Immunotherapy for nonalcoholic steatohepatitis using the multiple cytokine production modulator Y-40138

AIM: To investigate the possible use of the multiple cytokine production modulator, Y-40138, as a novel immunotherapy in the rat nonalcoholic steatohepatitis(NASH) model.METHODS: We allocated 6-wk-old male F344 rats to choline-supplemented, L-amino acid-defined (CSAA) diet (control group), CSAA diet + Y-40138 (control +Y-40138 group), choline-deficient, L-amino acid-defined (CDAA) diet (NASH group), or CDAA diet + Y-40138 (NASH + Y-40138 group). In each group, we measured the plasma alanine aminotransferase (ALT) levels, and the plasma and liver levels of tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and interleukin-10 (IL-10). Tissue specimens of phosphate buffered saline-perfused liver were subjected to hematoxylin and eosin staining, Azan staining, Sirius red staining, and immunohistochemical staining (for Kupffer cells and TNF-α). We then extracted Kupffer cells from the collagenase-perfused livers using the Percoll gradient centrifugation method, and measured the TNF-α levels in the supernatant ( in vitro TNF-α production by Kupffer cells) using an enzyme-linked immunosorbent assay kit. RESULTS: In comparison to the NASH group, serum ALT elevation was mild, production of serum and liver TNF-α and IFN-γ was inhibited, and IL-10 production was increased in the NASH + Y-40138 group. Amelioration of liver histology was also noted in the NASH + Y-40138 group. Kupffer cell immunohistochemical staining revealed no differences between groups, whereas TNF-α immunohistochemical staining showed fewer stained cells in the NASH + Y-40138 group than in the NASH group. The TNF-α levels in the in-vitro Kupffer cell culture supernatant were lower in the NASH + Y-40138 group than in the NASH group.CONCLUSION: Administration of Y-40138 to NASH model rats reduced hepatic inflammation and suppressed fibrosis. These results indicate that the multiple cytokine production modulator, Y-40138, is promising as a novel treatment for NASH.     

Melatonin ameliorates nonalcoholic fatty liver induced by high-fat diet in rats

Nonalcoholic fatty liver disease (NAFLD) is an increasingly recognized condition that may progress to end-stage liver disease, which ranges from simple steatosis to steatohepatitis, advanced fibrosis, and cirrhosis. Oxidative stress and lipid peroxidation are key pathophysiological mechanisms in NAFLD. We investigate the preventive effects of intraperitoneal administration of melatonin (2.5, 5, 10 mg/kg, daily, respectively) in NAFLD rats induced by high-fat diets for 12 wk. Liver damage was evaluated by serological analysis, serum and hepatic lipid assay as well as hematoxylin-eosin staining in liver sections. Oxidative stress and lipid peroxidation were assessed by measuring malondialdehyde (MDA) levels and superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in liver. The results showed that high-fat diet induced oxidative stress with extensive liver steatosis in rats. Melatonin (5 or 10 mg/kg) was effective in reducing hepatic steatosis and inflammation with lowering serum alanine aminotransferase, aspartate aminotransferase, and levels liver total cholesterol and triglycerides in high-fat diet rats. Moreover, melatonin (2.5, 5, 10 mg/kg) increased SOD and GSH-Px activities and the 10 mg/kg dose of melatonin reduced MDA levels in liver. This study shows that melatonin exerts protective effects against fatty liver in rats induced by high-fat diet possibly through its antioxidant actions.     

Ghrelin对高脂喂养大鼠肝脏氧化应激及Akt/GSK3β信号通路的影响

目的探讨Ghrelin对高脂喂养的大鼠肝脏氧化应激水平及Akt/GSK3β信号通路的影响。方法成年雄性Wistar大鼠随机分为正常对照组(NC组)、高脂饮食组(HFD组)和Ghrelin组,每组10只小鼠。NC组给予正常饲料喂养,HFD组及Ghrelin组给予高脂饮食,喂养6周后,进行药物干预4周:Ghrelin组给予Ghrelin(60μg/kg)每日两次腹腔注射,相应NC组及HFD组给予0.9%氯化钠溶液进行对照;结束后处死大鼠,检测血清丙氨酸氨基转移酶(ALT)、三酰甘油(TG)及总胆固醇(TC);测定肝组织匀浆超氧化物歧化酶(SOD)及丙二醛(MDA);实时PCR检测肝脏组织Akt、GSK3βmRNA表达的改变。结果 Ghrelin组大鼠肝脏湿重、血TC及TG均低于HFD组(P0.05);Ghrelin组与HFD组比较,SOD明显增高(P0.05),MDA有所降低(P0.05);Ghrelin组与HFD组相比,肝脏组织Akt基因mRNA表达升高1.03倍(P0.05),GSK3β基因mRNA表达升高3.23倍,(P0.05)。结论 Ghrelin能改善高脂喂养大鼠血脂水平,减轻氧化应激损伤,其作用机制可能与Akt/GSK3β信号通路相关。     

