Z24经口染毒大鼠尿液的核磁共振谱代谢组学研究

目的　研究Z2 4染毒大鼠尿液代谢组学的改变及其与组织病理和血液生化指标的相关性 ,探讨代谢组学在药物毒性早期筛选中的应用。方法Wistar大鼠连续经口给予Z2 4 6 0 ,130及 2 0 0mg·kg- 1,连续 5d后收集 2 4h尿液 ,测定核磁共振([1H]NMR)谱 ,并进行血浆生化指标测定和肝脏组织病理学检查。结果　Z2 4 2 0 0mg·kg- 1组大鼠血浆谷丙转氨酶、谷草转氨酶和总胆红素分别升高14 8% ,14 0 %和 110 % ;130和 2 0 0mg·kg- 1组均有不同程度的肝脏炎症和坏死。 [1H]NMR谱主成分分析发现各组在不同染毒条件下的代谢状态可相互区分 ,与肝脏病理和血浆生化改变相一致。结论　大鼠尿液 [1H]NMR代谢谱与Z2 4毒性作用强度密切相关 ,代谢组学分析是一种有良好发展前景的体内药物毒性早期筛选的方法。     

异烟肼肝毒性的代谢组学特征研究*

目的:研究大鼠灌胃异烟肼后其尿液的代谢表型改变及其与组织病理学和血浆生化指标变化的相关性,探讨代谢组学在药物毒理学研究中的应用。方法:Wistar大鼠连续灌胃0,25,50,100,200和400 mg.kg-1异烟肼14 d后收集尿样,测定1H-NMR谱,并进行血浆生化指标测定和肝脏组织病理学检查。结果:常规毒理学评价方法发现大鼠在中、高剂量表现明显的肝毒性;给药组尿样1H-NMR谱2-氨基己二酸、葡萄糖和牛磺酸明显增加,2-酮戊二酸和柠檬酸明显降低。各剂量组的代谢产物谱变化与肝脏病理和血浆生化改变相一致,并且其敏感性优于常规毒理学检测指标。结论:大鼠尿液1H-NMR代谢产物谱与异烟肼毒性作用强度密切相关,异烟肼引起的肝毒性与线粒体功能受损及三羧酸循环中能量代谢异常有关,还与葡萄糖代谢紊乱有关。代谢组学分析在毒理学研究中有着广泛的应用前景。     

利福平致肝脏毒性的代谢组学特征研究*

目的:研究大鼠灌胃抗结核病药物利福平后其尿液的代谢表型改变及其与组织病理学和血浆生化指标的相关性,寻找可能的毒性标志物,探讨代谢组学在药物毒理学研究中的应用。方法:Wistar大鼠灌胃给予利福平0,25,50和100mg·kg-1,qd,连续14d。收集最后一次给药后的24h尿样,测定1H-NMR谱,并进行血浆生化指标测定和肝脏组织病理学检查。结果:常规毒性评价方法发现大鼠在高剂量表现出轻度肝毒性;给药组尿样1H-NMR谱中葡萄糖和牛磺酸明显增加,2-酮戊二酸和枸橼酸明显降低。各组动物在不同剂量下的代谢谱变化与肝脏病理和血浆生化改变相一致,并且其敏感性优于常规毒理学检测指标。结论:大鼠尿液1H-NMR代谢产物谱与利福平毒性作用强度密切相关,利福平引起的肝毒性与三羧酸循环能量代谢和糖代谢有关。代谢组学分析在毒理学研究中有着广泛的应用前景。     

全氟辛烷磺酸对SD大鼠肝毒性及其肝脏细胞色素P450 mRNA表达的影响

目的研究全氟辛烷磺酸盐(PFOS)染毒SD大鼠后,其对大鼠肝脏毒性及细胞色素P450(CYP450)亚型mRNA表达的影响。方法 40只SD雄性大鼠,随机分为5组:4个PFOS染毒组,染毒剂量分别为0.5、1.0、3.0和10.0mg/(kg.d),1个对照组。连续灌胃染毒28 d后,分析血清生化指标和观察肝脏病理变化,并检测肝脏CYP450各亚型mRNA的表达水平。结果与对照组相比,大鼠染毒PFOS 28 d后,各染毒组大鼠的体重明显降低,10.0 mg/kg染毒组大鼠的肝脏重量显著增加。各染毒组大鼠的血清谷丙转氨酶、胆汁酸等水平显著升高,三酰甘油、总胆固醇含量降低。病理检查发现,各染毒组大鼠的肝脏细胞出现浊肿、变性,甚至坏死。此外,3.0和10.0 mg/kg组大鼠肝脏的CYP1A2mRNA水平降低,而CYP17A1 mRNA水平升高。各染毒组CYP2B1 mRNA水平均升高,呈剂量效应关系。结论 PFOS的肝毒性呈剂量效应关系,并对CYP450的各个亚型有不同影响。     

