S-adenosylmethionine (SAM)-accumulating sake yeast suppresses acute alcohol-induced liver injury in mice

The suppressive effects on acute alcoholic liver injury of S-adenosylmethionine (SAM) and the sake yeast, Saccharomyces cerevisiae Kyokai No. 9, have been shown previously. To enhance the suppression of acute alcoholic liver injury by sake yeast, we prepared SAM-accumulating sake yeast (SAM yeast). Male C57BL/6 mice that had been fed on a diet containing 0.25% SAM yeast or sake yeast for two weeks received three doses of ethanol (5 g/kg BW). In the mice fed on the SAM yeast, the ethanol-induced increases in both triglyceride (TG) and alanine aminotransferase (ALT) were significantly repressed. In addition, the SAM yeast-fed mice did not show an ethanol-induced decrease in hepatic SAM level, suggesting that a disorder of methionine metabolism in the liver caused by ethanol was relieved by the SAM yeast. These results suggest that the SAM yeast had a stronger effect suppressing acute alcoholic liver injury in mice than the sake yeast.     

Sake Yeast Suppresses Acute Alcohol-Induced Liver Injury in Mice

Brewer’s and baker’s yeasts appear to have components that protect from liver injury. Whether sake yeast, Saccharomyces cerevisiae Kyokai no. 9, also has a hepatoprotective effect has not been examined. Here we show that sake yeast suppresses acute alcoholic liver injury in mice. Male C57BL/6 mice that had been fed a diet containing 1% sake yeast for two weeks received three doses of ethanol (5 g/kg BW). In the mice fed sake yeast, ethanol-induced increases in triglyceride (TG) and glutamate pyruvate transaminase (GPT) were significantly attenuated and hepatic steatosis was improved. In addition, sake yeast-fed mice showed a smaller decrease in hepatic S-adenosylmethionine (SAM) level and a smaller increase in plasma homocysteine (Hcy) level after ethanol treatment than the control mice, suggesting that a disorder of methonine metabolism in the liver caused by ethanol was relieved by sake yeast. These results indicate that sake yeast protects against alcoholic liver injury through maintenance of methionine metabolism in the liver.     

Sake yeast suppresses acute alcohol-induced liver injury in mice

Brewer's and baker's yeasts appear to have components that protect from liver injury. Whether sake yeast, Saccharomyces cerevisiae Kyokai no. 9, also has a hepatoprotective effect has not been examined. Here we show that sake yeast suppresses acute alcoholic liver injury in mice. Male C57BL/6 mice that had been fed a diet containing 1% sake yeast for two weeks received three doses of ethanol (5 g/kg BW). In the mice fed sake yeast, ethanol-induced increases in triglyceride (TG) and glutamate pyruvate transaminase (GPT) were significantly attenuated and hepatic steatosis was improved. In addition, sake yeast-fed mice showed a smaller decrease in hepatic S-adenosylmethionine (SAM) level and a smaller increase in plasma homocysteine (Hcy) level after ethanol treatment than the control mice, suggesting that a disorder of methionine metabolism in the liver caused by ethanol was relieved by sake yeast. These results indicate that sake yeast protects against alcoholic liver injury through maintenance of methionine metabolism in the liver.     

Inhibition of ethanol-induced liver disease in the intragastric feeding rat model by chlormethiazole

The purpose of this investigation was to assess the effect of chlormethiazole treatment on liver damage in the experimental rat intragastric ethanol-feeding model of alcoholic liver disease. Chlormethiazole has been used in the treatment of alcoholic withdrawal and has been shown to inhibit cytochrome P4502E1. Since treatment of experimental alcoholic liver disease with CYP2E1 inhibitors had an ameliorating effect on liver injury in the rat, chlormethiazole was used to see if it had a similar effect. Rats fed ethanol for 2 months had significantly less liver injury when chlormethiazole was added to the diet, fed intragastrically. The CYP2E1 apoprotein levels, which were increased by ethanol feeding, were also increased when chlormethiazole was fed with ethanol. Chlormethiazole inhibited the increase in the ethanol-induced CYP2E1 activity in vivo, as measured by chlorzoxazone 6-hydroxylation, but did not affect the level of CYP2E1 apoprotein. Likewise, the reduction in proteasome proteolytic enzyme activity produced by ethanol feeding was blunted in chlormethiazole-fed rats. These results support the conclusion that chlormethiazole treatment partially protects the liver from injury by inhibiting CYP2E1 activity in vivo.     