Influence of chronic stress on the compositions of hepatic cholesterol and triglyceride in male Wistar rats fed a high fat diet

Aim: We determined the influence of chronic stress (CS) on the compositions of hepatic cholesterol and triglyceride (TG) in rats fed a high fat diet (HFD). Methods: Male Wistar rats were fed either a standard diet or a HFD and half of the HFD fed rats were given CS (electric foot shock assisted with noise) for 8 weeks. Results: Compared with the control group, the levels of hepatic total cholesterol (TC) and TG were significantly elevated in the HFD and HFD with chronic stress (HFD+CS) groups, and the more severe elevations of them were found in the HFD group. Inversely, the more severe elevations of hepatic water‐soluble parts of TC and TG were found in the HFD+CS group, as the elevations of low‐density lipoprotein cholesterol, very low‐density lipoprotein cholesterol in liver and serum, tumor necrosis factor‐α, interleukin‐1β and malondialdehyde in liver. Meanwhile, downregulated mRNA expressions of hepatic liver X receptor‐α (LXR‐α) and peroxisome proliferator‐activated receptor‐γ (PPAR‐γ) were also more severe in the HFD+CS group. Conclusion: CS can aggravate the high levels of water‐soluble compositions of hepatic TC and TG induced by HFD as it aggravates hepatic inflammation and oxidative stress; in spite of that, however, it cannot further promote hepatic lipidosis. This is consistent with the downregulated mRNA expressions of LXR‐α and PPAR‐γ.     

Altered distribution of regulatory lymphocytes by oral administration of soy-extracts exerts a hepatoprotective effect alleviating immune mediated liver injury,non-alcoholic steatohepatitis and insulin resistance

AIM: To determine the immune-modulatory and the hepatoprotective effects of oral administration of two soy extracts in immune mediated liver injury and non-alcoholic steatohepatitis (NASH).METHODS: Two soy extracts, M1 and OS, were orally administered to mice with concanavalin A (ConA) immune-mediated hepatitis, to high-fat diet (HFD) mice and to methionine and choline reduced diet combined with HFD mice. Animals were followed for disease and immune biomarkers.RESULTS: Oral administration of OS and M1 had an additive effect in alleviating ConA hepatitis manifested by a decrease in alanine aminotransferase and aspartate aminotransferase serum levels. Oral administration of the OS and M1 soy derived fractions, ameliorated liver injury in the high fat diet model of NASH, manifested by a decrease in hepatic triglyceride levels, improvement in liver histology, decreased serum cholesterol and triglycerides and improved insulin resistance. In the methionine and choline reduced diet combined with the high fat diet model, we noted a decrease in hepatic triglycerides and improvement in blood glucose levels and liver histology. The effects were associated with reduced serum tumor necrosis factor alpha and alteration of regulatory T cell distribution.CONCLUSION: Oral administration of the combination of OS and M1 soy derived extracts exerted an adjuvant effect in the gut-immune system, altering the distribution of regulatory T cells, and alleviating immune mediated liver injury, hyperlipidemia and insulin resistance.     

