近红外光谱法快速测定木香中木香烃内酯与去氢木香内酯的含量

本文主要研究近红外光谱法在快速测定木香药材中木香烃内酯与去氢木香内酯含量的应用。采用近红外漫反射光谱法采集木香的近红外光谱,以HPLC测量值为参考值,运用偏最小二乘法(PLS)建立木香烃内酯与去氢木香内酯含量的定量模型,并用未知样品验证该模型。结果表明所建定量模型的校正集内部交叉验证相关系数(R2)、校正均方差(RMSEC)和内部交叉验证均方差(RMSECV)分别为0.9783、0.161和0.374;经外部验证的预测相关系数(r2)和预测均方差(RMSEP)分别为0.9546和0.162。该方法操作简便,测定快速,结果准确,无污染,可用于木香药材中木香烃内酯与去氢木香内酯含量的快速测定。     

土木香内酯与异土木香内酯的提取与纯化工艺(英文)

本文报道了一种从土木香药材中提取以及纯化倍半萜内酯的方法。乙醇回流提取的方法采用正交试验设计方法[L9(34)],考察了4个因素对产率与内酯浓度的影响,最终确定了乙醇回流提取的最佳方法:药材加10倍量的95%乙醇,加热回流提取1次,2 h。而硅胶柱层析的最佳纯化方法为:以100~200目的硅胶,1∶3的上样量,径高比为1∶2。其洗脱剂成分为石油醚∶丙酮(100∶3,v/v),洗脱流速为35 m L/min。采用该方法,异土木香内酯与土木香内酯的提取率大于70%,其纯度大于90%。     

穿心莲内酯激活Nrf2抑制乙醇诱导肝细胞氧化应激损伤

本研究为观察穿心莲内酯(AD)对乙醇诱导肝细胞氧化应激损伤的保护作用,体外培养肝细胞L-02,用不同浓度(0~30μmol/L)AD孵育1 h,随后加入100 mmol/L乙醇作用24 h。ELISA测定AD处理前后细胞培养上清中谷丙转氨酶(ALT)和谷草转氨酶(AST)的含量;比色法检测丙二醛(MDA)和谷胱氨肽(GSH)的变化;荧光探针DCFH2-DA检测胞内活性氧(ROS)的产生;Western blotting和分析血红素氧合酶-1(HO-1)m RNA和蛋白的表达。电泳迁移率实验(EMSA)检测核转录因子Nrf2的DNA结合活性。结果表明,100 mmol/L乙醇处理肝细胞后,可在不影响L-02活性的情况下显著增加培养上清中ALT和AST的含量,而AD预处理后可抑制ALT、AST、MDA和ROS的增加以及上调胞内GSH的水平。此外,Western blotting和实时定量PCR结果也证实乙醇可降低肝细胞内源性HO-1的表达,而AD预处理后可增强转录因子Nrf2的活性并进一步上调HO-1的表达水平。AD可能通过激活Nrf2上调HO-1表达而发挥对乙醇所致肝细胞损伤的保护作用。     

穿心莲内酯联合S-腺苷甲硫氨酸抑制乙醇诱导肝细胞氧化应激损伤

氧化应激是酒精性肝病(ALD)发生的主要机制,因此具有抗氧化作用的活性物质对ALD具有潜在的治疗意义。在本研究当中,我们探讨了S-腺苷甲硫氨酸(SAM)和(或)穿心莲内酯(AD)对乙醇诱导肝细胞氧化应激损伤的保护作用。首先我们体外培养肝细胞L-02,用100 mmol/L乙醇作用24 h后发现,细胞的活性明显降低,胞内活性氧(ROS)含量显著增多以及脂质蓄积,同时细胞释放多种与肝病相关酶类如甘油三脂、胆固醇、转氨酶以及同型半胱氨酸等物质。而乙醇刺激前采用100μmol/L SAM或(和)30μmol/L AD处理细胞后,可明显降低细胞的氧化应激水平,同时能减少上述肝病相关标志物的的释放。此外,乙醇处理也可降低细胞内去乙酰化酶SIRT1的表达并抑制其核转位,而采用SAM或(和)AD处理后可进一步改善SIRT1的表达及活性。以上结果表明SAM或(和)AD能降低乙醇所致的氧化应激水平,两者联合应用可能对ALD具有潜在的治疗效果。     