Glutamine supplementation attenuates ethanol-induced disruption of apical junctional complexes in colonic epithelium and ameliorates gut barrier dysfunction and fatty liver in mice

Previous in vitro studies showed that glutamine (Gln) prevents acetaldehyde-induced disruption of tight junctions and adherens junctions in Caco-2 cell monolayers and human colonic mucosa. In the present study, we evaluated the effect of Gln supplementation on ethanol-induced gut barrier dysfunction and liver injury in mice in vivo. Ethanol feeding caused a significant increase in inulin permeability in distal colon. Elevated permeability was associated with a redistribution of tight junction and adherens junction proteins and depletion of detergent-insoluble fractions of these proteins, suggesting that ethanol disrupts apical junctional complexes in colonic epithelium and increases paracellular permeability. Ethanol-induced increase in colonic mucosal permeability and disruption of junctional complexes were most severe in mice fed Gln-free diet. Gln supplementation attenuated ethanol-induced mucosal permeability and disruption of tight junctions and adherens junctions in a dose-dependent manner, indicating the potential role of Gln in nutritional intervention to alcoholic tissue injury. Gln supplementation dose-dependently elevated reduced-protein thiols in colon without affecting the level of oxidized-protein thiols. Ethanol feeding depleted reduced protein thiols and elevated oxidized protein thiols. Ethanol-induced protein thiol oxidation was most severe in mice fed with Gln-free diet and absent in mice fed with Gln-supplemented diet, suggesting that antioxidant effect is one of the likely mechanisms involved in Gln-mediated amelioration of ethanol-induced gut barrier dysfunction. Ethanol feeding elevated plasma transaminase and liver triglyceride, which was accompanied by histopathologic lesions in the liver; ethanol-induced liver damage was attenuated by Gln supplementation. These results indicate that Gln supplementation ameliorates alcohol-induced gut and liver injury.     

解酒护肝饮解酒及对急慢酒精性肝损伤的保护作用

为了评价解酒护肝饮解酒效果及其对急、慢性酒精性肝损伤保护作用机制,本研究通过建立醉酒模型,确定致醉剂量;通过醉酒睡眠实验比较解酒护肝饮解酒特性;通过测定醉酒小鼠血乙醇含量的变化,研究解酒护肝饮对乙醇代谢的影响;通过建立急慢性酒精性肝损伤模型,测定AST、ALT、SOD活性,GSH、MDA水平,HE染色切片观察肝组织形态学的变化。研究发现小鼠最佳致醉剂量为11 m L/kg;与模型组比较,解酒护肝饮高(HD)、中剂量组(MD)均可延长醉酒时间、缩短醒酒时间(p<0.05),高、中剂量组可降低酒精灌胃后2 h、3 h时间点血乙醇含量(p<0.05);与模型组比较,急慢性酒精肝损伤模型各剂量组均能显著降低血清AST、ALT活性(p<0.05),急性酒精性肝损伤模型中,各剂量组肝组织SOD、GSH水平上升(p<0.05),MDA水平下降(p<0.05),而在慢性酒精性肝损伤模型肝组织中,低剂量组(LD)的SOD、GSH及MDA水平没有统计学差异;病理切片观察可见,急慢性酒精肝损伤模型高、中、低剂量组均能显著改善肝组织因乙醇而导致的肝损伤,并且高、中剂量组效果较好。本研究表明解酒护肝饮可显著延长醉酒时间,缩短醒酒时间,降低血乙醇的含量,对酒精诱导的肝损伤有较好的保护作用。     