利用蛋白质组学技术研究Z24对大鼠给药血浆蛋白质表达的改变

目的利用2-DE-MAIDI-TOFMS/MS技术研究Z24对Wistar大鼠连续5d灌胃给药血浆蛋白质表达的变化,进一步分析Z24对大鼠肝毒性的作用机制。方法雌性Wistar大鼠,每组6只,每天以不同剂量的Z24(0、50、100和200mg/kg),麻醉动物后取血,分离血浆,一部分用于生化指标检测,一部分用于血浆蛋白质组分析,处死动物后取肝组织做病理检查。2-DE分离血浆蛋白,考马斯亮蓝R-250染色,利用ImageMaster2DPlatinum5.0软件进行图像分析,确定发生表达变化的差异蛋白点(P<0.05),选取分离好且呈一定剂量关系的蛋白点进行质谱鉴定,MS/MS-MS方法获取差异蛋白的肽质量指纹图谱和序列信息,在IPI-RATv3.23数据库中进行搜索,以C.I.%>95%作为判断依据鉴定差异蛋白,检索差异蛋白的生物学功能,进一步分析Z24对大鼠肝毒性的作用机制。结果血浆生化检测结果显示,与对照组相比,50mg/kg组ALP、Tch含量升高(P<0.05),100mg/kg组ALP、TG、Tch含量升高(P<0.05),200mg/kg组ALT、AST、ALP、AL、TBI、TG和Tch含量升高(P<0.05);AST、ALP、TBI和Tch含量变化呈剂量-效应关系。肝组织病理结果显示,各给药组动物肝脏均发生了不同程度的肝细胞空泡变性及纤维组织增生,且病变程度随剂量增加而加重。以上结果表明本实验剂量下Z24已引起了大鼠肝损伤。2-DE结果显示,与对照组相比,50、100和200mg/kg组分别有90、111和160个蛋白点发生明显的表达改变(P<0.05),其中100和200mg/kg组同时改变的蛋白点有34个,50、100和200mg/kg组同时改变的蛋白点有38个;对其中的29个差异蛋白点进行了质谱分析,有16个蛋白点经数据库检索后鉴定出相应蛋白,去冗余后包括11种蛋白,包括表达上调的载脂蛋白E、精氨琥珀酸合成酶、血浆视黄醇结合蛋白前体、丛生蛋白前体、触珠蛋白、肌动蛋白前体以及表达下调的胎球蛋白等。结论载脂蛋白E表达上调提示脂类代谢出现紊乱,丛生蛋白与细胞凋亡有关,精氨琥珀酸合成酶与鸟氨酸循环有关,血浆视黄醇结合蛋白的功能是输送肝内储存的视黄醇(VitA)到周围组织,这些蛋白质表达的改变提示Z24的肝脏毒性作用与脂类代谢紊乱及细胞凋亡有关,进而引起了肝脏功能的改变。     

利用1H-NMR技术研究大黄素染毒后大鼠内源性代谢物的改变

目的 采用¹H NMR的代谢组学技术揭示大黄素的肾毒性机制,寻找肾脏损害的早期生物标志物.方法 雄性SD大鼠20只,随机分为溶剂对照,大黄素170、500、1 500 mg/(kg·d)3个剂量组,连续给药16 d,给药结束后收集24 h尿液,血浆及肾组织,测定¹H NMR谱,并进行血浆生化指标测定和肝脏组织病理学检查.结果 1 500 mg/(kg·d)大黄素服用16 d可引起大鼠血肌酐下降,大黄素可导致肾细胞胞浆中出现明显的空泡化改变.代谢成分的改变主要表现为血液中乳酸、糖、氨基酸和脂肪酸成分下降;尿液中乳酸、糖和氨基酸成分增加;肾脏组织中醋酸盐和肌酐/肌酸明显升高,乳酸和胆碱/磷酸卵磷脂水平下降,饱和与不饱和脂肪酸及磷脂的成分比例明显改变.结论 代谢组学分析在识别药物诱导代谢成分改变方面较传统技术更灵敏;脂肪和能量代谢紊乱参与了大黄素的肾毒性,尿液中氨基酸、葡萄糖氧化三甲胺(TMAO)及肌酐可作为大黄素诱导肾组织损害的潜在生物标志物.     

