非酒精性脂肪性肝炎大鼠肠道分泌液sIgA的变化

目的探讨非酒精性脂肪性肝炎形成过程中小肠分泌液sIgA和血浆内毒素水平的变化。方法 32只SD大鼠随机均分为对照组和模型组,对照组用普通饲料喂养,模型组通过高脂饮食建立大鼠非酒精性脂肪性肝炎（non-alcoholic steatohepatitis,NASH）模型,并分别在8、12周末处死每组大鼠各8只,测定大鼠小肠分泌液中sIgA的水平和门静脉血浆中内毒素水平,测定小肠组织匀浆中SOD的活性和MDA的含量,并测定大鼠血清中TG、TC、ALT、AST,HE染色观察肝脏病理改变。结果 8、12周模型组较正常对照组大鼠血清TC、ALT、AST明显升高（P〈0.05）,肝脏病理分别表现为单纯性脂肪肝、脂肪性肝炎。8周末时模型组大鼠门静脉血浆中内毒素、小肠分泌液中sIgA的水平与对照组相比无明显变化（P〉0.05）;12周末大鼠NASH阶段与对照组相比小肠分泌液中sIgA的水平明显降低（P〈0.05）,门静脉血浆中内毒素水平与对照组相比明显升高（P〈0.05）。并且门静脉血浆内毒素水平与小肠分泌液中sIgA水平呈负相关（r=-0.873,P〈0.05）。8、12周末时模型组大鼠小肠组织匀浆中SOD活性明显降低,MDA含量明显升高（P〈0.05）。结论非酒精性脂肪性肝炎形成过程中小肠分泌液中sIgA明显降低,说明肠道免疫屏障受损,并且可能与肠道脂质过氧化增强有关,可能是NASH发生发展的重要发病机制之一。     

Dynamic alterations in the gut microbiota and metabolomeduring the development of methionine-choline-deficient diet-induced nonalcoholic steatohepatitis

AIM To investigate changes in gut microbiota and metabolism during nonalcoholic steatohepatitis(NASH) development in mice fed a methionine-choline-deficient(MCD) diet. METHODS Twenty-four male C57 BL/6 J mice were equally divided into four groups and fed a methionine-choline-sufficient diet for 2 wk(Control 2 w group,n = 6) or 4 wk(Control 4 w group,n = 6) or the MCD diet for 2 wk(MCD 2 w group,n = 6) or 4 wk(MCD 4 w group,n = 6). Liver injury,fibrosis,and intestinal barrier function were evaluated after 2 and 4 wk of feeding. The fecal microbiome and metabolome were studied using 16 s r RNA deep sequencing and gas chromatography-mass spectrometry. RESULTS The mice fed the MCD diet presented with simple hepatic steatosis and slight intestinal barrier deterioration after 2 wk. After 4 wk of feeding with the MCD diet,however,the mice developed prominent NASH with liver fibrosis,and the intestinal barrier was more impaired. Compared with the control diet,the MCD diet induced gradual gut microbiota dysbiosis,as evidenced by a marked decrease in the abundance of Alistipes and the(Eubacterium) coprostanoligenes group(P 0.001 and P 0.05,respectively) and a significant increase in Ruminococcaceae UCG 014 abundance(P 0.05) after 2 wk. At 4 wk,the MCD diet significantly reduced the promising probiotic Bifidobacterium levels and markedly promoted Bacteroides abundance(P 0.05,and P 0.01,respectively). The fecal metabolomic profile was also substantially altered by the MCD diet: At 2 wk,arachidic acid,hexadecane,palmitic acid,and tetracosane were selected as potential biomarkers that were significantly different in the corresponding control group,and at 4 wk,cholic acid,cholesterol,arachidic acid,tetracosane,and stearic acid were selected. CONCLUSION The MCD diet induced persistent alterations in the gut microbiota and metabolome.     

