Tissue-specific alterations of methyl group metabolism with DNA hypermethylation in the Zucker (type 2) diabetic fatty rat

Background Altered methyl group and homocysteine metabolism were tissue‐specific, persistent, and preceded hepatic DNA hypomethylation in type 1 diabetic rats. Similar metabolic perturbations have been shown in the Zucker (type 2) diabetic fatty (ZDF) rat in the pre‐diabetic and early diabetic stages, but tissue specificity and potential impact on epigenetic marks are unknown, particularly during pathogenesis. Methods ZDF (fa/fa) and lean (+/?) control rats were killed at 12 and 21 weeks of age, representing early and advanced diabetic conditions. Blood and tissues were analysed with respect to methyl group and homocysteine metabolism, including DNA methylation. Results At 12 weeks, hepatic glycine N‐methyltransferase (GNMT), methionine synthase, and cystathionine β‐synthase (CBS) activity and/or abundance were increased in ZDF rats. At 21 weeks, GNMT activity was increased in liver and kidney; however, only hepatic CBS protein abundance (12 weeks) and betaine‐homocysteine S‐methyltransferase mRNA expression (21 weeks) were significantly elevated (78 and 100%, respectively). Hepatic phosphatidylethanolamine N‐methyltransferase expression was also elevated in the ZDF rat. Homocysteine concentrations were decreased in plasma and kidney, but not in liver, at 12 and 21 weeks. In contrast to hepatic DNA hypomethylation in the type 1 diabetic rat, genomic DNA was hypermethylated at 12 and 21 weeks in the liver of ZDF rats, concomitant with an increase in DNA methyltransferase 1 expression at 21 weeks. Conclusions The pathogenesis of type 2 diabetes in the ZDF rat was associated with tissue and disease stage‐specific aberrations of methyl group and homocysteine metabolism, with persistent hepatic global DNA hypermethylation. Copyright © 2011 John Wiley & Sons, Ltd.     

EFFECTS OF NITRIC OXIDE SYNTHESIS INHIBITION ON FK506-INDUCED NEPHROTOXICITY IN RATS

This study was designed to evaluate the role of nitric oxide (NO) in FK506-induced nephrotoxicity by administering an inhibitor of NO synthesis, Nω-nitro-L-arginine methyl ester (L-NAME) to rats treated with FK506. After one week of treatment with FK506 (3.2 mg/kg/day, intramuscularly) and/or L-NAME (5 mg/100 mL of L-NAME in the drinking water), the arterial pressure, urinary NOx, and parameters for renal function were measured, and histological analysis of the kidney was made. In the L-NAME without FK506 group, L-NAME administration effectively inhibited urinary NOx excretion and increased mean arterial pressure (MAP) without any change in renal function. In the FK506 without L-NAME group, FK506 treatment showed increase in urinary NOx excretion and mild renal dysfunction. In the FK506 with L-NAME group, urinary NOx excretion was decreased by L-NAME administration and renal function was significantly worsened than FK506 without L-NAME group. The plasma creatinine, BUN and urinary N-acetyl-β-D-glucosaminidase increased 2-, 3-, and 3-fold, respectively and the creatinine clearance was reduced by 50% as compared with that in the FK506 without L-NAME group. Histological analysis revealed severe interstitial fibrosis and tubular atrophy in the FK506 + L-NAME treatment group. Thus, results suggest that NO synthesis is enhanced in the kidney during FK506-induced nephrotoxicity and that NO synthesis inhibition aggravates FK506-induced nephrotoxicity. NO may play a protective role attributable to the balance of vasoactive substances in FK506-induced nephrotoxicity.     