Dietary fructose augments ethanol-induced liver pathology

Certain dietary components when combined with alcohol exacerbate alcohol-induced liver injury (ALI). Here, we tested whether fructose, a major ingredient of the western diet, enhances the severity of ALI. We fed mice ethanol for 8 weeks in the following Lieber-DeCarli diets: (a) Regular (contains olive oil); (b) corn oil (contains corn oil); (c) fructose (contains fructose and olive oil) and (d) corn + fructose (contains fructose and corn oil). We compared indices of metabolic function and liver pathology among the different groups. Mice fed fructose-free and fructose-containing ethanol diets exhibited similar levels of blood alcohol, blood glucose and signs of disrupted hepatic insulin signaling. However, only mice given fructose–ethanol diets showed lower insulin levels than their respective controls. Compared with their respective pair-fed controls, all ethanol-fed mice exhibited elevated levels of serum ALT; the inflammatory cytokines TNF-α, MCP-1 and MIP-2; hepatic lipid peroxides and triglycerides. All the latter parameters were significantly higher in mice given fructose-ethanol diets than those fed fructose-free ethanol diets. Mice given fructose-free or fructose-containing ethanol diets each had higher levels of hepatic lipogenic enzymes than controls. However, the level of the lipogenic enzyme fatty acid synthase (FAS) was significantly higher in livers of mice given fructose control and fructose–ethanol diets than in all other groups. Our findings indicate that dietary fructose exacerbates ethanol-induced steatosis, oxidant stress, inflammation and liver injury, irrespective of the dietary fat source, to suggest that inclusion of fructose in or along with alcoholic beverages increases the risk of more severe ALI in heavy drinkers.     

Downregulation of matrix metalloproteinase-9 by melatonin during prevention of alcohol-induced liver injury in mice

Matrix metalloproteinases (MMPs) have been implicated in inflammatory and degradative processes in several diseases. The study aims to explore the mechanism of MMP-9 regulation in alcohol-induced acute liver injury and its protection by melatonin in mice. Alcohol-induced acute liver injury was induced in female Balb/C mice by ethanol administration and protection studies were carried out with a well-known antioxidant molecule, melatonin. Degree of liver injury was monitored by histological and biochemical analysis of liver tissues. Oral administration of ethanol in mouse caused significant increase in alanine amino transferase (ALT) activity in serum. Depletion of glutathione and enhancement of lipid peroxidation as well as protein oxidation was observed in liver tissues following ethanol treatment. However, melatonin exhibited potent hepatoprotective activity by inhibiting ALT activity and oxidative stress. Additionally, MMP-9 expression was increased by ethanol in a dose and time dependent manner in liver tissue and serum. Increased secretion of proMMP-9 was strongly correlated with the expression of proinflammatory cytokines e.g., tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL6. Melatonin showed hepatoprotective role by downregulation of MMP-9 and upregulation of tissue inhibitor of metalloproteases (TIMP-1) expression in liver tissue. Nuclear factor (NF)-κB, plays an important role in inducing inflammatory genes during oxidative stress, thus the role of NF-κB in ethanol-induced liver injury was investigated. Ethanol induced nuclear translocation of NF-κB and increased degradation of inhibitor of NF-κB (IκBα) in liver tissues. Moreover, ethanol-induced NF-κB translocation into nucleus was inhibited significantly by melatonin. This is the first study to elucidate the induction of MMP-9 expression by NF-κB-dependent pathway in ethanol-induced acute liver injury in mice. This study also identifies the novel role of melatonin in hepatoprotection via MMP-9 down regulation.     

Cytochrome P450 2E1 potentiates ethanol induction of hypoxia and HIF-1α in vivo

Ethanol induces hypoxia and elevates HIF-1α in the liver. CYP2E1 plays a role in the mechanisms by which ethanol generates oxidative stress, fatty liver, and liver injury. This study evaluated whether CYP2E1 contributes to ethanol-induced hypoxia and activation of HIF-1α in vivo and whether HIF-1α protects against or promotes CYP2E1-dependent toxicity in vitro. Wild-type (WT), CYP2E1-knock-in (KI), and CYP2E1 knockout (KO) mice were fed ethanol chronically; pair-fed controls received isocaloric dextrose. Ethanol produced liver injury in the KI mice to a much greater extent than in the WT and KO mice. Protein levels of HIF-1α and downstream targets of HIF-1α activation were elevated in the ethanol-fed KI mice compared to the WT and KO mice. Levels of HIF prolyl hydroxylase 2, which promotes HIF-1α degradation, were decreased in the ethanol-fed KI mice in association with the increases in HIF-1α. Hypoxia occurred in the ethanol-fed CYP2E1 KI mice as shown by an increased area of staining using the hypoxia-specific marker pimonidazole. Hypoxia was lower in the ethanol-fed WT mice and lowest in the ethanol-fed KO mice and all the dextrose-fed mice. In situ double staining showed that pimonidazole and CYP2E1 were colocalized to the same area of injury in the hepatic centrilobule. Increased protein levels of HIF-1α were also found after acute ethanol treatment of KI mice. Treatment of HepG2 E47 cells, which express CYP2E1, with ethanol plus arachidonic acid (AA) or ethanol plus buthionine sulfoximine (BSO), which depletes glutathione, caused loss of cell viability to a greater extent than in HepG2 C34 cells, which do not express CYP2E1. These treatments elevated protein levels of HIF-1α to a greater extent in E47 cells than in C34 cells. 2-Methoxyestradiol, an inhibitor of HIF-1α, blunted the toxic effects of ethanol plus AA and ethanol plus BSO in the E47 cells in association with inhibition of HIF-1α. The HIF-1α inhibitor also blocked the elevated oxidative stress produced by ethanol/AA or ethanol/BSO in the E47 cells. These results suggest that CYP2E1 plays a role in ethanol-induced hypoxia, oxidative stress, and activation of HIF-1α and that HIF-1α contributes to CYP2E1-dependent ethanol-induced toxicity. Blocking HIF-1α activation and actions may have therapeutic implications for protection against ethanol/CYP2E1-induced oxidative stress, steatosis, and liver injury.     