HBx与肝细胞脂肪变性关系及可能机制的细胞学研究

从细胞水平探讨乙型肝炎病毒X蛋白(hepatitis B virus X protein,HBx)与肝细胞脂肪变性的关系,并探讨其可能分子机制。油红O染色及细胞内甘油三酯含量测定鉴定HepG2.2.15细胞和HepG2细胞的脂变程度;Western blotting检测HBx,肝X受体(liver X receptor alpha,LXRα)及脂肪酸合成酶(fatty acid synthase,FAS)蛋白的表达。结果显示,C2.2.15组细胞脂变程度较CG2组细胞重。O2.2.15组细胞在24,48及72h的脂变程度及TG含量均较同一时间段的OG2组增加;Western blotting结果显示,HepG2.2.15细胞内有HBx蛋白表达,而HepG2细胞则无此蛋白表达;C2.2.15组细胞LXRα及FAS蛋白表达强度较CG2组细胞高。HBx蛋白与肝细胞脂肪变性存在密切的关系,其机制可能与HBx/LXRα/FAS信号通路有关。     

去氢木香内酯干预人乳腺癌MCF-7细胞机制的探究

目的:探讨去氢木香内酯对乳腺癌MCF-7细胞凋亡、线粒体跨膜电位及代谢物的影响,为研究去氢木香内酯诱导MCF-7细胞凋亡的作用机制提供新的视角。方法:采用流式细胞仪测定不同浓度去氢木香内酯(0、2、4、8μg/m L)对MCF-7细胞凋亡及线粒体跨膜电位的影响;GC-TOFMS测定去氢木香内酯作用前后,MCF-7细胞内具有显著性变化的代谢差异物。结果:研究结果表明,去氢木香内酯能诱导MCF-7细胞的凋亡、促进线粒体跨膜电位的降低;正交偏最小二乘法判别分析(OPLS-DA)多维统计方法对代谢组学数据分析得到柠檬酸、D-核糖、脯氨酸、苯丙氨酸、赖氨酸等16种代谢差异物。结论:推测去氢木香内酯通过引起线粒体跨膜电位降低而破坏了线粒体的结构,进一步阻碍了线粒体的功能,导致了细胞内代谢物的紊乱,最终诱导了细胞的凋亡。     

穿心莲内酯抑制人结肠癌SW1116细胞增殖及诱导细胞凋亡作用的研究

目的:观察穿心莲内酯对人结肠癌SW1116细胞生长及肿瘤细胞凋亡的影响,探讨其可能的机制.方法:用不同浓度的穿心莲内酯处理SW1116细胞,MTT检测穿心莲内酯对SW1116细胞生长增殖的抑制作用;流式细胞术(FCM)检测细胞凋亡率;比色法测定Caspase-3酶活性;Western blot法检测bax、Bcl-2的蛋白表达.结果:穿心莲内酯能够剂量依赖型的抑制人结肠癌SW1116细胞的增殖,并诱导凋亡;穿心莲内酯与SW1116细胞作用48小时后Caspase-3酶活性显著增强;同时,穿心莲内酯处理SW1116细胞后,Bax蛋白表达增强,Bcl-2蛋白表达下调.结论:穿心莲内酯可抑制人结肠癌SW1116的增殖,诱导其凋亡,机制可能与调节Caspase-3、Bcl-2和Bax表达水平有关.     

肝细胞生长因子抑制糖基化终产物诱导人脐静脉内皮细胞的凋亡作用

目的探讨肝细胞生长因子(HGF)抑制糖基化终产物(AGEs)诱导人脐静脉内皮细胞凋亡的作用及其相关分子机制。方法体外培养ECV-304人脐静脉内皮细胞,采用噻唑蓝(MTT)法测定HGF对AGEs作用后ECV-304细胞生长抑制率的影响;通过Hoechst33258荧光染色观察细胞形态学改变、流式细胞术测定AnnexinV-FITC/PI双染标记的细胞凋亡率,检测HGF对AGEs诱导ECV-304细胞凋亡的影响;Western印迹法检测Bax、Bcl-2蛋白的表达。结果HGF能明显降低AGEs对ECV-304细胞生长的抑制作用;AGE诱导培养的ECV-304细胞出现明显的凋亡形态学改变,在一定浓度范围内,ECV-304细胞凋亡率与AGEs的浓度和作用时间呈依赖关系,加入HGF处理后可显著降低不同时间的内皮细胞凋亡率;HGF作用ECV-304细胞后Bcl-2蛋白表达明显升高,而Bax蛋白表达无明显变化。结论AGEs能诱导内皮细胞凋亡,而HGF能部分抑制AGEs诱导的内皮细胞凋亡,其作用机制可能与上调Bcl-2蛋白的表达水平有关。     

