Effect of glucocorticoid on liver regeneration after partial hepatectomy in the rat.

The increase in activities of hepatic thymidylate synthetase (EC 2.1.1.45) and thymidine kinase (EC 2.7.1.21), which catalyse the formation of thymidylate through the de novo and salvage pathways, respectively, were significantly suppressed during liver regeneration in rats which were given glucocorticoids (hydrocortisone and dexamethasone) or indomethacin. These drugs also prevented the augment of hepatic DNA content in 24 h regenerating liver.     

5-羟色胺2A受体阻断剂对大鼠肝脏再生的影响

目的观察5-羟色胺2A受体阻断剂酮色林对大鼠肝部分切除后肝再生的影响,了解5-羟色胺及其受体在肝脏再生中的作用。方法 80只雄性Wistar大鼠随机分为实验组和对照组。采用肝大部分切除术建立肝再生模型,术后16 h分别给予腹腔内注射酮色林（实验组）和生理盐水（对照组）,采用免疫组化及流式细胞技术动态观察并比较两组大鼠术后24、36、48、72 h肝脏Ki67、增殖细胞核抗原的表达情况。结果大鼠肝大部切除术后24、36 h肝脏表达Ki67、增殖细胞核抗原最为活跃,而后表达逐渐下降。实验组大鼠肝脏表达Ki67、增殖细胞核抗原较对照组显著下降（P〈0.05）。结论 5-羟色胺2A受体阻断剂酮色林显著抑制大鼠肝大部切除术后的肝脏再生,说明5-羟色胺具有一定的促进肝再生的作用,2A受体是其重要的信号传导受体之一。     

Effect of gastrin on liver regeneration after partial hepatectomy in rats.

Gastrin has been shown to be an important trophic hormone for the mucosa of the stomach and the proximal intestine. In the present study the effect of gastrin on liver regeneration after partial hepatectomy in rats was investigated. After partial hepatectomy a significant rise in the concentration of gastrin in portal venous blood was found six, 12, and 18 hours after 70% hepatectomy. The effect of changes in the endogenous gastrin concentration on the liver regeneration was investigated in rats subjected to antrectomy or to fundectomy. Partial hepatectomy was done three weeks after the primary surgery. We found antrectomy to decrease liver regeneration, whereas fundectomy had no effect. Administration of pentagastrin 300 micrograms/kg sc three times daily for two and four days after partial hepatectomy significantly increased the rate of liver regeneration compared with controls. This study suggests that gastrin has a hepatotrophic effect. Whether this effect is caused by a direct action of gastrin on the hepatocytes or it is an indirect effect mediated by for instance insulin, glucagon or epidermal growth factor has to be further investigated.     

白藜芦醇促进肝部分切除术后肝再生的实验研究

目的研究白藜芦醇对小鼠70%肝切除后残余肝的再生是否有促进作用。方法实验动物为雄性C57BL/6小鼠。将100只小鼠随机分为实验组(白藜芦醇预处理组)和对照组(生理盐水预处理组)。采用肝大部分切除术建立肝再生模型,术前连续5 d分别给予小鼠腹腔内注射白藜芦醇12 g/kg(实验组)和生理盐水(对照组),第5天注射完白藜芦醇和生理盐水2 h后给两组小鼠分别进行70%的肝切除手术(pH)。用肝重/体重比,实时定量聚合酶链式反应及免疫组化等方法来评估白藜芦醇对小鼠肝再生的促进作用。结果 pH术后36 h、48 h实验组与对照组相比,肝重/体重比增高(4.56±0.07对3.93±0.07;5.36±0.07对4.6±0.09)。肝脏ki-67术后36 h表达最为活跃,48 h后下降,实验组与对照组相比ki-67表达明显增高。实验组中组织肝细胞生长因子(HGF)及肿瘤坏死因子(TNF-α)水平明显比对照组增强。结论白藜芦醇能明显促进小鼠部分肝切除后的肝再生。     

Amelioration of hepatic ischemia/reperfusion injury in the remnant liver after partial hepatectomy in rats