Melatonin improves metabolic syndrome induced by high fructose intake in rats

Abstract: In this study, we examined whether melatonin improves metabolic syndrome induced by high fructose intake in male Wistar rats. Feeding of a diet containing 60% fructose (HFD) for 4 or 6 wk caused increased serum insulin, triglyceride, total cholesterol, free fatty acids, uric acid, leptin, and lipid peroxide concentrations as well as hepatic triglyceride and cholesterol concentrations, and relative intra‐abdominal fat and liver weights. The 4‐ or 6‐wk HFD feeding reduced serum high‐density lipoprotein cholesterol and adiponectin concentrations. The 6‐wk HFD feeding increased serum tumor necrosis factor‐α concentration and hepatic lipid peroxide concentration and lowered hepatic reduced glutathione concentration. Daily intraperitoneal administration of melatonin (1 or 10 mg/kg body weight), starting at 4‐wk HFD feeding, attenuated these changes at 6‐wk HFD feeding more effectively at its higher dose than at its lower dose. In an oral glucose tolerance test, rats with 4‐ or 6‐wk HFD feeding showed higher serum insulin response curve and normal serum glucose response curve when compared with the corresponding animals that received the control diet. The 4‐ or 6‐wk HFD feeding caused insulin resistance, judging from the scores of HOMR‐IR and QUICKI, which are indices of insulin resistance. The daily administered melatonin (1 or 10 mg/kg body weight) ameliorated the higher serum insulin response curve in the oral glucose tolerance test and insulin resistance at 6‐wk HFD feeding more effectively at its higher dose than at its lower dose. These results indicate that melatonin improves metabolic syndrome induced by high fructose intake in rats.     

胡桃苷对非酒精性脂肪性肝小鼠中肝脂质代谢紊乱、肝损伤以及小肠完整性的改善作用

背景现有研究对胡桃苷在非酒精性脂肪性肝病(nonalcoholicfattyliverdisease,NAFLD)中的治疗作用尚未得到充分关注.目的本研究通过高脂饮食(high fatty diet, HFD)小鼠模型评估了胡桃苷在NAFLD中的治疗效果.方法C57B L/6小鼠分为标准饮食组、H F D组、胡桃苷低、中和高剂量治疗组.给药方案结束后,采集小鼠血样和组织(肝和小肠)进行生化及组织学测定.结果胡桃苷抑制了HFD诱导的肝组织形态学改变和肝脂质沉积,并降低了血清中谷草转氨酶、谷丙转氨酶和胆固醇含量以及葡萄糖、血清胰岛素水平和胰岛素抵抗稳态模型值.胡桃苷显著改善了HFD引起的代谢损伤,增加了肝脏过氧化物酶体增殖体激活受体及其下游调节基因成纤维细胞生长因子21的m RNA水平,并且提高了乙酰辅酶A羧化酶的磷酸化水平和肉碱-棕榈酰基转移酶的m RNA水平.此外,胡桃苷还减少了肝脏炎症,恢复了肠道屏障的完整性和功能(FITC-dextran通透性下降和小肠组织紧密连接蛋白1表达增加).结论胡桃苷可恢复NAFLD引起的脂肪变性、减少肝脏炎症、恢复葡萄糖稳态和改善肠道完整性.     

Characterization of High-Fat,Diet-Induced,Non-alcoholic Steatohepatitis with Fibrosis in Rats

An ideal animal model is necessary for a clear understanding of the etiology, pathogenesis, and mechanisms of human non-alcoholic steatohepatitis (NASH) and for facilitating the design of effective therapy for this condition. We aimed to establish a rat model of NASH with fibrosis by using a high-fat diet (HFD). Male Sprague–Dawley (SD) rats were fed a HFD consisting of 88 g normal diet, 10 g lard oil, and 2 g cholesterol. Control rats were fed normal diet. Rats were killed at 4, 8, 12, 16, 24, 36, and 48 weeks after HFD exposure. Body weight, liver weight, and epididymal fat weight were measured. Serum levels of fasting glucose, triglyceride, cholesterol, alanine aminotransferase (ALT), free fatty acids (FFA), insulin, and tumor necrosis factor-alpha (TNF-α) were determined. Hepatic histology was examined by H&E stain. Hepatic fibrosis was assessed by VG stain and immunohistochemical staining for transforming growth factor beta 1 (TGF-β1), and alpha-smooth-muscle actin (α-SMA). The liver weight and liver index increased from week 4, when hepatic steatosis was also observed. By week 8, the body weight and epididymal fat weight started increasing, which was associated with increased serum levels of FFA, cholesterol, and TNF-α, as well as development of simple fatty liver. The serum ALT level increased from week 12. Steatohepatitis occurred from weeks 12 through 48. Apparent hepatic perisinosodial fibrosis did not occur until week 24, and progressed from week 36 to 48 with insulin resistance. Therefore, this novel model may be potentially useful in NASH study.     

