姜黄素对CCl_4处理的大鼠PAI-1与u-PA蛋白表达的影响

目的:探讨姜黄素对CCl4处理的大鼠肝组织中PAI-1和u-PA蛋白表达的影响.方法:100只♂SD大鼠,随机分为5组:正常对照组(N),肝纤维化模型组(M),姜黄素低剂量组(Cl),姜黄素中剂量组(Cm),姜黄素高剂量组(Ch).M组以CCl4腹腔注射造模,Cl、Cm、Ch组除腹腔注射CCl4外,分别以不同剂量的姜黄素灌胃;每组分别在实验第4、7、21、42天随机取大鼠5只处死,留取同部位肝脏组织行HE染色,用免疫组织化学法检测各组大鼠肝脏组织中PAI-1和u-PA蛋白的表达情况.结果:在M组,随时间延长,PAI-1和u-PA蛋白表达均不同程度增加,姜黄素低、中、高剂量干预组与M组相比,姜黄素能降低PAI-1蛋白表达(42d:5.60±1.673,3.40±1.673,2.40±1.140vs8.80±2.168,均P<0.05),增加u-PA蛋白表达(42d:6.00±1.414,9.20±1.643,9.80±2.049vs4.20±1.095,P<0.05),其作用强度具有剂量和时间依赖性.结论:姜黄素可通过调节肝纤维化大鼠PAI-1与u-PA蛋白表达,发挥抗肝纤维化作用.     

肝纤维化大鼠肝组织Smads基因表达状况及意义

目的:研究CCl4诱导的肝纤维化大鼠肝组织Smad基因表达的变化及其意义.方法:80只健康雄性SD大鼠分为2组:正常组(C组,n=40)和模型组(M组,n=40).以CCl4 sc 法诱导肝纤维化,HE和VG胶原染色观察肝脏胶原沉积情况,原位杂交法及免疫组化法检测肝组织Smads分子表达水平变化.结果:与C组比较,M组大鼠肝脏组织学积分显著增加(3.29±0.68 vs0,P<0.05),平均胶原面积显著增加(290.86±89.37 μm2 vs 56.12±21.45 μm2,P<0.01),肝组织Smad4蛋白表达率较C组明显增加(4.27%±0.43% vs 2.86%±0.86%,P<0.05),而Smad7蛋白表达虽然增加,但水平低下;Smad 3 mRNA表达A值明显增加(0.167±0.092 vs 0.010±0.002,P<0.05),Smad4 mRNA表达A值也明显增加(0.24 1±0.098 vs 0.021±0.004,P<0.05),Smad6、Smad7 mRNA虽然增加,但表达水平仍然低下.结论:实验性大鼠肝纤维化存在肝脏Smads分子表达水平的比例失调,TGF-Smad信号通路可能参与了肝纤维化的形成与发展.     

熊果酸对肝纤维化大鼠肝组织TGF-β1和α-SMA表达的

织TGF-β1基因与蛋白及α平滑肌肌动蛋白(α-SMA)表达的影响, 并探讨其抗肝纤维化作用机制.方法: SD大鼠96只随机分为正常对照组(N组)、模型组(M组)、UA低剂量组(U1组)、UA中剂量组(U2组)、UA高剂量组(U3组)及秋水仙碱组(C组), 每组16只. 除N组外, 均用二甲基亚硝胺(Dimethylnitrosamine, DMN)诱导肝纤维化4 wk, 分别给予安慰剂、不同剂量的UA、秋水仙碱腹腔注射, 治疗4 wk处死大鼠,取肝组织行病理HE染色及VG染色判断炎症和肝纤维化程度; 分别采用免疫组织化学和Western blot检测TGF-β1蛋白和α-SMA蛋白的表达; 采用RT-PCR检测TGF-β1 mRNA的表达.结果: U2和U3组肝细胞坏死和纤维组织增生明显减轻; M组TGF-β1蛋白、TGF-β1 mRNA及α-SMA蛋白较N组的表达明显增加(8.76±1.47 vs 1.48±0.24; 0.60±0.11 vs 0.05±0.02;0.51±0.10 vs 0.09±0.02, 均P<0.01). U1组和C组TGF-β1蛋白的表达较M组降低( P<0.05),U2和U3组TGF-β1蛋白的表达较M组明显降低(5.32±1.63, 3.98±0.67 vs 8.76±1.47,均P<0.01), 且低于C组的表达(7.14±1.29,P<0.05或0.01). U2和U3组的TGF-β1 mRNA的表达也明显低于M组(0.36±0.07, 0.25±0.06 vs 0.60±0.11, 均P<0.01)和C组(0.47±0.10, P<0.05或0.01). U1-U3组较M组α-SMA蛋白的表达明显降低(0.36±0.08, 0.23±0.02,0.15±0.03 vs 0.51±0.10, 均P<0.01); U2和U3组α-SMA蛋白的表达也显著低于C组(0.43±0.05, 均P<0.01).结论: UA能明显改善肝纤维化大鼠的肝脏组织结构, 减轻肝纤维化; 其抗肝纤维化的机制可能与降低TGF-β1表达, 抑制HSC的激活有关.     