Effect of lactulose on establishment of a rat non-alcoholic steatohepatitis model

AIM: To explore the relationship between changes of intestinal environment and pathogenesis of non-alcoholic steatohepatitis (NASH). METHODS: Forty-two Sprague-Dawley rats were randomly divided into model group (n = 24), treatment group (n = 12), and control group (n = 6). The rats of model and treatment groups were given high-fat diet, and those of the control group were given normal diet. Furthermore, the rats of treatment group were given lactulose after 8 wk of high-fat diet. Twelve rats of the model group were killed at 8 wk of high-fat diet. At the 16 wk the rats of treatment group, control group, and the rest of the model group were killed. The serum levels of aminotransferase were measured and the histology of livers was observed by H&E staining. RESULTS: The livers of rats presented the pathological features of steatohepatitis with higher serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in the model group after 16 wk. Compared to the model group, the serum levels of ALT and AST in treatment group decreased significantly and were close to the normal group, and the hepatic inflammation scores also decreased markedly than those in the model group after 16 wk (5.83±2.02 vs3.63±0.64, P<0.05), but were still higher than those in the model group after 8 wk (3.63±0.64 vs 1.98±0.90, P<0.05). However, the degree of hepatic steatosis had no changes in treatment group compared to the model group after 16 wk. CONCLUSION: Lactulose could ameliorate the hepatic inflammation of rats with steatohepatitis induced by fat-rich diet, but could not completely prevent the development of steatohepatitis. It is suggested that intestinal environmental changes such as intestinal bacteria overgrowth, are one of the important factors in the pathogenesis of NASH.     

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.     

乳果糖降低非酒精性脂肪性肝炎患者肠道通透性及血清内毒素水平

目的探讨乳果糖对非酒精性脂肪性肝炎(non-alcoholic steatohepatitis,NASH)患者肠道通透性的干预作用。方法选择健康正常成人30例作为正常对照组(A组),非酒精性脂肪性肝炎共60例,随机分为NASH对照组(B组)和乳果糖干预组(C组)各30例,其中C组给予乳果糖(10 mL/d)进行干预。检测所有被研究者的血清内毒素、二胺氧化酶(diamine oxidase,DAO)、D-乳酸及ALT的浓度。干预4周后,再次检测B、C两组的血清内毒素、二胺氧化酶(DAO)、D-乳酸及ALT的浓度。结果与A组比较,治疗前B、C两组内毒素、DAO、D-乳酸水平显著增高(P<0.01),B组干预前后比较,内毒素、DAO、D-乳酸及ALT水平无显著改变(P>0.05),而C组干预前后比较,内毒素、DAO、D-乳酸及ALT水平显著降低(P<0.01)。结论 NASH患者血清内毒素水平及肠道通透性增高,乳果糖可降低NASH患者肠道的通透性及血浆内毒素水平。     

N-acetylcysteine attenuates oxidative stress and liver pathology in rats with non-alcoholic steatohepatitis

AIM To evaluate attenuating properties of N-acetylcysteine (NAC) on oxidative stress and liver pathology in rats with non-alcoholic steatohepatitis (NASH).METHODS Male Sprague-Dawley rats were randomly divided into three groups. Group 1 (control, n = 8) was free accessed to regular dry rat chow (RC) for 6 wk.Group 2 (NASH, n = 8) was fed with 100% fat diet for 6 wk. Group 3 (NASH NAC20, n = 9) was fed with 100% fat diet plus 20 mg/kg per day of NAC orally for 6 wk. All rats were sacrificed to collect blood and liver samples at the end of the study.RESULTS The levels of total glutathione (GSH)and hepatic malondialdehyde (MDA) were increased significantly in the NASH group as compared with the control group (GSH; 2066.7 ± 93.2 vs 1337.5 ± 31.5 μmol/L and MDA; 209.9± 43.9 vs 3.8 ±1.7 μmol/g protein, respectively, P ＜ 0.05). Liver histopathology from group 2 showed moderate to severe macrovesicular steatosis, hepatocyte ballooning, and necroinflammation.NAC treatment improved the level of GSH (1394.8 ± 81.2 μmol/L, P ＜ 0.05), it did not affect MDA (150.1 ± 27.0 μmol/g protein), but led to a decrease in fat deposition and necroinflammation.CONCLUSION NAC treatment could attenuate oxidative stress and improve liver histology in rats with NASH.     