Potentiation of carbon tetrachloride-induced liver damage by dibutylyl-3',5'-cyclic AMP in unstarved rats

It has been reported that carbon tetrachloride-induced liver damage is potentiated by starvation partly due to fat accumulation in the liver and a decrease in hepatic reduced glutathione concentration and that dibutylyl-3′,5′-cyclic AMP (DBcAMP) affects fuel metabolism and decreases hepatic reduced glutathione. We investigated the effects of DBcAMP on carbon tetrachloride-induced liver damage both in unstarved and starved rats. In unstarved rats, intraperitoneal administration of DBcAMP potentiated an increase in serum alanine aminotransferase activity and fatty vacuolization in the liver, both of which were induced by carbon tetrachloride. Hepatic reduced glutathione concentration was also reduced by DBcAMP, although the change was not significant. In contrast, the administration of DBcAMP in starved rats did not affect carbon tetrachloride-induced changes in serum alanine aminotransferase activity, histological alterations and hepatic reduced glutathione concentration. Administration of DBcAMP to control rats induced different responses in unstarved control rats compared with starved control rats: in unstarved rats, blood glucose concentration decreased but serum free fatty acid concentration increased, whereas in starved rats, blood glucose concentration increased and serum free fatty acid concentration decreased. It was suggested that DBcAMP potentiated carbon tetrachloride-induced liver damage in unstarved rats, probably due to hepatic fat accumulation and a decreased hepatic reduced glutathione concentration. The former could increase the affinity of the liver for carbon tetrachloride and the latter could accelerate carbon tetrachloride-induced lipid peroxidation. It was also suggested that DBcAMP failed to affect carbon tetrachloride-induced liver damage in starved rats, probably because starvation had already decreased hepatic glutathione concentration and DBcAMP had different effects on fuel metabolism compared with effects observed in unstarved rats.     

Preventive effect of cyclosporin A on experimentally induced acute liver injury in rats

Abstract: We examined the effect of cyclosporin A (CsA) on the pathogenesis of acute experimental liver injury in rats induced by injection of heat-killed Propionibacterium acnes (P. acnes) and subsequent injection of lipopolysaccharide (LPS). Pretreatment with CsA significantly reduced serum alanine aminotransferase (ALT), serum tumor necrosis factor-α (TNF-α) production, without changing the TNF-α mRNA level in the liver, and plasma interferon-γ (IFN-γ), following LPS injection in this model. Twenty-four-hour mortality was also markedly improved, from 100% in the P. acnes plus LPS group to 0% in the CsA-pretreated group. Although direct addition of CsA to isolated hepatic macrophages from P. acnes-pretreated rats did not prevent the production of TNF-α and active oxygen species, isolated hepatic macrophages from P. acnes plus CsA-pretreated rats significantly reduced their production in response to the addition of LPS. These results suggest that CsA protects against P. acnes plus LPS-induced acute liver injury, not by direct inhibition of hepatic macrophage activation, but by indirect prevention of hepatic macrophage activation, presumably related to the reduction in plasma IFN-γ levels.     

脂联素及其受体在脂肪肝病理机制中的意义及中药干预作用

目的 研究脂联素(ADP)及其脂联素受体 2 (AdipoR2)在脂肪肝病理变化中的意义及中药的干预作用. 方法采用单纯高脂饮食(高脂模型组)和四氯化碳皮下注射复合高脂低蛋白饮食诱导(复合模型组)的两组大鼠脂肪肝模型,各随机分为正常组、模型组和中药干预组.高脂模型组大鼠造模10周,其中药组在第7周起予以中药(祛湿化瘀方)灌胃干预4周;复合模型组大鼠造模4周,其中药组在第3周起予中药干预2周.观察项目:(1)肝组织HE染色,观察各组大鼠肝脂肪变性程度变化;(2)肝组织甘油三酯(TG)、游离脂肪酸(FFA)、AdipoR2含量及血清ADP含量;(3)肝组织TG、FFA、AdipoR2、血清ADP含量间的相关性分析.数据均使用SPSS12.0软件包进行统计学分析.组间比较采用单因素方差分析S-N-K检验(q检验).等级资料用Ridit分析.相关分析采用Bivariate相关分析.结果 (1)在两个模型大鼠实验中,模型组肝组织均出现严重的脂肪变性,肝组织TG、FFA含量均显著升高,高脂模型组分别达正常组的3.2倍和3.5倍,q值分别为16.00和8.10,p值均<0.01;复合模型组分别达正常组的3.8倍和3.6倍,q值分别为10.10和10.87,P值均<0.01.血清ADP与肝组织AdipoR2均显著降低,高脂模型组分别为正常组的56.1%和56.0%,q值分别为10.19和9.03,P值均<0.01;复合模型组分别达正常组的55.6%和71.1%,q值分别为5.48和7.16,P值均<0.01;在两个模型中,中药干预组的TG,FFA含量显著低于模型组,ADP、AdipoR2含量显著高于模型组.(2)肝脏TG、FFA含量与血清ADP含量、肝组织AdipoR2含量之间均呈显著负相关.结论 (1)血清ADP和肝AdipoR2水平均显著低下,在脂肪肝病理机制中有重要意义.(2) 中药祛湿化瘀方可显著提高脂肪肝大鼠的ADP、AdipoR2水平,这可能为该方防治脂肪肝作用的重要药理环节.     