抑制血红素氧合酶-1对大鼠免疫性肝纤维化的影响

目的:逆向观察肝纤维化大鼠血红素氧合酶-1(heme oxygenase 1, HO-1)的表达与肝纤维化形成的关系, 探讨HO-1对免疫性肝纤维化大鼠肝脏的保护作用.方法:应用人体血清白蛋白建立免疫性肝纤维化模型, Zn组在攻击阶段同时腹腔注射Znpp, HE染色、VG染色、Foot氏网状纤维染色等三种染色方法观察肝纤维组织增生程度,Western blot和免疫组化法观察肝组织中HO-1的表达.结果:F组和Zn组免疫组化阳性计分较N组明显升高(4.00±1.31, 2.33±0.78 vs 0.80±0.79,P<0.01);且F组免疫组化阳性计分比Zn组高(4.00±1.31 vs 2.33±0.78, P<0.05). F组成纤维细胞、Ⅰ型胶原及Ⅲ型胶原增生较N组明显( P<0.01);Zn组成纤维细胞、Ⅰ型胶原及Ⅲ型胶原增生较F组更明显( P<0.01).结论:免疫性肝纤维化模型中, 肝脏能够高水平表达HO-1, 对肝脏起保护作用.     

红景天甙对肝纤维化大鼠肝组织ROCK表达的影响

目的:研究红景天甙对肝纤维化大鼠肝组织ROCK基因表达的影响,了解其干预肝纤维化的机制.方法:健康雄性SD大鼠,随机分为3组:对照组( n = 10),红景天甙干预组( n = 40)和肝纤维化模型组( n = 40).大鼠肝纤维化采用CCl4皮下注射法(300 mL/L,3 mL/kg,每周2次,共8 wk)诱导.红景天甙干预采用腹腔注射法,剂量5 mg/kg,每周2次.肝脏胶原沉积状况采用Masson胶原染色以及HE染色观察,ROCKⅠ、ROCKⅡ表达水平分别采用原位杂交(in situ hybridization,ISH) 和免疫组化(immunohisto chemistry,IH)方法检测.实验图像经电子计算机扫描,数据采用专业图像分析软件统计分析.结果:肝纤维化大鼠肝脏肝细胞坏死、再生明显,假小叶形成,胶原纤维沉积明显增加,肝实质结构紊乱.红景天甙干预组大鼠肝组织胶原沉积明显减少,组织学积分平均胶原面积降低(2.1±0.3 vs 3.6±0.8,74.82±21.51μm2 vs 290.86±89.37 μm2,均P<0.05).与模型组比较,红景天甙干预性治疗组ROCKⅠ,Ⅱ蛋白表达水平均明显下降(0.203±0.068 vs0.357±0.182,0.237±0.056 vs 0.394±0.238,均P<0.05),ROCKⅠ,Ⅱ mRNA表达水平明显下降(0.197±0.019 vs 0.394±0.238,0.185±0.031 vs 0.279±0.112,均P<0.01).结论:红景天甙可能通过调节Rho-ROCK信号传导通路,减少肝脏胶原纤维的合成与沉积,有效干预CCl4诱导的大鼠肝纤维化.     

