Effects of tanshinone IIA on the hepatotoxicity and gene expression involved in alcoholic liver disease

Tanshinone IIA is one of the most abundant constituents of the root of Salvia miltiorrhiza BUNGE which exerts antioxidant and anti-inflammatory actions in many experimental disease models. In the present study, we demonstrated that the standardized fraction of S. miltiorrhiza (Sm-SF) was able to protect RAW 264.7 cells from ethanol-and lipopolysaccharide (LPS)-induced production of superoxide radical, activation of NADPH oxidase and subsequently death of the cells. Among four main components of Sm-SF, tanshinone IIA was the most potent in protecting cells from LPS-and ethanol-induced cytotoxicity. LPS or ethanol induced the expression of CD14, iNOS, and SCD1 and decreased RXR-alpha, which was completely reversed by tanshinone IIA. In H4IIEC3 cells, 10 microM tanshinone IIA effectively blocked ethanol-induced fat accumulation as evidenced by Nile Red binding assay. These results indicate that tanshinone IIA may have potential to inhibit alcoholic liver disease by reducing LPS-and ethanol-induced Kupffer cell sensitization, inhibiting synthesis of reactive oxygen/nitrogen species, inhibiting fatty acid synthesis and stimulating fatty acid oxidation.     

Preventive effects of a purified extract isolated from Salvia miltiorrhiza enriched with tanshinone I,tanshinone IIA and cryptotanshinone on hepatocyte injury in vitro and in vivo

Salvia miltiorrhiza is traditionally used to treat liver disease in Asia. In this study, we tested the ability of a purified extract of S. miltiorrhiza (PF2401-SF) and its constituents, tanshinone I, tanshinone IIA, and cryptotanshinone, to protect against acute and subacute liver damage induced by carbon tetrachloride by measuring serum transaminase levels, the reduced form of glutathione (GSH), antioxidant enzyme activities, and lipid peroxidation levels in the liver. We also evaluated their ability to protect primary cultured rat hepatocytes from tertiary-butylhydroperoxide (tBH) or d-galactosamine (GalN). PF2401-SF was protective at 50–200 mg/kg per day in acute liver injury and 25–100 mg/kg per day in subacute liver injury. Tanshinone I, tanshinone IIA, and cryptotanshinon (40 μM), inhibited lactate dehydrogenase leakage, GSH depletion, lipid peroxidation and free radical generation in vitro. PF2401-SF and its major constituents, tanshinone I, tanshinone IIA and cryptotanshinone, can protect against liver toxicity in vivo and in vitro due to its antioxidant effects.     

Effects of clofibrate on ethanol-induced modifications in liver and adipose tissue metabolism: role of hepatic redox state and hormonal mechanisms.

Mechanisms by which clofibrate decreases the development of acute alcoholic fatty liver were studied, especially in regard to hepatic redox state and hormonal regulation of carbohydrate and lipid metabolism. A partial inhibition of the ethanol-induced increase in cytosolic NADH/NAD ratio was observed. As a result, in clofibrate-treated rats hepatic α-GP concentration during ethanol oxidation also remained at the same level as in normal control rats. Clofibrate treatment prevented the ethanol-induced increase in the adipose tissue cAMP and plasma FFA concentrations. Hepatic concentrations of CoA-SH, acetyl-CoA and long chain acyl-CoA were markedly increased by clofibrate treatment. Plasma insulin concentration was decreased in clofibrate-treated rats, which also showed an impaired glucose tolerance. The results show that clofibrate is able to restrict the availability of substrates (α-GP and fatty acids) for hepatic triglyceride synthesis in vivo. In addition, it was concluded that the partial inhibition of ethanol-induced fatty liver by clofibrate may result from the enhancement of the oxidation pathway of fatty acid metabolism as suggested by the enormous increase in hepatic content of CoA-SH and its derivatives.     

