Biliary lipid secretion in the regenerating liver of the rat.

The effect of two-thirds hepatectomy on biliary lipid secretion was studied in fasted rats. Bile acids, cholesterol and phospholipids were determined in the bile of rats with biliary drainage. Bile acid and phospholipid concentrations were not significantly modified during liver regeneration but there was a significant decrease in cholesterol concentrations in bile at 12 h after hepatectomy, with a gradual return to normal values. The molar percentage of cholesterol and the calculated lithogenic index of bile were also significantly decreased by 12 h. The biliary secretion of bile acids and phospholipids, expressed per gram of liver, showed a tendency to increase regeneration, but cholesterol secretion was significantly decreased from 12 to 48 h following liver resection. Some possibilities to explain the uncoupling between cholesterol secretion and bile acid secretion are discussed.     

Biliary lipid secretion in the regenerating liver of the rat

The effect of two-thirds hepatectomy on biliary lipid secretion was studied in fasted rats. Bile acids, cholesterol and phospholipids were determined in the bile of rats with biliary drainage. Bile acid and phospholipid concentrations were not significantly modified during liver regeneration but there was a significant decrease in cholesterol concentrations in bile at 12 h after hepatectomy, with a gradual return to normal values. The molar percentage of cholesterol and the calculated lithogenic index of bile were also significantly decreased by 12 h. The biliary secretion of bile acids and phospholipids, expressed per gram of liver, showed a tendency to increase regeneration, but cholesterol secretion was significantly decreased from 12 to 48 h following liver resection. Some possibilities to explain the uncoupling between cholesterol secretion and bile acid secretion are discussed.     

Bile secretion by the rat liver during synchronized regeneration

Simultaneous coexistence of differentiated, proliferating and re-differentiated hepatocytes occurs during normal liver regeneration (LR). The aim of the present work was to study the time course of the capacity of the liver to form bile during synchronized LR. Following two-thirds partial hepatectomy (PH) in rats, i.v. administration of the ribonucleotide reductase reversible inhibitor hydroxyurea (HU) was used to transiently block liver cells at G1/S boundary. Experiments were performed at 0 and 4 hours, and 1, 3 or 7 days after releasing HU-induced inhibition. Bile acid pool size was determined by collecting bile samples over 24 hours. Initial (first hour) bile flow and bile acid output were increased early on during synchronized LR as compared with the values found in non-hepatectomized control animals. These values were thereafter (1 day) reduced, but increased again at 3 days after halting HU infusion. The time course of bile acid depletion and changes in bile flow were very similar in control and synchronized LR, except that in the latter a more important early reduction in bile flow and bile acid output was found. Shortly after PH, part of the bile acid pool was lost, but this was quickly restored, soon (1 day) reaching a net bile acid pool size very similar to that found in control rats. The highest pool size relative to liver weight was found on day 1, when bile acid output and bile flow reached their lowest values. Additional experiments were performed using in situ perfused regenerating rat livers in which stepwise infusion of taurocholate (TC) was carried out. PH alone modified neither the bile acid-independent (BAIF) nor the bile acid-dependent fraction of bile flow (BADF). However, in normal LR, the BAIF decreased on day 1 and recovered at 7 days, while in synchronized LR it remained depressed up to 7 days. The BADF was only reduced during the early phase of normal LR and did not change significantly in synchronized LR. The maximal secretion rate (SRmax) for TC, as expressed per gram of remaining liver tissue, was not affected immediately after PH, but a marked reduction was observed on day 1 in both normal and synchronized LR. Afterwards, SRmax was quickly restored in both synchronized LR and, although in a slower way, normal LR. These results suggest that synchronization of LR involves changes in the time required to the recovery of specific liver functions such as bile formation.     

大鼠肝再生启动阶段能量代谢物靶向定量分析

目的 探讨大鼠肝再生(LR)启动阶段能量代谢物的变化对LR的调控作用.方法 大鼠随机分为3组,每组5只,包括两个部分肝切除组(PH)和1个正常对照组.运用质谱选择反应检测扫描/多反应检测扫描(SRM/MRM)对29种能量代谢物的含量进行靶向代谢组学鉴定.运用Ingenuity Pathway Analysis(IPA)...     