拆方益肝康不同药物血清对肝星状细胞胶原代谢及TGF-β1的影响

目的:探讨益肝康抗肝纤维化作用机制、配伍意义,并采用对比血清药理学方法探讨更为科学的中药研究方法.方法:分别制备益肝康及其拆方-丹参小复方正常大鼠(A组,A1组:正常大鼠血清对照组;A2组:正常大鼠丹参小复方血清组;A3组:正常大鼠益肝康血清组)与肝纤维化大鼠(B组,B1组:肝纤维化大鼠血清对照组:B2组:肝纤维化大鼠丹参小复方血清组:B3组:肝纤维化大鼠益肝康血清组)药物血清,温育体外培养的HSC,3H-脯氨酸掺入法检测胶原合成,Western blot技术检测TGF-β1蛋白表达,RT-PCR技术检测TGF-β1 mRNA表达.结果:益肝康及丹参小复方正常大鼠与肝纤维化大鼠药物血清均可抑制HSC胶原合成(100mL/L时A组:2275.00±114.30 cpm,2401.87±108.50 cpm vs 2963.62±128.01 cpm;B组:2205.3l±108.97 clom,2462.70±177.02 epm vs 3179.12±223.34 cpm;200 mL时A组:2372.96±123.3 cpm Vs 2515.37±98.25 cpm vs 3209.38±110.75 cpm;B组:2394.29±1 50.50 cpm vs 2611.25±126.05 cpm vs 3490.46±183.16 cpm,P<0.05或0.01).100 mL时降低TGF-β1基因及蛋白表达(均P<0.01).2组在胶原合成、TGF-β1基因及蛋白表达益肝康组作用优于丹参小复方(均P<0.01),而益肝康组与丹参小复方组比较则B组血清作用优于A组(益肝康组:TGF-β1基因:0.356±0.032 vs 0.568±0.028;TGF-β1蛋白:0.458±0.009 vs 0.639±0.102;丹参小复方组:0.601±0.047 vs 0.810±0.051:0.612±0.126vs 0.860±0.138.P<0.05或LP<0.01).结论:益肝康及丹参小复方均可抑制HSC胶原合成,其主要机制之一是抑制TGF-β1基因和蛋白表达,益肝康更具配伍意义,肝纤维化大鼠药物血清药效优于正常大鼠血清药效.     

EGCG对肝纤维化大鼠TGF-β1和CTGF表达的影响

目的:研究表没食子儿茶素-3-没食子酸酯(EGCG)的抗肝纤维化作用及其机制.方法:运用腹腔注射CCl4构建大鼠肝纤维化模型,观察EGCG对大鼠肝纤维化的影响.运用HE染色、Massion三色染色检测肝纤维化的变化;生化检测血清丙氨酸转移酶(ALT)及天冬氨酸转移酶(AST);同时检测肝组织的羟脯氨酸、还原型谷胱甘肽(GSH)和硫代巴比妥酸反应底物(TBARS)含量.免疫组织化学法观察α-平滑肌肌动蛋白(α-SMA)的表达;分别运用RT-PCR和Western blot法检测转化生长因子β1(TGF-β1)及结缔组织生长因子(CTGF)mRNA和蛋白质表达.结果:EGCG对CCl4诱导的大鼠肝纤维化程度具有显著的抑制作用.EGcG对肝细胞具有显著的保护作用,与纤维化模型组比较,EGCG干预组血清ALT、AST水平降低(138.4±45.8vs 234.6±63.2,96.4±20.5 vs 186.2±36.6,均P<0.05).EGCG显著抑制肝组织α-SMA的表达.EGCG通过抑制TBARS的形成和提高GSH含量,显著改善CCl4诱导的肝纤维化大鼠肝脏的氧化状态.同时EGCG显著抑制肝组织TGF-β1及CTGF的mRNA和蛋白质的表达(均P<0.05).结论:EGCG能够显著抑制肝纤维化的进展,其机制与EGCG改善大鼠肝脏的氧化状态及抑制TGF-β1和CTGF的表达有关.     