Inhibition of mitochondrial fatty acid oxidation in pentenoic acid-induced fatty liver: A possible model for Reye's syndrome

Rats treated with six to eight doses (80 mg/kg, i.p.) of 4-pentenoic acid, an inhibitor of mitochondrial fatty arid oxidation in vitro, during a 48-hr starvation period developed microvesicular fatty infiltration of the liver similar to that observed in Reye's Syndrome. Hepatic triglycorides were elevated an average of 5-fold, although considerable variability was found between individual rats. Fed rats did not develop fatty liver upon similar treatment with pentenoic acid. Liver mitochondria isolated from rats with pentenoic acid-induced fatty liver showed a persistent inhibition of fatty acid oxidation. Rates of oxidation of pahnitoylcamitine and decanoylcamitine were decreased about 70%, while that of octanoylcamitine was decreased 50%. Camitine-independent oxidation of octanoate was also inhibited. Oxidation rates for substrates other than fatty acids, including glutamate, succinate, pyruvate, and α-ketoglutarate, were unaffected. Measurements of flavoprotein reduction in intact mitochondria indicated that neither palmitoylcamitine nor palmitoyl CoA plus l-carnitine could elicit reduction of acyl-CoA dehydrogenase and electron transferring flavoprotein in mitochondria from rats with pentenoic acid-induced fatty liver. These results support a site of inhibition of mitochondrial β-oxidation at the level of acyl-CoA dehydrogenase for pentenoic add treatment in vivo, and they suggest a role for nutritional or hormonal factors in the metabolic disposition of pentenoic add _vivo and in the development of fatty liver.     

A role for lipid rafts in the protection afforded by docosahexaenoic acid against ethanol toxicity in primary rat hepatocytes

Previously, we demonstrated that eicosapentaenoic acid enhanced ethanol-induced oxidative stress and cell death in primary rat hepatocytes via an increase in membrane fluidity and lipid raft clustering. In this context, another n-3 polyunsaturated fatty acid, docosahexaenoic acid (DHA), was tested with a special emphasis on physical and chemical alteration of lipid rafts. Pretreatment of hepatocytes with DHA reduced significantly ethanol-induced oxidative stress and cell death. DHA protection could be related to an alteration of lipid rafts. Indeed, rafts exhibited a marked increase in membrane fluidity and packing defects leading to the exclusion of a raft protein marker, flotillin. Furthermore, DHA strongly inhibited disulfide bridge formation, even in control cells, thus suggesting a disruption of protein–protein interactions inside lipid rafts. This particular spatial organization of lipid rafts due to DHA subsequently prevented the ethanol-induced lipid raft clustering. Such a prevention was then responsible for the inhibition of phospholipase C-γ translocation into rafts, and consequently of both lysosome accumulation and elevation in cellular low-molecular-weight iron content, a prooxidant factor. In total, the present study suggests that DHA supplementation could represent a new preventive approach for patients with alcoholic liver disease based upon modulation of the membrane structures.     

Protective effect of dieckol isolated from Ecklonia cava against ethanol caused damage in vitro and in zebrafish model

In the present study, the protective effects of phlorotannins isolated from Ecklonia cava against ethanol-induced cell damage and apoptosis were investigated both in vitro and in vivo. Three phlorotannin compounds, namely phloroglucinol, eckol and dieckol, were successively isolated and identified from the extract. Dieckol showed the strongest protective effect against ethanol-induced cell apoptosis in Chang liver cells, with the lowest cytotoxicity. It was observed that dieckol reduced cell apoptosis through activation of Bcl-xL and PARP, and down-regulation of Bax and caspase-3 in Western blot analyses. In the in vivo study, the protective effect of ethanol induced by dieckol was investigated in a zebrafish model. The dieckol treated group scavenged intracellural reactive oxygen species and prevented lipid peroxidation and ethanol induced cell death in the zebrafish embryo. In conclusion, dieckol isolated from E. cava might possess a potential protective effect against ethanol-induced liver diseases.     

