熊胆粉对二甲基亚硝胺诱发大鼠肝纤维化的抑制作用

目的:探讨熊胆粉对二甲基亚硝胺(dimethylnitrosamine,DMN)诱发大鼠肝纤维化的抑制作用.方法:将30只大鼠随机分为正常组、模型组及熊胆组,每组各10只.用10g/LDMN腹腔注射诱发大鼠肝纤维化模型,用400mg/kg熊胆粉灌胃共4wk,检测血清AST、ALT值和总蛋白(TP)含量.肝组织做HE、直接红染色,观察肝组织的病理变化,并检测肝组织内胶原纤维的面密度.免疫组化采用SP法,利用单克隆抗体ED1和α-SMA观察库普弗细胞(Kupffercell,KC)和肝星状细胞(hepaticsatellitecell,HSC)的数量及分布.结果:熊胆组与模型组比较血清ALT值下降,AST值明显下降(4370.87±1338.60nkat/Lvs5741.15±1000.20nkat/L,P<0.05),TP升高,肝/体质量比增加,胶原纤维的面密度明显下降(6.73±1.31vs9.90±1.93,P<0.01).熊胆组肝组织病理变化较模型组轻,纤维间隔变细、或消失,形成弥漫性肝硬化的少.KC和HSC在增生的纤维组织及间隔内分布,熊胆组两种细胞的数量明显减少.结论:熊胆粉具有较好的抑制DMN诱发大鼠肝纤维化的作用,其机制可能与抑制KC,减少细胞因子的分泌,从而抑制HSC的激活和转化,减少胶原纤维合成和分泌有关.     

Melatonin reduces dimethylnitrosamine-induced liver fibrosis in rats

Increased deposition of the extracellular matrix components, particularly collagen, is a central phenomenon in liver fibrosis. Stellate cells, the central mediators in the pathogenesis of fibrosis are activated by free radicals, and synthesize collagen. Melatonin is a potent physiological scavenger of hydroxyl radicals. Melatonin has also been shown to be involved in the inhibitory regulation of collagen content in tissues. At present, no effective treatment of liver fibrosis is available for clinical use. We aimed to test the effects of melatonin on dimethylnitrosamine (DMN)-induced liver damage in rats. Wistar albino rats were injected with DMN intraperitoneally. Following a single dose of 40 mg/kg DMN, either saline (DMN) or 100 mg/kg daily melatonin was administered for 14 days. In other rats, physiologic saline or melatonin were injected for 14 days, following a single injection of saline as control. Hepatic fibrotic changes were evaluated biochemically by measuring tissue hydroxyproline levels and histopathogical examination. Malondialdehyde (MDA), an end product of lipid peroxidation, and glutathione (GSH) and superoxide dismutase (SOD) levels were evaluated in blood and tissue homogenates. DMN caused hepatic fibrotic changes, whereas melatonin suppressed these changes in five of 14 rats (P < 0.05). DMN administration resulted in increased hydroxyproline and MDA levels, and decreased GSH and SOD levels, whereas melatonin reversed these effects. When melatonin was administered alone, no significant changes in biochemical parameters were noted. In conclusion, the present study suggests that melatonin functions as a potent fibrosuppressant and antioxidant, and may be a therapeutic choice.     

在二甲基亚硝胺诱导大鼠肝纤维化时铁超载和脂肪堆积的作用

目的:探讨铁超载和脂肪堆积在二甲基亚硝胺(Dimethylnitrosamine,DMN)诱导的肝纤维化大鼠组织病理学变化中的作用.方法:模型组大鼠(n=30)腹腔注射DMN,10μl*kg-1*d-1,每周连续3日,共4周.模型A、B组大鼠分别于注射DMN完毕后的第1日、第21日处死.对照组大鼠(n=10)腹腔注射等体积生理盐水.各组大鼠肝组织分别予HE染色、Masson染色及普鲁士蓝染色,电镜下观察.结果:伴随着胶原生成的铁沉积于肝小叶是腹腔注射DMN完毕后的第1日、第21日肝组织的显著特点.但肝细胞脂肪堆积仅仅发生在腹腔注射DMN完毕后的第21日.结论:铁超载和脂肪堆积可能在DMN诱导的大鼠肝纤维化病理变化中发挥重要作用,其具体机制有待进一步研究.     