BACKGROUND AND AIMS: Reactive oxygen species have been implicated in the development of hepatic ischemia/reperfusion (I/R) injury. I/R injury remains an important problem in massive hepatectomy and organ transplantation. The aim of this study was to examine the effect of edaravone, a newly synthesized free radical scavenger, on I/R injury in the remnant liver after partial hepatectomy in rats. METHODS: Partial (70%) hepatic ischemia was induced in rats by occluding the hepatic artery, portal vein, and bile duct to left and median lobes of liver. Total hepatic ischemia (Pringle maneuver) was induced by occluding the hepatoduodenal ligament. Edaravone was intravenously administered to rats just before reperfusion and partial (70%) hepatectomy was performed just after reperfusion. RESULTS: Edaravone significantly reduced the increases in the levels of serum alanine aminotransferase and aspartate aminotransferase in rats with liver injury induced by 90-min of partial ischemia followed by 120-min of reperfusion. Histopathological analysis showed that edaravone prevented inflammatory changes in the livers with I/R injury. Edaravone also decreased the levels of myeloperoxidase activity, which is an index of neutrophil infiltration, and interleukin-6 mRNA, which is a proinflammatory cytokine. Additionally, edaravone improved the survival rate in partial hepatectomy rats with I/R injury induced by the Pringle maneuver. CONCLUSIONS: Edaravone administration prior to reperfusion protected the liver against I/R injury. Edaravone also improved the function of the remnant liver with I/R injury after partial hepatectomy. Therefore, edaravone may have applicability for major hepatectomy and liver transplantation in the clinical setting.     

Ischemic preconditioning improves liver regeneration by sustaining energy metabolism after partial hepatectomy under ischemia in rats.

BACKGROUND: The protective effect of ischemic preconditioning (IPC) has been reported on improvement of survival, reduction of liver necrosis and enhancement of the regenerative capacity of hepatocytes after partial hepatectomy. This study was undertaken to confirm that IPC has a significant impact on regeneration of hepatocytes after partial hepatectomy in ischemically damaged liver. In addition, we sought to examine the role of adenine nucleotides in this process. METHODS: Wistar rats were subjected to 60 min of total hepatic ischemia, followed by 70% hepatectomy. The animals were subdivided into an IPC (10/15 min) group and a non-IPC (control) group. Liver function tests and arginase activity were analyzed. Hepatic adenosine triphosphate (ATP), adenosine diphosphate and adenosine monophosphate were measured using gradient high-performance liquid chromatography. The liver regeneration was identified using relative liver weight and proliferating cell nuclear antigen (PCNA) labeling index. RESULTS: IPC treatment improved serum liver enzymes and tissue arginase activity (P<0.05) when compared with the control group. The preconditioned livers were associated with upregulation of ATP expression and also increased tissue energy charge. Regenerated liver weight in the IPC group was significantly higher than in the control group (P<0.05). The PCNA labeling index in the remnant livers in the IPC group was also significantly increased at 24 and 48 h after partial hepatectomy (P<0.05). CONCLUSION: These results suggest that IPC-augmented liver regeneration after hepatectomy, probably due to the stabilization of energy metabolism in rats.     

Liver regeneration and restoration of liver function after partial hepatectomy in patients with liver tumors

Liver regeneration and restoration of liver function were studied in six patients who underwent partial hepatectomy with removal of 30-70% of the liver. Liver volume and liver regeneration were studied by single-photon computed tomography (SPECT), using 99mTc-colloid as tracer. The method was assessed in 11 patients by comparing the pre- and post-operative volume measurements with the volume of the resected liver mass. The correlation coefficient between these methods was 0.899 (P less than 0.01). Liver function was determined by measuring the galactose elimination capacity and the caffeine clearance. After a postoperative follow-up period of 50 days the liver had regenerated maximally to a volume of 75 +/- 2% of the preoperative liver mass. Maximal restoration of liver function was achieved 120 days after operation and amounted to 75 +/- 10% for the caffeine clearance and to 100 +/- 25% for the galactose elimination capacity. This study shows that SPECT is a useful method for assessing liver regeneration in patients after partial hepatectomy. Our study furthermore shows that caffeine clearance correlates well with total liver volume, whereas the galactose elimination capacity overestimates total liver volume after partial hepatectomy.     

Effect of serotonin receptor 2 blockage on liver regeneration after partial hepatectomy in the rat liver.