LXR-α antagonist meso-dihydroguaiaretic acid attenuates high-fat diet-induced nonalcoholic fatty liver

Collaborative regulation of liver X receptor (LXR) and sterol regulatory element binding protein (SREBP)-1 are main determinants in hepatic steatosis, as shown in both animal models and human patients. Recent studies indicate that selective intervention of overly functional LXRα in the liver shows promise in treatment of fatty liver disease. In the present study, we evaluated the effects of meso-dihydroguaiaretic acid (MDGA) on LXRα activation and its ability to attenuate fatty liver in mice. MDGA inhibited activation of the LXRα ligand-binding domain by competitively binding to the pocket for agonist T0901317 and decreased the luciferase activity in LXRE-tk-Luc-transfected cells. MDGA significantly attenuated hepatic neutral lipid accumulation in T0901317- and high fat diet (HFD)-induced fatty liver. The effect of MDGA was so potent that treatment with 1 mg/kg for 2 weeks completely reversed the lipid accumulation induced by HFD feeding. MDGA reduced the expression of LXRα co-activator protein RIP140 and LXRα target gene products associated with lipogenesis in HFD-fed mice. These results demonstrate that MDGA has the potential to attenuate nonalcoholic steatosis mediated by selective inhibition of LXRα in the liver in mice.     

Mitochondrial fatty acid oxidation alterations in heart failure,ischaemic heart disease and diabetic cardiomyopathy

Heart disease is a leading cause of death worldwide. In many forms of heart disease, including heart failure, ischaemic heart disease and diabetic cardiomyopathies, changes in cardiac mitochondrial energy metabolism contribute to contractile dysfunction and to a decrease in cardiac efficiency. Specific metabolic changes include a relative increase in cardiac fatty acid oxidation rates and an uncoupling of glycolysis from glucose oxidation. In heart failure, overall mitochondrial oxidative metabolism can be impaired while, in ischaemic heart disease, energy production is impaired due to a limitation of oxygen supply. In both of these conditions, residual mitochondrial fatty acid oxidation dominates over mitochondrial glucose oxidation. In diabetes, the ratio of cardiac fatty acid oxidation to glucose oxidation also increases, although primarily due to an increase in fatty acid oxidation and an inhibition of glucose oxidation. Recent evidence suggests that therapeutically regulating cardiac energy metabolism by reducing fatty acid oxidation and/or increasing glucose oxidation can improve cardiac function of the ischaemic heart, the failing heart and in diabetic cardiomyopathies. In this article, we review the cardiac mitochondrial energy metabolic changes that occur in these forms of heart disease, what role alterations in mitochondrial fatty acid oxidation have in contributing to cardiac dysfunction and the potential for targeting fatty acid oxidation to treat these forms of heart disease.

LINKED ARTICLES

This article is part of a themed issue on Mitochondrial Pharmacology: Energy, Injury & Beyond. To view the other articles in this issue visit http://dx.doi.org/10.1111/bph.2014.171.issue-8     

Magnolia officinalis Reverses Alcoholic Fatty Liver by Inhibiting the Maturation of Sterol Regulatory Element–Binding Protein-1c

The generally accepted hypothesis for the pathogenesis of alcoholic liver disease (ALD) is the two-hit model, which proposes that fat accumulation in the liver increases the sensitivity of the liver to a second hit that leads to inflammatory liver cell damage. In this study we evaluated the effects of Magnolia officinalis (MO), which contains honokiol and magnolol as the primary pharmacological components, to eradicate fatty liver in rats fed an ethanol diet. In vitro studies showed that MO was able to protect RAW 264.7 cells from ethanol-induced production of tumor necrosis factor-α, reactive oxygen species, and superoxide anion radicals; the activation of NADPH oxidase; and subsequent cell death. We also investigated the therapeutic effects of MO on alcoholic fatty liver in Lieber-DeCarli ethanol diet–fed rats. MO treatment of the rats for the last 2 weeks of ethanol feeding completely reversed all the serum, hepatic parameters, and fatty liver changes. The increased maturation of sterol regulatory element– binding protein-1c in the liver by ethanol treatment was completely inhibited by treatment with MO. Therefore, MO may be a promising candidate for development as a therapeutic agent for ALD.[Supplementary Figures: available only at http://dx.doi.org/10.1254/jphs.08182FP]     