血管新生在肝脏疾病发生与发展中作用的研究进展

血管新生是在现有血管的基础上,通过多种细胞因子的调控进而形成新的毛细血管的过程。近年来研究发现,血管新生不仅在组织修复过程中发挥其重要作用,而且在肝脏疾病的发生发展中扮演着重要的角色。本文就血管新生的概念以及其在各类肝脏疾病,如:酒精性肝病、非酒精性脂肪肝炎、病毒性肝炎、肝纤维化、肝细胞癌中的作用机制及研究进展作一综述,旨在为肝病的预防及治疗提供新的思路,并且为药物的开发提供一定的理论支持。     

高脂饮食诱导肥胖与肥胖抵抗型非酒精性脂肪肝大鼠模型的建立

目的:利用高脂饲料复制肥胖与肥胖抵抗型非酒精性脂肪肝SD大鼠模型。方法:体质量100±10g的雄性SD大鼠140只,按照体重随机抽取120只用于模型建立,喂食高脂、高能饲料。连续8周后,将体质量大于正常对照组平均体质量+1.96倍标准差的模型大鼠作为肥胖型非酒精性脂肪肝组(NO组),体质量小于正常对照组平均体质量+1.0倍标准差的作为肥胖抵抗型非酒精性脂肪肝组(NOR组)。8周内动态观察大鼠的一般情况、体质量变化,8周末每组随机取8只处死,比较血清谷丙转氨酶(ALT)、谷草转氨酶(AST)、胆固醇(TC)、甘油三脂(TG)水平变化及肝指数、脂体比,观察肝脏形态学改变。剩余20只作为正常对照组,喂食普通饲料。结果:NO与NOR组大鼠体重增长差距逐渐增大,至8w末,NO组体重显著高于NOR组及正常对照组(P0.01),脂肪重量和脂体比均显著升高,NO组脂肪重量显著高于NOR组(P0.05,0.01),但脂体比间未见显著差异;NO与NOR组TG、ALT显著升高(P0.05),其中NO组大鼠血清TG、TC显著高于NOR组(P0.05);两组肝重量和肝指数均显著升高,NO组肝重量显著高于NOR组(P0.05,0.01),但肝指数间未见显著差异,两组肝细胞内均弥散大量脂肪空泡。结论:利用高脂饲料成功建立肥胖与肥胖抵抗型非酒精性脂肪肝SD大鼠模型,与人类发病特征相似,为肥胖与非酒精性脂肪的研究提供更有针对性的动物模型。     

Clinical relevance of lipid panel and aminotransferases in the context of hepatic steatosis and fibrosis as measured by transient elastography (FibroScan®)

BackgroundNonalcoholic fatty liver disease (NAFLD) is one of the most common causes of chronic liver disease and is associated with various co-morbidities. Transient elastography (FibroScan®) is a non-invasive method to detect NAFLD using the controlled attenuation parameter (CAP). We aimed to evaluate the association of the lipid panel and aminotransferases concentrations with the presence or absence of steatosis and fibrosis.MethodsOne hundred and five patients with NAFLD were included. Hepatic steatosis was quantified by CAP (dB/m) and liver stiffness by Kilopascals (kPa), these values were then analyzed against patient lipid panel and serum concentrations of the liver enzymes aspartate aminotransferase (AST) and alanine aminotransferase (ALT). A correlation and multiple regression were used. Mann-Whitney U test was used as non-parametric analysis.ResultsWe observed an association between hepatic steatosis and total cholesterol (B = 0.021, p = 0.038, Exp (B) = 1.021, I.C = 1.001-1.041) as well as serum triglycerides (B = 0.017, p = 0.006, Exp (B) = 1.018 and I.C = 1.005-1.030). Similarly, we found an association between significant hepatic fibrosis and lower concentrations of total cholesterol (B = -0.019, p = 0.005, Exp (B) = 0.982 I.C = 0.969-0.995) and elevated AST (B = 0.042, p = 3.25 × 10^-4, Exp (B) = 1.043 I.C = 1.019-1.068) independent of age, gender and BMI.ConclusionsOur results suggest that, total cholesterol and triglyceride concentrations positively correlate with hepatic steatosis while significant hepatic fibrosis is associated with lower total cholesterol and higher AST concentrations.     

