂苷 d对小鼠骨骼增长的作用比较

目的比较柴胡提取物及其所含皂苷 a和皂苷 d促进骨骼增长的作用及其机制研究。方法自 2021年 3月至 2022年 1月进行了高效液相色谱法测定柴胡提取物中柴胡皂苷 a与 d含量;然后将昆明种小鼠 40只采用随机数字表法分为健康对照组、柴胡皂苷 a组(简称皂苷 a组)、柴胡皂苷 d组(简称皂苷 d组)、柴胡提取物组(简称提取物组)和阳性对照组,每组 8只。健康对照组灌胃去离子水,皂苷 a组灌胃柴胡皂苷 a 1.15 μg/g体质量,皂苷 d组灌胃柴胡皂苷 d 0.2 μg/g体质量,柴胡提取物组按照 0.94 mg/g体质量灌胃,阳性对照组灌胃酸枣仁皂苷 a0.013 mg/g体质量灌胃。灌胃 25 d后于末次给药 30 min后取脑组织,蛋白质印迹法检测脑组织色氨酸羟化酶 2(TPH2)含量, ELISA法检测脑组织 5-羟色胺( 5-HT)、生长激素( GH)含量的变化和 5-HT与 5-羟色胺 1A受体( 5-HT1AR)结合活性,并测量各组药物对小鼠胫骨长度的影响。结果柴胡提取物中柴胡皂苷 a含量为 1.22 mg/g,柴胡皂苷 d含量为 0.22 mg/g;提取物组和皂苷 a组的脑组织 5-HT含量( 60.93±11.09,59.51±11.02)μg/L、GH含量(68.91±9.10,68.42±9.03)μg/L、5-HT1AR与 5-HT结合活性( 39.90±8.36,37.27±6.59)及胫骨长度( 10.56±0.53,10.55±0.54)cm均较健康对照组［(40.89±8.74)μg/L,(44.87±8.92)μg/L,27.34±3.45,(9.48±0.63)cm］明显增高( P<0.01),同时这两组 TPH2含量较健康对照组升高( P<0.01)均差异有统计学意义。皂苷 d组脑组织 TPH2蛋白含量、 5-HT含量( 47.46±8.62)、 GH含量( 45.81± 7.14)、 5-HT1AR与 5-HT结合,活性( 30.87±5.52)及胫骨长度( 9.88±0.56)cm较健康对照组差异无统计学意义( P>0.05)。与皂苷 a组比较,皂苷 d组的脑组织 TPH2蛋白含量、 5-HT含量、 5-HT1AR与 5-HT结合活性及胫骨长度减少( P<0.05)GH含量明显减少( P<0.01),差异有统计学意义。与皂苷 d组比较,提取物组 GH含量、 5-HT1AR与 5-HT结合活性及胫骨长度增,加明显增高(P<0.01),5-HT含量增高( P<0.05),差异有统计学意义。结论柴胡提取物延缓慢波睡眠时长的主要成分为柴胡皂苷 a,其可     

Effects of osthol on activity,mRNA and protein expression of Cyp3a in rats in vivo

Osthol (OST) has a wide range of pharmacological effects and has long been used in clinical medicine in China. Previous studies have indicated that osthol has weak inhibitory effects on CYP3A4 in human liver microsomes. The aim of the present study was to investigate the inhibition of Cyp3a by osthol in rats in vivo. A substrate assay was used to corroborate the inhibitory effect on Cyp3a by osthol in rats, and the substrate probe (midazolam) was detected by high-performance liquid chromatography (HPLC). Semi-quantitative RT-PCR (SqRT-PCR) analysis was used to study the effect of osthol on Cyp3a1 and Cyp3a2 mRNA expression and Western blot analysis was used to investigate the effect of OST on Cyp3a1 and Cyp3a2 protein expression. Our study confirmed the inhibitory effect of osthol on Cyp3a and indicated that the inhibitory effect on Cyp3a was stronger in the group receiving multiple doses compared with the single dose group. The SqRT-PCR analysis results showed that medium and high doses of osthol (20 and 40 mg/kg, respectively) had an inhibitory effect on Cyp3a1 mRNA expression but not on Cyp3a2 mRNA expression. Western blot analysis results indicated that the inhibitory effect of the medium and high osthol doses on Cyp3a1 and Cyp3a2 protein expression was significantly different. It was also demonstrated that the inhibitory effect of osthol on Cyp3a in rats resulted from the comprehensive effect of the direct inhibition of the Cyp3a enzyme, as well as the down-regulation of its mRNA and protein expression level.     

