大鼠肝再生过程中毛细胆管增生的形态计量研究

Morphometric analysis of the liver during regeneration after partial hepatectomy showed that the mean area and number of bile canaliculi increased, while the volume density of microvilli related to the lumina of the canaliculi decreased. These changes were observed 12 hours after the operation, which gradually returned to normal on the third day after operation. It indicated that the decrease of volume density of microvilli was the result of enlargement of bile canaliculi, which was different from the decrease of microvilli due to passive widening of the canaliculi such as in cholestasis from loss of microvilli. All these phenomena suggest that enlargement of the area of bile canaliculi during liver regeneration may be due to the increase of membranous protein synthesis. Moreover, the increase of the number of bile canaliculi suggests that the proliferation of hepatocytes is associated with formation of new branches of bile canaliculi.     

缺血预处理对大鼠肝大部切除后肝再生基因表达谱的影响

目的应用基因芯片研究大鼠肝缺血预处理后残存肝组织再生过程中基因表达谱的动态变化。方法Sprague—dawley（SD）大鼠肝在缺血再灌注前行缺血预处理（10min缺血后10min再灌注）,再灌注期间行70％肝叶切除建立余肝再生模型．用affmetrix RAT GeneArray 1．0ST基因表达谱芯片筛选大鼠再生肝组织中差异表达基因进行功能分析及归类。结果再生肝组织有差异表达基因1103条,涉及代谢相关基因、细胞周期调控基因、炎症反应相关基因、凋亡相关基因、信号传导相关基因、细胞因子相关基因、生长因子基因等,差异表达基因显著性的表达趋势有7种。结论缺血预处理后肝再生的过程是多基因调控的动态变化过程,用基因芯片有助于研究肝再生的机制,为促进肝再生提供治疗的潜在靶点。     

肝硬变大鼠肝大部分切除后肝再生的实验研究

本实验通过用四氯化碳(CCl_4)诱发大鼠肝硬变模型,进行肝大部分切除.观察残肝的再生动态变化.发现四氯化碳诱发的中轻度肝硬变大鼠可以耐受70%的肝切除,其残肝有再生能力,但较正常鼠肝缓慢.术后1个月左右才恢复术前大小.     

大鼠肝大部切除后再生时贮脂细胞的动态变化

目的 研究大鼠肝大部切除后再生时贮脂细胞的动态变化。方法 用结蛋白免疫组织化学法显示肝贮脂细胞并计量，以图像分析仪测灰度值。结果 正常肝小叶内贮脂细胞呈网架状分布，肝大部切除后再生时贮脂细胞数量递减，至第５ｄ时为正常肝的１／３。结论肝大部切除后再生时贮脂细胞动态变化明显不同于肝中毒等损伤后的增殖变化。     

应用流式细胞计对大鼠肝大部切除后肝细胞增殖周期动态的研究

本文报道应用激光流式细胞计(FCM)研究大鼠肝大部切除后肝细胞增殖周期的动态,并计数了肝细胞分裂指数和双核肝细胞数。正常大鼠4倍体(4n)肝细胞占76％,肝再生过程中也以4n肝细胞增殖为主。术后12～20小时,部分4n肝细胞迅速分裂,2n肝细胞比例增多,双核肝细胞比例减少。术后24小时,出现4n肝细胞S期和8n肝细胞比例高峰,直至120小时仍可见8n肝细胞峰。术后36小时,肝细胞分裂达高峰。此后,双核肝细胞明显减少。术后48～72小时,出现第2次肝细胞DNA合成峰和分裂峰,但在出现的时间和细胞比例上个体差异较大。     

大鼠肝再生过程中miR-27b与Tmub1表达相关性研究

目的探讨miR-27b与Tmub1在大鼠70%肝大部分切除术肝脏再生过程中的表达相关性。方法将SD雄性大鼠(180±20)g,随机分为实验组(肝部分切除术,partial hepatectomy,PH)和假手术组(剖腹探查手术,exploratory laparotomy),依次提取0、12、24、48及72 h原代肝细胞并留取组织标本,利用real-time PCR检测不同时间段肝脏内miR-27b与Tmub1 m RNA的量,并利用Western blot检测不同时间段肝脏内Tmub1蛋白含量,从而分析出miR-27b与Tmub1蛋白表达的时间相关性;将miR-27b模拟物转染入肝细胞,采用荧光素酶报告基因检测系统观察miR-27b对Tmub1表达的影响。结果肝切除12、24、48及72 h后PH组miR-27b表达较假手术组均显著下降(P0.05),而该相同时相点Tmub1 m RNA及蛋白水平显著增高(P0.05);改变miR-27b的表达后,含Tmub1基因序列的报告基因荧光素酶活性明显下降(P0.05)。结论肝再生过程中miR-27b与Tmub1的表达呈负相关,miR-27b可能参与了Tmub1的表达调控过程。     