氧化苦参碱防治二甲基亚硝胺诱导的大鼠肝纤维化的实验研究

目的　观察氧化苦参碱预防及治疗大鼠肝纤维化的疗效并探讨其作用机制。方法　采用二甲基亚硝胺诱导的大鼠肝纤维化模型 ,观察氧化苦参碱 (30mg/kg、90mg/kg)干预前后肝指数、血及肝组织生化、羟脯氨酸含量、肿瘤坏死因子 (TGF) β1mRNA表达水平、电镜及病理组织学改变。结果　氧化苦参碱干预组较模型组丙氨酸转氨酶、天冬氨酸转氨酶下降 ,肝组织羟脯氨酸含量及TGF β1mR NA表达水平降低 (P <0 .0 1) ;干预组肝组织内超氧化物歧化酶、谷胱甘肽过氧化物酶较模型组升高 ,而丙二醛低于模型组 ;电镜显示肝细胞损伤减轻 ,病理组织学改善。结论　氧化苦参碱对二甲基亚硝胺诱导的肝纤维化有预防及治疗作用 ,其部分机制为通过抗脂质过氧化而保护肝细胞、抑制纤维生成等     

Hepatocyte growth factor gene transfer with naked plasmid DNA ameliorates dimethylnitrosamine-induced liver fibrosis in rats

Aim: Hepatocyte growth factor (HGF) has various biological properties, including antifibrogenic activity. In the present study, we tested the efficacy of HGF gene therapy using naked plasmid DNA in dimethylnitrosamine (DMN)-induced liver fibrosis in a rat model. Methods: Naked plasmid DNA encoding human HGF was injected once, together with a hypertonic solution, into the hepatic artery after DMN treatment on three consecutive days per week for 3 weeks. Naked plasmid DNA encoding beta-galactosidase was injected similarly in the DMN-treated control rats. DMN treatment was continued once weekly after gene transfer for additional 3 weeks. Results: The human HGF protein expression was detected in livers transfected with human HGF naked plasmid DNA, gradually decreasing by day 21. The expression of the endogenous rat HGF protein was also upregulated after human HGF gene transfer. Phosphorylation of c-Met, a HGF receptor, was detected only in livers transfected with human HGF plasmid DNA. Fibrosis was attenuated significantly in livers transfected with the human HGF plasmid. Attenuation wasaccompanied by decreased expression of alpha-smooth muscle actin. Increased portal vein pressure after treatment with DMN was suppressed significantly by HGF gene transfer. The upregulated hepatic protein expression of transforming growth factor-beta (TGF-beta) in response to DMN was markedly attenuated by HGF gene transfer accompanied by the increased protein expression for matrix metalloproteinases (MMP)-3 and -13. Conclusion: The hepatic arterial injection of human naked plasmid HGF DNA was effective in suppressing liver fibrosis induced in rats by DMN. The mechanisms by which HGF expression attenuated liver fibrosis may include the suppression of hepatic TGF-beta expression and the induction of MMP expression.     

新型生长抑素类似物SOM230减轻胆总管结扎大鼠肝纤维化

目的 应用胆总管结扎大鼠肝纤维化模型,观察长效生长抑素类似物SOM230对胆管结扎所致大鼠肝纤维化的治疗作用.方法 雄性SD大鼠80只,随机分为模型组、高剂量预防组(80 mg/kg SOM230)、低剂量预防组(8 mg/kg SOM230)、假手术组及正常对照组.分别在术后第2周和第4周取心脏血及肝组织,观察肝组织...     

Iron deposition and fat accumulation in dimethylnitrosamine-induced liver fibrosis in rat

AIM： To investigate if iron deposition and fat accumulation in the liver play a pathogenetic role in dimethylnitrosamine （DMN）-induced liver fibrosis in rat.
METHODS： Thirty rats were treated with DMN at does consecutive days of 10 μL/kg daily, i.p., for 3 consecutive day each week for 4 wk. Rats （n = 30） were sacrificed on the first day （model group A） and 21st d （model group B） after cessation of DMN injection. The control group （n = 10） received an equivalent amount of saline. Liver tissues were stained with hematoxylin ＆ eosin （HE） and Masson and Prussian blue assay and oberserved under electron microscopy. Serum alanine aminotransferase （ALT）and liver tissue hydroxyproline （Hyp） content were tested.
RESULTS： The liver fibrosis did not automaticallyreverse, which was similar to previous reports, the perilobular deposition of iron accompanied with collagen showed marked characteristics at both the first and 21st d after cessation of DMN injection. However, fat accumulation in hepatocytes occurred only at the 21^st d after cessation of DMN injection.
CONCLUSION： Iron deposition and fat accumulation may play important roles in pathological changes in DMN-induced rat liver fibrosis. The detailed mechanisms of these characteristics need further research.     

