不同性别小鼠化学性肝损伤后的肝再生能力比较

背景：肝脏再生能力受多重因素的影响,而性别是否是再生修复过程的一个重要因素尚无定论。 目的：比较不同性别小鼠化学性肝损伤后肝脏再生能力是否有差异。 方法：采用四氯化碳小鼠皮下注射方法建立急性化学性肝损伤模型。120只昆明小鼠随机均分为糖原染色组和5-溴脱氧尿嘧啶核苷组,各组再按照性别均分为雌雄两组,于造模后第1,3,5,7,10天完整取下小鼠肝脏并称质量,取材前称量小鼠体质量。 结果与结论：造模后第7天雌性鼠恢复原肝质量/体质量比,而雄性鼠则表现为下降趋势,不同性别小鼠肝质量/体质量比在各时间点差异无显著性意义(P > 0.05);四氯化碳诱导的急性肝损伤主要部位为肝小叶周围的门管区及界板区,损伤部位肝细胞出现脂肪变,少数肝组织出现点状坏死;损伤后1,5,7 d雌性小鼠糖原染色明显强于雄性组(P < 0.05);肝损伤后3 d雌性鼠肝脏5-溴脱氧尿嘧啶核苷标记指数高于雄性小鼠(P < 0.05),而第1,5,7,10天则未见明显差异(P > 0.05)。说明肝损伤后雌性鼠的再生修复比雄性鼠强,于第7天完成修复。不同性别的昆明小鼠对四氯化碳诱导的急性肝损伤后恢复期中肝脏再生能力具有差异性。     

丹参酮IIA对CCl4诱导小鼠急性肝损伤的保护作用

目的 研究丹参酮IIA(tanshinone ⅡA, Tan ⅡA)对CCl4诱导小鼠急性肝损伤的抗氧化、保护作用及其可能的作用机制。 方法 将C57BL/6J小鼠随机分成正常组、CCl4组以及Tan ⅡA保护组(Tan ⅡA 20 mg/kg+CCl4),每组10只。腹腔注射CCl4构建小鼠急性肝损伤模型。计算各组小鼠的肝脏指数,检测血清AST和ALT活性,测定肝组织SOD活性及GSH、MDA含量,HE染色观察肝组织病理变化,免疫组织化学法和Western blot检测肝组织PI3K、p-PI3K、Akt、p-Akt、Nrf2和HO-1蛋白表达水平。 结果 与CCl4组相比,Tan ⅡA保护组肝脏指数显著下降(P<0.01),血清AST(P<0.01)和ALT活性降低(P<0.05),肝组织SOD活性(P<0.01)及GSH含量升高(P<0.05),MDA含量降低(P<0.05),肝组织病理变化得到显著改善。同时,Tan ⅡA使肝组织p-PI3K和p-Akt表达水平明显升高(P<0.01),显著诱导Nrf2转位入核(P<0.01),促使其下游靶蛋白HO-1表达水平明显升高(P<0.01)。 结论 Tan ⅡA能够显著改善CCl4诱导的急性肝损伤,其机制可能与PI3K/Akt/Nrf2/HO-1信号通路有关。     

大麻素受体2缺失促进伴刀豆球蛋白A所致急性肝损伤小鼠肝巨噬细胞的增殖与活化

目的探讨大麻素受体2(CB2)缺失对伴刀豆球蛋白A(ConA)所致急性肝损伤小鼠肝巨噬细胞的影响。方法 20只8周龄野生型(WT)C57BL/6J雄性小鼠分为对照组、模型组; 20只CB2基因敲除(CB2~(-/-))C57BL/6J雄性小鼠随机分为CB2~(-/-)对照组、 CB2~(-/-)模型组。WT和CB2~(-/-)小鼠模型组尾静脉注射ConA(20 mg/kg)复制小鼠急性肝损伤模型,对照组注射等量PBS。造模9 h后,留取血清检测丙氨酸氨基转移酶(ALT), HE染色观察各组肝损伤情况, Western blot法分别检测肝巨噬细胞相关CD68、肿瘤坏死因子α(TNF-α)蛋白水平,免疫组织化学染色法检测肝组织F4/80的表达。结果与两组对照组相比,两组模型组小鼠肝脏损伤程度严重,血清ALT明显增高,肝组织F4/80阳性表达及CD68、 TNF-α蛋白水平均明显增强;与WT模型组比较, CB2~(-/-)模型组小鼠肝损伤程度和损伤面积增加,血清ALT有所增高,肝组织F4/80阳性表达以及CD68和TNF-α蛋白水平均有所升高。结论 CB2基因缺失促进ConA所致急性肝损伤小鼠肝脏中巨噬细胞的增殖与活化。     