IL-10对实验性肝纤维化大鼠基质金属蛋白酶-2影响的研究

目的研究IL-10对实验性肝纤维化大鼠基质金属蛋白酶-2(MMP-2)的影响.方法建立大鼠肝纤维化模型并行IL-10干预实验,从正常大鼠(N组)和CCl4诱导肝纤维化大鼠(C组)及IL-10干预肝纤维化大鼠(E组)中取肝脏组织,采用S-P免疫组织化学方法检测分析不同组大鼠肝脏组织中MMP-2的表达状况.结果N组MMP-2阳性染色偶见于窦内皮细胞及肝细胞的胞浆;C组MMP-2阳性染色多见于汇管区新生的胆管细胞及纤维隔内条索状的成纤维细胞,26例标本中阳性13例,强阳性8例.第5周开始MMP-2有阳性表达,第9周阳性表达明显增强;E组MMP-2阳性染色明显减少,多见于汇管区的新生胆管细胞,27例标本中阳性10例,强阳性1例.Redit分析表明3组间MMP-2阳性表达有显著性差异(P＜0.01).结论MMP-2随着大鼠肝纤维化进展阳性表达升高,IL-10对CCl4诱导的大鼠肝纤维化具有保护作用,可明显抑制纤维化的生成和沉积.     

大鼠非酒精性脂肪性肝纤维化形成过程中骨桥蛋白的表达及其意义

目的 通过观察非酒精性脂肪性肝纤维化形成过程中肝组织内骨桥蛋白(OPN)的变化规律,探讨OPN在非酒精性脂肪性肝纤维化形成过程中的作用. 方法选用纯系Wistar雄性大鼠56只,体质量180～200g,随机分为正常对照组和高脂饮食4、8、12,16、20、24周组(其中每组各8只).肝组织常规进行HE及Masson三色胶原染色,免疫组织化学染色检测肝组织α-平滑肌肌动蛋白的表达,RT-PeR、Western blot观察肝组织中OPN动态变化.结果 与正常对照组相比,高脂饲料组大鼠肝脏内OPN含量明显升高,随着脂肪肝程度的加重,OPN表达逐渐增强,mRNA及蛋白质表达比较,F值分别为7.30和7.15,尸值均<0.01;与α-平滑肌肌动蛋白表达及肝组织胶原纤维面积百分比呈显著正相关(r值分别为0.94和0.82,P值均<0.01).结论 在非酒精性脂肪性肝纤维化形成过程中,OPN在肝组织中表达显著上调,可能在非酒精性脂肪性肝纤维化的形成过程中发挥重要作用.     

中药软肝饮对CCl4诱导的肝纤维化大鼠模型Smad3表达的影响

目的研究中药软肝饮对CCl4诱导的大鼠肝纤维化模型Smad3表达的影响,探讨其抗纤维化的作用机制。方法 40只Wistar大鼠,随机分成正常对照组、模型组、软肝饮组和复方鳖甲软肝片组,采用CCl4背部皮下注射构建肝纤维化模型,进行HE和Van-Gieson染色,光镜下观察肝组织纤维化程度。同时以免疫组织化学SABC法检测各组Smad3的表达。结果与正常对照组相比,模型组Smad3表达明显增强,软肝饮组大鼠肝脏Smad3的表达显著下调(0.279±0.085vs0.885±0.904,P<0.05)。另外,软肝饮组大鼠肝脏纤维化病理变化显著改善。结论软肝饮对CCl4诱导的大鼠肝脏纤维化模型肝脏Smad3表达有明显的下调作用,可能是其抗肝纤维化主要作用机制之一。     

