肝硬化患者外周血单核细胞内毒素受体表达与慢性炎症反应关系的临床意义

背景:内毒素受体在内毒素、细胞因子等介导的炎性信号转导过程中具有重要作用。目的:了解肝硬化患者外周血单核细胞(PBMC)内毒素受体的表达变化与慢性炎症反应关系的临床意义。方法:应用荧光素标记的抗人Toll样受体(TLR)4/抗人CD14单抗,以流式细胞术检测40例肝硬化患者和15名健康志愿者PBMC内毒素受体TLR4和CD14蛋白的表达;以逆转录聚合酶链反应(RT-PCR)检测内毒素受体TLR4 mRNA、CD14 mRNA和信号转导分子MyD88 mRNA的表达;以酶联免疫吸附测定(ELISA)检测血清白细胞介素(IL)-1β、IL-10和肿瘤坏死因子(TNF)-α水平;以偶氮基质显色法测定血浆内毒素水平。结果:肝硬化患者PBMC内毒素受体TLR4和CD14蛋白的表达水平显著高于对照组(P<0.05),但不同Child-Pugh分级组间差异无统计学意义;与对照组相比,PBMC内毒素受体TLR4 mRNA、CD14 mRNA和信号转导分子MyD88 mRNA的表达水平也有增高的趋势,但差异无统计学意义(P>0.05);肝硬化患者血清细胞因子IL-1β、IL-10和TNF-α水平,以及血浆内毒素水平均较对照组显著升高(P<0.05),且高内毒素水平患者内毒素受体的表达显著高于低内毒素水平患者(P<0.05),细胞因子水平也较低内毒素水平者增高。结论:肝硬化患者PBMC内毒素受体的表达明显上调,与患者的慢性炎症反应状态一致。     

内毒素受体在肝星状细胞的表达及其作用

目的了解内毒素受体在肝星状细胞活化中的变化和作用。方法分离正常大鼠的肝星状细胞，以逆转录聚合酶链反应法检测其在体外培养过程中内毒素受体（CD14和TLR4）mRNA的表达变化。以细胞免疫染色法检测肝星状细胞内毒素受体CD14的表达。制作肝纤维化和肝硬化的大鼠模型，免疫组织化学法动态检测肝组织内CD14和α平滑肌肌动蛋白的表达变化和定位。结果初分离的肝星状细胞表达低水平的CD14 mRNA，不表达TLR4 mRNA，培养活化的肝星状细胞内毒素受体的表达增强，内毒素可上调这种表达。体外培养10d的肝星状细胞表达CD14蛋白，内毒素作用后CD14表达更明显。在肝纤维化的发展过程中，肝组织内CD14阳性细胞增多，阳性细胞多分布于肝窦周围，晚期CD14阳性细胞聚集在纤维隔内，与α平滑肌肌动蛋白阳性细胞的分布一致。结论肝星状细胞在体内外的活化过程中内毒素受体的表达增强，因此，内毒素受体可能参与肝星状细胞在肝脏炎症和纤维化中的作用。     

乳黄制剂对肝硬化大鼠肠源性内毒素血症的影响

[目的]研究乳黄制剂对肝硬化大鼠肠源性内毒素血症(IETM)的影响.[方法]60只SPF级雄性Wistar大鼠随机分为4组:正常对照(正常)组、模型组、预防组、模型治疗组.采用CC14复合因素法制造肝硬化模型,用乳黄制剂进行预防和治疗,分别检测血内毒素、D-乳酸、二胺氧化酶(DAO)水平和肠道细菌移位的情况.[结果]预防组、模型治疗组内毒素水平明显低于模型组(P＜0.05);预防组血清D-乳酸、DAO水平明显低于模型组(P＜0.05),模型治疗组介于预防组和模型组之间.且预防组没有出现肠道细菌移位.[结论]乳黄制剂能有效保护肠黏膜,阻止肠通透性的增加,阻止肠道细菌移位,减少肝硬化大鼠IETM的发生.     