Small intestinal bacteria overgrowth decreases small intestinal motility in the NASH rats

AIM： To explore the relationship between small intestinal motility and small intestinal bacteria overgrowth （SIBO） in Nonalcoholic steatohepatitis （NASH）, and to investigate the effect of SIBO on the pathogenesis of NASH in rats. The effect of cidomycin in alleviating severity of NASH is also studied.
METHODS： Forty eight rats were randomly divided into NASH group （n = 16）, cidomycin group （n = 16） and control group （n = 16）. Then each group were subdivided into small intestinal motility group （n = 8）, bacteria group （n = 8） respectively. A semi-solid colored marker was used for monitoring small intestinal transit. The proximal small intestine was harvested under sterile condition and processed for quantitation for aerobes （E. coli and anaerobes （Lactobacilli）. Liver pathologic score was calculated to qualify the severity of hepatitis. Serum ALT, AST levels were detected to evaluate the severity of hepatitis.
RESULTS： Small intestinal transit was inhibited in NASH group （P 〈 0.01）. Rats treated with cidomycin had higher small intestine transit rate than rats in NASH group （P 〈 0.01）. High fat diet resulted in quantitative alterations in the aerobes （E. coli） but not in the anoerobics （Lactobacill）. There was an increase in the number of E. coli in the proximal small intestinal flora in NASH group than in control group （1.70 ± 0.12 log10 （CFU/g） vs 1.28 ± 0.07 log10 （CFU/g）, P 〈 0.01）. TNF-α concentration was significantly higher in NASH group than in control group （1.13 ± 0.15 mmol/L vs 0.57 ± 0.09 mmol/L, P 〈 0.01）. TNF-α concentration was lower in cidomycin group than in NASH group （0.63 ± 0.09 mmol/L vs 1.13 ± 0.15 mmol/L, P 〈 0.01）. Treatment with cidomycin showed its effect by significantly lowering serum ALT, AST and TNF-α levels of NASH rats.
CONCLUSION： SIBO may decrease small intestinal movement in NASH rats. SIBO may be an important pathogenesis of Nash. And treatment with cidomycin by mouth can allevi     

枯草杆菌肠球菌二联活菌胶囊对非酒精性脂肪性肝炎肠道菌群失调的干预作用

目的:探讨枯草杆菌肠球菌二联活菌胶囊对非酒精性脂肪性肝炎(non-alcoholic steatohepatitis,NASH)患者肠道菌群失调的干预作用.方法:选择肠道菌群中具有代表性的细菌共8种(肠杆菌、肠球菌、葡萄球菌、双歧杆菌、乳杆菌、拟杆菌、梭菌、酵母样真菌)进行培养和计数,检测所有被研究者的血清内毒素、TNF-α、IL-6和ALT的浓度.选择健康正常成人30例作为正常对照组(A组),NASH共60例,随机分为常规治疗组(B组)和观察组(C组)各30例,B组采用常规保肝治疗,C组常规保肝治疗的同时联用枯草杆菌肠球菌二联活菌胶囊治疗,治疗4wk,比较各组治疗前后肠道细菌数量的变化和内毒素、TNF-α、IL-6、ALT的变化,并比较B组和C组治疗后临床症状的缓解情况.结果:与A组比较,治疗前NASH组肠杆菌显著增多(7.28±1.22 vs 6.54±1.08,t=4.83,P<0.01),而双歧杆菌、乳酸杆菌、拟杆菌显著减少(7.13±1.28 vs 8.83±1.24,t=-6.65,P<0.01;6.67±1.21 vs 7.31±1.12,t=-2.16,P<0.05;6.99±1.31 vs 7.82±1.15,t=-2.41,P<0.05);血清中内毒素、IL-6、TNF-的浓度显著增高(168.37EU/L±24.13EU/L vs 110.53EU/L±18.33EU/L,t=11.69,P<0.01;42.62ng/L±12.65ng/L vs 21.58ng/L±8.47ng/L,t=7.71,P<0.01;15.98ng/L±3.19ng/L vs 8.63ng/L±2.49ng/L,t=11.97,P<0.01);C组治疗后与治疗前比较双歧杆菌、乳杆菌、拟杆菌的数量显著增多(P<0.01),肠杆菌的数量显著减少(P<0.05),血清中内毒素、TNF-α、IL-6、ALT的浓度显著降低(P<0.01),C组治疗后临床症状较B组有显著改善.结论:NASH患者存在肠道菌群失调、革兰氏阴性杆菌过度生长,提示肠道微生态失衡可能参与了NASH的发生发展.枯草杆菌肠球菌二联活菌胶囊可明显改善NASH肠道菌群失调,降低血清中内毒素、TNF-α、IL-6、ALT的水平,改善临床症状.     