Hormonal regulation of Cyp4a isoforms in mouse liver and kidney

Abstract

1. Mouse Cyp4a subfamily, including Cyp4a10, Cyp4a12a, Cyp4a12b and Cyp4a14, demonstrate a gender- and strain-specific expression in liver and kidney. In C57BL/6 mouse liver and kidney, Cyp4a12a and 4a12b are male-predominant, whereas Cyp4a14 is female-predominant. Cyp4a10 is female-predominant in liver, but shows no gender difference in kidney.

2. The present study was aimed to determine whether sex hormones and/or growth hormone (GH) secretion patterns are responsible for the gender-specific Cyp4a expression in C57BL/6 mice. Gonadectomized mice, GH-releasing hormone receptor-deficient little (lit/lit) mice and hypophysectomized mice were used with replacement of sex hormones or GH in male or female secretion patterns. Both androgens and male-pattern GH regulated the gender-divergent Cyp4a10, 4a12a and 4a12b in liver, whereas androgens played an exclusive role in regulating Cyp4a10 and 4a12a in kidney. In contrast, Cyp4a12b was increased by male-pattern GH but not androgens in kidney.

3. The female-predominant Cyp4a14 in liver and kidney was due to a combined effect of male-pattern GH and androgens. In addition, estrogens played a minor role in regulation of Cyp4a isoforms through an indirect pathway.

4. In conclusion, gender-divergent Cyp4a mRNA expression in liver is caused by male-pattern GH secretion pattern and androgens, whereas in kidney, Cyp4a mRNA expression is primarily regulated by androgens.     

Differences in the pharmacokinetics of Cyp3a substrates in TSOD and streptozotocin-induced diabetic mice

1. The pharmacokinetics of drugs can change in diabetes mellitus and even among diabetics. They may differ between type I diabetes (T1DM) and type 2 diabetes (T2DM).

2. As triazolam was administered orally to Tsumura, Suzuki, obese, diabetes (TSOD) mice and streptozotocin (STZ) mice, clearance per body (CL/F) in TSOD mice did not differ compared with Tsumura, Suzuki, non-obesity (TSNO) mice. In STZ mice, CL/F was greater than in control mice. Small intestinal cytochrome P450 (Cyp) 3a expression in TSOD mice was significantly lower than in TSNO mice. No significant difference existed in small intestinal Cyp3a expression between STZ mice and control mice. In insulin-treated mice, small intestinal Cyp3a expression was significantly lower than in control mice.

3. These results suggested that the differences in changes in small intestinal Cyp3a expression between T1DM and T2DM may be due to differences in plasma insulin concentrations. This may be a factor in the difference in the drug pharmacokinetics between T2DM and T1DM patients.

     

Murine Cyp3a knockout chimeric mice with humanized liver: prediction of the metabolic profile of nefazodone in humans

Chimeric mice with humanized livers (PXB mice) are used to investigate the metabolism and pharmacokinetics of drugs in humans. However, residual murine enzymatic activities derived from the liver and the presence of mouse small intestinal metabolism can hamper the prediction of human drug metabolism. Recently murine Cytochrome P450 3a gene knockout chimeric mice with humanized livers (Cyp3a KO CM) were developed. To evaluate the prediction of drug metabolism, nefazodone (NEF) was administered orally at 10 mg/kg to the following mouse strains: Cyp3a KO CM, murine Cyp3a gene knockout (Cyp3a KO), PXB and severe combined immunodeficiency (SCID) mice. Liquid chromatography‐mass spectrometry was used for metabolic profiling of plasma, urine and bile. The prediction of human metabolite levels such as hydroxy nefazodone (OH‐NEF), triazoledione form (TD), m‐chlorophenylpiperazine and dealkyl metabolites in Cyp3a KO CM was superior to that in Cyp3a KO, PXB or SCID mice. Further, clinical exposure levels of NEF, OH‐NEF and TD were reproduced in Cyp3a KO CM. In contrast, NEF was rapidly metabolized to TD in both PXB and SCID mice but not in Cyp3a KO mice, suggesting that murine CYP3A is involved in the elimination of NEF in these mice. These findings demonstrate that the metabolic profile of NEF in Cyp3a KO CM differs qualitatively and quantitatively from that in PXB mice due to the higher metabolic rate of NEF and its metabolites via murine CYP3A. Therefore Cyp3a KO CM might be useful in predicting the metabolic profiles of drug candidates in humans. Copyright © 2016 John Wiley & Sons, Ltd.     