普通肝素通过抑制炎症反应和细胞凋亡缓解内毒素血症小鼠肝损伤

目的探讨普通肝素对内毒素血症小鼠肝损伤的保护作用及其机制。方法成年雄性C57BL/6小鼠,随机分成3组(每组8只):正常对照组,脂多糖组,脂多糖+普通肝素组。脂多糖(30mg/kg)腹腔内注射建立内毒素血症小鼠模型。造模前0.5h予以普通肝素(8单位/20g体重)或等量生理盐水腹腔注射,造模后8h处死小鼠,留取血及肝脏组织做进一步分析。血清ALT和AST的水平用商业试剂盒测定,小鼠肝脏的组织病理学用苏木精-伊红(HE)染色观察,用免疫组织化学(IHC)染色观察肝组织内巨噬细胞(F4/80阳性)的浸润情况,肝组织caspase-3蛋白的表达用免疫组化和Western-blot法检测,实时荧光定量PCR测定肝脏IL-1β和IL-6m RNA的表达,TUNEL染色技术检测肝细胞凋亡。结果普通肝素预处理显著降低内毒素血症小鼠肝脏炎症因子(IL-1β和IL-6)的表达水平,减少肝脏巨噬细胞浸润,减轻脂多糖诱导的肝脏损伤与肝细胞凋亡。结论普通肝素可能通过抑制炎症反应和细胞凋亡对脂多糖诱导的肝损伤发挥保护作用。     

β-catenin在四氯化碳诱导的小鼠肝纤维化过程中的定位、表达及意义

目的 探讨肝纤维化发生过程中β-连环蛋白(β-catenin)定位、表达及意义.方法 健康雄性昆明小鼠(n=45)随机分为对照组(n=15)与实验组(n=30).实验组小鼠皮下注射50% 四氯化碳(CCl4)-粟米油混合液(6ml/kg),2次∕周,对照组皮下注射同等剂量的粟米油.各组分别于造模1周、4周和8周后取小鼠肝脏,常规制作石蜡切片,Masson染色及Desmin免疫组织化学法观察比较不同组别小鼠肝纤维化病理变化,RT-PCR及免疫组织化学方法检测不同时间点各组小鼠肝组织内β-catenin的表达及定位.结果 Masson染色结果显示,对照组肝汇管区结缔组织内及血管壁有少量细小纤维,实验组小鼠肝脏汇管区和中央静脉及其周围胶原纤维增多;随损伤时间延长纤维增生愈加明显.Desmin免疫组织化学结果显示,各组别均有阳性表达,但损伤组各时间点desmin阳性表达细胞数明显高于对照组(P<0.05 或P<0.001).RT-PCR结果显示,CCl4损伤1周后肝内β-catenin mRNA水平与对照组相比无明显差别(P＞0.05),损伤4周及8周β-catenin mRNA水平则明显下降,与对照组相比差异均有显著性(P<0.01).免疫组织化学结果显示,对照组β-catenin弱表达于肝细胞膜及胆管上皮细胞膜和胞质,而损伤组β-catenin阳性反应主要定位于肝内增生的细胞团及新生胆管上皮细胞质,各组间积分吸光度值差别有显著性(P<0.01).结论 CCl4诱导的肝纤维化过程中β-catenin mRNA表达与蛋白表达不同步,阳性表达细胞主要为新生的细胞团及胆管上皮细胞.     