疏肝祛瘀通络降浊法对大鼠非酒精性脂肪性肝炎的保护作用

目的探讨非酒精性脂肪性肝炎大鼠内毒素性肝损伤机制及中药对其影响。方法用喂饲高脂饮食的方法建立非酒精性脂肪性肝炎大鼠模型。4周后用疏肝祛瘀通络降浊法分小、中、大剂量进行治疗,12周后处死测定血脂、ALT、内毒素(ET)、肿瘤坏死因子(TNF-α)和白细胞介素(IL-1β)的含量;免疫组化法观察肝组织CD14和核转录因子(NF-κB)的表达;RT-PCR检测脂多糖结合蛋白(LBP)和4型Toll样受体(TLR-4)mRNA的表达。同期正常饮食饲养大鼠作对照。结果第12周时,模型组大鼠腹主动脉血清内毒素水平较正常组明显升高,有显著性差异;中剂量治疗组大鼠血清ET、TNF-α、IL-1β水平明显低于模型组,差异有显著意义。模型组大鼠肝组织CD14阳性细胞数量明显增多,主要分布于肝窦内,部分呈灶型聚集;与模型组相比,中剂量治疗组大鼠肝组织CD14阳性细胞数量明显减少。模型组可见少量细胞核染色的NF-κB阳性细胞散在分布于汇管区。模型组肝组织LBPmRNA和TLR-4mRNA表达均明显上调,与正常组比较差异均有显著意义;中剂量治疗组大鼠肝组织LBPmRNA和TLR-4mRNA表达均较模型组明显下调,且有显著性差异。结论疏肝祛瘀通络降浊法对非酒精性脂肪肝有疗效,可能与其降低血清内毒素水平和下调肝组织内毒素相关受体表达继而减轻炎症性肝损害有关。     

益气化痰解毒中药对脂肪肝大鼠脂多糖结合蛋白CD14表达的作用

[目的]揭示益气化痰解毒中药抗脂肪性肝损伤药效学机制，探寻其辨证施治规律及安全、有效、持久的治疗方法，为中医药治疗脂肪性肝炎提供理论和实验依据。[方法]采用高脂饮食和乙醇灌胃，经8周建立大鼠脂肪肝炎模型，用益气化痰解毒中药（肝脂消颗粒剂）治疗4周，与东宝肝泰对比，观测肝组织脂多糖结合蛋白（LBP）、脂多糖受体CD14表达；血清白细胞介素6（IL-6）、丙氨酸氨基转移酶（ALT）、天冬氨酸转氨酶（AST）水平。[结果]模型组大鼠CD14 mRNA与LBP mRNA的表达明显高于正常组（P〈0．01）；肝脂消组抑制肝组织LBP、CD14 mRNA表达和降低血清IL-6、ALT、AST水平均明显优于东宝肝泰组（P〈0．05，〈0．01）。[结论]益气化痰解毒中药通过抑制肝组织LBP、CD14 mRNA的表达，阻断内毒素血症致病途径，达到有效治疗脂肪性肝炎的作用。     

葛花醒酒养胃颗粒对酒精性肝病内毒素损伤的防治作用

目的探讨葛花醒酒养胃颗粒对酒精性肝病(ALD)内毒素损伤的防治作用.方法Wistar大鼠48只随机分为正常组、模型组、葛花醒酒养胃颗粒治疗组(简称治疗组)和肝泰乐对照组(简称对照组).实验采用梯度酒精定量灌胃法制备酒精性肝病大鼠模型,造模同时治疗组予葛花醒酒养胃颗粒汤150mg·kg-1·d-1,分2次灌胃,对照组予肝泰乐水38mg·kg-1·d-1,分2次灌胃,正常组予同容积生理盐水,每日灌胃2次,连续灌胃8周后采血,检测大鼠血浆内毒素(LPS)、血清酶(ALT、AST、GGT)、血脂(Tch、TG)及血清肿瘤坏死因子(TNF-α)的含量,同时用RT-PCR法测定肝组织中脂多糖结合蛋白(LBP)和脂多糖受体CD14mRNA的表达.结果模型组大鼠血浆内毒素和血清TNF-α水平明显高于对照组(P＜0.05),肝组织中LBP和CD14mRNA的表达明显高于对照组(P＜0.05);同时血清ALT、AST、GGT、TG明显升高(P＜0.05);治疗组血浆内毒素和血清TNF-α水平明显低于模型组(P＜0.05),LBP和CD14mRNA的表达明显低于对照组(P＜0.05),血清ALT、AST、GGT、TG水平明显降低(P＜0.05).结论葛花醒酒养胃颗粒对大鼠酒精性肝损伤有较好的防治作用.     

