肝纤维化形成中细胞学机制的研究进展

一、肌成纤维细胞:目前认为肌成纤维细胞主要来自激活的肝星状细胞(hepatic stellate cell,HSC)及门静脉成纤维细胞(portal fibroblast,PF),也可从骨髓源性细胞分化而来.也有报道称肝细胞及胆管上皮细胞可以通过上皮-间质转化(epithelial-to-mesenchymal transition,EMT)而来,然而仍存在争议.     

干扰素治疗肝纤维化机制的研究进展

肝纤维化是多种病因导致慢性肝病共有的病理改变,肝纤维化为一动态过程,属可逆性病变,但若进一步发展至肝硬化阶段,则不可逆,因此阻断抑制或逆转肝纤维化是治疗慢性肝病的一个十分重要的目标.干扰素(interferon,IFN)具有广泛的抗病毒、抗肿瘤和免疫调节作用.目前有许多研究认为干扰素(IFN)具有抗肝纤维化作用,并已在临床应用中取得一定效果,但其抗肝纤维化的确切机制尚不明了,有学者认为可能与其抗病毒,抑制肝星状细胞的活化增殖,促进肝星状细胞的凋亡,抑制细胞外基质(ECM)合成,促进细胞外基质降解等作用有关.     

Jak/Stat信号通路在经典CCl_4大鼠肝纤维化模型中的动态变化及扶正化瘀方对其影响

目的探讨Jak/Stat信号通路在经典的CCl4大鼠肝纤维化模型中的动态变化及扶正化瘀方对其影响。方法复制经典的CCl4大鼠肝纤维化模型和肝纤维化扶正化瘀方干预模型,收集纤维化形成、逆转和干预过程中不同时间的血液和肝组织,观察血清指标、肝组织病理、α-SMA表达及肝组织Jak1、Stat3蛋白和mRNA表达变化。多组间比较采用单因素方差分析。结果 CCl4应用后模型组大鼠肝组织炎症及纤维化逐渐加重,α-SMA及Jak1、Stat3表达逐渐升高,8周时达高峰。8周后随着CCl4停用,大鼠肝组织炎症和纤维化逐渐好转,上述指标亦较前明显降低;扶正化瘀方干预组第4、6、8周时大鼠血清指标,肝组织炎症和纤维化程度、Jak1、Stat3表达均较模型组相同时间点明显降低。结论 Jak/Stat信号通路在肝纤维化发生和逆转中发挥重要作用,扶正化瘀方可通过阻断Jak/Stat通路及减少肝星状细胞活化发挥抗肝纤维化作用。     

MMPs在动脉粥样硬化斑块局部的调控机制

基质金属蛋白酶（MMPs）在动脉粥样硬化的发生、发展过程中扮演重要角色,不仅涉及斑块局部炎性细胞浸润、血管平滑肌细胞迁移,还可通过降解细胞外基质促使斑块破裂。动脉粥样硬化斑块局部MMPs的调控机制十分复杂,包括转录、翻译、酶原激活及激活后调节等多个方面。     

放射性肺纤维化中细胞因子的调控机制研究现状

放射性肺纤维化是胸部肿瘤放疗及骨髓移植预处理中常见而难治的并发症.近年来对放射性肺纤维化形成机制的最重要的认识就是细胞因子作为中心环节启动和维持胶原蛋白代谢调控失衡,使得放射性肺纤维化成为一个正反馈的进行性加重过程.细胞因子的合成受到转录因子调控,其调控过程错综复杂.钙振荡作为普遍存在的信号形式能够高效、特异地调节转录因子的活性和细胞因子表达·与放射性肺纤维化的形成机制相关联.     

基质金属蛋白酶-9与肝纤维化关系的研究进展

肝纤维化是由于基质金属蛋白酶(matrix metalloproteinases,MMPs)及其组织抑制因子(tissue inhibitor of metalloproteinasas,TIMPs)比例失调,造成细胞外基质大量沉积在细胞间质中,引起的病理改变。目前研究发现MMP-9在肝纤维化形成过程中有诱发和促进作用,但也有一些相反的意见,认为其具有逆转肝纤维化的作用,与肝纤维化呈负相关。因此,本文就近年来对MMP-9功能的研究作一概述。     

实验性肝纤维化大鼠Ⅳ型胶原酶的表达

肝纤维化是以胶原为中心的细胞外基质(ECM)在肝脏异常的沉积。这种异常的沉积,更大程度是由于降解的绝对或相对减少而引起的。肝纤维化时,在ECM降解过程中起主导作用是基质金属蛋白酶(MMPs)。Ⅳ型胶原酶(MMP-2)是特异性Ⅳ型胶原降解酶,与肝纤维化的形成有关。现以四氯化碳(CCl4)大鼠肝纤维化模型,采用northern印迹杂交,明胶酶谱     