肝再生增强因子通过增加调节T细胞数量保护小鼠急性肝损伤

目的研究肝再生增强因子(ALR)保护急性肝损伤的作用及机制。方法将30只BALB/c小鼠随机分为正常对照组、急性肝损伤组和ALR干预组。急性肝损伤组小鼠按2 m L/kg体质量的剂量予以腹腔注射500 m L/L四氯化碳(CCl4)矿物油溶液1次。ALR干预组于CCl4注射前8 h尾静脉注射ALR质粒,正常对照组注射等量生理盐水注射液。收集小鼠肝组织和血液标本,HE染色观察肝组织病理形态学变化;生化法检测血清丙氨酸氨基转移酶(ALT)、天冬氨酸氨基转移酶(AST)水平;流式细胞术检测肝组织中调节性T细胞(Treg)的数量,实时定量PCR(qRT-PCR)检测肝组织Foxp3、ALR、白细胞介素6(IL-6)、肿瘤坏死因子α(TNF-α)的mRNA水平。结果 ALR干预组小鼠肝组织中ALR mRNA表达水平显著高于急性肝损伤组和正常对照组,急性肝损伤组与正常对照组相比无明显差异;流式细胞术检测结果显示ALR干预组小鼠肝组织中CD25+Foxp3+Treg/CD4+T细胞为(5.90±0.10)%,高于急性肝损伤组的(4.23±0.46)%和正常对照组的(2.93±0.74)%,急性肝损伤组显著高于正常对照组;ALR干预组小鼠肝组织中Foxp3 mRNA表达水平高于急性肝损伤组和正常对照组,急性肝损伤组高于正常对照组,但差异无统计学意义;ALR干预组与急性肝损伤组相比,IL-6 mRNA、TNF-αmRNA表达水平降低,而与正常对照组相比无明显变化,急性肝损伤组与正常对照组相比,IL-6 mRNA、TNF-αmRNA表达水平明显升高。结论 ALR通过上调Treg数量保护小鼠急性肝损伤,可能与Treg下调肝脏IL-6、TNF-α表达有关。     

LPS预处理减轻CCl4诱导的慢性肝损伤

目的:探讨脂多糖(LPS)预处理对四氯化碳(CCl4)诱导的肝损伤的影响及相关的信号转导分子的变化。方法:雄性Wistar大鼠随机分为正常对照组、肝损伤组和LPS预处理组。肝损伤组和LPS预处理组经皮下注射CCl4并同时饲以高脂饮食造模,于实验第4周末处死动物,取血浆测定内毒素水平和ALT活性;取肝组织测定TNF-α水平;Western blotting测定肝组织中TLR4、p38、p-p38、IκΒ、NF-κΒp65表达;制备肝脏切片,观察肝脏病理改变。结果:LPS预处理可明显减轻CCl4所致肝损伤,经LPS预处理动物血浆ALT活性显著低于肝损伤组（P<0.01）;肝匀浆的TNF-α测定结果表明,LPS预处理组TNF-α含量明显低于肝损伤组（P<0.01）。LPS预处理组TLR4、p-p38、NF-κΒ的表达显著低于肝损伤组,而IκΒ表达显著高于肝损伤组。结论:LPS预处理可以减轻CCl4诱导的肝损伤, LPS预处理引起相关信号转导通路发生了改变,致使致炎因子分泌减少可能是其作用机制。     

小鼠骨骼肌电转移hPON1 Q基因可以减轻CCl4诱导的急性肝损伤

目的 研究人Q型对氧磷酶1(human paraoxonase 1 Q,hPON1Q)转基因表达对小鼠四氯化碳(carbon tetrachloride,CCl4)诱导急性肝损伤的缓解效果,为防治肝脏疾病寻找新的途径.方法 小鼠骨骼肌直接注射含hPON1Q的真核表达质粒裸DNA并用电刺激介导表达,测量血清芳香酯酶的活性变化显示hPON1Q转基因表达效果,并使用血清谷丙转氨酶(ALT)、谷草转氨酶(AST)为指标及肝组织病理切片检测肝损伤的程度.结果 hPON1Q转基因表达小鼠血清中芳香酯酶活性提高约50%,并可持续到16 d以后.使用PON1裸DNA电刺激治疗组比对照组小鼠在用CCl4诱导24 h后血清芳香酯酶活性高60%,两种血清转氨酶指标及肝组织切片的病理学分析表明肝脏损伤程度有明显的减轻.结论 电刺激介导的重组人PON1Q基因裸DNA在小鼠体内的表达对CCl4诱导的肝损伤具有显著的防护作用.     