大蒜素对高脂饮食致大鼠肝慢性损伤的影响

目的观察大蒜素对高脂饮食致大鼠发生肝脏慢性损伤时,大鼠肝功能及肝组织病理形态学的变化。方法以高脂饮食复制大鼠慢性肝损伤组模型,大蒜素分别按大剂量（1 ml/kg）、小剂量（0.5 ml/kg）灌胃给药。分别于4周、8周、12周末腹主动脉采血测定血浆丙氨酸氨基转移酶（ALT）,取肝组织用于组织病理切片的制备及丙二醛（MDA）及甘油三脂（TG）水平的检测。结果大蒜素可降低血清ALT、肝脏MDA及4周末TG水平;减轻肝细胞脂肪变性或炎症细胞的浸润。结论大蒜素对高脂饮食致大鼠肝慢性损伤有明显保护作用。     

Helianthus tuberosus(Jerusalem artichoke) tubers improve glucose tolerance and hepatic lipid profile in rats fed a high-fat diet

Objective:To analyze the effects of feeding Helianthus tuberosus(HT) tubers on glucose tolerance and lipid profile in rats fed a high-fat diet(HFD). Methods:A normal HFD or HFD including 10 w/w% HT tubers(HFD + HT) was fed to F334/Jcl rats. After 10 weeks,organ weights,glucose tolerance,and lipid profile were analyzed. Results:The body weight,liver weight,and epidermal fat content in the HFD group were higher than those of the normal group,and similar to those of the HFD + HT group. The oral glucose tolerance test at 10 weeks revealed that the blood glucose level 30 minutes after beginning the test in the HFD + HT group was significantly lower than that in the HFD group. Liver triglyceride and total cholesterol levels in the HFD + HT group were significantly lower than those in the HFD group. Fecal triglyceride and total cholesterol levels in the HFD + HT group were higher than those in the HFD group. Histological analyses revealed that fat and glycogen accumulation increased in the HFD group,but decreased in the HFD + HT group. Conclusions:These results indicate that HT tubers have anti-fatty liver effects based on improvements in glucose tolerance and the hepatic lipid profile.     

Effect of Carnitine and herbal mixture extract on obesity induced by high fat diet in rats

Background

Obesity-associated type 2 diabetes is rapidly increasing throughout the world. It is generally recognized that natural products with a long history of safety can modulate obesity.

Aim

To investigate the development of obesity in response to a high fat diet (HFD) and to estimate the effect of L-carnitine and an Egyptian Herbal mixture formulation (HMF) (consisting of T. chebula, Senae, rhubarb, black cumin, aniseed, fennel and licorice) on bodyweight, food intake, lipid profiles, renal, hepatic, cardiac function markers, lipid Peroxidation, and the glucose and insulin levels in blood and liver tissue in rats.

Method

White male albino rats weighing 80-90 gm, 60 days old. 10 rats were fed a normal basal diet (Cr), 30 rats fed a high-fat diet (HFD) for 14 weeks during the entire study. Rats of the HFD group were equally divided into 3 subgroups each one include 10 rats. The first group received HFD with no supplement (HFD), the 2^nd group HFD+L-carnitine and the third group received HFD+HMF. Carnitine and HMF were administered at 10^th week (start time for treatments) for 4 weeks. Body weight, lipid profile & renal function (urea, uric acid creatinine) ALT & AST activities, cardiac markers, (LDH, C.K-NAC and MB) the oxidative stress marker reduced glutathione (GSH), and Malondialdehyde (MDA) catalase activity, in addition to glucose, insulin, and insulin resistance in serum & tissues were analyzed.