Delivery of matrix metalloproteinase-1 attenuates established liver fibrosis in the rat

BACKGROUND & AIMS: During hepatic fibrogenesis, the hepatic extracellular matrix changes to fibrillar collagens types I and III, and cirrhosis is believed to produce an irreversible scar. In this study, we investigated whether gene delivery of human matrix metalloproteinase-1, which degrades collagens types I and type III, would attenuate established hepatic fibrosis in the rat, induced by either thioacetamide or bile duct ligation. METHODS: Hepatic fibrosis induced by thioacetamide for 7 weeks was persistent for at least 2 months, even after discontinuation of the treatment. The rats were infected once with a recombinant adenovirus, Ad5MMP-1, into which human pro-human matrix metalloproteinase-1 complementary DNA was packaged, or with a control adenovirus, Ad5LacZ. RESULTS: In Ad5MMP-1-infected, but not in Ad5LacZ-infected, rats, the fibrosis was dramatically attenuated at 2 weeks after the infection. It is interesting to note that the number of activated hepatic stellate cells was also decreased in Ad5MMP-1-infected rats. Moreover, disorganization of the hepatic trabecula, heterogeneity in the size of hepatocytes, and increased dried liver weight were observed only in Ad5MMP-1-treated rats, suggesting that human matrix metalloproteinase-1 stimulated hepatocyte proliferation, which was confirmed by bromodeoxyuridine staining. After 4 weeks, the proliferative effect of human matrix metalloproteinase-1 almost disappeared, but the hepatic fibrosis remained attenuated, whereas the fibrosis in Ad5LacZ-treated rats persisted. Furthermore, the administration of Ad5MMP-1, but not Ad5LacZ, decreased type I collagen and generated a small collagen fragment in hepatic fibrosis induced by bile duct ligation. CONCLUSIONS: Our findings show that transient human matrix metalloproteinase-1 overexpression in the liver effectively attenuates established fibrosis and induces hepatocyte proliferation.     

肝卵圆细胞分化调控机制的研究进展

卵圆细胞是肝脏的干细胞，具备多向分化潜能，体内外实验证实其可以分化为肝细胞、胆管细胞、胰腺及肠型上皮细胞。在胚胎发育过程中，肝脏干细胞以肝细胞的形式存在，而在成年哺乳动物的肝组织中则以卵圆细胞的形式存在。对卵圆细胞分化调控机制的研究在基础理论和临床应用等方面均有重要意义，一方面，卯圆细胞可能参与肝脏损伤的修复与重建，研究其分化机制有助于阐明肝脏的发育机制；另一方面，卵圆细胞可分化为具有功能的成熟肝细胞，将为肝细胞移植和生物型人工肝提供重要的细胞来源，可能缓解供体肝脏严重缺乏的矛盾。但卵圆细胞的分化过程和机制非常复杂，分化异常可能导致肝细胞癌的发生。     

酒精性肝纤维化基质降解机制的研究

目的：揭示酒精性肝病肝纤维化基质降解的病原机制。方法：28例酒精性肝炎肝穿刺组织按其纤维化程度分为3组，利用原位杂交技术以寡聚核苷酸为探针，分别检测各组MMP－1、MMP－2、MT1－MMP和TIMP－1 mRNA的表达情况。结果：发现MMP－1、MMP-2、MT1－MMP和TIMP－1 mRNA表达阳性的细胞主要是肝窦壁细胞（可能为增生的HSC）和少数肝细胞；MMP－2、MT1－MMP 和TIMP－1mRNA表达阳性细胞数随肝纤维化程度的增加而增多，相反，MMP－1 mRNA表达阳性细胞数则随肝纤维化程度的增加而减少。结论：HSC可能是肝组织内产生MMP－1、MMP－2、MT1－MMP和TIMP－1的主要细胞，在酒精性肝纤维化ECM沉积中起重要作用；MMP－1减少和TIMP－1增多可能是EMC沉积，尤其是I型胶原过量沉积的原因；而MMP－2和MT1－MMP增多的意义尚须进一步确定。     