索拉菲尼对肝硬化大鼠部分肝切除术后肝脏再生的影响

目的: 在大鼠肝硬化模型的基础上行肝脏部分切除(PH),研究索拉菲尼(sorafenib)对大鼠肝脏再生的影响。方法: 使用二乙基亚硝胺(DEN)诱导Wistar大鼠肝硬化,成功建立30只肝硬化大鼠PH模型后,随机分2组,每组15只。术后第1 d开始,分别给予实验组索拉菲尼(30 mg·kg^-1·d^-1)、对照组生理盐水灌胃10 d后处死。留取PH后及实验结束后的血液及肝脏标本,检测2组肝脏再生率(LRR),增殖细胞核抗原(PCNA),生化指标: 丙氨酸转移酶(ALT)和血清白蛋白(ALB)、血清总胆红素(TBIL)和血清直接胆红素(DBIL)的变化,血管生成相关因子:血管内皮生长因子(VEGF)、血管内皮生长因子受体2(VEGFR-2)、血小板源性生长因子受体β(PDGFR-β),以及肝脏微血管密度(MVD)的变化。结果: (1)LRR在实验组及对照组分别为45.43%±3.36%和44.21%±2.77%,无显著差异(P>0.05);(2)免疫组织化学(IHC)没有检测到PCNA;(3)2组的生化指标无显著差异(P>0.05);(4)实验组VEGFR-2和PDGFR-β的表达受到抑制,MVD降低,并且实验组与对照组差异有统计学意义(P<0.01)。结论: 索拉菲尼虽然对肝硬化血管再生相关因子有抑制作用,但是对肝细胞再生和肝功能没有明显影响。     

大鼠再生肝提取物对肝再生中肝细胞增殖的影响

大鼠肝大部(67%)切除24小时后取残肝匀浆,经加热,酒精沉淀、透析等步骤制备提取物,腹腔注射给正常大鼠和32%肝切术后的大鼠。光镜下观察肝组织切片,计算肝细胞有丝分裂百分率。鼠再生肝提取物可使32%肝切术后24-48小时再生肝细胞有丝分裂百分率明显增加,尤其在术后30小时可达对照组的3.9倍。结果表明,再生肝提取物中含有能够促进肝细胞增生的肝再生刺激因子(HSS),此因子对增殖前期(G_0/G_1早期)细胞作用不明显。     

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。     

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.     

Lateral hypothalamic lesions facilitate hepatic regeneration after partial hepatectomy in rats

It has been reported that ventromedial hypothalamic lesions facilitate hepatic regeneration through the hepatic vagal nerve after partial hepatectomy. However, whether the lateral area of the hypothalamus is involved in liver regeneration after partial hepatectomy is unknown. To determine the role of the lateral hypothalamic area in this phenomenon, we studied hepatic DNA synthesis during liver regeneration after partial hepatectomy with bilateral lesions of the area. Lesioning of the lateral hypothalamus accelerated the increase in hepatic DNA synthesis and raised the peak level of [methyl-³H]thymidine incorporation after partial hepatectomy. These effects of hypothalamic lesioning were inhibited by combined hepatic vagotomy and sympathectomy. Our results demonstrate that lesioning of the lateral hypothalamus promotes hepatic regeneration through the autonomic nervous system after partial hepatectomy and suggest that the lateral hypothalamic area is involved in liver regeneration through neural mediation.     

Facilitation of liver regeneration after partial hepatectomy by ventromedial hypothalamic lesions in rats

Whether or not the hypothalamus is involved in initiating hepatic DNA synthesis after partial hepatectomy is unclear. To determine the role of the ventromedial hypothalamic nuclei in liver regeneration after partial hepatectomy, we studied hepatic DNA synthesis during liver regeneration in rats with bilateral lesions of these nuclei. Lesions of the ventromedial hypothalamus accelerated the increase in hepatic DNA synthesis and raised the peak level of thymidine incorporation after partial hepatectomy. These effects of hypothalamic lesions were completely inhibited by hepatic vagotomy. Thus, lesions of the ventromedial hypothalamus appear to promote hepatic regeneration by increasing vagal stimulation of the liver.     

Reparative regeneration of rat fetal liver after partial hepatectomy

A reproducible model of fetal liver regeneration was created. Resection of 20% liver was carried out in rat fetuses on day 17 of prenatal development. The organ weight was restored after 2 days at the expense of an increase in hepatocyte mitotic activity; cell hypertrophy was minor. After recovery, the cell composition of the operated liver did not differ from the control, i.e. the regeneration was organotypical.     

Dynamic change in expression of LECT2 during liver regeneration after partial hepatectomy in mice

Leukocyte-cell-derived chemotaxin 2 (LECT2) was first isolated from the culture fluid of phytohemagglutinin-activated human T-cell leukemia SKW-3 cells and was found to be expressed in the human, bovine and murine livers. To further analyze the role of LECT2 in the liver, we investigated the expression of mouse LECT2 (mLECT2) during liver regeneration after partial hepatectomy (PHx) using immunohistochemical and in situ hybridization techniques. Mouse LECT2 protein and mRNA were detected in most hepatocytes in normal mouse; however, at 30 min after PHx, they were not detected in liver tissue. At 2 h after PHx, expression of mLECT2 protein was seen in hepatocytes surrounding the central vein, although mRNA expression levels were still low. At 6 h after PHx, a marked number of hepatocytes expressing mLECT2 protein and mRNA were seen throughout the liver, and at 12 h after PHx, hepatocytes expressing mLECT2 protein and mRNA further increased in number. However, expression levels of mLECT2 protein and mRNA at 24 h after PHx were significantly lower when compared with levels after 12 h. These results indicate that LECT2 triggers the early events of regeneration with concomitant suppression of hepatocyte proliferation.