肝窦毛细血管化在二甲基亚硝胺大鼠肝纤维化门静脉高压形成中的作用

目的 研究肝窦毛细血管化在二甲基亚硝胺(DMN)大鼠肝纤维化门静脉高压形成中的作用。方法经4周12次腹腔注射DMN制备火鼠肝纤维化模型,应用电镜技术、免疫组织化学方法结合大鼠门静脉压力测定,24周动态分析肝纤维化形成过程中肝窦毛细血管化与门静脉压力变化的相关性。结果 大鼠门静脉压力随着造模的进行不断升高,造模4周时达(1.10 ±0.18)kPa,明显高于对照组(0.52±0.04)kPa(t=6.41.P<0.0 1)。造模停止后,大鼠门静脉压力逐渐恢复正常。其动态变化与电镜下肝窦毛细血管化的变化规律一致;与反映肝窦内皮表型改变的第Ⅷ因子相关抗原的动态变化成正相关(r=0.833,P<0.01);与反映肝窦内皮下基底膜形成的层黏连蛋白的动态变化成正相关(r=0.953,P<0.01);与反映肝窦壁星状细胞活化收缩的α-平滑肌肌动蛋白的动态变化成正相关(r=0.919,P<0.01)。结论 肝窦毛细血管化是DMN肝纤维化模型门静脉高压产生的主要原因。     

胰腺弹力蛋白酶在大鼠肝纤维化组织中的表达

目的:观察胰腺丝氨酸弹力蛋白酶的基因、蛋白及活性在大鼠肝纤维化中的表达,探讨弹力蛋白酶在肝纤维化形成中的作用.方法:采用二甲基亚硝胺(DMN)4周12次腹腔注射制备Wistar雄性大鼠肝纤维化模型,以正常组作对照.观察肝功能,肝脏病理组织学,肝组织羟脯氨酸含量以及肝组织弹力蛋白酶mRNA、蛋白及其活性的表达.结果:弹力蛋白酶mRNA、蛋白及其活性在正常大鼠肝组织均有一定程度的表达,在肝纤维化模型组,假小叶内肝细胞弹力蛋白酶mRNA表达有所减少,弹力蛋白酶活性在正常组和模型组分别为(11.43±2.35)U/g、(8.02±1.62)U/g,模型组显著降低(P＜0.05).结论:某种程度的弹力蛋白酶表达是维持正常细胞外基质合成与降解动态平衡的需要;在肝纤维化形成过程中,大鼠胰腺丝氨酸弹力蛋白酶的表达下降是促进肝纤维化形成的因素之一.     

地龙2号对肝纤维化大鼠uPA和PAI-1蛋白表达的影响

目的研究蚯蚓提取物地龙2号对实验性大鼠肝纤维化的uPA和PAI-1蛋白表达的影响。方法52只雄性Wistar大鼠,随机分成6组:正常大鼠组(N);秋水仙碱对照组(CC);造模同时用秋水仙碱0.1mg.Kg-1.d-1灌胃,假模型组(NC):皮下注射花生油(CCl4),灌单蒸水;模型组对照组(MC):皮下注射CCl4花生油混合物,每日单蒸水灌胃;地龙大剂量组(Eh):造模同时用地龙2号50mg.Kg-1.d-1灌胃;地龙小剂量组(El):造模同时用地龙2号25mg.Kg-1.d-1灌胃。8周末处死大鼠,用免疫组化法检测各组大鼠肝脏组织中uPA和PAI-1的表达情况。结果地龙2号大、小剂量组与模型组相比,uPA和PAI-1的表达均显著降低,且uPA与PAI-1的表达下降呈明显的正相关。结论地龙2号可能通过抑制肝纤维化大鼠肝组织中肝星状细胞(HSC)的活化及抑制uPA、PAI-1的表达发挥抗肝纤维化作用。     

Antifibrotic effects of green tea on in vitro and in vivo models of liver fibrosis