Decreased exposure of atorvastatin in diabetic rats partly due to induction of hepatic Cyp3a and Oatp2

1. Atorvastatin is frequently prescribed for lowering blood cholesterol and for prevention of events associated with cardiovascular disease. The aim of this study was to investigate the pharmacokinetics of atorvastatin in diabetic rats.

2. Diabetes was induced in rats by combination of high-fat diet and low-dose streptozotocin (35?mg/kg). Plasma concentrations of atorvastatin following oral (10?mg/kg) and intravenous (2?mg/kg) administrations to rats were measured by LC-MS. Metabolism and uptake of atorvastatin in primary hepatocytes of experimental rats were assessed. Protein expressions and activities of hepatic Cyp3a and Oatp2 were further investigated.

3. Clearances of atorvastatin in diabetic rats following oral and intravenous administrations were remarkably increased, leading to marked decreases in area-under-the-plasma concentration–time curve (AUC). The estimated oral and systematic clearances of atorvastatin in diabetic rats were 4.5-fold and 2.0-fold of control rats, respectively. Metabolism and uptake of atorvastatin in primary hepatocytes isolated from diabetic rats were significantly increased, which were consistent with the up-regulated protein expressions and activities of hepatic Cyp3a and Oatp2.

4. All these results demonstrated that the plasma exposure of atorvastatin was significantly decreased in diabetic rats, which was partly due to the up-regulated activities and expressions of both hepatic Cyp3a and Oatp2.     

A dual function of the furanocoumarin chalepensin in inhibiting Cyp2a and inducing Cyp2b in mice: the protein stabilization and receptor-mediated activation

Chalepensin, a furanocoumarin, is present in several medicinal Rutaceae plants and causes a mechanism-based inhibition of human and mouse cytochrome P450 (P450, CYP) 2A in vitro. To address the in vivo effect, we investigated the effects of chalepensin on multiple hepatic P450 enzymes in C57BL/6JNarl mice. Oral administration of 10?mg/kg chalepensin to mice for 7?days significantly decreased hepatic coumarin 7-hydroxylation (Cyp2a) and increased 7-pentoxyresorufin O-dealkylation (Cyp2b) activities, whereas activities of Cyp1a, Cyp2c, Cyp2e1, and Cyp3a were not affected. Without affecting its mRNA level, the decreased Cyp2a activity was accompanied by an increase in the immunodetected Cyp2a5 protein level. In chalepensin-treated mice, microsomal Cyp2a5 was less susceptible to ATP-fortified cytosolic degradation than that in control mice, resulting in the elevated protein level. The in vitro inactivation through NADPH-fortified pre-incubation with chalepensin also protected microsomal Cyp2a5 against protein degradation. Using cell-based reporter systems, chalepensin at a concentration near unbound plasma concentration activated mouse constitutive androstane receptor (CAR), in agreement with the observed induction of Cyp2b. These findings revealed that suicidal inhibition of Cyp2a5 and the CAR-mediated Cyp2b9/10 induction concurrently occurred in chalepensin-treated mice.     

Dose-response relationship of cytochrome P4501b1 mRNA induction by 2,3,7,8-tetrachlorodibenzo-p-dioxin in livers of C57BL/6J and DBA/2J mice

 The dose-response relationship of cytochrome P4501b1 (Cyp1b1) and Cyp1a1 induction in livers of TCDD-treated female C57BL/6J and DBA/2J mice are described. The animals were treated i.p. with 0.001, 0.01, 0.1, 1, 10 and 50 μg TCDD/kg for 24 h, and Cyp1b1 and Cyp1a1 mRNA expression was analyzed by RT-PCR. In the livers of both mouse strains, the Cyp1b1 and Cyp1a1 mRNA content was increased after TCDD exposure in a dose-dependent manner. These effects were more pronounced in TCDD-responsive C57BL/6J mice than in the less responsive DBA/2J mice, although Cyp1a1 was more responsive to TCDD than Cyp1b1 in both strains. The calculated ED₅₀ values for Cyp1b1 and Cyp1a1 induction in livers of TCDD-treated C57BL/6J mice were 1.3 and 0.08 μg TCDD/kg, respectively. The corresponding values for half-maximal induction response in livers of DBA/2J mice were 3.4 μg TCDD/kg for Cyp1b1 and 1.5 μg TCDD/kg for Cyp1a1. These results show that Cyp1b1 mRNA expression is less inducible by TCDD than Cyp1a1. Both genes are highly inducible in TCDD-responsive C57BL/6J mice expressing the high affinity arylhydrocarbon receptor (Ah receptor), suggesting that Cyp1b1, like Cyp1a1, is a potential Ah receptor-regulated gene. Received: 8 December 1995/Accepted: 6 February 1996