Increased intestinal permeability in pathogenesis and progress of nonalcoholic steatohepatitis in rats

AIM: To investigate whether increased intestinal permeability contributes to the pathogenesis and progress of nonalcoholic steatohepatitis by observing its dynamic change in rat models. METHODS: Rat models of nonalcoholic steatohepatitis were established by giving a fat-rich diet. The rats were sacrificed at wk 8, 12 and 16 during the study. Rats fed with normal diet were taken as control. Plasma D-lactate, plasma diamine oxidase, serum lipids and liver transaminases were measured in blood of the femoral artery. Hepatic steatosis and inflammation were assessed by haematoxylin-eosin staining. RESULTS: A rat model of nonalcoholic steatohepatitis was established successfully. Plasma D-lactate level in model group at wk 8, 12 and 16 and diamine oxidase level in model group at wk 12, 16 increased significantly compared with those in control group. There were notable differences of D-lactate and diamine oxidase level in model group between wk 8 and 12 as well as between wk 12 and 16. Serum lipids, liver transaminases and liver injury also increased with disease development. CONCLUSION: Increased intestinal permeability caused by intestinal bacterial overgrowth and endotoxin-induced intestinal destruction exists in rats with nonalcoholic steatohepatitis, which may partially explain the pathogenesis and progress of this disease.     

口服抗生素对NASH大鼠肝组织TLR4信号通路的影响

目的观察口服抗生素对非酒精性脂肪性肝炎大鼠代谢性内毒素血症激活肝脏4型Toll样受体(TLR4)信号通路的影响。方法将30只SD大鼠随机分为正常对照组、模型组和干预组,后者给予高脂饮食喂养,正常组予普通饲料喂养。干预组大鼠自第9周起给予环丙沙星灌胃。造模12周末,比较各组门静脉血内毒素、谷丙转氨酶、谷草转氨酶、甘油三酯和空腹血糖水平;计算非酒精性脂肪性肝病评分;采用Real time PCR及Westernblot法检测大鼠肝脏TLR4、胰岛素受体底物-1(IRS-1)mRNA及蛋白表达水平;采用ELISA法检测血清和肝匀浆肿瘤坏死因子-α(TNF-α)和白细胞介素-6(IL-6)水平。结果模型组动物门静脉内毒素为0.361±0.018EU/ml,而正常组为0.324±0.013EU/m(l P<0.05);肝脏TLR4 mRNA水平为正常组的7.7倍,IRS-1 mRNA水平下降69%,血清及肝脏TNF-α分别为105.7±30.1pg/ml和608.7±78.8pg/ml,IL-6分别为60.9±12.5pg/ml和756.4±90.8pg/ml,均显著高于正常组(P<0.05);与模型组比,干预组门静脉血内毒素为0.341±0.016EU/m(lP<0.05),NAS积分为4.40±0.26(P<0.05),肝脏TLR4 mRNA和蛋白表达水平分别下降44%和14%,肝脏IRS1 mRNA和蛋白表达水平分别增加2.3倍和1.6倍,TNF-α和IL-6水平分别为531.1±64.6pg/ml和575.1±84.5pg/m(lP<0.05)。结论 NASH大鼠肝脏TLR4信号通路被激活,口服抗生素可减少肠源性内毒素血症,减轻肝脏炎症。     