AIM: To examine the protective effect of green tea extract (GT) on hepatic fibrosis in vitro and in vivo in dimethylnitrosamine (DMN)-induced rats. METHODS: HSC-T6, a rat hepatic stellate cell line, was used as an in vitro assay system. Cell proliferation,collagen content, and type 1 collagen expression were examined in activated HSC-T6 cells. Collagen was determined by estimating the hydroxyproline content.In rats with DMN-induced hepatic fibrosis, serum aspartate aminotransferase and alanine aminotransferase concentrations, liver hydroxyproline and lipid peroxides were determined. Pathologic changes were examined by hematoxylin & eosin staining.RESULTS: GT administration prevented the development of hepatic fibrosis in the rat model of DMN-induced liver fibrosis. These results were confirmed both by liver histology and by quantitative measurement of hepatic hydroxyproline content, a marker of liver collagen deposition. Accordingly, inhibition of proliferation, reduced collagen deposition, and type 1 collagen expression were observed in activated HSC-T6 cells following GT treatment. These results imply that GT reduced the proliferation of activated HSC and down regulated the collagen content and expression of collagen type 1, thereby ameliorating hepatic fibrosis. tea administration can effectively improve liver fibrosis caused by DMN, and may be used as a therapeutic option and preventive measure against hepatic fibrosis.     

肝窦内皮细胞损伤在大鼠肝纤维化形成中的作用

目的 研究肝窦内皮细胞损伤在二甲基亚硝胺大鼠肝纤维化形成中的作用。方法 采用二甲基亚硝胺(dimethylnitrosamine,DMN)4周12次腹腔注射制备大鼠肝纤维化模型,应用电镜技术、免疫组织化学及图像分析方法结合血清生化测定,24周动态观察肝纤维化形成过程中肝窦内皮细胞损伤及其表型的改变。结果 造模2d后肝结构未见明显改变,肝窦内皮细胞(sinusoidal endothelial cell,SEC)远侧胞浆窗孔数减少、造模1周SEC失窗孔更明显,肝组织内未见明显变性坏死及纤维间隔形成,造模4周时见肝组织内大片出血坏死,有大量假小叶形成,内皮下出现SEC窗孔减少。SEC失窗孔早于肝细胞发生较为严重的坏死、肝纤维化的形成以及肝窦内皮下基底膜的形成。造模4周HA(ng/ml)和肝羟脯氨酸(ug/g)平均含量分别为231.30±143.80和223.04±37.09,对照组分别为56.50±18.10和61.55±20.85,t值在3.14～8.28,P<0.05。结论 DMN引起大鼠肝窦内皮细胞损伤及其表型改变可能是其诱导肝纤维化重要的始动机制之一。     

Morphological and serum hyaluronic acid, laminin and type IV collagen changes in dimethylnitrosamine-induced hepatic fibrosis of rats

AIM: To study the morphological and serum hyaluronic acid (HA), laminin (LN), and type IV collagen changes in hepatic fibrosis of rats induced by dimethylnitrosamine (DMN). METHODS: The rat model of liver fibrosis was induced by DMN. Serum HA, type IV collagen, and LN were measured by ELISA. The liver/weight index and morphological changes were examined under electron microscope on d 7, 14, 21, and 28 by immunohistochemical alpha smooth muscle actin alpha-SMA staining as well as Sirius-red and HE staining. RESULTS: The levels of serum HA, type IV collagen and LN significantly increased from d 7 to d 28 (P = 0.043). The liver/weight index increased on d 7 and decreased on d 28. In the model group, the rat liver stained with HE and Sirius-red showed evident hemorrhage and necrosis in the central vein of hepatic 10 lobules on d 7. Thin fibrotic septa were formed joining central areas of the liver on d 14. The number of alpha-SMA positive cells was markedly increased in the model group. Transitional hepatic stellate cells were observed under electron microscope. All rats in the model group showed micronodular fibrosis in the hepatic parenchyma and a network of alpha-SMA positive cells. Typical myofibroblasts were embedded in the core of a fibrous septum. Compared to the control group, the area-density percentage of collagen fibrosis and pathologic grading were significantly different in the model group (P<0.05) on different d (7, 14, and 28). The area-density percentage of collagen fibrosis in hepatic tissue had a positive correlation with the levels of serum HA, LN, and type IV collagen. CONCLUSION: The morphological and serum HA, type IV collagen, and LN are changed in DMN-induced liver fibrosis in rats.     