四氯化碳诱导大鼠肝纤维化过程中TLR4的作用机制研究

目的 动态观察Kupffer细胞(KCs) Toll样受体4(TLR4)及其蛋白在四氯化碳(CCl4)致大鼠肝纤维化过程中的表达及作用.方法 用40％四氯化碳花生油溶液皮下注射建立肝纤维化模型,于第0、4、6、8、10周收集血液和肝脏组织.检测血清内毒素、Ⅳ型胶原(collagenⅣ,CⅣ)、转化生长因子β1(TGF-β1)水平,并检测KCsTLR4 mRNA表达水平,免疫组化SP法检测肝脏TLR4蛋白、核因子κB(nuclear factor-κB,NF-κB)蛋白和组织金属蛋白酶组织抑制剂-1(TIMP-1)蛋白表达.结果 大鼠4、6、8、10周组肝组织TLR4蛋白、NF-κB蛋白、纤维化积分和KCs TLR4 mRNA以及血清内毒素、TGF-β1、CⅣ型胶原水平明显升高,同0周组比较差异有统计学意义(P＜0.01).NF-κB蛋白、TLR4蛋白和KCs TLR4 mRNA在第10周时较第8周有轻度下降;肝KCs TLR4 mRNA的表达与血浆内毒素水平呈正相关(r=0.845,P＜0.01),与血清TGF-β1水平成正相关(r=0.665,P＜0.01).结论 在CCl4诱导的肝纤维化过程中,内毒素可上调Kupffer细胞TLR4的表达,其可能为通过TLR4信号途径在肝纤维化中起重要作用.     

TLR4在细菌性肺炎老龄大鼠多器官损伤中的表达及意义

目的 探讨Toll样受体4(TLR4)在老龄大鼠感染性多器官损伤发病中的意义.方法 将大鼠分为老龄对照组、老龄模型组和青年对照组、青年模型组；选用气管插管法注入肺炎克雷伯杆菌,由肺炎导致多器官损伤；采用免疫组织化学和分子生物学技术,观察肺、心、小肠组织TLR4样受体信号转导通路主要相关分子表达变化.结果 老龄模型组和青年模型组肺、心、小肠组织内毒素结合蛋白(LBP)、CD14、TLR4、白介素-1受体相关激酶(IRAK) mRNA和TLR4、肿瘤坏死因子受体相关因子-6(TRAF-6)、核因子-kB(NF-κB)阳性细胞数和/或光密度表达分别较老龄对照组和青年对照组明显增强(P＜0.01或P＜0.05),老龄模型组肺、心、小肠组织TLR4和NF-κB分子表达又较青年模型组增高显著(P＜0.01或P＜0.05).结论 TLR4信号转导介导了老年感染性多器官损伤,并发挥了重要作用.     

清肝活血方及其拆方对酒精性肝病大鼠CD14、TLR4表达的影响

目的:探讨清肝活血方及其拆方对酒精性肝病(alcoholic liver disease,ALD)大鼠肝组织CD14、TLR4表达的影响.方法:♂ Wistar大鼠100只随机分成空白组、CCl4组各10只,余80只为造模组,采用复合因素复制ALD模型6 wk.CCl4组予微量CCl4腹腔注射,每周2次.造模4 wk后将模型组随机分成4组,清肝活血方及其拆方组各15只,余为模型组.予等效剂量清肝活血方及拆方ig 2 wk.检测血清ALT,AST水平:留取肝脏标本进行HE染色.RT-PCR检测肝组织CD14 mRNA、TLR4 mRNA表达,免疫组织化学染色检测肝组织CD14表达,Wlestern blot检测肝组织TLR4蛋白表达.结果:与模型组比较,清肝活血方及其拆方均可明显改善ALD大鼠肝脏脂肪变及肝脏炎症程度(0.67±0.50,2.15±1.28,1.38±1.06 vs4.56±0.73,均P<0.01).清肝活血方能显著降低模型大鼠血清ALT水平(725.65±111.02 vs884.68±177.54,P<0.05),清肝方和活血方无明显作用;清肝方、活血方、清肝活血方均可明显降低ALD大鼠血清AST水平(2383.81±888.18,2158.93±922.85,2001.90±519.27vs 3210.98±640.63.P<0.01或0.05),组间比较无显著差异.清肝方及清肝活血方能显著降低模型大鼠CD14 mRNA表达(1.46±0.52,1.10±0.40 vs 2.67±0.66,均P<0.01).活血方作用不明显,清肝活血方优于活血方.清肝方、活血方、清肝活血方均能显著降低模型大鼠肝组织TLR4 mRNA表达(1.91±0.03,2.11±0.03,1.53±0.01 vs 2.37±0.03,均P<0.01),组间比较无显著差异.清肝活血方显著降低模型大鼠肝组织CD14表达(13 392.28±9287.54vs 32 288.89±15 631.03,P<0.01).清肝方、活血方、清肝活血方均能显著降低模型大鼠肝组织TLR4表达(1.06±0.10,1.19±0.05,0.98±0.12 vs 1.40±0.11,均P<0.01).结论:清肝活血方及其拆方发挥对ALD的防治作用,其作用机制可能与降低CD14、TLR4基因和蛋白的表达有关.     