疏肝祛瘀通络降浊法对大鼠非酒精性脂肪性肝炎作用的研究

[目的]观察疏肝祛瘀通络降浊法对非酒精性脂肪性肝炎（NASH）大鼠肝组织髓样分化蛋白-2（MD-2）和诱导型一氧化氮合酶（iNOS）基因表达的影响,以探讨二者在NASH发病中的作用。[方法]雄性SD大鼠分为模型组,疏肝祛瘀通络降浊法低剂量（低剂量）组、中剂量组、高剂量组,阳性对照组,预防组和正常组,除正常组外,其余各组大鼠以高脂饮食喂养4周后用不同剂量的中药和阳性对照药灌胃治疗,12周后全部处死。同期设正常饮食组作为对照。免疫组织化学方法观察肝组织核转录因子-κB（NF-κB）表达,逆转录聚合酶链反应（RT-PCR）法观察肝组织MD-2和iNOS mRNA的表达。[结果]12周时,中剂量组大鼠肝组织NF-κB表达较模型组下调;肝组织MD-2mRNA（0.132±0.058）和iNOS mRNA（0.164±0.061）表达较模型组（0.795±0.294和1.029±0.388）减弱（均P〈0.01）。[结论]大鼠NASH形成后,肝组织MD-2和iNOS mRNA的表达上调,可能与二者参与了NASH大鼠内毒素性肝损伤有关。疏肝祛瘀通络降浊法可以通过减轻内毒素性肝损伤下调NASH大鼠肝组织MD-2和iNOSmRNA的表达。     

内毒素在非酒精性脂肪性肝炎发生发展中对过氧化物酶体增殖物激活受体α表达的影响

目的 观察内毒素在非酒精性脂肪性肝炎(NASH)形成过程中对肝组织表达过氧化物酶体增殖物激活受体α(PPAR α)的影响。 方法 采用20％玉米油饲料喂饲大鼠14周建立NASH模型的同时,内毒素组于实验结束前4 h腹腔注射内毒素脂多糖(1g／L,3.0 ml／kg)1次。检测动物血浆和肝组织脂质水平以及血浆内毒素、肿瘤坏死因子、丙二醛、游离脂肪酸含量,并做病理切片。以逆转录聚合酶链反应检测大鼠肝组织PPAR α mRNA表达。 结果 腹腔注射内毒素的NASH大鼠的PPAR α表达较对照组大鼠明显下调,导致游离脂肪酸在血浆内升高[(1925.0±130.7)μmol／L],肝内甘油三酯蓄积增多[(542.7±142.8)mmol/g]。游离脂肪酸与内毒素通过肿瘤坏死因子α增高而使丙二醛增多[(4.7±1.4)μmol／ml],使肝细胞发生脂质过氧化,血浆丙氨酸氨基转移酶活性增强[(5 2.3±5.5)U／L],加重肝细胞的破坏与炎症反应。 结论 内毒素血症可下调肝组织PPAR α的表达,从而加剧肝脂变与促进脂肪性肝炎的形成。     

大鼠非酒精性脂肪性肝炎形成过程中血清内毒素含量的变化

目的 探讨内毒素在非酒精性脂肪性肝炎发病中的作用。方法 通过高脂饮食建立大鼠非酒精性脂肪性肝炎(NASH)模型,并在实验第4、8、12、16、24周分批处死,同期设正常饮食组作为对照。腹主动脉采血,测定血清内毒素,肿瘤坏死因子(TNFα)和白细胞介素-1(IL-1)β水平,肝组织切片行溶菌酶、CD14免疫组织化学染色。 结果 成功建立大鼠NASH伴肝纤维化模型,NASH大鼠外周血内毒素水甲仅在24周脂肪性肝炎肝纤维化阶段明显升高为(0.23±O.06)Eu/L,对照组为(0.15±0.03)Eu/L(t>2.179,P<0.05),而4周起肝组织CD14表达就上调,溶菌酶阳性的库普弗细胞被激活,并随着实验的进展更加明显。血清TNFα水平从8周起明显增高为(26.39±24.21)pg/ml,对照组为(9.82±9.29)pg/ml(t>2.145,P<0.05),IL-1β从16周起升高为(23.76±21.81)pg/ml,对照组为(6.25±2.98)pg/ml(t>2.145,P<0.05)。 结论 NASH时存在内毒素性肝损伤。内毒素激活肝脏库普弗细胞以及促使TNFα等细胞因子释放可能是NASH的发病机制之一。     