CD38蛋白下调炎症因子的表达减轻脂多糖联合D-氨基半乳糖诱导的急性肝脏损伤

目的研究CD38蛋白在脂多糖联合D-氨基半乳糖(LPS/D-GalN)所诱发的小鼠急性肝损伤中的作用。方法野生型C57BL/6小鼠(WT)和CD38基因敲除小鼠(CD38 KO)随机分为正常对照组,模型早期组和模型晚期组。在造模后2 h和6 h处死动物,检测血清谷丙转氨酶(ALT)和谷草转氨酶(AST),实时荧光定量PCR检测肝脏组织炎症因子的表达,HE染色检测组织病理改变。结果在LPS/D-GalN诱导的模型小鼠中,与WT小鼠相比,CD38 KO小鼠血清ALT和AST水平显著升高,肝脏组织中炎性因子白细胞介素1β(IL-1β)、IL-6、肿瘤坏死因子α(TNF-α)以及γ干扰素(IFN-γ)的表达水平显著升高;病理组织学检测显示肝脏组织出血严重,肝实质细胞空泡变形明显增多,肝细胞死亡显著增加。结论 CD38蛋白通过下调炎症因子的表达,减少肝细胞死亡,减轻LPS/D-GalN诱导的急性肝脏损伤。     

表没食子儿茶素没食子酸酯通过Wnt/β-catenin信号通路改善免疫性肝炎小鼠肝损伤

目的观察表没食子儿茶素没食子酸酯(EGCG)对免疫性肝炎小鼠肝损伤的保护作用,探讨Wnt/β-catenin信号通路的作用机制。方法 SPF级C57B6小鼠45只,随机分为3组:对照组(Control)、EGCG药物干预组(EGCG)、免疫性肝炎模型组(AIH),采用ConA诱导性肝损伤法建立AIH模型,EGCG组小鼠予以EGCG(100 mg/kg)灌胃,余组予以等量生理盐水,连续给药28 d,ELISA检测各组谷丙转氨酶(ALT)、谷草转氨酶(AST)变化,苏木精-伊红(HE)染色染色及PAS染色观察各组大鼠肝脏病理学变化及糖原表达,Western blot、qPCR法检测肝脏组织中Wnt/β-catenin信号通路相关因子Wnt1、β-catenin的表达情况。结果 ConA诱导性肝损伤法可以明显导致小鼠肝功能损伤,血浆总ALT、AST表达水平显著升高,病理学可见肝脏组织广泛被破坏,细胞排列紊乱,界线模糊不清,汇管区可见大量条索状胶原纤维增生向肝小叶内延伸,分割破坏肝小叶结构,PAS染色可见糖原表达较低。经EGCG干预后,小鼠肝功能明显得到改善,血浆总ALT、AST表达显著降低,病理学可见肝细胞结构较完整,界线清楚,细胞排列基本有序,部分可见炎性细胞浸润及假小叶形成,PAS染色显著得到改善,且EGCG可以明显下调肝脏组织中Wnt1、β-catenin表达(P0.05)。结论 EGCG可以明显改善免疫性肝炎小鼠肝功能,减轻肝细胞损伤,其作用机制可能与其介导Wnt/β-catenin信号通路有关。     

原卟啉钠对急性肝损伤小鼠肝组织SOD、MDA的影响

 目的 探讨原卟啉钠对四氯化碳（CCl4）致急性肝损伤小鼠血清转氨酶和肝组织超氧化物歧化酶（SOD）、脂质过氧化产物丙二醛（MDA）的影响。方法 60只ICR小鼠随机分为正常对照组、CCl4模型组、联苯双酯组、原卟啉钠低、中、高剂量组。各治疗组每天灌胃给药及造模16h后,摘眼球取血测定血清中谷丙转氨酶（ALT）和谷草转氨酶（AST）活性,剖腹取肝测定肝脏SOD活力和MDA含量。结果 CCl4模型组小鼠血清ALT和AST活力分别为（1879±1219）、（2210±1585）U/L,与正常对照组比较,降低显著（P<0.01）;联苯双酯组、原卟啉钠低、中、高剂量组的SOD活力和MDA含量分别为（207.61±16.02）、（184.35±13.42）、（190.88±17.77）、（199.38±14.43）U/mgprot和（1.08±0.15）、（1.35±0.26）、（1.07±0.16）、（0.92±0.18）nmol/mgprot,与CCl4模型组比较,差异有统计学意义（P<0.05～P<0.01）。结论 原卟啉钠能有效阻止CCl4致急性肝损伤小鼠肝组织SOD活性降低,脂质过氧化产物MDA含量升高,具有一定的保肝降酶作用。     