Results

Data showed that feeding HFD diet significantly increased final body weight, triglycerides (TG), total cholesterol, & LDL concentration compared with controls, while significantly decreasing HDL; meanwhile treatment with L-carnitine, or HMF significantly normalized the lipid profile. Serum ALT, urea, uric acid, creatinine, LDH, CK-NAC, CK-MB were significantly higher in the high fat group compared with normal controls; and administration of L-carnitine or herbal extract significantly lessened the effect of the HFD. Hyperglycemia, hyperinsulinemia, and high insulin resistance (IR) significantly increased in HFD in comparison with the control group. The treatment with L-carnitine or HMF improved the condition. HFD elevated hepatic MDA and lipid peroxidation associated with reduction in hepatic GSH and catalase activity; whereas administration of L-carnitine or herbal extract significantly ameliorated these hepatic alterations.

Conclusion

HFD induced obesity associated with a disturbed lipid profile, defective antioxidant stability, and high values of IR parameters; this may have implications for the progress of obesity related problems. Treatment with L-carnitine, or HMF extract improved obesity and its associated metabolic problems in different degrees. Also HMF has antioxidant, hypolipidaemic insulin sensitizing effects. Moreover HMF might be a safe combination on the organs whose functions were examined, as a way to surmount the obesity state; and it has a distinct anti-obesity effect.     

Effects of ursodeoxycholic acid and／or low-calorie diet on steatohepatitis in rats with obesity and hyperlipidemia

AIM: To evaluate the effects of ursodeoxycholic acid (UDCA) and/or low-calorie diet (LCD) on a rat model of nonalcoholic steatohepatitis (NASH). METHODS: Fifty-five Sprague-Dawley rats were divided into five groups. The control group (n = 9) was fed with standard rat diet for 12 wk, NASH group (n = 10) was fed with high-fat diet consisted of normal diet, 10% lard oil and 2% cholesterol for 12 wk, UDCA group (n = 10) was fed with high-fat diet supplemented with UDCA at a dose of 25 mg/(kg · d) in drinking water for 12 wk, LCD group (n = 10) was fed with high-fat diet for 10 wk and then LCD for 2 wk, and UDCA+LCD group (n = 15) was fed with high-fat diet for 10 wk, followed by LCD+UDCA for 2 wk. At the end of the experiment, body weight, serum biochemical index, and hepatopathologic changes were examined. RESULTS: Compared with the control group, rats in the NASH group had significantly increased body weight, liver weight, and serum lipid and aminotransferase levels. All rats in the NASH group developed steatohepatitis, as determined by their liver histology. Compared with the NASH group, there were no significant changes in body weight, liver weight, blood biochemical index, the degree of hepatic steatosis, and histological activity index (HAI) score in the UDCA group; however, body and liver weights were significantly decreased, and the degree of steatosis was markedly improved in rats of both the LCD group and the UDCA+LCD group, but significant improvement with regard to serum lipid variables and hepatic inflammatory changes were seen only in rats of the UDCA+LCD group, and not in the LCD group. CONCLUSION: LCD might play a role in the treatment of obesity and hepatic steatosis in rats, but it exerts no significant effect on both serum lipid disorders and hepatic inflammatory changes. UDCA may enhance the therapeutic effects of LCD on steatohepatitis accompanied by obesity and hyperlipidemia. However, UDCA alone is not effective in the prevention of steatohepatitis induced by high-fat diet.     