Malonylation of Acetyl-CoA carboxylase 1 promotes hepatic steatosis and is attenuated by ketogenic diet in NAFLD

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Genetic determinants of hepatic steatosis in man

Hepatic steatosis is one of the most common liver disorders in the general population. The main cause of hepatic steatosis is nonalcoholic fatty liver disease (NAFLD), representing the hepatic component of the metabolic syndrome, which is characterized by type 2 diabetes, obesity, and dyslipidemia. Insulin resistance and excess adiposity are considered to play key roles in the pathogenesis of NAFLD. Although the risk factors for NAFLD are well established, the genetic basis of hepatic steatosis is largely unknown. Here we review recent progress on genomic variants and their association with hepatic steatosis and discuss the potential impact of these genetic studies on clinical practice. Identifying the genetic determinants of hepatic steatosis will lead to a better understanding of the pathogenesis and progression of NAFLD.     

Dantrolene prevents hepatic steatosis by reducing cytoplasmic Ca2+ level and ER stress

IntroductionOur previous studies demonstrated that dantrolene, a ryanodine receptor stabilizer, prevents endoplasmic reticulum (ER) stress in the heart. ER stress is a strong mediator of impaired lipid metabolism in the liver, thereby contributing to fatty liver disease. In this study, we investigated the effects of dantrolene on fatty liver disease in mice and ER stress in hepatocytes.Methods and resultsEight weeks old C57BL/6 mice were fed high-fat diet (HFD) for 8 weeks with or without the oral administration of dantrolene (100 mg/kg/day). The livers of mice without dantrolene (HFD group) showed severe fatty liver, whereas the livers of the mice treated with dantrolene (HFD + DAN group) only showed slightly fatty liver. To address the preventive effects of dantrolene, primary hepatocytes were cultured with palmitate in the presence or absence of dantrolene. Dantrolene reduced lipid load and prevents palmitate-induced increase in cytoplasmic Ca²⁺ and ER stress. Based on these findings, we propose that dantrolene is a potential new therapeutic agent against fatty liver disease.     

Amelioration of hepatic steatosis by dietary essential amino acid-induced ubiquitination

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Evidence for regulated monoacylglycerol acyltransferase expression and activity in human liver

Intrahepatic lipid accumulation is extremely common in obese subjects and is associated with the development of insulin resistance and diabetes. Hepatic diacylglycerol and triacylglycerol synthesis predominantly occurs through acylation of glycerol-3-phosphate. However, an alternative pathway for synthesizing diacylglycerol from monoacylglycerol acyltransferases (MGAT) could also contribute to hepatic glyceride pools. MGAT activity and the expression of the three genes encoding MGAT enzymes (MOGAT1, MOGAT2, and MOGAT3) were determined in liver biopsies from obese human subjects before and after gastric bypass surgery. MOGAT expression was also assessed in liver of subjects with nonalcoholic fatty liver disease (NAFLD) or control livers. All MOGAT genes were expressed in liver, and hepatic MGAT activity was readily detectable in liver lysates. The hepatic expression of MOGAT3 was highly correlated with MGAT activity, whereas MOGAT1 and MOGAT2 expression was not, and knockdown of MOGAT3 expression attenuated MGAT activity in a liver-derived cell line. Marked weight loss following gastric bypass surgery was associated with a significant reduction in MOGAT2 and MOGAT3 expression, which were also overexpressed in NAFLD subjects. These data suggest that the MGAT pathway is active and dynamically regulated in human liver and could be an important target for pharmacologic intervention for the treatment of obesity-related insulin resistance and NAFLD.     