Protective effect of xanthohumol on toxin-induced liver inflammation and fibrosis

Xanthohumol, the major prenylated chalcone found in hops, is known for its anti-inflammatory properties. We have recently shown that xanthohumol inhibits hepatic inflammation and fibrosis in a murine model of nonalcoholic steatohepatitis. The aim of this study was to investigate the effect of xanthohumol in an acute model of liver injury. Carbon tetrachloride (CCl(4)), an industrial solvent, is a hepatotoxic agent and its administration is widely used as an animal model of toxin-induced liver injury. Xanthohumol was applied orally at a dose of 1 mg/g body weight 2 days prior as well as during and after exposure to CCl(4). 72 h after a single CCl(4) application histomorphology and serum levels of transaminases revealed considerable hepatocellular necrosis, which was accompanied by significantly enhanced hepatic expression of pro-inflammatory cytokines. Furthermore, elevated hepatic alpha-smooth muscle actin expression indicated activation of hepatic stellate cells, and in accordance, we detected enhanced hepatic expression levels of TGF-β and collagen type I reflecting a marked fibrogenic response to CCl(4) exposure. While the degree of hepatocellular damage in response to CCl(4) was similar in mice which received xanthohumol and the control group, pro-inflammatory and profibrogenic hepatic gene expression were almost completely blunted in xanthohumol fed mice. Furthermore, xanthohumol fed mice revealed decreased hepatic NFκB activity. These results suggest that the protective effects of xanthohumol in this toxic liver injury model involves direct mechanisms related to its ability to block both hepatic inflammation and the activation of hepatic stellate cells, presumable at least in part via decreasing NFκB activity. Thus, this study further indicates the potential of xanthohumol application to prevent or ameliorate the development and progression of liver fibrosis in response to hepatic injury.     

敲除Colgalt2基因加重小鼠急性肝损伤

目的：初步探讨Colgalt2基因介导的胶原Glcα1,2 Galβ1?糖基化修饰在急性肝损伤过程中的作用。方法取60只Colgalt2＋／＋小鼠和60只Colgalt2－／－小鼠进行急性肝损伤实验,雌雄各半。每组随机选取20只小鼠腹腔注射CCl4（CCl4∶橄榄油＝2∶7,20 ml／kg）。观察小鼠死亡情况,并绘制生存曲线。每组剩余40只小鼠随机分为0、4、8、12 h组,每组10只,腹腔注射CCl4（剂量同上）。分别于0、4及8 h各处死6只小鼠,之后将4及8 h组剩余的小鼠均纳入12 h组（ Colgalt2＋／＋小鼠, n＝14; Colgalt2－／－小鼠, n＝16）,并于12 h处死小鼠。 HE染色观察肝组织的病理学改变,取血清进行生化指标ALT、 AST测定。利用qRT?PCR和Western印迹技术检测小鼠Colgalt2在基因及蛋白水平的表达情况。结果Colgalt2基因在Col?galt2＋／＋小鼠肝组织内表达,而在Colgalt2－／－小鼠肝组织内不表达。注射CCl4后10 h, Colgalt2＋／＋小鼠死亡率为35％, Colgalt2－／－小鼠死亡率为70％,两组小鼠死亡率差异显著（P＜0．05）。注射CCl4后12 h, Colgalt2＋／＋小鼠死亡率达50％, Colgalt2－／－小鼠死亡率为70％,差异不显著（P＞0．05）。肝功检测及HE染色结果均提示,与Colgalt2＋／＋小鼠相比, Colgalt2－／－小鼠肝损伤较重。注射CCl4后,野生型小鼠Colgalt2在RNA水平和蛋白水平表达下调。结论 Colgalt2基因敲除在一定程度上可加重小鼠急性肝损伤。该观察结果提示, Colgalt2基因介导的胶原Glcα1,2 Galβ1?糖基化修饰可能与肝损伤的修复有关。     