Binuclear rat liver cells during reparative regeneration of the organ

In the early stages after partial hepatectomy (17 h after the operation) binuclear cells take part in proliferation (the number of binuclear cells in proportion to the total number of cells labeled 1 h after injection of thymidine-³H was considerably smaller, whereas in the later stages (37 and 53 h after the operation) their relative fraction in the population was twice or three times greater. The formation of new binuclear cells from mononuclear cells (reflected in the number of labeled binuclear cells 20 h after injection of thymidine-³H) took place most intensively in the early periods of regeneration (16–36 h after the operation) when about 20% of mitoses were acytokinetic and led to the formation of a binuclear cell. In the later periods only 8% of mitoses ended with the formation of binuclear cells.Laboratory of Chemical Factors of Regulation of Growth and Cell Division, Institute of Biological and Medical Chemistry, Academy of Medical Sciences of the USSR, Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR V. N. Orekhovich.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 87, No. 4, pp. 347–349, April, 1979.     

大鼠肝再生过程中caspase-8的表达与时间相关性

目的:观察大鼠肝再生过程中caspase-8表达的动态变化,探讨大鼠肝再生过程中细胞凋亡的调控机制.方法:健康雄性SD大鼠75只,随机分为3组,手术组35只,10％水合氯醛麻醉后行70％肝大部切除;假手术组35只,正常对照组5只.手术组和假手术组各自分为7个亚组,即手术完成后分别饲养大鼠3h、6h、24 h、3d、7d、11d、14d后处死,切取残肝,称重;正常组直接切取肝,称重后取材进行组织学处理,石蜡包埋,切片,做免疫组织化学显色,检测不同时间点caspase-8的表达及分布.结果:caspase-8蛋白阳性产物呈棕黄色,主要分布于细胞核.手术组caspase-8表达趋势为术后3h阳性细胞表达率开始上升,术后7d达到峰值后开始下降,但14 d时仍明显高于假手术组和正常对照组.假手术组术后3hcaspase-8表达开始上升,到24 h时达峰值并开始下降,11d时恢复到正常水平.结论:肝大部切除后肝再生中,存在着细胞凋亡的分子调控机制,早期细胞凋亡活性的升高可能为手术应激反应所致,后期持续增高的细胞凋亡则可能与肝再生终止和肝组织结构重塑的调控有关.     

大鼠肝再生氨基酸靶向代谢组学分析

目的 探讨氨基酸代谢对大鼠肝再生 (LR)的调控作用。 方法 大鼠随机分为10组,每组5只,包括9个部分肝切除组 (PH)和1个正常对照组。运用质谱选择反应检测扫描/多反应检测扫描 (SRM/MRM)对大鼠肝再生中10个时间点的20种氨基酸的含量进行靶向代谢组学鉴定,并对氨基酸含量变化进行聚类分析。 结果 丙氨酸在30、36和72 h上调;精氨酸在6和12 h上调;天冬氨酸在6、12和36 h上调;谷氨酸在6、12、30、36、72和120 h上调;组氨酸在12、24、30、36、72和120 h上调;谷氨酰胺在72 h上调;异亮氨酸在24 h下调。通过对氨基酸聚类分析发现,这些氨基酸可以聚为3类。 结论 肝再生过程中多种氨基酸发生了变化,且贯穿大鼠肝再生的全过程。氨基酸含量的变化,对肝再生中肝细胞增殖有重要作用。     

哺乳动物雷帕霉素靶蛋白信号通路相关基因对大鼠再生肝8种细胞生长过程的调节作用

个基因含于大鼠Genome 230 2.0芯片,82个基因与大鼠肝再生相关。其中,在启动阶段,mTOR信号通路主要参与激活、促进肝细胞、陷窝细胞、库普弗细胞、树突状细胞、肝星形细胞和窦内皮细胞的生长过程;在进展阶段,mTOR信号通路明显地促进肝细胞、胆管上皮细胞、卵圆细胞、肝星形细胞、库普弗细胞、陷窝细胞和树突状细胞的生长过程;在终止阶段,mTOR信号通路的大多数途径对肝细胞、库普弗细胞和树突状细胞的生长过程的促进作用减弱,而途径25却对肝细胞、窦内皮细胞、肝星形细胞和陷窝细胞的生长过程有明显的抑制作用。 结论 mTOR信号通路的25条途径和82个基因参与大鼠再生肝8种细胞的生长调控。     

Catalase-negative peroxisomes: transient appearance in rat hepatocytes during liver regeneration after partial hepatectomy.