Z24对大鼠肝脏抗氧化体系的影响

目的 研究Z24对大鼠肝脏抗氧化体系的影响.方法 雌性Wistar大鼠,灌胃给予Z24(0、50、100、200 mg/kg),1次/d,连续5 d,以生理盐水作对照.给药结束后次日,检测血浆生化指标,肝匀浆丙二醛(MDA)、还原型谷胱甘肽(GSH)含量和铜锌-超氧化物歧化酶(CuZn-SOD)、谷胱甘肽过氧化物酶(GSH-Px)、谷胱甘肽-S-转移酶(GST)活力,并做肝组织病理学检测.结果 100、200 mg/kg组丙氨酸转氨酶(ALT)、天冬氨酸转氨酶(AST)、碱性磷酸酶(ALP)、总胆红素(TB1)升高(P＜0.05),200 mg/kg组总胆汁酸(TBA)降低(P＜0.05),光学显微镜下见各给药组均出现肝细胞空泡变性和纤维组织增生,电子显微镜下见200 mg/kg组有线粒体嵴断裂等改变,表明该剂量下Z24已引起了肝损伤.50 mg/kg组CuZn-SOD活力代偿性升高,100、200 mg/kg组GSH-Px活力降低(P＜0.05),各给药组GST活力均升高,未见MDA含量升高和GSH含量降低,表明该剂量下Z24未引起肝氧化和抗氧化能力失平衡.结论 Z24对GSH-Px有抑制作用,但氧化应激效应并不是Z24肝毒性作用的主要机制.     

基于GC/TOF/MS的关木通肾毒性代谢组学研究

目的研究经关木通染毒后大鼠尿液及血浆的代谢组经时变化规律及其与组织病理指标的相关性,探讨代谢组学在关木通肾毒性研究中的应用。方法取4只SD大鼠,灌胃给予关木通醇提水溶液,剂量为72mg/(kg·d)的马兜铃酸A,1次/d,连续给药4d。分别采集给药前(0d),及给药后2、4d的尿液及血浆样品供代谢组学研究。实验结束后采集组织标本进行组织病理学检验。结果关木通给药后,大鼠肾脏均可见不同程度的肾小管上皮细胞变性、坏死,间质血管充血显示肾功能受到损害。利用GC/TOF/MS及模式识别技术为核心的代谢组学方法对尿样及血浆样品进行研究,结果表明,给药后2,4d大鼠尿液,血浆中代谢组水平与给药前产生明显变化,内源性代谢产物谱随时间动态变化明显,能够明显区分出各天的变化趋势,表征出毒性发生,发展的动态过程。结论关木通能够对肾脏造成损害,应用基于GC-MS的代谢组学方法,初步获得关木通致肾脏损害的"代谢产物谱",根据不同的代谢表型能够区分出关木通的毒性作用。大鼠尿液、血浆中的代谢产物谱与关木通毒性作用的经时过程密切相关,能够很好区分出机体的不同中毒状态。代谢组学分析是一种有良好发展前景的体内药物毒性早期筛选的方法,它可作为药物毒性评价的有效方法手段,在毒理学研究中有着广泛的应用前景。     