Trimethylamine N-oxide attenuates high-fat high-cholesterol dietinduced steatohepatitis by reducing hepatic cholesterol overload in rats

BACKGROUND Trimethylamine N-oxide (TMAO) has been shown to be involved in cardiovascular disease (CVD). However, its role in nonalcoholic steatohepatitis (NASH) is unknown. AIM To determine the effect of TMAO on the progression of NASH. METHODS A rat model was induced by 16-wk high-fat high-cholesterol (HFHC) diet feeding and TMAO was administrated by daily oral gavage for 8 wk. RESULTS Oral TMAO intervention attenuated HFHC diet-induced steatohepatitis in rats. Histological evaluation showed that TMAO treatment significantly alleviated lobular inflammation and hepatocyte ballooning in the livers of rats fed a HFHC diet. Serum levels of alanine aminotransferase and aspartate aminotransferase were also decreased by TMAO treatment. Moreover, hepatic endoplasmic reticulum (ER) stress and cell death were mitigated in HFHC diet-fed TMAOtreated rats. Hepatic and serum levels of cholesterol were both decreased by TMAO treatment in rats fed a HFHC diet. Furthermore, the expression levels of intestinal cholesterol transporters were detected. Interestingly, cholesterol influxrelated Niemann-Pick C1-like 1 was downregulated and cholesterol efflux-related ABCG5/8 were upregulated by TMAO treatment in the small intestine. Gut microbiota analysis showed that TMAO could alter the gut microbial profile and restore the diversity of gut flora. CONCLUSION These data suggest that TMAO may modulate the gut microbiota, inhibit intestinal cholesterol absorption, and ameliorate hepatic ER stress and cell death under cholesterol overload, thereby attenuating HFHC diet-induced steatohepatitis in rats. Further studies are needed to evaluate the influence on CVD and define the safe does of TMAO treatment.     

甘氨酸对NASH大鼠肝组织环氧合酶-2表达的影响

目的 探讨环氧合酶-2在非酒精性脂肪性肝炎发病机制中的作用以及甘氨酸对其表达的影响。方法 选择雄性Wistar大鼠54只,随机分为对照组、高脂饮食组和甘氨酸干预组,比较实验第8、12和16周末动物血浆ALT和内毒素水平及肝组织COX-2的表达情况。结果 在实验第12周和16周末,脂肪肝组动物血浆ALT较对照组明显增高（P〈0．05）,各期脂肪肝组和甘氨酸组动物腹主动脉血内毒素水平与对照组比较均无差异,而门静脉血内毒素水平明显上升,腹主动脉血与相对应的门静脉血内毒素比较有显著性差异（P〈0．01）;在第16周脂肪肝组和甘氨酸组COX-2表达呈阳性,甘氨酸处理组积分光密度值比脂肪肝组明显降低（P〈0．05）;在对照组、实验第8周和12周脂肪肝组肝内无COX-2 mRNA表达,但在第16周脂肪肝组动物肝内COX-2的相对表达量为0．67±0．04,甘氨酸组为0．43±0．04,两者比较有显著性差异（P〈0．05）;血浆内毒素水平与COX-2表达呈正相关（r=0．58,P〈0．01）。结论肠源性内毒素血症上调肝组织COX-2表达,后者在NASH发病机制中起着重要的作用,甘氨酸能降低内毒素水平,并使NASH大鼠肝内COX-2表达减少。     

饮食调整治疗大鼠非酒精性脂肪性肝炎

目的:观察单纯饮食改变治疗大鼠非酒精性脂肪性肝炎(NASH)的作用。方法:30只SD大鼠随机分为3组(每组n=10):正常组喂普通饲料;模型组喂高脂饲料;饮食治疗组在高脂饮食12周后恢复正常饲料喂养。16周后处死动物。结果:正常饮食能显著降低造模大鼠的体重、肝指数、转氨酶,还能改善肝脏脂肪变性和炎症坏死的程度。结论:单纯恢复正常饮食即可治疗大鼠NASH。     

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.     