Protective effects of sulforaphane and aerobic exercise on acute alcoholic hepatic injury in mice

ObjectiveThe paper intends to study the protective effects of sulforaphane (SF) on acute alcoholic hepatic injury in mice by intragastric administration of SF, aerobic exercise and the approach of SF integrated with aerobic exercise.Methodology60 NIH mice were randomly divided into 6 groups of equal number according to their body weight and were intragastrically administrated with 50% ethanol. The serum and liver indexes of each group of mice were detected, and the liver was stained with oil red O for pathological examination.ResultsCompared with the model group, the serum TG and the ratio of liver to body weight of the model mice that suffered from acute alcoholic hepatic injury could be significantly decreased in the group that practiced aerobic exercise, the group administered with SF, and the group treated with the approach of SF integrated with aerobic exercise (P < 0.05). The contents of TG and MDA in liver could be significantly decreased (P < 0.05) and SOD activity could be significantly increased (P < 0.05) both in the group administered with SF and the group treated with the approach of SF integrated with aerobic exercise. Serum VLDL (P < 0.05) could also be significantly reduced in the group treated with the approach of SF integrated with aerobic exercise.ConclusionBoth SF and aerobic exercise could alleviate alcohol-induced acute alcoholic hepatic injury in mice possibly thanks to the working mechanism related to antioxidant stress that reduced the harm posed by alcohol on hepatic cells. In addition, the protective effect of SF on acute alcoholic hepatic injury in mice was stronger than that of aerobic exercise, while the approach of SF integrated with aerobic exercise had the strongest protective effect on acute alcoholic hepatic injury in mice.     

Occludin deficiency promotes ethanol-induced disruption of colonic epithelial junctions,gut barrier dysfunction and liver damage in mice

BackgroundDisruption of epithelial tight junctions (TJ), gut barrier dysfunction and endotoxemia play crucial role in the pathogenesis of alcoholic tissue injury. Occludin, a transmembrane protein of TJ, is depleted in colon by alcohol. However, it is unknown whether occludin depletion influences alcoholic gut and liver injury.MethodsWild type (WT) and occludin deficient (Ocln^−/−) mice were fed 1–6% ethanol in Lieber–DeCarli diet. Gut permeability was measured by vascular-to-luminal flux of FITC-inulin. Junctional integrity was analyzed by confocal microscopy. Liver injury was assessed by plasma transaminase, histopathology and triglyceride analyses. The effect of occludin depletion on acetaldehyde-induced TJ disruption was confirmed in Caco-2 cell monolayers.ResultsEthanol feeding significantly reduced body weight gain in Ocln^−/− mice. Ethanol increased inulin permeability in colon of both WT and Ocln^−/− mice, but the effect was 4-fold higher in Ocln^−/− mice. The gross morphology of colonic mucosa was unaltered, but ethanol disrupted the actin cytoskeleton, induced redistribution of occludin, ZO-1, E-cadherin and β-catenin from the junctions and elevated TLR4, which was more severe in Ocln^−/− mice. Occludin knockdown significantly enhanced acetaldehyde-induced TJ disruption and barrier dysfunction in Caco-2 cell monolayers. Ethanol significantly increased liver weight and plasma transaminase activity in Ocln^−/− mice, but not in WT mice. Histological analysis indicated more severe lesions and fat deposition in the liver of ethanol-fed Ocln^−/− mice. Ethanol-induced elevation of liver triglyceride was also higher in Ocln^−/− mice.ConclusionThis study indicates that occludin deficiency increases susceptibility to ethanol-induced colonic mucosal barrier dysfunction and liver damage in mice.     