Effects of estradiol on liver estrogen receptor-alpha and its mRNA expression in hepatic fibrosis in rats

AIM:Estradiol treatment regulates estrogen receptor (ER) level in normal rat liver.However,little information is available concerning the role of estrogen in regulating liver ER in hepatic fibrosis in rats.The present study was conducted to determine whether estradiol treatment in CCl4-induced liver fibrosis of female and ovariectomized rats altered liver ERα and its mRNA expression,and to investigate the possible mechanisms.METHODS:Seventy female rats were divided into seven groups with ten rats in each. The ovariectomy groups were initiated with ovariectomies and the sham operation groups were initiated with just sham operations.The CCl4 toxic fibrosis groups received 400mL/L CCI4 subcutaneously at a dose of 2 mL/kg twice weekly.Estrogen groups were treated subcutaneously with estradiol 1mg/kg, the normal control group and an ovariectomy group received injection of peanut oil vehicle twice weekly.At the end of 8 weeks,all the rats were killed to detect their serum and hepatic indicators,their hepatic collagen content, and liver ER and ER mRNA expression.RESULTS: Estradiol treatment in both ovariectomy and sham ovariectomy groups reduced liver levels of ALT (from 658&#177;220nkat/L to 311&#177;146nkat/L and 540&#177;252nkat/L to 314&#177;163nkat/L,P&lt;0.05) and AST (from 697&#177;240nkat/L to 321&#177;121nkat/L and 631&#177;268nkat/L to 302&#177;153nkat/L,P&lt;0.05),increased serum nitric oxide (NO) level (from 53.7&#177;17.1μmol/L to 93.3&#177;4.2μmol/L and 55.3&#177;3.1μmol/Lto 87.5&#177;23.6μmol/L, P&lt;0.05) and hepatic nitric oxide synthase (NOS) activity (from 1.73&#177;0.71KU/g to 2.49&#177;1.20KU/g and 1.65&#177;0.46KU/g to 2.68&#177;1.17KU/g, P&lt;0.05),diminished the accumulation of hepatic collagen,decreased centrolobular necrotic areas as well as the inflammatory reaction in rats subjected to CCl4. The positive signal of ER and ER mRNA distributed in parenchymal and non-parenchymal hepatic cells,especially near the hepatic centrolobular and periportal areas.Ovariectomy decreased ER level (from 10.2&#177;3.2 to 4.3&#177;1.3) and ER mRNA expression (from 12.8&#177;2.1 to 10.9&#177;1.3) significantly (P&lt;0.05). Hepatic ER and ER mRNA concentrations were elevated after treatment with estradiol in both ovariectomy (15.8&#177;2.4, 20.8&#177;3.1) and sham ovariectomy(18.7&#177;3.8, 23.1&#177;3.7) fibrotic groups (P&lt;O.05).CONCLUSION: The increase in hepatic ER and mRNA expression may be part of the molecular mechanisms underlying the suppressive effect of estradiol on liver fibrosis induced by CCI4 administration.     

An herbal formula, CGX, exerts hepatotherapeutic effects on dimethylnitrosamine-induced chronic liver injury model in rats

INTRODUCTION Several pathologic conditions, including chronic alcohol consumption, viral B or C hepatitis, and constant cholestasis, induce chronic injury to liver tissue. Moreover, these chronic liver disorders lead progressively to fibrosis or liver cir…     