Pentoxifylline and propentofylline prevent proliferation and activation of the mammalian target of rapamycin and mitogen activated protein kinase in cultured spinal astrocytes

Astrocyte activation is an important feature in many disorders of the central nervous system, including chronic pain conditions. Activation of astrocytes is characterized by a change in morphology, including hypertrophy and increased size of processes, proliferation, and an increased production of proinflammatory mediators. The xanthine derivatives pentoxifylline and propentofylline are commonly used experimentally as glial inhibitors. These compounds are generally believed to attenuate glial activity by raising cyclic AMP (cAMP) levels and inhibiting glial tumor necrosis factor (TNF) production. In the present study, we show that these substances inhibit TNF and serum‐induced astrocyte proliferation and signaling through the mammalian target of rapamycin (mTOR) pathway, demonstrated by decreased levels of phosphorylated S6 kinase (S6K), commonly used as a marker of mTOR complex (mTORC) activation. Furthermore, we show that pentoxifylline and propentofylline also inhibit JNK and p38, but not ERK, activation induced by TNF. In addition, the JNK antagonist SP600125, but not the p38 inhibitor SB203580, prevents TNF‐induced activation of S6 kinase, suggesting that pentoxifylline and propentofylline may regulate mTORC activity in spinal astrocytes partially through inhibition of the JNK pathway. Our results suggest that pentoxifylline and propentofylline inhibit astrocyte activity in a broad fashion by attenuating flux through specific pathways. © 2012 Wiley Periodicals, Inc.     

Enhanced prefrontal serotonin 2A receptor signaling in the subchronic phencyclidine mouse model of schizophrenia

Prefrontal serotonin 2A receptors (5‐HT_2ARs) have been linked to the pathogenesis and treatment of schizophrenia. Many antipsychotics fully occupy 5‐HT_2AR at clinical relevant doses, and activation of 5‐HT_2A receptors by lysergic acid diethylamide (LSD) and LSD‐like drugs induces a schizophrenia‐like psychosis in humans. Subchronic phencyclidine (PCP) administration is a well‐established model for schizophrenia‐like symptoms in rodents. The aim of the present study was to investigate whether subchronic PCP administration changes expression, binding, or functionality of cortical 5‐HT_2ARs. As a measure of 5‐HT_2AR functionality, we used the 5‐HT_2AR agonist 2,5‐dimethoxy‐4‐iodoamphetamine (DOI)‐induced head‐twitch response (HTR) and mRNA expression of the immediate‐early genes (IEGs) activity‐related cytoskeletal associated‐protein (Arc), c‐fos, and early growth response protein 2 (egr‐2) in the frontal cortex. Mice were treated with PCP (10 mg/kg) or saline for 10 days, followed by a 5‐day washout period. The PCP pretreatment increased the overall induction of HTR and frontal cortex IEG mRNA expression following a single challenge with DOI. These functional changes were not associated with changes in 5‐HT_2AR binding. Also, binding of the 5‐HT_1AR and the 5‐HT transporter was unaffected. Finally, basal mRNA level of Arc was increased in the prefrontal cortex after subchronic PCP administration as revealed with in situ hybridization. Together these findings indicate that PCP administration produces changes in the brain that result in an increase in the absolute effect of DOI. Therefore, neurotransmission involving the 5‐HT_2AR could contribute to the behavioral deficits observed after PCP treatment. © 2013 Wiley Periodicals, Inc.     

New thiazolyl-pyrazoline derivatives bearing nitrogen mustard as potential antimicrobial and antiprotozoal agents

A new series of N-substituted pyrazoline derivatives 6a–g , 7a–g , 8a–g , and 9a–g was synthetized by reaction of hydrazine derivatives and chalcone–thiazole hybrids bearing nitrogen mustard 5a–g . The chalcones 5a–g were obtained by Claisen–Schmidt condensation of thiazole-2-nitrogen mustard 3 and selected acetophenones 4a–g . These new compounds 6/7/8/9a–g were screened for their antifungal activity against Cryptococcus neoformans, with IC₅₀ values of 3.9–7.8 µg/ml for the N-3,5-dichlorophenyl pyrazolines 9e – g . Interestingly, those compounds show low cytotoxic effects toward erythrocytes (RBC). In addition, N-acetyl ( 6a,b ) and N-formyl pyrazolines ( 7a , 7b , 7c , and 7g ) showed inhibitory activity against methicillin-susceptible Staphylococcus aureus, methicillin-resistant S. aureus, and vancomycin-intermediate S. aureus, with the most important minimum inhibitory concentration values ranging from 31.25 to 125 µg/ml. Regarding the antiprotozoal activity, thiazolyl-pyrazolines 9g , 8f , and 7c display high activity against Plasmodium falciparum, Leishmania (V) panamensis, and Trypanosoma cruzi, with EC₅₀ values of 11.80, 6.46, and 4.98 μM, respectively, and with 7c being approximately 2.6-fold more potent than benznidazole with a selectivity index of 1.61 on U-937 human cells, showing promising potential as a novel antitrypanosomal agent.     