汉防己甲素对大鼠实验性肝纤维化的防治作用

目的:汉防己甲素(Tet)为中药粉防己根的提取物。本研究的目的为评价其抗肝纤维作用。方法:用40％CCl_41.2ml/kg体重皮下注射,2次/周,共12周,诱发SD大鼠肝纤维化。于初次注射开始,用Tet(治疗组)或盐水(对照组)灌胃,隔日1次共12周。分别于4、8、12、14周处死动物测定血清Ⅲ型前胶原(PCⅢ)、肝及血清透明质酸(HA)、胶原、储脂细胞(FSC)及其细胞器。结果:Tet可使血清PCⅢ、HA及肝HA降低,肝内胶原沉积减少。治疗结束时,血清PCⅢ为61.8±21.0ug/L,而对照组为270.2±46.1ug/L(P<0.01);血清HA分别为204.0±70.8ug/L与565.2±161.9ug/L(P<0.01);肝组织HA为86.9±15.3ug/g与186.5±46.2ug/g(P<0.01)。FSC及其内织网与线粒体受抑。结论:我们的实验结果显示Tet能抑制肝内胶原的沉积,可用于治疗慢性肝病之肝纤维化。     

肝星状细胞活化相关信号通路在肝纤维化中的研究进展

肝纤维化是多种慢性肝损伤造成的细胞外基质(extracellular matrix, ECM)过度累积及降解不足的病理结果,如不加以干预会逐渐进展为肝硬化,甚至肝细胞癌。肝星状细胞(hepatic stellate cell, HSC)是ECM的主要来源,并且HSC在肝纤维化的起始、发展和消退过程中发挥关键作用。近年来,HSC活化涉及的信号传导通路成为研究热点,本文总结了HSC活化过程中的重要信号通路。     

中药双甲五灵冲剂对免疫性肝纤维化大鼠抗肝纤维化的分子机制研究

目的探讨中药双甲五灵冲剂对免疫诱导型肝纤维化大鼠的治疗作用及机制。方法90只雌性Wistar大鼠。10只大鼠为正常对照组,80只大鼠予尾静脉注射人血白蛋白,建立免疫损伤性肝纤维化大鼠模型,分为5组：预防组、治疗1组、治疗2组、秋水仙碱组、观察组。用光镜观察肝脏HE染色、VanGieson（VG）胶原染色,采用原位杂交及免疫组织化学染色技术检测大鼠肝脏组织中TIMP-1、TIMP-2、Ⅰ型胶原、Ⅲ型胶原mRNA及蛋白的表达强度;用电镜观察肝脏超微结构的变化。结果免疫诱导型肝纤维化大鼠在造模结束后肝组织学改变呈进行性加重,以造模结束后3个月为著;TIMP-1、TIMP-2、Ⅰ型胶原、Ⅲ型胶原mRNA及蛋白呈强阳性表达,电镜见观察组有较多激活的HSC及大量胶原纤维沉积在肝窦间隙及肝细胞间,经双甲五灵冲剂治疗后的大鼠与观察组大鼠相比,肝组织结构明显好转,纤维组织减少,未见到激活的HSC、TIMP-1和TIMP-2mRNA及蛋白表达与观察组相比均明显降低,Ⅰ、Ⅲ型胶原蛋白及基因表达明显降低（P〈0．05）,并且其效果为预防组效果最好,治疗1组较治疗2组效果好,三组均明显优于秋水仙碱组。结论双甲五灵冲剂可以逆转肝纤维化,抗肝纤维化机制可能是：①抑制肝星状细胞活化,减少ECM的生成及TIMP分泌;②直接抑制TIMP—1、TIMP-2mRNA及蛋白的表达;二者共同作用使得TIMP分泌减少,从而降低对MMPs的抑制,有利于MMPs对ECM的降解;③具有加速Ⅰ、Ⅲ型胶原的降解,抑制其生成及沉积的作用。     

Study of heteroseruminduced rat liver fibrosis model and its mechanism

AIM: To investigate the morphological changes in the process of heteroserum induced rat liver fibrosis and the mechanism of fibrogenesis of this model.METHODS: A model of heteroserum-induced rat liver fibrosis was established by intraperitoneal injection of porcine serum. In addition to the observation of the morphological changes of this model, the infiltration of eosinophils and mast cells were measured quantitatively and the deposition of IgG and complement C₃ was detected by immunofluorescence.RESULTS: The rat liver fibrosis was induced successfully at the end of the 8th week after the injection of heteroserum. Besides the increase of hepatic stellate cells (HSC) during the process of liver fibrosis, proliferation and activation of primary mesenchyma cells (PMCs) were also found. In the early stage, the infiltration of eosinophils and mast cells was significantly increased and the deposition of IgG and complement C₃ was positive in the portal tracts and septa, while gradually reduced after the injection was stopped.CONCLUSIONS: This model is suitable for the research on liver fibrogenesis; the pathogenesis of this model may be related with the allergen-induced late phasereaction (LPR) caused by the injection of heteroserum, and the HSCs and the PMCs are important sources of ECM-producing cells.     