基于TLR4/MyD88/NF-κB信号通路探讨毒消肝清丸对肝硬化内毒素血症大鼠肝组织炎症反应的影响

目的通过CCl4复合造模制备肝硬化内毒素血症模型,探讨毒消肝清丸对大鼠肝脏炎性损伤的保护机制。方法:66只大鼠造模过程中有17只死亡,取3只大鼠检测内毒素和观察肝脏结构,确定造模成功,剩余随机分成正常组(n=6),模型组(n=8)、乳果糖组(n=8)、毒消肝清丸高、中、低剂量组(223. 4 mg/kg、111. 7 mg/kg、58. 9 mg/kg,n=8)。采用CCl4复合造模法造模8周,制备肝硬化内毒素血症动物模型。正常组和模型组给予蒸馏水,乳果糖组予乳果糖,毒消肝清丸药物组按上述剂量每天给药1次,连续8周。测定内毒素含量变化、HE染色观察肝脏组织变化情况、采用ELISA检测肝脏组织TNFα、IL-1β、IL-6的含量;Western Blot和RT-PCR技术检测TLR4、MyD88、NF-κB蛋白及其mRNA的表达。计量资料多组间比较采用单因素方差分析,进一步两两比较采用LSD-t法。结果各组间大鼠血浆内毒素水平差异有统计学意义(F=26. 011,P 0. 001);模型组内毒素水平较正常组显著升高(P 0. 01);给药后乳果糖组、毒消肝清丸不同剂量组大鼠血清内毒素含量较模型组均显著降低(P值均0. 01)。各组间大鼠血清IL-6、IL-1β以及TNFα水平差异均有统计学意义(F值分别为35. 390、38. 271、40. 241,P值分别为0. 002、0. 001、0. 001);与正常组比较,模型组大鼠血清IL-1β、IL-6以及TNFα显著升高(P值均0. 01);给药后乳果糖组及毒消肝清丸不同剂量药物组大鼠血清IL-1β、IL-6以及TNFα水平较模型组均显著降低(P值均0. 01)。各组间大鼠肝组织TLR4、MyD88、NF-κB mRNA及其蛋白表达差异均有统计学意义(F值分别为24. 483、29. 547、19. 242、18. 752、22. 146、15. 834,P值均0. 01);与正常组大鼠相比,模型组大鼠肝脏TLR4、MyD88、NF-κB mRNA及其蛋白相对表达量均显著升高(P值均0. 01);乳果糖和毒消肝清丸不同剂量治疗后大鼠肝组织TLR4、MyD88、NF-κB mRNA及其蛋白相对表达量较模型组均显著下降(P值均0. 01)。与低剂量治疗组比较,中高剂量组大鼠肝脏TLR4、MyD88、NF-κB mRNA及其蛋白相对表达量下降尤为显著(P值均0. 01)。结论药物组可能通过下调肝脏组织TLR4/MyD88/NF-κB信号通路来抑制炎症信号的转导,减少了细胞因子TNFα、IL-1β、IL-6的表达,进而缓解内毒素血症并对肝脏组织起到保护作用。     