丹参有效成分及丹参类制剂抗炎药理作用的研究进展

中药在治疗炎症方面具有疗效较好、毒副作用小等优点。综述丹参Salvia miltiorrhiza中的水溶性成分（丹酚酸A、丹参茎叶总酚酸、丹酚酸B、迷迭香酸、丹参素等）、脂溶性成分（丹参酮II_A、丹参酮I、隐丹参酮、甲基丹参酮等）、丹参多糖,丹参类注射液（丹参注射液、注射用丹参多酚酸、丹红注射液等）以及丹参其他类制剂（如丹参凝胶、丹参涂膜剂等）的抗炎药理作用研究进展,以期为丹参抗炎作用研究及丹参的临床应用提供参考。     

Inhibition of p-chlorophenoxyisobutyrate by 1-methyl-2-mercaptoimidazole and related compounds

The induction of both rat liver mitochondrial α-glycerophosphate dehydrogenase (GPD) and the soluble malic enzyme by thyroid hormone is enhanced by p-chlorophenoxyisobutyrate (CPIB). CPIB also affects lipid metabolism by a mechanism which is unrelated to the thyroid hormone.The intensification of the T₄ response by CPIB was blocked by the simultaneous administration of the goitrogen, l-methyl-2-mercaptoimidazole (methimazole, MI), and this particular inhibition of CPIB by MI was shared by a number of other compounds containing the ureido or substituted ureido grouping: 1-methylimidazole, imidazole, thiourea, 2-thiouracil, 2-mercaptobenzimidazole, 2-hydroxybenzimidazole and 2- mercaptopyrimidine. However, the effect of CPIB in (a) preventing an orotic acid fatty liver, or (b) intensifying the β-lipoprotein band in serum gel electrophoresis was not inhibited by imidazole.Rat liver malic enzyme activity was increased somewhat by MI and other ureido compounds per se.     

Effect of baicalin on toll-like receptor 4-mediated ischemia/reperfusion inflammatory responses in alcoholic fatty liver condition

Alcoholic fatty liver is susceptible to secondary stresses such as ischemia/reperfusion (I/R). Baicalin is an active component extracted from Scutellaria baicalensis, which is widely used in herbal preparations for treatment of hepatic diseases and inflammatory disorders. This study evaluated the potential beneficial effect of baicalin on I/R injury in alcoholic fatty liver. Rats were fed an alcohol liquid diet or a control isocaloric diet for 5 weeks, and then subjected to 60 min of hepatic ischemia and 5 h of reperfusion. Baicalin (200 mg/kg) was intraperitoneally administered 24 and 1 h before ischemia. After reperfusion, baicalin attenuated the increases in serum alanine aminotransferase activity, tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) levels in alcoholic fatty liver. The increased levels of TNF-α and IL-6 mRNA expression and inducible nitric oxide synthase and cyclooxygenase-2 protein and mRNA expressions increased after reperfusion, which were higher in ethanol-fed animals, were attenuated by baicalin. In ethanol-fed animals, baicalin attenuated the increases in toll-like receptor 4 (TLR4) and myeloid differentiation factor 88 protein expressions and the nuclear translocation of NF-κB after reperfusion. In conclusion, our findings suggest that baicalin ameliorates I/R-induced hepatocellular damage by suppressing TLR4-mediated inflammatory responses in alcoholic fatty liver.     

Saponins isolated from the root of Platycodon grandiflorum protect against acute ethanol-induced hepatotoxicity in mice

The protective effects of saponins isolated from the root of Platycodon grandiflorum (Changkil saponins: CKS) against alcoholic steatosis in liver injury induced by acute ethanol administration were investigated. Pretreatment with CKS prior to ethanol administration significantly prevented the increases in serum alanine aminotransferase activity, hepatic TNF-α level, hepatic lipid peroxidation and hepatic triglyceride level. CKS prevented ethanol-induced steatosis and necrosis, as indicated by liver histopathological studies. Additionally, CKS protected against ethanol-induced depletion of hepatic glutathione levels. CYP2E1 has been suggested as a major contributor to ethanol-induced oxidative stress and liver injury. The concurrent administration of CKS efficaciously abrogated the CYP2E1 induction and CYP2E1-dependents hydroxylation of aniline as compared to the individual treatment at higher doses. These findings suggest that CKS may prevent ethanol-induced acute liver injury, possibly through its ability to block CYP2El-mediated ethanol bioactivation and its free radical scavenging effects.     