纳米铜经口染毒大鼠尿液的代谢组学研究

目的 研究纳米铜经口反复染毒大鼠尿液的代谢表型改变,探讨纳米铜的毒作用特征,并寻找早期损害的代谢标志物.方法 雄性Wistar大鼠42只,每组6只分别经口给予溶剂羟丙甲基纤维素(1% HPMC),微米铜(200mg/kg),纳米铜(50、100和200 mg/ks),连续染毒5 d,核磁共振(NMR)分析不同时点收集的24 h尿液,并作血液生化分析和肝肾组织病理学检查.结果 纳米铜200 mg/kg连续染毒5 d,大鼠血清丙氨酸转移酶、天冬氨酸转移酶、三酰甘油、总胆红素、总胆汁酸、肌酐和尿素氮均明显升高;肝细胞呈点状或局灶性坏死,肾小管上皮细胞弥漫性坏死;毒性明显重于其余处理组.尿液代谢组学分析表明纳米铜200 mg/kg染毒早期可诱导大鼠尿液中肌酐、牛磺酸和N-乙酰葡糖苷酶水平升高;染毒5 d,尿液中柠檬酸、乳酸和醋酸盐、糖、氨基酸和N-氧三甲胺水平明显升高,肌酐水平降低;纳米铜200 mg/kg组大鼠停止染毒一周,尿液代谢轨迹不能回到处理前状态.结论 肝脏和肾脏是纳米铜的靶器官,细胞能量代谢紊乱可能是纳米铜诱导肝肾损害过程中的重要事件,代谢组学分析可作为纳米材料在体毒性评价的技术平台之一.     

氯仿亚急性吸入染毒的肝肾毒性研究

采用亚急性动式吸入染毒,观察氯仿对雄性SD大鼠的肝肾毒性作用。结果表明,592mg/m~3氯仿可致大鼠肝脏组织丙二醛含量增高、血清谷丙转氨酶活性明显升高、个别动物肝细胞肿胀等异常改变;染毒停止6天后,肝脏异常基本恢复。在2488mg/m~3浓度下,肝脏改变明显,肾脏出现轻度损伤。     

Study of a novel indolin-2-ketone compound Z24 induced hepatotoxicity by NMR-spectroscopy-based metabonomics of rat urine, blood plasma, and liver extracts

Antiangiogenic compound has been believed to be an ideal drug in the current cancer biological therapy, but the angiogenesis inhibitors suffer setback for unknown toxicity now. A novel synthetic indolin-s-ketone small molecular compound, 3Z-3-[((1)H-pyrrol-2-yl)-methylidene]-1-(1-piperidinylmethyl)-1,3-2H-indol-2-one (Z24) can inhibit angiogenesis in new blood vessels. The hepatotoxicity effects of Z24 oral administration (dosed at 60, 130 and 200 mg/kg) have been investigated in female Wistar rats by using metabonomic analysis of (1)H NMR spectra of urine, plasma and liver extracts, as well as by clinical chemistry analysis, liver histopathology and electron micrographs examination. The (1)H NMR spectra of the biofluids were analyzed visually and via pattern recognition by using principal component analysis. The metabonomic trajectory analysis on the time-related hepatotoxicity of Z24 was carried out based on the (1)H NMR spectra of urine samples, which were collected daily predose and postdose over an 8-day period. Urinary excretion of citrate, lactate, 2-oxo-glutarate and succinate increased following Z24 dosing. Increased plasma levels of lactate, TMAO and lipid were observed, with concomitant decrease in the level of glucose and phosphatidylcholine. Metabolic profiling on aqueous soluble extracts of liver tissues with the high dose level of Z24 showed an increase in lactate and glutamine, together with a decrease in glucose, glycogen and choline. On the other hand, studies on lipid soluble extracts of liver tissues with the high dose level of Z24 showed increased level in lipid triglycerides and decreased level in unsaturated fatty acids and phosphatidylcholine. Moreover, the most notable effect of Z24 on the metabolism was the reduction in the urinary levels of creatinine and TMAO and the increase in acetate, citrate, succinate and 2-oxo-glutamate with time dependence. The results indicate that in rats Z24 inhibits mitochondrial function through altering the energy and lipid metabolism, which results in the accumulation of free fatty acids and lactate because of the lack of aerobic respiration. These data show that the metabonomic approach represents a promising new technology for the toxicological mechanism study.     

Sensitivity of (1)H NMR analysis of rat urine in relation to toxicometabonomics. Part I: dose-dependent toxic effects of bromobenzene and paracetamol.