The effect of serotonin receptor 2 blockade (5-HT(2)) on liver regeneration after 30-34% and 60-70% partial hepatectomy in the rat liver was investigated. Materials and methods: Male Wistar rats were subjected to 60-70% (group I) and 30-34% (group II) partial hepatectomy. Serotonin receptor 2 blockade was exerted by intraperitoneal administration of ketanserin at different doses and time points after partial hepatectomy. The rats of all groups were killed at different time points until 96 h after partial hepatectomy. The rate of liver regeneration was evaluated by the mitotic index in hematoxylin and eosin sections, the immunochemical detection of Ki67 and proliferating cell nuclear antigens, the rate of [(3)H]-thymidine incorporation into hepatic DNA and liver thymidine kinase enzymatic activity. Results: Liver regeneration peaked at 24 and 32 h after partial hepatectomy in 60-70% hepatectomized rats. In 30-34% hepatectomized rats liver regeneration peaked at 60 h, whereas low rates of regenerative activity were observed between 24 and 72 h after partial hepatectomy. Ketanserin administration arrested liver regeneration only when administered at 16 h after 60-70% partial hepatectomy. Ketanserin also abrogated the observed peak of regenerative activity at 60 h in 30-34% hepatectomized rats when administered at 52 h after partial hepatectomy. All indices of liver regeneration were affected by ketanserin administration. Conclusions: Serotonin receptor 2 blockade can arrest liver regeneration only when administered close to G1/S transition point, and that while serotonin may be a cofactor for DNA synthesis, it does not play a role in initiation of liver regeneration.     

Mechanisms of reperfusion injury after warm ischemia of the liver

The review highlights recent advances in our understanding of basic mechanisms of reperfusion injury after warm hepatic ischemia. Kupffer cells play a central role as the initial cytotoxic cell type and as a source of many proinflammatory mediators. Subsequently, neutrophils are activated and recruited into the liver. Factors and conditions are outlined that determine whether neutrophils undergo apoptosis without causing damage or migrate out of the sinusoids and attack parenchymal cells. In addition to the inevitable inflammatory response during reperfusion, microcirculatory perfusion failure, due to an imbalance between the actions of vasodilators and vasoconstrictors, also has a serious impact on reperfusion injury. A better understanding of the basic pathophysiology will reveal potential targets for therapeutic interventions and will show us how to avoid risk factors that may aggravate reperfusion injury.     

供肝冷热缺血移植后损伤与炎症细胞的关系

目的 探讨冷、热缺血移植术后引起供肝损伤的炎性细胞是否相同。方法 雄性SD大鼠随机分成2组,每组各24只。供肝分别在乳酸林格氏中保存120或240min后行原位肝移植术;另雄性SD大鼠随机分成3组,每组各24只供肝分别经心跳停搏90、120和150min后行原位肝移植术。大鼠分别于术后1、3、6和24h处死采样。结果 随着冷、热缺血时间的延长,移植后血清ALT等值不断升高,如冷缺血120min和240min移植术后1h ALT值(U/L)分别为454.8±45.2和1063.0±166.1,3h分别为712.0±65.9和1639.0±241.2,6h分别为1702.0±169.2和4193.0±672.7,24h分别为1067.0±141.2和1316.7±205.2,热缺血90、120和150min移植术后1hALT值(U/L)分别为5035.2±786.7、6075.3±1613.1和 7449.5±1052.0,3h分别为5564.5±696、4、7900.7±863.0和8854.8±2089.3,6h分别为7363.8±616.7、10459.3±1573.7和10294.0±530.0,24h90min组为1942.5±188.5;且术后移植肝的病理损害也逐渐加重。冷缺血移植术后3、6h肝细胞出现坏死,且有大量中性粒细胞浸润;热缺血移植术后3、6h肝细胞也有大量坏死,但却出现淋巴细胞趋润。电镜表现与镜下基本一致,旦电镜证实热缺血移植后浸润的淋巴细胞为T淋巴细胞。结论 冷、热缺血移植术后供肝的损伤似乎是由两种不同的炎性     

Liver regeneration and restoration of liver function after partial hepatectomy: the relation of fibrosis of the liver parenchyma

BACKGROUND/AIMS: Patients who survive partial hepatectomy sometimes have unsatisfactory liver regeneration and restoration of liver function. Although the extent of resection should be adjusted to attain favorable liver regeneration and restoration of liver function, a guiding principle for this has not been established. METHODOLOGY: Seventy patients with hepatic tumors associated with liver disorders of various severity who underwent hepatectomy were studied. We calculated the removal rate of the liver and the regeneration rate of the remnant liver using computed tomography. The liver function was investigated using ICG R-15 (retention rate of indocyanine green). Liver disorder was classified into 4 groups, according to the severity of fibrosis. RESULTS: The regeneration rates of the remnant liver indicated a significant decline in patients with severe fibrosis. In the no fibrosis and mild fibrosis groups, an increased removal rate was associated with increased regeneration rate, and post-operative ICG R-15 improved with time. However, in the moderate fibrosis and severe fibrosis groups, an increased removal rate was not associated with increased regeneration rate, and post-operative ICG R-15 showed no change or became worse with time. CONCLUSIONS: Severe fibrosis of the liver parenchyma is associated with poorer regeneration of the remnant liver leading to poor restoration of post-operative liver function. The severity of fibrosis is useful as a predictive factor for liver regeneration and restoration of liver function after partial hepatectomy.     