基于活细胞固相色谱法联合高分辨质谱及网络药理学的丹参标准汤剂抗神经病理性疼痛作用成分及机制探讨

目的 采用活细胞固相色谱法联合高分辨质谱技术快速筛选鉴定丹参标准汤剂中潜在的抗神经病理性疼痛活性成分,通过网络药理学技术分析其作用机制。方法 小鼠背根神经元细胞与丹参标准汤剂磷酸盐缓冲液(PBS)溶液共孵育,吸附成分采用超高效液相色谱-四极杆-静电场轨道阱高分辨质谱(UPLC-Q-Orbitrap HRMS)鉴别;鉴定得到的活性成分基于网络药理学分析其作用机制:采用中药系统药理学数据库与分析平台(TCMSP)数据库联合 Swiss 数据库寻找成分作用靶点,以"neuropathic pain"为关键词在 Genecards 数据库及 OMIM 数据库检索去重即得疾病靶点,将成分靶点与神经病理性疼痛靶点交集筛选得到共同靶点;将共同靶点导入 STRING数据库进行检索,得蛋白质相互作用(PPI)网络,并导入Cytoscape 3.7.2 绘图,以度值(degree)为标准选取前 10 靶点作为关键靶点;将共同靶点采用 ClusterProfiler 包进行基因本体(GO)、京都基因与基因组百科全书(KEGG)富集分析。结果 共鉴定得到以酚酸类物质为主的潜在活性成分 11 个,分别为香草酸、丹参素、咖啡酸、原儿茶酸、原儿茶醛、阿魏酸、迷迭香酸、紫草酸、丹酚酸 B、异丹酚酸 B、丹酚酸 E。网络药理学分析结果显示活性成分作用靶点174 个,与神经病理性疼痛靶点集交集 67 个;PPI 分析显示信号转导及转录激活蛋白 3(STAT3)、白蛋白(ALB)、原癌基因 c-Jun(JUN)、淀粉样 β 前体蛋白(APP)、基质金属蛋白酶 9(MMP9)、胱天蛋白酶3(CASP3)、toll 样受体 4(TLR4)、丝裂原活化蛋白激酶 1(MAPK1)、环加氧酶 2(PTGS2)、转录因子 p65(RELA)为关键靶点,"药味成分-靶点"网络拓扑分析显示各活性成分可能存在协同作用;GO 富集分析显示与碳酸氢盐转运、对脂多糖反应、对细菌来源分析反应等生物过程,膜筏、膜微区、膜区、分泌颗粒管腔等细胞组成以及碳酸脱水酶活性、水解酶活性、碳氧裂解酶活性等分子功能相关;KEGG 富集显示与氮代谢、糖尿病并发症中的晚期糖基化产物(AGE)-晚期糖基化终末产物受体(RAGE)信号通路、脂质和动脉粥样硬化、缺氧诱导因子 1(HIF-1)信号通路等通路相关;结合文献分析丹参抗神经病理性疼痛起效机制与炎症和免疫反应、神经元恢复及再生、代谢紊乱、病毒、疼痛递质传导、神经元超敏、疼痛阈等相关。结论 应用活细胞固相色谱与高分辨质谱联用技术筛选出丹参标准汤剂中抗神经病理性疼痛活性成分 11 个,桥接网络药理学分析其作用机制可能与炎症和免疫反应、调节代谢紊乱、抑制超敏等相关。     

Beneficial effects of danshensu, an active component of Salvia miltiorrhiza, on homocysteine metabolism via the trans-sulphuration pathway in rats

Background and purpose:

Elevated plasma total homocysteine (tHcy) level has been established as an independent risk factor for cardiovascular diseases. Danshensu, an active ingredient of Salvia miltiorrhiza, shows wide cardiovascular benefit. However, in terms of its own methylation, danshensu could elevate tHcy level, which would act against its cardiovascular benefit, thus posing a ‘therapeutic paradox’. As this paradox has not been fully assessed, we have evaluated the effects of danshensu on tHcy levels to uncover the underlying mechanisms.