丹黄方对大鼠肝再生过程中PC3、c—fos、LRF—1影响的实验研究

目的：探讨丹黄方对大鼠肝切除肝再生模型中促肝细胞再生的作用机制。方法：采用肝部分切除肝再生模型，用丹黄方进行干预，通过RT-PCR、电泳凝胶等方法检测与肝再生密切相关因子PC3 mRNA、c-fos mRNA、LRF-1 mRNA的表达，观察丹黄方对肝细胞再生的影响。结果：丹黄方对肝再生模型大鼠肝组织PC3 mRNA、c-fos mRNA的表达有增强作用，与模型比较，差异有显著性意义；对肝组织LRF-1 mRNA表达的影响不显著。结论：丹黄方可能是通过增强肝组织PC3 mRNA、c-fosmRNA的表达而促进肝细胞的增殖。     

Regulation of liver angiotensinogen mRNA by glucocorticoids and thyroxine

This study examines the immediate and longer-term changes in angiotensinogen mRNA and in plasma angiotensinogen which follow the withdrawal and replacement of glucocorticoids or thyroxine. RNA from rat liver was analysed by Northern blot and dot-blot hybridization with a 40-mer oligodeoxynucleotide probe specific for angiotensinogen mRNA. Adrenalectomy decreased plasma angiotensinogen and angiotensinogen mRNA to 55 and 50% of control values respectively over a period of 16 days. Similar decreases were obtained after propylthiouracil (1 mg/kg for 16 days) treatment, except when injected simultaneously with T3 (3 micrograms/kg/day). Over the same period plasma renin activity increased in adrenalectomized rats from 4.1 +/- 0.8 to 7.0 +/- 1.5 pmol angiotensin I (AI)/ml/h, and decreased in propylthiouracil-treated rats from 3.8 +/- 0.4 to 1.6 +/- 0.4 pmol AI/ml/h. Approximate half-times of 2-3 days were calculated for both plasma angiotensinogen and angiotensinogen mRNA post-adrenalectomy or after propylthiouracil treatment. Dexamethasone (400 micrograms/kg, i.m.) given to intact rats rapidly increased angiotensinogen mRNA to a maximum of 250% of control by 8 h and with a half-maximal response of 2.8 h. Plasma angiotensinogen responded similarly, apart from an initial delay of 2 h. Treatment with different doses of propylthiouracil and dexamethasone showed that responses were dose-related. We conclude that changes in plasma angiotensinogen and angiotensinogen mRNA are closely correlated, and that under various physiological circumstances angiotensinogen mRNA has a rapid rate of accumulation but a slow rate of decay.     

Effect of feeding, fasting, and diabetes on liver glycogen synthase activity, protein, and mRNA in rats

Summary Hepatic glycogen synthase activity is increased in diabetic animals. However, the relationship between enzymic activity, enzyme protein mass, and mRNA abundance has not been well characterized. In the present study, these relationships were determined in 3- and 8-day diabetic, fed and fasted rats. The results were compared to data obtained in normal fed and fasted animals. In normal rats, total synthase specific activity and protein mass were similar in the fed and fasted state. However, in fed animals, the synthase mRNA abundance was increased 1.7-fold. In 3-day diabetic rats, total synthase specific activity was increased approximately 29 % compared to normal controls. It was unaffected by feeding and fasting and was associated with an approximate 15 % increase in enzyme mass. Synthase mRNA was increased 1.8 and 2.6-fold in fasted and fed animals, respectively. In 8-day diabetic rats, total synthase specific activity was increased more than 2-fold compared to controls. However, the enzyme protein mass was decreased by approximately 20 %. The mRNA abundance in 8-day diabetic fasted rats was only 30 % of controls, while in fed rats it was increased by 40 %. These data indicate that feeding and fasting have a major effect on synthase mRNA abundance which is independent of synthase activity, or protein mass, or both, in normal and diabetic animals. Total synthase specific activity increased with duration of diabetes. This was associated with only a modest change in protein mass. Thus, diabetes induces an increase in synthase catalytic efficacy. The specific activity of phosphorylase is decreased in diabetic rats. [Diabetologia (1997) 40: 758–763] Received: 18 October 1996 and in revised form: 23 January 1997     

Presence of albumin mRNA precursors in nuclei of analbuminemic rat liver lacking cytoplasmic albumin mRNA.

