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Smad3和Smad7在梗阻性黄疸大鼠肝纤维化形成过程中的表达及意义

2021-07-11 来源:好走旅游网
本实验结果显示。随着胆总管结扎离断后时间延 长.肝纤维化程度加重,肝组织中Smad3表达呈递 增趋势,Smad7表达呈下降趋势。Liu等_11 研究HSC 内Smad表达时发现 活化的HSC主要表达Smad3, 与对照组相比。模型组纤维化的肝细胞内Smad3表 达明显增高、Smad7表达明显减少。Smad7的低水平 表达及Smad3的磷酸化作用加强刺激HSC不断增 生、合成分泌ECM[ ],激活周围静止的HSC,使之转 化为肌成纤维细胞,导致肝纤维化n 。 本实验结果发现,肝纤维化组织中Smad3与 Smad7的表达呈负的直线相关(r=一0.951,P< 0.001),提示Smad7对Smad3有抑制作用。Dooley 等 】 ]也认为.Smad7短暂的高表达可能会阻碍HSC 的转分化和减弱实验小鼠体内的纤维化。但Lee等 发现,Smad7可阻碍TGF—B的信号传递,却不能减 少 一平滑肌肌动蛋白的表达。 通过本实验,我们认为,阻塞性黄疸能够激活 TGF—Smad信号传导系统,使肝组织中Smad3蛋白 合成增加,Smad7蛋白的表达下降,最终活化HSC, 使之转变为肌纤维样细胞.造成肝脏ECM的过度 沉积,最终导致肝纤维化。在此过程中,如果采取干 预措施可能会减轻肝纤维化程度,甚至终止其进一 步发生。陶艳艳等 坫]、宋仕玲等 ]、张国等[18 发现粉 防已碱、郁金、小柴胡等一些药物能够抑制TGF— Smad信号通路,发挥抗纤维化的作用。这为临床上 治疗长期梗阻性黄疸引起的肝纤维化提供了一个新 途径 参 考 文 献 [1 Do]oley S,Hamzavi J,Breitkopf K,et 1a.Smad 7 prevents activation of hepatic stellate cells and liver fibrosis in rats[J].Gastroenterolo・ gY,2003,125(1):178—191. 『2 Uemuza M,Swenson Es,Gaca Md,et2] a1.Smad2 and smad3 play dif- ferent roles in rat hepatic stellate cell function and alpha-smooth muscle actin organization .Mol Biol Cell,2005,16(9):4214-4224. [3]Gressner AM,Weiskirehen R.Modem pathogenetic concepts of liver ifbrosis suggest stellate cells and TGF—beta as major players and therapeutic targets[J].Cell Mol Med,2006,10(1):76-79. 【4】Kavsak P,Rasmussen Rk,Causing Cg,et a1.Smad7 binds to smurf2 to form an E3 ubiquitin ligase that targets the TGF-beta receptor ofr degradation[J].Mol Cell,2000,6(6):l365一l375. 中国现代普通外科进展2012年2月 第15卷第2期 [5]Atisano L,Wrana J.Signaling transduction by the TGF—beta super- family[J].Science,2002,296(5573):1646-1647. 【6]Chen W,Fu X,Sheng Z.Review of current progress in the structure andfunction ofSmad ptotein .ChinMed 2002,115(3):446-450. [7】Seo GY,Park SR,Kim PH.Analyses of TGF-betal—inducible Ig germ-line gamma2b promoter activity:involvement of Smads and NF—kappaB[J】.European Journal of Immunology,2009,39(4):1 157- 1166. 【8]Yan X,Liu Z,Chen Y.Regulation of TGF-beta signaling by Smad7 【J】_Acta Biochimica et Biophysica Sinica,2009,41(4):263—272. [9]Ramesh S,Qi xj,Wildey GM,et a1.TGF beta-mediated BIM ex— pression and apoptosis are regulated through SMAD3一dependent ex— pression of the MAPK phosphatase MKP2[JI.EMBO Journal,2008,9 (10):990—997. [10]Schnabl B,Kweon Yo,Frederick Jp,et a1.The role of Smad3 in me— diating mouse hepatic stellate cell activation[aq.Hepatology,2001,34 (1):89—100. [1 1]Liu C,Gaca Md,Swenson Es,et a1.Smad2 and3 are differentially actibated by transforming growth factor—-beta inquiescent and acti・- vated hepatic stellate cells.Constitutive nuclear localization of Smads in activated cells iS TGF-beta—independent[J].Biol Chem, 2003,278(13):11721—11728 [12]Murata M,Matsuzaki K,Yoshida K,et a1.Hepatitis B virus X pro— tein shitfs human hepatic transforming growth factor(TGF)一beta signaling from tumor suppression to oncogenesis in early chronic hepatitis B[J】.Hepatology,2009,49(4):12O3—1217. [13]Muhanna N,Doron S,wald O,et a1.Activation of hepatic stellate cells after phagocytosis of lymphocytes:A novel pathway of ifbro— genesis[J].Hcpatology,2008,48(3):963—977. [14】Dooley S,Hamzavi J,Breitkopf K,et a1.Smad7 Prevents activation of hepatic stellate cells and liber fibrosis in rats[J].Gastroenterol— ogy,2003,125(1):178—191. [15]Lee SJ,Kim YG,Kang KW,et a1.effects of colchicine on liver Functions of cirrhotic rats;beneficial effects result from stellate cell inactivation and inhibition of TGF-beta expression[J].Chem Biol Interract,2004,147(1):9—21. 【16】陈艳艳,王晓玲,刘成海.丹酚酸B对NIH/3T3成纤维细胞TGF2因/ ERK胞内信号转导的影响[J].首都医科大学学报,2007,28(2): l92-195. [17】宋仕玲,龚作炯,张全荣.金三羲对肝纤维化大鼠TGF—beta及其 IⅡ型受体mRNA与Smad3,Smad7表达的影响【J1冲医药学刊, 2004,22(6):1044—1o47. [18]张国,张法灿,王天才,等-活’血软坚方对肝星状细胞Smad信号的 影响及意义【J].中华肝脏病杂志,2004,12(4):213. (收稿日期:2011—09-05) (本文编辑:毕轶) 8 

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