(1)H nuclear magnetic resonance (NMR) spectroscopy of rat urine in combination with pattern recognition analysis was evaluated for early noninvasive detection of toxicity of investigational chemical entities. Bromobenzene (B) and paracetamol (P) were administered at five single oral dosages between 2 and 500 mg/kg and between 6 and 1800 mg/kg, respectively. The sensitivity of the proposed method to detect changes in the NMR spectra 24 and 48 h after single dosing was compared with histopathology and biochemical parameters in plasma and urine. Both B and P applied at the highest dosages induced liver necrosis and markedly increased aspartate aminotransferase (AST) and alanine aminotransferase (ALT) plasma levels. At dosages of 125 mg/kg B and 450 mg/kg P, liver necrosis and changes in AST and ALT were less pronounced, while at lower dose levels these effects could not be detected. Changes in kidney pathology or standard urine biochemistry were not observed at any of these dosages. Evaluation of the total NMR dataset showed 80 signals to be sensitive for B and P dosing. Principal component analysis on the reduced dataset revealed that NMR spectra were significantly different at dosages above 8 mg/kg (B) and 110 mg/kg (P) at both sampling times. This implies a 4- to 16-fold increased sensitivity of NMR versus histopathology and clinical chemistry in recognizing early events of liver toxicity.     

Metabonomic evaluation of idiosyncrasy-like liver injury in rats cotreated with ranitidine and lipopolysaccharide

Idiosyncratic liver injury occurs in a small fraction of people on certain drug regimens. The cause of idiosyncratic hepatotoxicity is not known; however, it has been proposed that environmental factors such as concurrent inflammation initiated by bacterial lipopolysaccharide (LPS) increase an individual's susceptibility to drug toxicity. Ranitidine (RAN), a histamine-2 receptor antagonist, causes idiosyncratic liver injury in humans. In a previous report, idiosyncrasy-like liver toxicity was created in rats by cotreating them with LPS and RAN. In the present study, the ability of metabonomic techniques to distinguish animals cotreated with LPS and RAN from those treated with each agent individually was investigated. Rats were treated with LPS or its vehicle and with RAN or its vehicle, and urine was collected for nuclear magnetic resonance (NMR)- and mass spectroscopy-based metabonomic analyses. Blood and liver samples were also collected to compare metabonomic results with clinical chemistry and histopathology. NMR metabonomic analysis indicated changes in the pattern of metabolites consistent with liver damage that occurred only in the LPS/RAN cotreated group. Principal component analysis of urine spectra by either NMR or mass spectroscopy produced a clear separation of the rats treated with LPS/RAN from the other three groups. Clinical chemistry (serum alanine aminotransferase and aspartate aminotransferase activities) and histopathology corroborated these results. These findings support the potential use of a noninvasive metabonomic approach to identify drug candidates with potential to cause idiosyncratic liver toxicity with inflammagen coexposure.     

Metabonomic deconvolution of embedded toxicity: application to thioacetamide hepato- and nephrotoxicity

We present here the potential of an integrated metabonomic strategy to deconvolute the biofluid metabolic signatures in experimental animals following multiple organ toxicities, using the well-known hepato- and nephrotoxin, thioacetamide. Male Han-Wistar rats were dosed with thioacetamide (150 mg/kg, n = 25), and urine, plasma, liver, and kidney samples were collected postdose for conventional NMR and magic angle spinning (MAS) NMR spectroscopy. These data were correlated with histopathology and plasma clinical chemistry collected at all time points. 1H MAS NMR data from liver and kidney were related to sequential 1H NMR measurements in urine and plasma using pattern recognition methods. One-dimensional 1H NMR spectra were data-reduced and analyzed using principal components analysis (PCA) to show the time-dependent biochemical variations induced by thioacetamide toxicity. From the eigenvector loadings of the PCA, those regions of the 1H NMR spectra, and hence the combinations of endogenous metabolites marking the main phase of the toxic episode, were identified. The thioacetamide-induced biochemical manifestations included a renal and hepatic lipidosis accompanied by hypolipidaemia; increased urinary excretion of taurine and creatine concomitant with elevated creatine in liver, kidney, and plasma; a shift in energy metabolism characterized by depleted liver glucose and glycogen; reduced urinary excretion of tricarboxylic acid cycle intermediates and raised plasma ketone bodies; increased levels of tissue and plasma amino acids leading to amino aciduria verifying necrosis-enhanced protein degradation and renal dysfunction; and elevated hepatic and urinary bile acids indicating secondary damage to the biliary system. This integrated metabonomic approach has been able to identify the tissue of origin for biomarkers present in the metabolic profiles of biofluids, following the onset and progression of a multiorgan pathology, and as such highlights its potential in the evaluation of embedded toxicity in novel drug candidates.     