疏肝祛瘀通络降浊法对大鼠非酒精性脂肪性肝炎的保护作用

目的探讨非酒精性脂肪性肝炎大鼠内毒素性肝损伤机制及中药对其影响。方法用喂饲高脂饮食的方法建立非酒精性脂肪性肝炎大鼠模型。4周后用疏肝祛瘀通络降浊法分小、中、大剂量进行治疗,12周后处死测定血脂、ALT、内毒素(ET)、肿瘤坏死因子(TNF-α)和白细胞介素(IL-1β)的含量;免疫组化法观察肝组织CD14和核转录因子(NF-κB)的表达;RT-PCR检测脂多糖结合蛋白(LBP)和4型Toll样受体(TLR-4)mRNA的表达。同期正常饮食饲养大鼠作对照。结果第12周时,模型组大鼠腹主动脉血清内毒素水平较正常组明显升高,有显著性差异;中剂量治疗组大鼠血清ET、TNF-α、IL-1β水平明显低于模型组,差异有显著意义。模型组大鼠肝组织CD14阳性细胞数量明显增多,主要分布于肝窦内,部分呈灶型聚集;与模型组相比,中剂量治疗组大鼠肝组织CD14阳性细胞数量明显减少。模型组可见少量细胞核染色的NF-κB阳性细胞散在分布于汇管区。模型组肝组织LBPmRNA和TLR-4mRNA表达均明显上调,与正常组比较差异均有显著意义;中剂量治疗组大鼠肝组织LBPmRNA和TLR-4mRNA表达均较模型组明显下调,且有显著性差异。结论疏肝祛瘀通络降浊法对非酒精性脂肪肝有疗效,可能与其降低血清内毒素水平和下调肝组织内毒素相关受体表达继而减轻炎症性肝损害有关。     

非酒精性脂肪肝大鼠小肠黏膜机械屏障的变化

目的 探讨在非酒精性脂肪肝(NAFLD)的进展过程中小肠黏膜机械屏障的变化.方法 雄性SD大鼠90只均分为3组,即为正常饮食组、高糖饮食组和高脂饮食组,建立NAFLD动物模型,并于4、8、12周各组分别处死10只.另取SD大鼠20只,随机均分为四氯化碳(CCl4)组和对照组,CCl4组予以CCl4建立肝损伤模型,4周时处死两组大鼠.肝脏石蜡切片HE染色观察脂肪变性程度.鲎试验终点显色法检测门静脉血中脂多糖(LPS)水平.免疫荧光法检测小肠黏膜紧密连接蛋白occludin,并对荧光强度进行评分.电镜下观察小肠黏膜紧密连接形态的变化.结果 肝脏组织病理表现提示NAFLD和肝损伤模型成功建立.高糖组LPS含量在各个时间点与正常饮食组差异均无统计学意义(P值均＞0.05).高脂组4周及12周时LPS含量与正常饮食组差异均无统计学意义(P值均＞0.05),而8周时显著高于正常饮食组(P＜0.05).CCl4组与对照组LPS含量差异无统计学意义(P＞0.05).在8周时正常饮食组、高糖组和高脂组occludin蛋白表量分别为1.80±0.42、1.50±0.53和1.30±0.67,高糖组和高脂组较正常饮食组略有减弱,差异均有统计学意义(P值均＜0.05);而12周时高糖组和高脂组较正常饮食组明显减弱(P值均＜0.05).CCl4组occludin的表达明显较对照组减弱(0.60±0.16比1.80±0.42,P＜0.05).高糖组、高脂组及CCl4组在各个时间点紧密连接形态均无明显变化.结论 NAFLD进程中紧密连接蛋白occludin的表达随肝脏脂肪变的进展逐渐减弱.因此在NAFLD的治疗中除改善胰岛素抵抗、保肝治疗外,尽早保护肠黏膜屏障可能有助于减慢肝损伤的进程.