CD36-deficient mice are resistant to alcohol- and high-carbohydrate-induced hepatic steatosis

CD36 is a scavenger receptor with multiple ligands and cellular functions, including facilitating cellular uptake of free fatty acids (FFAs). Chronic alcohol consumption increases hepatic CD36 expression, leading to the hypothesis that this promotes uptake of circulating FFAs, which then serve as a substrate for triglyceride (TG) synthesis and the development of alcoholic steatosis. We investigated this hypothesis in alcohol-fed wild-type and Cd36-deficient (Cd36^−/−) mice using low-fat/high-carbohydrate Lieber-DeCarli liquid diets, positing that Cd36^−/− mice would be resistant to alcoholic steatosis. Our data show that the livers of Cd36^−/− mice are resistant to the lipogenic effect of consuming high-carbohydrate liquid diets. These mice also do not further develop alcoholic steatosis when chronically fed alcohol. Surprisingly, we did not detect an effect of alcohol or CD36 deficiency on hepatic FFA uptake; however, the lower baseline levels of hepatic TG in Cd36^−/− mice fed a liquid diet were associated with decreased expression of genes in the de novo lipogenesis pathway and a lower rate of hepatic de novo lipogenesis. In conclusion, Cd36^−/− mice are resistant to hepatic steatosis when fed a high-carbohydrate liquid diet, and they are also resistant to alcoholic steatosis. These studies highlight an important role for CD36 in hepatic lipid homeostasis that is not associated with hepatic fatty acid uptake.     

Trout hepatocyte culture: Isolation and primary culture

Summary Rainbow trout (Salmo gairdneri) hepatocytes were isolated using a two-step perfusion through the portal vein. A typical perfusion yielded 2.92×10⁶ liver cells with a mean viability of 96.3%. Hepatocytes comprised 93.4% of the total cell isolate. Survival of hepatocytes in suspension culture was dependent on fetal bovine serum concentration and temperature of incubation. Serum concentrations of 5, 10, and 20% produced the highest survival during primary culture. Hepatocyte survival was in inverse proportion to the incubation temperature. Trout hepatocyte DNA synthesis and mitosis decreased during the culture period. Cytochromep ₄₅₀ activity decreased rapidly during the first 2 d of culture and then remained low but measurable during the remaining 8 d of culture. Culture temperature also influenced thep ₄₅₀ activity with lower temperatures producing greater activity. Morphologic changes occurred in the cells during culture. Isolated hepatocytes self-aggregated, forming strands and clumps that increased in size with time in culture. Junctional complexes between cells were evident within the aggregates. Nuclear atypia, increases in size and number of autophagic vacuoles, and the appearance of bundles of intermediate filaments also were observed with increased time in culture. This work was supported in part by an American Cancer Society Grant (Ohio Division, Inc.) and an NIH Biomedical Research Support Grant 5507RR05700010.     

Ethanol-induced hepatic steatosis is modulated by glycogen level in the liver

Alcoholic liver disease (ALD) is a major health problem worldwide and hepatic steatosis is an early response to alcohol consumption. Fat and glycogen are two major forms of energy storage in the liver; however, whether glycogen metabolism in the liver impacts alcohol-induced steatosis has been elusive. In this study, we used a mouse model with overexpression of PPP1R3G in the liver to dissect the potential role of glycogen on alcohol-induced fatty liver formation. PPP1R3G is a regulatory subunit of protein phosphatase 1 and stimulates glycogenesis in the liver. Chronic and binge ethanol (EtOH) feeding reduced glycogen level in the mouse liver and such inhibitory effect of EtOH was reversed by PPP1R3G overexpression. In addition, PPP1R3G overexpression abrogated EtOH-induced elevation of serum levels of alanine aminotransferase and aspartate aminotransferase, increase in liver triglyceride concentration, and lipid deposition in the liver. EtOH-stimulated sterol regulatory element-binding protein (SREBP)-1c, a master regulator of lipogenesis, was also reduced by PPP1R3G overexpression in vivo. In AML-12 mouse hepatocytes, PPP1R3G overexpression could relieve EtOH-induced lipid accumulation and SREBP-1c stimulation. In conclusion, our data indicate that glycogen metabolism is closely linked to EtOH-induced liver injury and fatty liver formation.