Effects of a low-fat diet on the hepatic expression of adiponectin and its receptors in rats with NAFLD

Background. Non-alcoholic fatty liver disease (NAFLD) is correlated with obesity, but specific therapeutic interventions are lacking. Adiponectin is an adipokine with anti-inflammatory activity and is considered a hepatic protector. We aimed to investigate effects of a low-fat diet on the hepatic expression of adiponectin and its receptors in rats with NAFLD.Materials and methods. Sixteen male SD rats were fed a high-fat diet for 8 weeks (HFD1 group) or 16 weeks (HFD2 group) to induce NAFLD, and these rats were compared with rats on a normal diet for 8 weeks (NC1 group) or 16 weeks (NC2 group). Another group of 8 rats was fed an HFD for 8 weeks and then switched to a low-fat diet (DIET group) until the 16th week. The expression of hepatic adiponectin and its receptors was detected by western blotting, immunohistochemistry and RT-qPCR.Results. The NAFLD activity score (NAS) in the HFD groups increased from 3.2 ± 0.45 (8th week) to 6.2 ± 0.84 (16th week) (P < 0.001), reflecting the progression in the NAFLD histology. In contrast to the HFD2 group, the low-fat diet ameliorated the steatosis, ballooning degeneration and inflammation. Dietary intervention augmented the expression of adiponectin and its receptors, which was down-regulated in the HFD2 group.Conclusions. The NAFLD rat model was successfully developed by feeding the animals a high-fat diet. Adiponectin may play a role in the pathogenesis of NAFLD, especially in the progression from steatosis to NASH. The low-fat diet alleviated the histological lesions associated with NAFLD by up-regulating the expression of adiponectin and its receptors.     

脂多糖预处理对非酒精性脂肪性肝炎的影响

目的 探讨脂多糖(lipopolysaccharide,LPS)预处理对非酒精性脂肪性肝炎(nonalcoholic steatohepatitis,NASH)的影响.方法 选取24只成年雄性Wistar大鼠,分为正常对照组、NASH组和LPS预处理组.NASH组饲以高糖高脂饲料;LPS预处理组饲料同肝损伤组,隔日皮下注射LPS 0.5 mg/kg;正常对照组饲以普通饲料;所有大鼠自由进食与饮水.于实验第9周末处死大鼠.制备肝组织切片,计数浸润肝组织的淋巴细胞;测定血浆内毒素水平和丙氨酸转氨酶(ALT)活性、肿瘤坏死因子-α(TNF-α)、白细胞介素-10(IL-10)含量.结果 NASH组血浆内毒素水平比正常对照组高;LPS预处理组血浆ALT水平、肝组织淋巴细胞计数与NASH组比较均显著降低;血浆TNF-α水平LPS预处理组与NASH组比较明显降低,而血浆IL-10则相反,差异有统计学意义(P＜0.05).肝组织切片HE染色结果显示,LPS预处理组与NASH组比较,肝细胞内脂肪空泡小、数量少,脂肪变性明显减轻.结论 小剂量LPS预处理与减轻NASH密切相关.其机制可能是LPS预处理影响了细胞因子的释放,导致Th1/Th2细胞因子失衡,Th1向Th2偏离,可能诱导了宿主的免疫耐受,表现为肝组织损伤减轻.

Abstract：

Objective To investigate the changes of Th1/Th2 cytokines and its relationship with lipopolysaccharide (LPS) in pretreatment of relieving nonalcoholic steatohepatitis (NASH).Methods The 24 male Wistar rats were randomly divided into 3 groups: normal control group, liver injury group and LPS pretreatment group. The rats were given normal diet in normal control group,high-sucrose and high-fat diet both in liver injury group and in LPS pretreatment group, and the rats in LPS pretreatment group were given hypodermic injection of LPS 0. 5 mg/kg every other day. The level of plasma endotoxin (ET), activity of alanine aminotransferase (ALT), content of tumor necrosis factor-α (TNF-α) and interleukin-10 (IL-10) were determined. At the end of week 9, the rats were executed, and the liver tissue slices were prepared to investigate hepatic pathologic change by hematoxylin and eosin (HE) staining.Results The level of plasma ET was significantly higher in liver injury group than in normal control group. The level of plasma ALT and infiltrating lymphocytes in liver tissue were significantly lower in LPS pretreatment group than in liver injury group. The level of plasma TNF-α was significantly lower in LPS pretreatment group compared with liver injury group.In contrast, the level of plasma IL-10 was higher (P＜0. 05). Histology with HE staining showed that hepatocyte steatosis was obviously relieved with smaller lipid droplet in LPS pretreatment group than in liver injury group. Conclusions LPS pretreatment can alleviate high-sucrose and high-fat induced NASH. The disequilibrium of Th1/Th2 cytokines may be an important part of mechanism.