曲美他嗪对大鼠心肌缺血再灌注后热休克蛋白70及超氧化物歧化酶表达的影响

目的探讨缺血再灌注模型大鼠给予曲美他嗪预处理在心肌缺血再灌注保护作用的可能机制。方法选择SD大鼠120只,随机分为对照组、缺血再灌注组、HSP70合成抑制剂组、曲美他嗪组、联合组,每组24只,每组又根据缺血后再灌注时间分为30min、4h及8h3个时间点,每个时间点8只大鼠。每组分别于各时间点测定心肌HSP70阳性细胞数,血清肌酸激酶(CK)、肌酸激酶同工酶(CK-MB)、丙二醛、超氧化物歧化酶(SOD)及心肌梗死面积百分比。结果与对照组比较,缺血再灌注组、HSP70合成抑制剂组、曲美他嗪组、联合组再灌注4及8h血清CK、CK-MB明显升高(P0.01)。曲美他嗪组再灌注4及8h血清CK、CK-MB较联合组和缺血再灌注组明显降低,再灌注30min、4h及8hHSP70、SOD较联合组和缺血再灌注组明显升高,丙二醛较联合组和缺血再灌注组明显降低(P0.01)。曲美他嗪组再灌注4及8h心肌梗死面积较联合组和缺血再灌注组明显减少[(39.15±3.62)%vs(44.65±5.14)%、(45.18±3.45)%,P0.05;(41.28±5.26)%vs(47.54±5.89)%、(46.27±3.94)%,P0.05]。结论曲美他嗪能升高心肌细胞HSP70水平,减少心肌梗死面积,对缺血再灌注大鼠心肌具有保护作用。     

Expressed genes in regenerating rat liver after partial hepatectomy

AIM: To reveal the liver regeneration (LR) and its control as well as the occurrence of liver disease and to study the gene expression profiles of 551 genes after partial hepatectomy (PH) in regenerating rat livers. METHODS: Five hundred and fifty-one expressed sequence tags screened by suppression subtractive hybridization were made into an in-house cDNA microarray, and the expressive genes and their expressive profiles in regenerating rat livers were analyzed by microarray and bioinformatics. RESULTS: Three hundred of the analyzed 551 genes were up- or downregulated more than twofolds at one or more time points during LR. Most of the genes were up- or downregulated 2-5 folds, but the highest reached 90 folds of the control. One hundred and thirty-nine of them showed upregulation, 135 displayed downregulation, and up or down expression of 26 genes revealed a dependence on regenerating livers. The genes expressed in 24-h regenerating livers were much more than those in the others. Cluster analysis and generalization analysis showed that there were at least six distinct temporal patterns of gene expression in the. regenerating livers, that is, genes were expressed in the immediate early phase, early phase, intermediate phase, early-late phase, late phase, terminal phase. CONCLUSION: In LR, the number of down-regulated genes was almost similar to that of the upregulated genes; the successively altered genes were more than the rapidly transient genes. The temporal patterns of gene expression were similar 2 and 4 h, 12 and 16 h, 48 and 96 h, 72 and 144 h after PH. Microarray combined with suppressive subtractive hybridization can effectively identify the genes related to LR.     

Endotoxin affects the expansion modes of liver macrophages after partial hepatectomy

We studied the effect of increased endotoxin levels on the expansion modes of liver macrophages after two-thirds partial hepatectomy using anti-endotoxin polymyxin B. The expansion consists of dual modes: local proliferation and immigration. Local proliferation of mature cells was evaluated by the S-phase proportion measured by flow cytometric DNA analysis. This proportion (11.8 +/- 1.3% before hepatectomy) decreased to 6.0 +/- 1.1% at 12 h and reached a maximum of 21.9 +/- 2.7% on the 5th day after hepatectomy. In polymyxin B treated rats, the proportion reached a maximum of 21.1 +/- 1.6% at 48 h without any preceding decrease. Immigration of macrophage precursors was evaluated by the decreasing proportion of latex beads-containing cells that were marked as resident liver macrophages by injection of latex beads before hepatectomy. This proportion (98.7 +/- 0.2% before hepatectomy) was significantly decreased to 90.5 +/- 1.6% at 48 h. In polymyxin B treated rats, however, the proportion showed no significant decrease within 3 days. These results indicate that endogenous endotoxin, which suppresses the local proliferation and promotes extrahepatic recruitment, regulates the number of liver macrophages in regenerating rat liver.