牛磺酸抑制实验性肝纤维化大鼠细胞外基质沉积

目的研究牛磺酸抗肝纤维化作用。大法用四氯化碳（ＣＣＩ４）制备肝纤维化模型;免疫组化检测肝Ⅰ、Ⅲ、Ⅵ型胶原和透明质酸、层粘连素沉积;Ｎｏｒｔｈｅｒｎｂｌｏｔ杂交检测肝Ⅰ、Ⅲ型前胶原、组织金属蛋白酶抑制因子－１（ＴＩＭＰ—１）ｍＲＮＡ含量。结果ＣＣＩ４肝纤维化大鼠肝脏Ⅰ、Ⅲ、Ⅵ型胶原、透明质酸和层粘连素染色明显增多;Ⅰ、Ⅲ型前胶原、ＴＩＭＰ－１ｍＲＮＡ显著增加。牛磺酸处理的大鼠,上述各指标的阳性染色明显减少,并可明显抑制Ⅰ、Ⅲ型前胶原基因表达,而对ＴＩＭＰ—１ｍＲＮＡ却无明显影响。结论牛磺酸对ＣＣＩ４诱导的大鼠肝纤维化具有保护作用,可明显抑制纤维生成与沉积。提示它对防治肝纤维化有一定的临床意义。     

Transglutaminase-mediated cross-linking is involved in the stabilization of extracellular matrix in human liver fibrosis

BACKGROUND/AIMS: Lysyl oxidase-mediated cross-linking contributes to the stabilization of collagen in liver fibrosis. We have investigated transglutaminase-mediated cross-linking, to determine if it participates in the stabilization of extracellular matrix in human liver fibrosis. METHODS: Transglutaminase activity was assessed in vitro by incorporation of biotinylated amine into liver proteins. The product of the transglutaminase-catalyzed cross-linking reaction, Nepsilon(gamma-glutamyl)lysine, and the extracellular proteins cross-linked by it, were localized by immunohistochemistry in fibrotic livers. The cross-linked complexes were extracted from liver tissue, immunopurified and characterized by Western blot. RESULTS: Transglutaminase, detected by immunohistochemistry, Western blot and by enzymatic activity, was found in higher amounts in fibrotic than in normal liver. The Nepsilon(gamma-glutamyl)lysine cross-link, undetectable in normal liver, was present extracellularly in fibrotic liver, where it was co-distributed with osteonectin, mostly in inflammatory areas submitted to an intense remodeling. Cross-linking of osteonectin by transglutaminase was confirmed by Western blot. In parasitic fibrosis transglutaminase also originates from the parasite. CONCLUSIONS: Transglutaminase-mediated cross-linking occurs in liver extracellular matrix during the early, inflammatory, stage of liver fibrosis, whereas cross-linking by pyridinoline occurs mostly later in the fibrotic process. This could lead to the development of new anti-fibrotic treatments targeted to a specific stage of fibrosis.     

肝素抗肝纤维化作用机制及临床疗效评价

探讨肝素对慢性乙型肝炎患者肝纤维化的影响及作用机制。将63例慢性乙型肝炎患者随机分为A(26例)、B(37例)两组,分别给予常规药物治疗和肝素治疗。治疗前后分别检测血清丙氨酸转氨酶(ALT)、总胆红素(TB il)、透明质酸(HA)、Ⅳ型胶原(CⅣ)和转化生长因子-β1(TGF-β1)、血管性假性血友病因子(vWF)水平。B组中6例分别于治疗前后行肝活检术。治疗后A、B两组的ALT、TB il水平均显著下降。B组治疗后HA、CⅣ、TGF-β1及vWF水平均显著下降,而A组HA、CⅣ水平反较治疗前升高,TGF-β1及vWF水平无明显变化。B组治疗后肝组织原纤维增生减轻,肝星状细胞恢复正常。肝素通过抑制肝星状细胞活化和改善肝脏微循环达到抗纤维化的目的。     

调节性T细胞在慢性阻塞性肺疾病与支气管哮喘中的作用机制研究

调节性T细胞（regulatoryTcell,Treg细胞）是一组以负免疫调节功能为主的CD4＋T细胞亚型,介导免疫调节及加强免疫耐受,维持内环境稳态。Treg细胞的异常与许多慢性炎症性疾病及自身免疫性疾病的发生发展有关。慢性阻塞性肺疾病（chronicobstructivepulmonarydisease,COPD）及支气管哮喘均表现为由不同的炎症细胞浸润的气道慢性炎症性疾病。但研究发现Treg细胞在两种疾病中的数量及水平表现不一,由此推测Treg细胞在两种疾病中的作用机制可能存有差异。现就Treg细胞在两种疾病中的作用机制做一综述。