蒺藜果实的化学成分研究

目的研究蒺藜科植物蒺藜Tribulus terrester的干燥成熟果实的化学成分。方法利用硅胶柱色谱、Sephadex LH-20凝胶柱色谱、制备HPLC和薄层色谱等方法进行分离、纯化,并结合HR-ESI-MS与现代波谱学技术鉴定化合物结构。结果从蒺藜果实中分离得到14个化合物,分别鉴定为N-p-阿魏酰酪胺(1)、N-trans-p-coumaroyl-3-O-methyldopamine(2)、甲基阿魏酸(3)、咖啡酸甲酯(4)、原儿茶酸甲酯(5)、trifilines A(6)、5β-spirost-25(27)-en-3β-ol-12-one 3-O-{β-D-glucopyranosyl-(1→2)-O-[β-D-glucopyranosyl-(1→3)]-β-D-glucopyranoside}(7)、tribulosaponin B(8)、isoterrestrosin B(9)、25(R)-螺甾烷-3,5-二烯-12-酮(10)、25(R)-螺甾烷-24β-羟基-4-烯-3,12-酮(11)、26-O-β-D-glucopyranosyl-(25S)-5α-furostane-20(22)-en-12-one-3β,26-diol-3-O-α-L-rhamnopyranosyl-(1→2)-[β-D-glucopyranosyl-(1→4)]-β-D-galactopyranoside(12)、terrestrinone A1(13)和terrestrinone A2(14)。结论化合物1～7为首次从蒺藜科植物中分离得到。     

基于化学计量学方法结合正交偏最小二乘判别分析的陈皮饮片HPLC指纹图谱研究

目的建立陈皮饮片HPLC指纹图谱分析方法,为其质量控制提供技术参考。方法采用HPLC法建立17批陈皮饮片的指纹图谱,通过聚类分析(clusteranalysis,CA)、主成分分析(principalcomponentanalysis,PCA)、正交偏最小二乘判别分析(orthogonal partial least square discrimina te analysis,OPLS-DA)对指纹图谱进行评价。结果建立了陈皮饮片指纹图谱,相似度均0.9,确定了25个共有峰,其中14个峰的变量投影重要性(variableimportance projection,VIP)均1,通过与对照品谱图比对,确定了13号峰为芸香柚皮苷、14号峰为橙皮苷、23号峰为川陈皮素、24号峰为3,5,6,7,8,3′,4′-七甲氧基黄酮、25号峰为桔皮素。结论该方法简单可靠,可用于陈皮饮片鉴别和质量控制。     

基于多成分同时定量和统计学分析的大黄利胆片质量评价研究

目的建立用HPLC波长切换法同时测定大黄利胆片中10个活性成分没食子酸、5-羟甲基糠醛、柯里拉京、对羟基苯甲醛、鞣花酸、芦荟大黄素、大黄酸、大黄素、大黄酚、大黄素甲醚含量的方法,并结合统计学分析对其质量进行评价。方法采用PhenomenexKinetexC18色谱柱,柱温为30℃,以甲醇-0.15%磷酸水溶液为流动相梯度洗脱,体积流量为1m L/min,检测波长分别为265.0 nm(0～5.8 min,检测没食子酸)、283.9 nm(5.8～7 min,检测5-羟甲基糠醛)、222.2(7～18 min,检测柯里拉京、对羟基苯甲醛)、256.7 nm(18～74 min,检测鞣花酸、芦荟大黄素、大黄酸、大黄素、大黄酚、大黄素甲醚);用SPSS21软件对10批药中成分含量进行统计学分析。结果 10个成分在各自质量浓度范围内线性关系良好(r0.9980),平均加样回收率98.45%～100.12%,RSD为0.80%～2.51%;含量分别为没食子酸8.371～11.438mg/片、5-羟甲基糠醛0.046～0.087mg/片、柯里拉京0.721～2.094mg/片、对羟基苯甲醛0.034～0.065mg/片、鞣花酸1.736～1.996mg/片、芦荟大黄素0.337～0.440mg/片、大黄酸1.636～2.562mg/片、大黄素0.602～0.846mg/片、大黄酚0.388～0.566mg/片、大黄素甲醚0.621～0.781 mg/片;10批样品质量基本一致。结论该方法简单准确,可用于大黄利胆片的质量控制。     