Analbuminemic rats, which lack serum albumin, were previously found to have no albumin mRNA in the cytoplasm of the liver. In the present study, the existence of nuclear albumin mRNA precursors in the liver of analbuminemic rats was examined by RNA X cDNA hybridization kinetics. Albumin mRNA precursors were present in the nuclei of analbuminemic rat liver at almost normal levels, despite the absence of albumin mRNA from the cytoplasm. Nuclear RNA of analbuminemic rat liver was subjected to electrophoresis on 1% agarose gel in parallel with nuclear RNA of normal rat liver. RNA was transferred from the gel to diazobenzyloxymethyl-paper and hybridized to cloned cDNA. Several bands of putative albumin mRNA precursors were obtained with nuclear RNA of analbuminemic rat liver and some of them were indistinguishable from those of normal rat liver. Nuclear RNA of analbuminemic rats was hybridized to 3'-end-labeled cloned cDNA under the conditions of RNA excess and then digested completely with S1 nuclease and subjected to electrophoresis on polyacrylamide gel. By this technique, nuclear RNA that could hybridized to cDNA was found to have the albumin mRNA sequence in at least the 3' half of the mRNa that was covered by cloned cDNA. For comparison of the structures of the albumin genes of analbuminemic and normal rats, DNAs from rat livers of both types were digested completely with EcoRI, HindIII, and Pst I; the fragments were separated by electrophoresis on 1% agarose gel, transferred to nitrocellulose paper, and hybridized to cloned cDNA. The intensities of the corresponding bands and the digestion patterns of the analbuminemic and normal rat genes were indistinguishable. From these data, it is concluded that analbuminemic rats have a unique type of mutation(s) affecting albumin mRNA maturation.     

Androgen receptor messenger ribonucleic acid (mRNA) in the rat liver: changes in mRNA levels during maturation, aging, and calorie restriction

By means of RNAase protection assay with an antisense cRNA probe, we have shown that the liver of the young adult male rat contains androgen receptor (AR) mRNA to a level of 4% compared to the prostate. Steady state levels of AR mRNA in the liver show both sex and age specificity. Compared to that of the male, the female liver contains a markedly reduced amount of AR mRNA. AR mRNA is almost undetectable in livers of prepubertal male (less than 35 days old) and senescent male (greater than 750 days old) rats. Both prepubertal and senescent animals are relatively insensitive to the androgenic induction of alpha 2u-globulin, a hepatic secretory protein. The age-dependent decline in hepatic androgen sensitivity and AR mRNA level can be delayed considerably by a 40% reduction in the dietary calorie intake. Analysis of poly(A)-containing RNA from two liver cell populations, hepatocytes and nonhepatocytes, revealed that only the hepatocytes that express alpha 2u-globulin gene contain AR mRNA. From these results and our earlier observation of in vitro induction of alpha 2u-globulin in isolated rat liver, we conclude 1) that androgen can act directly on hepatocytes to promote alpha 2u-globulin synthesis; 2) that changes in the hepatic androgen sensitivity during maturation and aging are reflections of the age-dependent expression of the receptor gene; and 3) that retardation of the age-dependent loss of androgen sensitivity by calorie restriction is due to a concomitant delay in the decline of the hepatic AR mRNA level.     

betaA- and betaC-activin, follistatin, activin receptor mRNA and betaC-activin peptide expression during rat liver regeneration