BMP-7 attenuates liver fibrosis via regulation of epidermal growth factor receptor

The aim of this study was to elucidate the effect of bone morphogenetic protein-7 (BMP-7) on liver fibrosis induced by carbon tetrachloride (CCl4) in vivo and on the hepatic stellate cells (HSC) activation in vitro. In vivo, thirty male ICR mice were randomly allocated to three groups, the control group (n = 6), the CCl4 group (n = 18) and the BMP-7+CCl4 group (n = 6). The model of liver fibrosis was induced by intraperitoneal injection with CCl4 three times per week lasting for 12 weeks in CCl4 group and the BMP-7+CCl4 group. After 8 weeks injection with CCl4, mice were intraperitoneal injected with human recombinant BMP-7 in BMP-7+CCl4 group. Meanwhile, mice in the CCl4 group were only intraperitoneal injection with equal amount of saline. The degree of liver fibrosis was assessed by HE and Masson’s staining. PCR and western blot were used to detect mRNA and protein levels. In BMP-7+CCl4 group, serum levels of alanine aminotransferase (ALT) and aminotransferase (AST) were decreased and serum albumin (Alb) was increased. Meanwhile, the expressions of transforming growth factor-β1 (TGF-β1) and α-smooth muscle actin (α-SMA) were down-regulated by BMP-7 intervention as compared to the CCl4 group (P < 0.05). Furthermore, BMP-7 also suppressed the expression of epidermal growth factor receptor (EGFR) and phosphorylated-epidermal growth factor receptor (pEGFR). HE and Masson stain showed that liver damage was alleviated in BMP-7+CCl4 group. In vitro study, expression of EGFR, TGF-β1 and α-SMA were down regulated by BMP-7 dose-dependently, indicating it might effect on suppression of HSC activation. Therefore, our data indicate BMP-7 was capable of inhibiting liver fibrosis and suppressing HSCs activation, and these effects might rely on its crosstalk with EGFR and TGF-β1. We suggest that BMP-7 may be a potential reagentfor the prevention and treatment of liver fibrosis.     

肝纤维化大鼠转化生长因子β1/Smad蛋白的动态表达及意义

目的 探讨转化生长因子TGF-β1/Smad信号通路在实验性肝纤维化发生中的作用.方法 50只健康雄性SD大鼠分为2组:正常组和模型组,模型组大鼠利用40％ CCl4油剂诱导形成肝纤维化模型,于6周及9周观测肝标本的病理,免疫组化法检测肝组织TGF-β1/Smad蛋白表达.结果 ①肝组织病理:与正常组比较,模型组大鼠肝组织都有不同程度的炎症和纤维化产生.模型组纤维化程度较正常对照组明显,差异有统计学意义(P＜0.05);②TGF-β1/Smad基因蛋白:免疫组织化学检测显示,与正常对照组相比,模型组大鼠肝脏中TGF-β1、转化生长因子βⅠ型受体(TβR-Ⅰ)、Smad2/3、Smad7蛋白表达均显著增强(P＜0.01),模型组大鼠肝脏TGF-β1、TβR-Ⅰ、Smad2/3和Smad7之间存在正相关关系(P ＜0.05或0.01);模型组大鼠肝脏纤维化分级与TGF-β1、TβR-Ⅰ、Smad2/3和Smad7之间存在正相关关系(P＜0.05或0.01).结论 肝组织TGF-β1/Smad蛋白表达水平与肝纤维化程度相关,TGF-β1/Smad信号的增强可能促进了肝纤维化的进展.     