缬沙坦抗大鼠肝纤维化疗效及机制的研究

目的 研究血管紧张素Ⅱ(AngⅡ)1型受体拮抗剂缬沙坦对大鼠肝纤维化模型的疗效及机制。 方法 制备二甲基亚硝胺(DMN)诱导的大鼠肝纤维化模型,同时缬沙坦灌胃20 mg·kg1·d1.共8周,肝组织进行常规HE及Masson三色染色。AngⅡ水平采用放射免疫法测定。大鼠肝组织Ⅰ型胶原(colⅠ)及金属蛋白酶组织抑制因子1(TIMP1)mRNA的水平以逆转录多聚酶链反应方法检测。 结果 缬沙坦可明显改善大鼠肝纤维化的程度。模型组肝组织AngⅡ水平(Pg/0.2g肝重)、col-Ⅰ和TIMP1 mRNA水平分别为186.0±80.7、0.827±0.094和0.924±0.110,缬沙坦组分别为62.6±7.7、0.587±0.037和0.541±0.026,缬沙坦可降低肝脏AngⅡ的水平及Col-Ⅰ和TIMP1 mRNA的水平,F值分别为19.420、31.897和29.622,P值均<0.01。 结论 缬沙坦具有良好的抗肝纤维化作用,可能为治疗肝纤维化和早期肝硬化提供一新的方法。     

Morphological and serum hyaluronic acid, laminin and type Ⅳ collagen changes in dimethylnitrosamine-induced hepatic fibrosis of rats

AIM: To study the morphological and serum hyaluronic acid (HA), laminin (LN), and type Ⅳ collagen changes in hepatic fibrosis of rats induced by dimethylnitrosamine (DMN).METHODS: The rat model of liver fibrosis was induced by DMN. Serum HA, type Ⅳ collagen, and LN were measured by ELISA. The liver/weight index and morphological changes were examined under electron microscope on d 7, 14, 21, and 28 by immunohistochemical alpha smooth muscle actin α-SMA staining as well as Sirius-red and HE staining.RESUJLTS: The levels of serum HA, type Ⅳ collagen and LN significantly increased from d 7 to d 28 (P = 0.043).The liver/weight index increased on d 7 and decreased on d 28. In the model group, the rat liver stained with HE and Sirius-red showed evident hemorrhage and necrosis in the central vein of hepatic 10 lobules on d 7. Thin fibrotic septa were formed joining central areas of the liver on d 14. The number of α-SMA positive cells was markedly increased in the model group. Transitional hepatic stellate cells were observed under electron microscope.All rats in the model group showed micronodular fibrosis in the hepatic parenchyma and a network of α-SMA positive cells. Typical myofibroblasts were embedded in the core of a fibrous septum. Compared to the control group, the area-density percentage of collagen fibrosis and pathologic grading were significantly different in the model group (P＜0.05) on different d (7, 14, and 28). The area-density percentage of collagen fibrosis in hepatic tissue had a positive correlation with the levels of serum HA, LN, and type Ⅳ collagen.CONCLUSION: The morphological and serum HA, type Ⅳ collagen, and LN are changed in DMN-induced liver fibrosis in rats.     

Protective Effect of Morin on Dimethylnitrosamine-Induced Hepatic Fibrosis in Rats

Morin, a plant-derived flavonoid, has been reported to exhibit a wide range of pharmacological properties. In this study, we investigated the protective effect of morin on hepatic fibrosis induced by dimethylnitrosamine (DMN) in rats. Oral administration of morin remarkably prevented weight loss in the body and liver from DMN and inhibited the elevation of serum alanine transaminase (ALT), aspartate transaminase (AST), and total bilirubin levels. For the evaluation of hepatic fibrosis-related factors, we investigated expressions of collagen type I, transforming growth factor β₁ (TGF-β₁), and α-smooth muscle actin (α-SMA) in mRNA and protein levels. We observed that morin significantly reduced the expression of collagen type I, TGF-β₁, and α-SMA on hepatic fibrosis induced by DMN. Taken together, this study demonstrated that morin showed hepatoprotective and antifibrogenic effects against DMN-induced hepatic injury. This suggests that morin may be useful in preventing the development of hepatic fibrosis and cirrhosis. Hee-Seung Lee and Kyung Hee Jung have contributed equally to this work.