Integrated NMR-based metabonomic investigation of early metabolic effects of ethylene glycol monomethyl ether (EGME) on male reproductive organs in rats

High-resolution Magic Angle Spinning (Hr-MAS) (1)H-NMR spectroscopy was used to analyze intact testicular tissues ex vivo and to investigate the toxicological effects of ethylene glycol monomethyl ether (EGME), a well-known spermatocytes toxicant, on male reproductive organs by NMR-based metabonomic analysis. Especially, we reported the first Hr-MAS (1)H-NMR spectra of epididymis. Sexually matured male rats were treated with 50 and 2,000 mg/kg EGME, and body weight, reproductive organs weight, histopathology and plasma biochemistry were examined at 6 and 24 hr after administration. Two multivariate statistical methods, namely, unsupervised PCA and supervised PLS-DA, indicated that the balance of endogenous metabolites was perturbed in both reproductive organs and biofluids. In the testes, lactate, creatine and glutathione were mainly affected by EGME treatment. In urine and plasma, altered excretions of the TCA cycle intermediates (2-oxoglutarate, citrate and succinate) and the ketone-bodies (acetoacetate and beta-hydroxybutyrate) were also observed. The finding in current integrated metabonomic analysis of both intact tissues and biofluids suggested that EGME-induced testicular toxicity was attributed to perturbation of the energy supply processes, suppression of the TCA cycle, or oxidative stress. Furthermore, Hr-MAS (1)H-NMR proved useful to investigate the molecular snapshot of biological tissues and the mechanism of toxicity.     

Metabonomic investigations into hydrazine toxicity in the rat

The systemic biochemical effects of oral hydrazine administration (dosed at 75, 90, and 120 mg/kg) have been investigated in male Han Wistar rats using metabonomic analysis of (1)H NMR spectra of urine and plasma, conventional clinical chemistry, and liver histopathology. Plasma samples were collected both pre- and 24 h postdose, while urine was collected predose and daily over a 7 day postdose period. (1)H NMR spectra of the biofluids were analyzed visually and via pattern recognition using principal component analysis. The latter showed that there was a dose-dependent biochemical effect of hydrazine treatment on the levels of a range of low molecular weight compounds in urine and plasma, which was correlated with the severity of the hydrazine induced liver lesions. In plasma, increases in the levels of free glycine, alanine, isoleucine, valine, lysine, arginine, tyrosine, citrulline, 3-D-hydroxybutyrate, creatine, histidine, and threonine were observed. Urinary excretion of hippurate, citrate, succinate, 2-oxoglutarate, trimethylamine-N-oxide, fumarate and creatinine were decreased following hydrazine dosing, whereas taurine, creatine, threonine, N-methylnicotinic acid, tyrosine, beta-alanine, citrulline, Nalpha-acetylcitrulline and argininosuccinate excretion was increased. Moreover, the most notable effect was the appearance in urine and plasma of 2-aminoadipate, which has previously been shown to lead to neurological effects in rats. High urinary levels of 2-aminoadipate may explain the hitherto poorly understood neurological effects of hydrazine. Metabonomic analysis of high-resolution (1)H NMR spectra of biofluids has provided a means of monitoring the progression of toxicity and recovery, while also allowing the identification of novel biomarkers of development and regression of the lesion.     