Experiment approach:

We evaluated the influence of danshensu on homocysteine (Hcy) metabolism in rats with normal tHcy levels and in rat models of elevated tHcy (single intravenous methionine loading model and a hyperhomocysteinemic model after 3 weeks methionine dosing, with and without 3 weeks of danshensu treatment). We also quantified some metabolic intermediates (S-adenosyl methionine, S-adenosyl-l-homocysteine, cysteine and glutathione) relevant to Hcy metabolism in rat liver and kidney.

Key results:

Acute treatment with a single dose of danshensu in rats with normal tHcy did not change plasma tHcy. In contrast, danshensu significantly lowered tHcy in rats with elevated tHcy. The relatively higher cysteine and glutathione levels after treatment with danshensu indicated that its tHcy-lowering effect was via increased activity of the trans-sulphuration pathway.

Conclusions and implications:

Our results suggested that danshensu may act both acutely to increase trans-sulphuration and after chronic exposure to up-regulate the activity of the trans-sulphuration enzymes. The tHcy-lowering effect of danshensu is another cardiovascular benefit provided by S. miltiorrhiza and suggests a potential tHcy-lowering therapy.     

Pharmacological inhibition of diacylglycerol acyltransferase 1 reduces body weight gain, hyperlipidemia, and hepatic steatosis in db/db mice

Aim:

To test whether pharmacological inhibition of Diacylglycerol acyltransferase 1 (DGAT1) by a small-molecule inhibitor H128 can improve metabolism disorders in leptin receptor-deficient db/db mice.

Methods:

To investigate the effect of H128 on intestinal fat absorption,db/db mice were acutely given a bolus of corn oil by gavage. The mice were further orally administered H128 (3 and 10 mg/kg) for 5 weeks. Blood glucose, lipids, insulin, ALT, and AST as well as hepatic triglycerides were measured. The insulin tolerance test was performed to evaluate insulin sensitivity. The expression of genes involved in fatty acid oxidation was detected by RT-PCR.

Results:

Oral administration of H128 (10 mg/kg) acutely inhibited intestinal fat absorption following a lipid challenge in db/db mice. Chronic treatment with H128 significantly inhibited body weight gain, decreased food intake, and induced a pronounced reduction of serum triglycerides. In addition, H128 treatment markedly ameliorated hepatic steatosis, characterized by decreased liver weight, lipid droplets, and triglyceride content as well as serum ALT and AST levels. Furthermore, H128 treatment increased the expression of the CPT1 and PPARα genes in liver, suggesting that H128 enhanced fatty acid oxidation in db/db mice. However, neither blood glucose nor insulin tolerance was affected by H128 treatment throughout the 5-week experimental period.

Conclusion:

DGAT1 may be an effective therapeutic target for the treatment of obesity, hyperlipidemia and hepatic steatosis.     

Protective effects of saponins from the root of Platycodon grandiflorum against fatty liver in chronic ethanol feeding via the activation of AMP-dependent protein kinase

Fatty liver and steatosis induced by alcohol is the earliest and most common response of the liver to alcohol and may be a precursor of more severe forms of liver injury. However, the mechanism of liver injury and deposition of fatty liver due to alcohol is complex. The protective effects of saponins from the root of Platycodon grandiflorum (Changkil saponins: CKS) against ethanol-induced liver injury in an enteral alcohol feeding model was investigated. Male Sprague–Dawley rats were given control diets or ethanol-containing diets enterally for 4 weeks. Treatment with CKS for 2 weeks significantly prevented the alcohol-induced increase in serum alanine aminotransferase and aspartate aminotransferase activities or decrease in serum albumin levels. Alcohol elevated the hepatic triglyceride content and induced cytochrome P450 2E1 (CYP2E1) expression. CKS treatment reduced CYP2E1 expression and hepatic triglyceride accumulation and prevented alcoholic liver steatosis. Chronic alcohol feeding decreased AMP-activated protein kinase-alpha (AMPKα) phosphorylation, which was restored by CKS treatment. Recovery of AMPKα phosphorylation by CKS was also followed by an increase in acetyl-CoA carboxylase phosphorylation. Our study suggests that CKS is a promising agent for preventing or treating human alcoholic fatty liver disease.