SCD1 deficiency protects mice against ethanol-induced liver injury

Stearoyl-CoA desaturase 1 (SCD1) is a delta-9 fatty acid desaturase that catalyzes the synthesis of mono-unsaturated fatty acids (MUFA). SCD1 is a critical control point regulating hepatic lipid synthesis and β-oxidation. Scd1 KO mice are resistant to the development of diet-induced non-alcoholic fatty liver disease (NAFLD). Using a chronic-binge protocol of ethanol-mediated liver injury, we aimed to determine if these KO mice are also resistant to the development of alcoholic fatty liver disease (AFLD).Mice fed a low-fat diet (especially low in MUFA) containing 5% ethanol for 10 days, followed by a single ethanol (5 g/kg) gavage, developed severe liver injury manifesting as hepatic steatosis. This was associated with an increase in de novo lipogenesis and inflammation. Using this model, we show that Scd1 KO mice are resistant to the development of AFLD. Scd1 KO mice do not show accumulation of hepatic triglycerides, activation of de novo lipogenesis nor elevation of cytokines or other pro-inflammatory markers. Incubating HepG2 cells with a SCD1 inhibitor induced a similar resistance to the effect of ethanol, confirming a role for SCD1 activity in mediating ethanol-induced hepatic injury.Taken together, our study shows that SCD1 is a key player in the development of AFLD and associated deleterious effects, and suggests SCD1 inhibition as a therapeutic option for the treatment of this hepatic disease.     

Changes in methionine adenosyltransferase and S-adenosylmethionine homeostasis in alcoholic rat liver

Liver-specific and non-liver-specific methionine adenosyltransferase (MAT) are products of two genes, MAT1A and MAT2A, respectively, that catalyze the formation of S-adenosylmethionine (SAM). We previously showed that MAT2A expression was associated with more rapid cell growth. Changes in MAT expression have not been examined in animal models of alcoholic liver injury, which is the focus of the current study. After rats were fed intragastrically with ethanol and high fat for 9 wk, the mRNA level of both MAT forms doubled but only the protein level of MAT2A increased. Although liver-specific MAT activity did not change, it was 32% lower after one and 68% lower after eight weekly enteral doses of lipopolysaccharide. Hepatic levels of methionine, SAM, and DNA methylation fell by approximately 40%. c-myc was hypomethylated, and its mRNA level increased. Genome-wide DNA strand break increased. Thus in the prefibrotic stage of alcoholic liver injury, there is already a switch in MAT expression, global DNA hypomethylation, increased c-myc expression, and genome-wide DNA strand break. These changes may be important in predisposing this liver disease to malignant degeneration.     

自噬抑制剂氯喹对急性酒精诱导小鼠肝损伤的影响

目的：探讨自噬抑制剂氯喹（CQ）对急性酒精诱导肝损伤的影响及其作用机制。方法：将雄性C57BL/6小鼠随机分为3组：正常对照组、酒精组、氯喹干预组（n=7）,其中酒精组按4.5 g/kg剂量给予33%（V/V）酒精灌胃。HE和油红O染色检测各组小鼠肝组织脂滴变化;检测肝组织甘油三酯（TG）含量变化;检测血清谷草转氨酶（AST）和谷丙转氨酶（ALT）活性;免疫荧光法检测微管相关蛋白轻链3（LC3）蛋白变化;Western blot法检测LC3蛋白和核蛋白P65表达的变化;ELISA法检测促炎因子TNF-α、IL-6的变化。结果：与对照组比较,酒精组脂滴形成、TG含量、血清AST和ALT活性明显增高。与对照组比较,酒精组LC3-Ⅱ蛋白表达明显增加;与酒精组比较,氯喹干预组使酒精诱导的LC3-Ⅱ蛋白表达增强进一步加剧,使酒精诱导的TG含量、血清AST和ALT活性进一步增高,同时增加了酒精诱导的p65入核及TNFα、IL-6释放。结论：急性酒精能引起小鼠肝脏脂肪变化及炎症,而自噬抑制剂氯喹抑制自噬进程,加剧酒精诱导的肝损伤,说明自噬在酒精诱导肝损伤中可能具有保护效应。     

The CYP inhibitor 1-aminobenzotriazole does not prevent oxidative stress associated with alcohol-induced liver injury in rats and mice