The toxicity and pharmacokinetics of dihydrosanguinarine in rat: A pilot study

The quaternary benzo[c]phenanthridine alkaloid sanguinarine (SG) is the main component of Sangrovit, a natural livestock feed additive. Dihydrosanguinarine (DHSG) has recently been identified as a SG metabolite in rat. The conversion of SG to DHSG is a likely elimination pathway of SG in mammals. This study was conducted to evaluate the toxicity of DHSG in male Wistar rats at concentrations of 100 and 500 ppm DHSG in feed for 90 days (average doses of 14 and 58 mg DHSG/kg body weight/day). No significant alterations in body or organ weights, macroscopic details of organs, histopathology of liver, ileum, kidneys, tongue, heart or gingiva, clinical chemistry or hematology markers in blood in the DHSG-treated animals were found compared to controls. No lymphocyte DNA damage by Comet assay, formation of DNA adducts in liver by 32P-postlabeling, modulation of cytochrome P450 1A1/2 or changes in oxidative stress parameters were found. Thus, repeated dosing of DHSG for 90 days at up to 500 ppm in the diet (i.e. approximately 58 mg/kg/day) showed no evidence of toxicity in contrast to results published in the literature. In parallel, DHSG pharmacokinetics was studied in rat after oral doses 9.1 or 91 mg/kg body weight. The results showed that DHSG undergoes enterohepatic cycling with maximum concentration in plasma at the first or second hour following application. DHSG is cleared from the body relatively quickly (its plasma levels drop to zero after 12 or 18 h, respectively).     

Species and tissue differences in the toxicity of 3-butene-1,2-diol in male Sprague-Dawley rats and B6C3F1 mice.

3-Butene-1,2-diol (BDD) is a major metabolite of 1,3-butadiene (BD), but the role of BDD in BD toxicity and carcinogenicity remains unclear. In this study, the acute toxicity of BDD was investigated in male Sprague-Dawley rats and B6C3F1 mice. Of the rats given 250 mg/kg BDD, 2 out of 4 died within 24 h; rats experienced hypoglycemia, significant alterations of liver integrity tests, and had lesions in the liver 4 h after treatment, but no lesions were detected in extrahepatic tissues. Rat hepatic GSH and GSSG levels were significantly depleted at both 1 and 4 h after the BDD treatment. Rats administered 200 mg/kg BDD also had liver lesions but no death or hypoglycemia was observed four or 24 h after treatment; these rats had depleted hepatic GSH and GSSG levels at 1 h but not at 4 or 24 h after treatment. Mice administered 250 mg/kg BDD exhibited modest alterations of liver integrity tests, but no death, hypoglycemia, or lesions in any tissue, and hepatic GSH and GSSG levels were depleted at 1 h but not at 4 h. The plasma half-life of BDD was four times longer in rats than in mice. Additional studies in rats showed the depletion of hepatic GSH and GSSG preceded the BDD-induced hypoglycemia and hepatotoxicity. Thus, the long half-life of BDD in rat plasma and the sustained depletion of hepatic GSH and GSSG may in part explain the higher sensitivity of the rat to BDD-induced hepatotoxicity. Furthermore, the results indicate that BDD may play a role in BD-induced toxicity.     

NMR-based metabonomic analysis of the hepatotoxicity induced by combined exposure to PCBs and TCDD in rats

A metabonomic approach using ¹H NMR spectroscopy was adopted to investigate the metabonomic pattern of rat urine after oral administration of environmental endocrine disruptors (EDs) polychlorinated biphenyls (PCBs) and 2,3,7,8-tetrachlorodibenzo- p-dioxin (TCDD) alone or in combination and to explore the possible hepatotoxic mechanisms of combined exposure to PCBs and TCDD. ¹H NMR spectra of urines collected 24 h before and after exposure were analyzed via pattern recognition by using principal component analysis (PCA). Serum biochemistry and liver histopathology indicated significant hepatotoxicity in the rats of the combined group. The PCA scores plots of urinary ¹H NMR data showed that all the treatment groups could be easily distinguished from the control group, so could the PCBs or TCDD group and the combined group. The loadings plots of the PCA revealed remarkable increases in the levels of lactate, glucose, taurine, creatine, and 2-hydroxy-isovaleric acid and reductions in the levels of 2-oxoglutarate, citrate, succinate, hippurate, and trimethylamine-N-oxide in rat urine after exposure. These changes were more striking in the combined group. The changed metabolites may be considered possible biomarker for the hepatotoxicity. The present study demonstrates that combined exposure to PCBs and TCDD induced significant hepatotoxicity in rats, and mitochondrial dysfunction and fatty acid metabolism perturbations might contribute to the hepatotoxicity. There was good conformity between changes in the urine metabonomic pattern and those in serum biochemistry and liver histopathology. These results showed that the NMR-based metabonomic approach may provide a promising technique for the evaluation of the combined toxicity of EDs.