The mRNA expression of two activin growth factor subunits (betaA- and betaC-activin), activin receptor subunits (ActRIIA, ActRIIB) and the activin-binding protein follistatin, and peptide expression of betaA-activin and betaC-activin subunits, were examined in regenerating rat liver after partial hepatectomy (PHx). Liver samples were collected from adult, male Sprague-Dawley rats, 12-240 h (n=3-5 rats per time point) after PHx or from sham-operated controls at the same time points. Hepatocyte mitosis and apoptosis were assessed histologically and by in situ cell death detection. RT and PCR were used to assess relative gene expression. betaA- and betaC-activin peptide immunoreactivity was assessed in liver and serum samples by western blotting, whereas cellular expression was investigated by immunohistochemistry, using specific monoclonal antibodies. betaA- and betaC-activin mRNA dropped to < 50% of sham control values 12 h after PHx and remained at this level until 168 h post-PHx, when betaA-activin expression increased to three times sham control values and betaC-activin mRNA returned to pre-PHx levels. A peak in follistatin expression was observed 24-48 h post-PHx, coincident with an increase in hepatocyte mitosis. No changes were observed in ActRIIA mRNA, whereas ActRIIB expression paralleled that of betaA-activin mRNA. betaC-activin immunoreactive homo- and heterodimers were observed in regenerating liver and serum. Mitotic hepatocytes frequently contained betaC-activin immunoreactivity, whereas apoptotic hepatocytes were often immunoreactive for betaA-activin. We conclude that betaA- and betaC-activin subunit proteins are autocrine growth regulators in regenerating liver and when expressed independently lead to hepatocyte apoptosis or mitosis in a subset of hepatocytes.     

Expression of collagen XVIII mRNA in rat liver fibrosis]

OBJECTIVE: To measure and study quantitatively the collagen XVIII mRNA in normal and fibrotic rat livers. METHODS: We used ribonuclease protection assay to investigate the collagen XVIII mRNA expression in rat liver fibrosis induced by complete bile duct occlusion (BDO). The expression level of procollagen 1 (XVIII) mRNA was compared with that of procollagen 1 (I) and tissue inhibitor of metalloproteinase 1 (TIMP1). RESULTS: mRNA levels of procollagen and TIMP 1 increased 20- and 4-fold in BDO rat livers, respectively. In contrast, hepatic procollagen 1 mRNA level increased only 1.8-fold in fibrotic rat livers. CONCLUSION: C XVIII mRNA is upregulated slightly in liver fibrosis, which is probably correlated with the fact that CXVIII is mainly expressed by hepatocytes.     

XⅧ型胶原mRNA在实验性肝纤维化大鼠肝脏中的表达

目的 了解ＸⅧ型胶原（ｃｏｌｌａｇｅｎ ＸⅧ，ＣＸⅧ）ｍＲＮＡ在实验性肝纤维化中的定量改变。方法 以逆行胆管硬化注射加结扎的方法制备大鼠胆管堵塞性肝纤维化模型，以假手术组大鼠为对照组。提取肝脏总ＲＮＡ，以核酸酶保护分析（ＲＮＡ酶保护分析）定量测定前胶原α１（ＸⅧ）ｍＲＮＡ水平，并与α（１）和金属蛋白酶组织抑制因子１（ＴＭＰ－１）的ｍＲＮＡ变化相比较。结果 与假手术组大鼠相比，胆管堵塞性肝纤维化大鼠     

The liver of Fundulus heteroclitus expresses deiodinase type 1 mRNA

The presence of a type 1 deiodinase (D1) in the liver of teleosts has been a controversial issue. Recently we characterized the deiodinase activity in rainbow trout and killifish liver and found that the liver of both species co-expresses the two enzymes (D1 and D2) that catalyze the outer ring-deiodinating pathway. We here report the cloning and characterization of an mRNA from the liver of the killifish Fundulus heteroclitus that encodes a D1 (FhD1). The cDNA amplified by RT-PCR from F. heteroclitus liver is 1314 nt long and encodes a protein of 248 aa. It contains a TGA codon in its open reading frame and a selenocysteine insertion sequence in its 3(') untranslated region, consistent with the structure of a selenoenzyme mRNA. The deduced peptide sequence is 73% identical to that encoded by the tilapia D1 cDNA cloned from kidney and 46% identical to the D1s reported in other vertebrates. Northern blot analysis shows that FhD1 mRNA is expressed in F. heteroclitus liver, consistent with prior biochemical evidence for hepatic D1 activity. Furthermore, heterologous expression of the FhD1 cDNA resulted in a protein with properties similar to the D1-like activity in F. heteroclitus liver. The cloned enzyme, like the native species, is relatively insensitive to inhibition by PTU, but mutation of Ser-159 in FhD1 to the Pro residue found in D2 and D3 isoforms increased the sensitivity to PTU. Our results show that, under basal conditions, killifish liver indeed expresses a D1 enzyme that is homologous to mammalian D1s, establishing this as a useful model in which to study the regulation of D1 and D2 concurrently.