雌二醇纳米粒对大鼠免疫性肝纤维化模型的作用

目的 比较β-雌二醇纳米化前、后对猪血清诱导的肝纤维化动物模型肝脏纤维化的疗效及雌二醇抗肝纤维化的机制.方法 将S-D大鼠随机分为健康对照组、模型对照组、雌二醇治疗组、雌二醇纳米粒组和空白纳米粒组,每组10只,除健康对照组外,其余4组均腹腔注射猪血清(0.5 mL/次,2次/周).雌二醇治疗组、雌二醇纳米粒组和空白纳米粒组在第9周给予腹腔注射相应的干预药物,每周2次;在12周末处死大鼠.免疫组织化学法检测平滑肌肌动蛋白(α-SMA)的表达;比色法检测一氧化氮合酶(NOS)、一氧化氮(NO)、总抗氧化能力(T-AOC)和谷胱甘肽(GSH);RT-PCR检测肝组织Ⅰ、Ⅲ型胶原、结缔组织生长因子(CTGF)、转化生长因子-β1(TGF-β1)及基质金属酶(MMP-1)、组织金属蛋白酶抑制剂(TIMP-1)mRNA的表达.结果 肝纤维化动物模型肝脏组织的Ⅰ、Ⅲ型胶原、TGF-β1、CTGF和TIMP-1 mRNA的表达在雌二醇纳米粒治疗组和雌二醇治疗组均有明显减少,MMP-1 mRNA的表达明显增多,与模型对照组、空白纳米粒组比较,差异有统计学意义(P＜0.05);经治疗后雌二醇治疗组和雌二醇纳米粒组的T-AOC、NO、NOS、GSH活性均有提高,与模型对照组、空白纳米粒组比较,差异有统计学意义(P＜0.05);但雌二醇治疗组和雌二醇纳米粒组比较,差异无统计学意义(P＞0.05).结论 β-雌二醇通过抗氧化、降低Ⅰ、Ⅲ型胶原产生,抑制与肝纤维化有关的细胞因子TGF-β1及其下游信号CTGF的表达,促进MMP-1表达但抑制TIMP-1的表达等发挥其抗肝纤维化作用.纳米化β-雌二醇的抗大鼠免疫性肝纤维化作用比无纳米化β-雌二醇更强.     

重组肝再生增强因子对大鼠肝纤维化的保护作用

目的　观察重组肝再生增强因子 (rALR)对大鼠肝纤维化的保护作用。方法　构建表达ALR的质粒 ,将得到的rALR用于CCl4 致肝纤维化的大鼠 ,观察rALR对肝纤维化动物模型肝功能、血清细胞外基质水平及肝组织纤维化程度的影响。结果　rALR可显著改善CCl4 肝纤维化模型大鼠肝功能 ,降低血清细胞外基质水平和肝组织纤维化程度。结论　rALR对实验大鼠肝功能具有显著的改善作用 ,对抗肝纤维化亦有一定的作用。     

Effects of estradiol on liver estrogen receptor-α and its mRNA expression in hepatic fibrosis in rats

AIM: Estradiol treatment regulates estrogen receptor (ER) level in normal rat liver. However, little information is available concerning the role of estrogen in regulating liver ER in hepatic fibrosis in rats. The present study was conducted to determine whether estradiol treatment in CCl4-induced liver fibrosis of female and ovariectomized rats altered liver Erα and its mRNA expression, and to investigate the possible mechanisms.METHODS: Seventy female rats were divided into seven groups with ten rats in each. The ovariectomy groups were initiated with ovariectomies and the sham operation groups were initiated with just sham operations. The CCl4 toxic fibrosis groups Received 400 mL/L CCl4 subcutaneously at a dose of 2 mL/kg twice weekly. Estrogen groups were treated subcutaneously with estradiol 1 mg/kg, the normal control group and an ovariectomy group Received injection of peanut oil vehicle twice weekly. At the end of 8 weeks, all the rats were killed to detect their serum and hepatic indicators,their hepatic collagen content, and liver ER and ER mRNA expression.RESULTS: Estradiol treatment in both ovariectomy and sham ovariectomy groups reduced liver levels of ALT (from 658±220 nkat/L to 311±146 nkat/L and 540±252 nkat/L to 314±163 nkat/L, P＜0.05) and AST (from 697±240 nkat/L to 321±121 nkat/L and 631±268 nkat/L to 302±153 nkat/L,P＜0.05), increased serum nitric oxide (NO) level (from 53.7±17.1 μmol/L to 93.3±24.2 μmol/L and 55.3±23.1 μmol/L to 87.5±23.6 μmol/L, P＜0.05) and hepatic nitric oxide synthase (NOS) activity (from 1.73±0.71 KU/g to 2.49±1.20 KU/g and1.65±0.46 KU/g to 2.68±1.17 KU/g, P＜0.05), diminished the accumulation of hepatic collagen, decreased centrolobular necrotic areas as well as the inflammatory reaction in rats subjected to CCl4. The positive signal of ER and ER mRNA distributed in parenchymal and non-parenchymal hepatic cells, especially near the hepatic centrolobular and periportal areas. Ovariectomy decreased ER level (from 10.2±3.2 to4.3±1.3) and ER mRNA expression (from 12.8±2.1 to 10.9±1.3)significantly (P＜0.05). Hepatic ER and ER mRNA concentrations were elevated after treatment with estradiol in both ovariectomy (15.8±2.4, 20.8±3.1) and sham ovariectomy(18.7±3.8, 23.1±3.7) fibrotic groups (P＜ 0.05).CONCLUSION: The increase in hepatic ER and mRNA expression may be part of the molecular mechanisms underlying the suppressive effect of estradiol on liver fibrosis induced by CCl4 administration.     