Invariant natural killer T-cell-deficient mice display increased CCl₄ -induced hepatitis associated with CXCL1 over-expression and neutrophil infiltration

Invariant natural killer T (iNKT) cells are involved in the intrahepatic immune response and in hepatitis. In particular, iNKT lymphocytes are responsible for hepatocyte death in concanavalin A-induced hepatitis in mice. We examined the role of iNKT cells in acute hepatitis induced by a hepatotoxic agent, carbon tetrachloride (CCl(4) ). WT and iNKT cell-deficient (Jα18(-/-) ) mice were challenged with a single dose of 2.4 g/kg CCl(4) and both hepatic physiopathology and immune responses were studied. Plasma alanine and aspartate amino-transferase levels were significantly higher in Jα18(-/-) mice than in WT mice two days after CCl(4) administration. Chemokine CXCL1/keratinocyte-derived chemokine (KC) and MMP-8 were significantly higher in iNKT cell-deficient mice than in control mice. The more severe liver injury in Jα18(-/-) mice was associated with greater leukocyte infiltrate, which was enriched in neutrophils (CD11b(+) CD11c(-) Gr-1(+) cells), in agreement with CXCL1/KC and MMP-8 levels. Complementary experiments with NK-depleted animals indicate a minor role for NK cells in the liver damage found in iNKT-deficient mice. Thus, unlike for ConA-induced hepatitis, we report that iNKT cells protect the liver against acute hepatitis induced by CCl(4) and limit neutrophil infiltration.     

肝纤维化大鼠转化生长因子β1／Smad蛋白的动态表达及意义

目的探讨转化生长因子TGF—β1／Smad信号通路在实验性肝纤维化发生中的作用。方法50只健康雄性SD大鼠分为2组：正常组和模型组,模型组大鼠利用40％CCl4油剂诱导形成肝纤维化模型,于6周及9周观测肝标本的病理,免疫组化法检测肝组织TGF—β1／Smad蛋白表达。结果①肝组织病理：与正常组比较,模型组大鼠肝组织都有不同程度的炎症和纤维化产生。模型组纤维化程度较正常对照组明显,差异有统计学意义（P〈0．05）;②TGF—β1／Smad基因蛋白：免疫组织化学检测显示,与正常对照组相比,模型组大鼠肝脏中TGF—β1、转化生长因子βI型受体（TβR—I）、Smad2、3、Smad,蛋白表达均显著增强（P〈0．01）,模型组大鼠肝脏TGF—β1、TβR-I、Smad。和Smad,之间存在正相关关系（P〈0．05或0．01）;模型组大鼠肝脏纤维化分级与TGF—β1、TβR—I、Smad2/3和Smad,之间存在正相关关系（P〈0．05或0．01）。结论肝组织TGF—β1／Smad蛋白表达水平与肝纤维化程度相关,TGF-β1／Smad信号的增强可能促进了肝纤维化的进展。     

Hepatoprotective versus oncogenic functions of STAT3 in liver tumorigenesis

Aberrantly hyperactivated STAT3 has been found in human liver cancers as an oncogene; however, STAT3 has also been shown to exert hepatoprotective effects during liver injury. The balancing act that STAT3 plays between hepatoprotection and liver tumorigenesis remains poorly defined. In this study, the diethylnitrosamine (DEN)-induced liver tumor model and the chronic carbon tetrachloride (CCl(4))-induced liver fibrosis model were both used to investigate the role of STAT3 in liver tumorigenesis. Hepatocyte-specific STAT3 knockout mice were resistant to liver tumorigenesis induced by a single DEN injection, whose tumorigenesis was associated with minimal chronic liver inflammation, injury, and fibrosis. In contrast, long-term CCl(4) treatment resulted in severe hepatic oxidative damage, inflammation, and fibrosis but rarely induced liver tumor formation in wild-type mice. Despite the oncogenic function of STAT3 in DEN-induced liver tumor, hepatocyte-specific STAT3 knockout mice were more susceptible to liver tumorigenesis after 16 weeks of CCl(4) injection, which was associated with higher levels of liver injury, inflammation, fibrosis, and oxidative DNA damage compared with wild-type mice. These findings suggest that the hepatoprotective feature of STAT3 prevents hepatic damage and fibrosis under the condition of persistent inflammatory stress, consequently suppressing injury-driven liver tumor initiation. Once liver tumor cells have developed, STAT3 likely acts as an oncogenic factor to promote tumor growth.