HPLC法同时测定乙肝益气解郁颗粒中的11种成分

目的建立HPLC法同时测定乙肝益气解郁颗粒中柴胡皂苷a、柚皮苷、芍药苷、毛蕊异黄酮苷、丹参酮IIA、桂皮醛、五味子醇甲、紫丁香苷、盐酸小檗碱、大黄酚和橙皮苷的含量,并采用主成分分析(PCA)法对其质量进行综合评价。方法采用HPLC法,色谱柱为Caprisil C18-AQ(250 mm×4.6 mm,5.0μm);流动相为0.1%磷酸水溶液-乙腈,梯度洗脱,体积流量0.8mL/min;柱温45℃。最后将定量结果与PCA法相结合对不同批次药物进行科学的质量评价分析。结果乙肝益气解郁颗粒中柴胡皂苷a、柚皮苷、芍药苷、毛蕊异黄酮苷、丹参酮IIA、桂皮醛、五味子醇甲、紫丁香苷、盐酸小檗碱、大黄酚和橙皮苷11种成分分别在1.6～80.0、14～700、10～500、1.6～80.0、1.6～80.0、2.4～120.0、1.2～60.0、1.2～60.0、8.0～400.0、2.0～100.0、2.0～100.0μg/m L线性关系良好;平均加样回收率分别为98.3%、99.2%、98.8%、99.3%、101.9%、97.5%、99.8%、101.7%、101.1%、102.5%、100.9%,RSD均2.0%;16批样品中11种有效成分的质量分数分别为0.233～0.322、3.007～3.142、2.201～2.273、0.320～0.355、0.317～0.399、0.451～0.523、0.265～0.297、0.209～0.226、1.848～1.873、0.380～0.425、0.615～0.647mg/g。结论实验建立的方法简便准确、重复性好,可用于乙肝益气解郁颗粒的质量控制,为乙肝益气解郁颗粒后续质量提高提供参考。     

Increased oxidative stress is associated with balanced increases in hepatocyte apoptosis and proliferation in glycerol-3-phosphate acyltransferase-1 deficient mice

The absence of mouse mitochondrial glycerol-3-phosphate acyltransferase-1 (Gpat1-/-) increases the amount of arachidonate in liver phospholipids and increases beta-hydroxybutyrate and acyl-carnitines, suggesting an elevated rate of liver fatty acid oxidation. We asked whether these alterations might increase reactive oxygen species (ROS), apoptosis, or hepatocyte proliferation. Compared to wildtype controls, liver mitochondria from Gpat1-/- mice showed a 20% increase in the rate of ROS production and a markedly increased sensitivity to the induction of the mitochondrial permeability transition. Mitochondrial phosphatidylethanolamine and phosphatidylcholine from Gpat1-/- liver contained 21% and 67% more arachidonate, respectively, than wildtype controls, and higher amounts of 4-hydroxynonenal, a product of arachidonate peroxidation. Oxidative stress was associated with an increase in apoptosis, and with 3-fold and 15-fold higher TUNEL positive cells in liver from young and old Gpat1-/- mice, respectively, compared to age-matched controls. Compared to controls, bromodeoxyuridine labeling was 50% and 7-fold higher in livers from young and old Gpat1-/- mice, respectively, but fewer glutathione-S-transferase positive cells were present. Thus, Gpat1-/- liver exhibits increased oxidative stress and sensitivity of the mitochondrial permeability transition pore, and a balanced increase in apoptosis and proliferation.