A selective ROCK inhibitor, Y27632, prevents dimethylnitrosamine-induced hepatic fibrosis in rats

BACKGROUND: p160ROCK is a direct Rho target which mediates Rho-induced assembly of focal adhesions and stress fibers. We previously reported that Rho signaling pathways are involved in the activation of hepatic stellate cells (HSC) in vitro. The aim of the present study was to test the hypothesis that an inhibitor specific for p160ROCK (Y27632) could prevent experimental hepatic fibrosis induced by dimethylnitrosamine (DMN) in rats. METHODS: Y27632 was given orally at 30 mg/kg daily for 4 weeks after the first injection of DMN. The degree of fibrosis was evaluated by image analysis and also by measurements of collagen and hydroxyproline content in the liver. The expression of alpha-smooth muscle actin (alpha-SMA) in the liver and in the primary cultured HSC was also evaluated. Semi-quantitative RT-PCR was performed to evaluate the expression of type I collagen mRNA in the liver. RESULTS: Y27632 treatment significantly decreased the occurrence of DMN-induced hepatic fibrosis and reduced the collagen and hydroxyproline content and alpha-SMA expression in the liver. The expression of alpha-SMA in HSC was also suppressed in vitro. CONCLUSIONS: These findings indicate that inhibitors of the Rho-ROCK pathway might be useful therapeutically in hepatic fibrosis.     

门冬氨酸鸟氨酸对肝纤维化大鼠的实验研究

目的通过大鼠肝纤维化动物模型，研究门冬氨酸鸟氨酸防止肝纤维化的作用。方法采用0．03％的硫代乙酰胺溶液腹腔注射制备大鼠肝纤维化模型，观察门冬氨酸鸟氨酸对大鼠肝功能指标、组织病理学改变和脯氨酸羟化酶表达的影响。结果门冬氨酸鸟氨酸能降低大鼠AST，ALT水平（P〈0．05），减轻肝纤维化的病理改变进程。结论门冬氨酸鸟氨酸具有一定的抗肝纤维化作用。     

Expression of type I and type III collagens during the course of dimethylnitrosamine-induced hepatic fibrosis in rats

ABSTRACT— Aims/Background: We wished to clarify the mechanisms that account for the increase in hepatic collagen accumulation during hepatic fibrosis. Methods: The gene expression of type I and type III procollagens and matrix metalloproteinase-1 (MMP-1) was measured by Northern blot analysis; immunolocalization of both types of collagen was estimated by indirect immunohistochemical assay; and the hepatic content of collagen and malondialdehyde (MDA), a product of lipid peroxidation, were assayed in hepatic fibrosis induced in rats with a single dose of dimethylnitrosamine (DMN). Results: During the experimental period, more type I procollagen mRNA was found than type III procollagen mRNA. The immunoreactive intensity of type I collagen was greater in necrotic areas near central veins 3 days after DMN treatment than it was on day 9, whereas the type III collagen immunodeposition for the latter period of the hepatic fibrosis was stronger than it was on day 3. As compared with controls, hepatic collagen content increased significantly after 3 days and continued, increasing gradually, as did type I and III procollagen mRNA levels. On day 14, fibrosis was greatest and both types of procollagen gene expression were at their highest, and type I and III procollagen mRNA levels and hepatic collagen content increased as the dosage of DMN was raised. MMP-1 mRNA levels increased early in hepatic fibrogenesis, and increased on day 14 when DMN dosages were low. Hepatic MDA levels increased rapidly for 3 days after DMN treatment, remaining significantly higher than control values and showing a significant increase even in response to low DMN doses on day 14. Conclusions: Our results suggested that fibrotic liver collagen content may make its first notable increase due in part to the balance between type I collagen and MMP-1 expression rates. Also, lipid peroxidation may be important in the mechanism of hepatofibrogenesis.