Cytochrome P450 (CYP) 2E1 is induced by ethanol and is postulated to be a source of reactive oxygen species during alcoholic liver disease. However, there was no difference in liver pathology and radical formation between wild-type and CYP2E1 knockout mice fed ethanol. Other CYP isoforms may contribute these effects if CYP2E1 is inhibited or absent. The purpose of this study was, therefore, to determine if blocking most of the P450 isoforms with 1-aminobenzotriazole (ABT; 100 mg/kg i.g.), has any effect on liver damage and oxidative stress due to alcohol in rats and mice. Male C57BL/6 mice and Wistar rats were fed either high-fat control or ethanol-containing enteral diet for 4 weeks. ABT had a significant inhibitory effect on many P450 isoforms independent of concomitant alcohol administration. However, ABT did not protect against liver damage due to alcohol in either species. Indices of oxidative stress and inflammation were also similar in livers from vehicle-treated and ABT-treated animals fed ethanol. In summary, suppression of P450 activity with ABT had no apparent effect on oxidative stress caused by alcohol in both rats and mice. These data support the hypothesis that oxidative stress and liver damage can occur independently of CYP activities in both rats and mice during early alcohol-induced liver injury.     

Characteristics of a rice beer (zutho) and a yeast isolated from the fermented product in Nagaland,India

Rice beer, known locally as zutho was collected in the Kohima district in Nagaland, India, and subjected to analytical and microbiological characterization. Zutho was a whitish porridge-like slurry containing 5.0% (v/v) ethanol. Volatile esters and higher alcohols, such as ethyl acetate and 3-methylbutanol, were detected in this indigenous alcoholic beverage by gas chromatography. The pH and acidity of zutho were 3.6 and 5.1, respectively. Zutho had a fruity aroma and sour taste and its unique aroma had characteristics similar to those of Japanese sake and sprouted rice sake. A fermentation yeast isolated from zutho was identified as being a strain of Saccharomyces cerevisiae and was found to be suitable as the brewing yeast for ethanol fermentation.     

Dietary Zinc Deficiency Exaggerates Ethanol-Induced Liver Injury in Mice: Involvement of Intrahepatic and Extrahepatic Factors

Clinical studies have demonstrated that alcoholics have a lower dietary zinc intake compared to health controls. The present study was undertaken to determine the interaction between dietary zinc deficiency and ethanol consumption in the pathogenesis of alcoholic liver disease. C57BL/6N mice were subjected to 8-week feeding of 4 experimental liquid diets: (1) zinc adequate diet, (2) zinc adequate diet plus ethanol, (3) zinc deficient diet, and (4) zinc deficient diet plus ethanol. Ethanol exposure with adequate dietary zinc resulted in liver damage as indicated by elevated plasma alanine aminotransferase level and increased hepatic lipid accumulation and inflammatory cell infiltration. Dietary zinc deficiency alone increased hepatic lipid contents, but did not induce hepatic inflammation. Dietary zinc deficiency showed synergistic effects on ethanol-induced liver damage. Dietary zinc deficiency exaggerated ethanol effects on hepatic genes related to lipid metabolism and inflammatory response. Dietary zinc deficiency worsened ethanol-induced imbalance between hepatic pro-oxidant and antioxidant enzymes and hepatic expression of cell death receptors. Dietary zinc deficiency exaggerated ethanol-induced reduction of plasma leptin, although it did not affect ethanol-induced reduction of white adipose tissue mass. Dietary zinc deficiency also deteriorated ethanol-induced gut permeability increase and plasma endotoxin elevation. These results demonstrate, for the first time, that dietary zinc deficiency is a risk factor in alcoholic liver disease, and multiple intrahepatic and extrahepatic factors may mediate the detrimental effects of zinc deficiency.     