Using light microscopy enzyme cytochemistry to localize catalase activity in peroxisomes, a population of peroxisome-negative hepatocytes was detected in livers of rats during liver regeneration induced by two-thirds partial hepatectomy. However, examination by electron microscopy revealed that this population of hepatocytes contained peroxisomes with a delimiting membrane and a nucleoid, but no cytochemically demonstrable catalase activity within their matrix. Regenerating livers 6, 18, 24, 36, 48 and 72 hours, and 1 week after partial hepatectomy showed hepatocytes without catalase activity. However, their numbers varied, with the most numerous appearing at 24 hours after partial hepatectomy. Mitosis of catalase-negative hepatocytes were seen along with mitosis of hepatocytes containing the normal complement of catalase-positive peroxisomes. The catalase-negative hepatocytes did not show evidence of apoptosis or necrotic cell death. Lysosomal acid phosphatase activity and bile canalicular ATPase activity were present in hepatocytes with catalase-negative peroxisomes. Another population of hepatocytes with a small number of catalase-positive peroxisomes appeared and were more numerous at 36 hours after partial hepatectomy; ultrastructurally, these hepatocytes contained both catalase-negative peroxisomes, which appeared to undergo dissolution, and catalase-positive peroxisomes, which were smaller in size. After complete restoration of the liver, all hepatocytes displayed essentially uniform numbers of catalase-positive peroxisomes. These studies indicated that during liver regeneration there is a transient loss of catalase in peroxisomes of some hepatocytes. These cells proliferate and with time acquire new catalase-positive peroxisomes. The observations are discussed in relation to peroxisome biogenesis, hepatocellular carcinogenesis, and oxidative stress during liver regeneration.     

大鼠肝再生过程中线粒体氧化磷酸化的调控

目的：探讨肝部分切除后肝再生过程中线粒体能量代谢的调控。方法：用雄性Ｗｉｓｔａｒ大鼠施行肝部分切除复制肝再生模型,肝部分切除后分别观察０５、１、２、４和７ｄ５个肝再生组以及５个相应的对照组,差速离心法分离肝线粒体并用氧电极极谱法测定其氧化磷酸化活性。结果：肝部分切除后肝再生过程中线粒体呼吸控制率（ＲＣＲ）明显高于相应对照组,其中肝部分切除后０５ｄ和４ｄ为二个峰值,７ｄ时降至对照组水平,早期ＲＣＲ的升高主要是Ｒ３升高的所致,１ｄ后ＲＣＲ升高是Ｒ４下降所致。磷氧比值（Ｐ／Ｏ）的变化类似于ＲＣＲ。结论：肝部分切除后肝再生过程中线粒体通过氧化磷酸化偶联增强来适应肝再生的能量需求,这种增强机制很可能主要是通过降低线粒体内膜通透性实现的。     

JNK信号通路调控大鼠再生肝8种细胞的增殖和凋亡

目的 从基因转录水平了解JNK信号通路在大鼠再生肝8种细胞中的作用。方法 用密度梯度离心和免疫磁珠等方法分离肝细胞（HC）、胆管上皮细胞（BEC）、卵圆细胞（OC）、肝星形细胞（HSC）、窦内皮细胞（SEC）、库普弗细胞（KC）、陷窝细胞（PC）、树突状细胞（DC）等8种肝脏细胞,用大鼠Genome 230 2.0芯片检测大鼠再生肝8种细胞的基因表达谱,用生物信息学和系统生物学等方法分析基因表达变化预示的JNK信号通路在调控大鼠再生肝8种细胞增殖、凋亡中的作用。用实时荧光定量PCR方法验证了芯片结果的可靠性。结果 JNK信号通路涉及240个基因和42条途径,其中,225个基因与大鼠肝再生相关。基因协同作用分析显示,在大鼠肝再生启动阶段,JNK信号通路启动HC和KC增殖,促进OC凋亡,启动部分PC和SEC增殖和促进部分PC和SEC凋亡;在进展阶段,JNK信号通路促进HC、BEC、KC和DC增殖,促进部分PC增殖、部分PC凋亡。在终止阶段,JNK信号通路促进HC、OC和PC凋亡,促进部分KC增殖、部分KC凋亡。结论 大鼠肝再生中JNK信号通路的42条途径和225个基因参与调控大鼠再生肝8种细胞的增殖和凋亡。