The effects of Insulin Pre-Administration in Mice Exposed to Ethanol: Alleviating Hepatic Oxidative Injury through Anti-Oxidative,Anti-Apoptotic Activities and Deteriorating Hepatic Steatosis through SRBEP-1c Activation

Alcoholic liver disease (ALD) has become an important liver disease hazard to public and personal health. Oxidative stress is believed to be responsible for the pathological changes in ALD. Previous studies have showed that insulin, a classic regulator of glucose metabolism, has significant anti-oxidative function and plays an important role in maintaining the redox balance. For addressing the effects and mechanisms of insulin pre-administration on ethanol-induced liver oxidative injury, we investigated histopathology, inflammatory factors, apoptosis, mitochondrial dysfunction, oxidative stress, antioxidant defense system, ethanol metabolic enzymes and lipid disorder in liver of ethanol-exposed mice pretreatment with insulin or not. There are several novel findings in our study. First, we found insulin pre-administration alleviated acute ethanol exposure-induced liver injury and inflammation reflected by the decrease of serum AST and ALT activities, the improvement of pathological alteration and the inhibition of TNF-α and IL-6 expressions. Second, insulin pre-administration could significantly reduce apoptosis and ameliorate mitochondrial dysfunction in liver of mice exposed to ethanol, supporting by decreasing caspases-3 activities and the ratio of Bax/Bcl-2, increasing mitochondrial viability and mitochondrial oxygen consumption, inhibition of the decline of ATP levels and mitochondrial ROS accumulation. Third, insulin pre-administration prevented ethanol-mediated oxidative stress and enhance antioxidant defense system, which is evaluated by the decline of MDA levels and the rise of GSH/GSSG, the up-regulations of antioxidant enzymes CAT, SOD, GR through Nrf-2 dependent pathway. Forth, the modification of ethanol metabolism pathway such as the inhibition of CYP2E1, the activation of ALDH might be involved in the anti-oxidative and protective effects exerted by insulin pre-administration against acute ethanol exposure in mice. Finally, insulin pre-administration deteriorated hepatic steatosis in mice exposed to ethanol might be through SRBEP-1c activation. In summary, these results indicated that insulin pre-administration effectively alleviated liver oxidative injury through anti-inflammatory, anti-oxidative and anti-apoptotic activities but also deteriorated hepatic steatosis through SRBEP-1c activation in mice exposed to ethanol. Our study provided novel insight about the effects and mechanisms of insulin on ethanol-induced liver injury.     

Role of lipopolysaccharide-binding protein in early alcohol-induced liver injury in mice

Cellular responses to endotoxins are enhanced markedly by LPS-binding protein (LBP). Furthermore, it has been demonstrated that endotoxins and proinflammatory cytokines such as TNF-alpha participate in early alcohol-induced liver injury. Therefore, in this study, a long-term intragastric ethanol feeding model was used to test the hypothesis that LBP is involved in alcoholic hepatitis by comparing LBP knockout and wild-type mice. Two-month-old female mice were fed a high-fat liquid diet with either ethanol or isocaloric maltose-dextrin as control continuously for 4 wk. There was no difference in mean urine alcohol concentrations between the groups fed ethanol. Dietary alcohol significantly increased liver to body weight ratios and serum alanine aminotransferase levels in wild-type mice (189 +/- 31 U/L) over high-fat controls (24 +/- 7 U/L), effects which were blunted significantly in LBP knockout mice (60 +/- 17 U/L). Although no significant pathological changes were observed in high-fat controls, 4 wk of dietary ethanol caused steatosis, mild inflammation, and focal necrosis in wild-type animals as expected (pathology score, 5.9 +/- 0.5). These pathological changes were reduced significantly in LBP knockout mice fed ethanol (score, 2.6 +/- 0.5). Endotoxin levels in the portal vein were increased significantly after 4 wk in both groups fed ethanol. Moreover, ethanol increased TNF-alpha mRNA expression in wild-type, but not in LBP knockout mice. These data are consistent with the hypothesis that LBP plays an important role in early alcohol-induced liver injury by enhancing LPS-induced signal transduction, most likely in Kupffer cells.     

The effect of trans-ferulic acid and gamma-oryzanol on ethanol-induced liver injury in C57BL mouse

The effects of the oral administration of trans-ferulic acid and gamma-oryzanol (mixture of steryl ferulates) with ethanol (5.0 g per kg) for 30 days to c57BL mice on ethanol-induced liver injury were investigated. Preventions of ethanol-induced liver injury by trans-ferulic acid and gamma-oryzanol were reflected by markedly decreased serum activities of plasma aspartate aminotransferase, alanine aminotransferase and significant decreases in hepatic lipid hydroperoxide and TBARS levels. Furthermore, the trans-ferulic acid- and gamma-oryzanol-treated mice recovered ethanol-induced decrease in hepatic glutathione level together with enhancing superoxide dismutase activity. These results demonstrate that both trans-ferulic acid and gamma-oryzanol exert a protective action on liver injury induced by chronic ethanol ingestion.