Effects of prior splenectomy on remnant liver after partial hepatectomy with Pringle maneuver in rats.

BACKGROUND/AIMS: In the case of the liver resection, the temporary occlusion of the hepatoduodenal ligament (Pringle maneuver) is often used. However, the maneuver causes hepatic ischemia/reperfusion (I/R) injury that strongly affects the recovery of patients. The present study investigated the effects of prior splenectomy on the remnant liver in partial hepatectomized rat with Pringle maneuver. METHODS: Pringle maneuver was conducted just before a two-thirds partial hepatectomy. Efficacy of splenectomy was assessed by survival rate, serum alanine aminotransferase (ALT), neutrophil infiltration into liver, recovery of remnant liver weight, and liver proliferating cell nuclear antigen (PCNA) levels. Ischemic preconditioning was performed as follows; 10 min of total hepatic ischemia followed by 10 min of reperfusion. RESULTS: In partial hepatectomized rats with 30 min of Pringle maneuver, seven out of 12 rats died within 3 days. On the other hand, when splenectomy was performed on 3 days before the maneuver, only one out of 12 rats died. When prior splenectomy was performed on eight and 18 days before the Pringle maneuver, respectively, similar efficacy was observed. In addition, prior splenectomy on 3 days before the maneuver showed that serum ALT activity, neutrophil infiltration, recovery of remnant liver weight, and PCNA levels in partial hepatectomized rats with Pringle maneuver were also ameliorated as compared with those of control rats without splenectomy. When effects of prior splenectomy were compared with those of ischemic preconditioning in these situations, efficacy of prior splenectomy was comparable with that of the ischemic preconditioning. CONCLUSIONS: Prior splenectomy ameliorated the I/R injury in the remnant liver after partial hepatectomy with Pringle maneuver. Effects of prior splenectomy may influence the liver for long duration, because splenectomy on 18 days before the maneuver still exerts effective action.     

生长激素对鼠部分肝切除术后肝再生影响

目的　探讨生长激素对 70 %肝切除后肝再生的影响。方法　 60只SD大鼠随机分为对照组及生长激素组 ,按Higgins方法行 70 %肝切除术 ,术后给药并分批于术后 6、2 4、48、72、96h处死 ,作如下比较 :①残肝肝重 ;②增殖细胞核抗原 (PCNA)标记指数 ;③图像定量分析法测量PCNA阳性产物面积及灰度值。结果　与对照组比较 ,生长激素组残肝肝重、PCNA标记指数、PCNA阳性产物面积在术后均显著增高 (P <0 .0 5 ) ,而灰度值则显著降低 (P <0 .0 5 )。结论　生长激素具有强烈促进肝细胞增殖和刺激肝再生的作用     

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。     

熊脱氧胆酸促进肝脏部分切除后肝细胞再生

目的 探讨熊脱氧胆酸（ｕｒｓｏｄｅｏｘｙｃｈｏｌｉｃ ａｃｉｄ，ＵＤＣＡ）对胆道梗阻肝脏部分切除（ＰＨ）后肝细胞再生的影响。方法Ｗｉｓｔａｒ大鼠随机分为正常７０％肝部分切除组（Ｎ－ＰＨ）、胆道梗阻２周７０％ＰＨ组（ＢＤＯ－ＰＨ）、ＢＤＯ—ＰＨ ＵＤＣＡ治疗组及ＢＤＯ—ＰＨ生理盐水治疗组。观察肝组织学改变，检测７０％ＰＨ后肝细胞ＢｒｄＵ标记、肝内肝细胞生长因子（ＨＧＦ）及其受体Ｍｅｔ ｍＲＮＡ表达。结果 ＵＤＣＡ治疗能促进胆道梗阻后肝功能好转并减轻肝组织学病变；ＵＤＣＡ治疗组大鼠７０％ＰＨ后肝内ＨＧＦ／Ｍｅｔ ｍＲＮＡ高峰表达值均高于ＢＤＯ—ＰＨ组（Ｐ ＜ ０．０５），肝细胞 ＢｒｄＵ高峰标记指数（５９．３９±１０．８２）％高于 ＢＤＯ—ＰＨ组肝细胞 ＢｒｄＵ高峰标记指数（３６．２２±８．３７％（ｔ＝４．１４９，Ｐ＜０．０１），而与Ｎ－ＰＮ组肝细胞ＢｒｄＵ高峰标记指数（６８．６４±１１．２６％）％相比差异无显著性（ｔ＝１．４５１，Ｐ＞０．０５）。结论 ＵＤＣＡ通过缓解胆道梗阻后肝组织损害并上调７０％ＰＨ后肝内ＨＧＦ／Ｍｅｔ ｍＲＮＡ表达，从而促进胆道梗阻肝脏部分切除后肝细胞再生。     

Preserved liver regeneration capacity after partial hepatectomy in rats with non-alcoholic steatohepatitis

AIM To evaluate the liver regeneration capacity(LRC) after partial hepatectomy(PH) in experimental non-alcoholic steatohepatitis(NASH).METHODS Fifty-four female rats were fed a high-fat, high-cholesterol diet(HFCD, 65% fat, 1% cholesterol) or standard diet(STD) for 16 wk. A 70% PH was performed and the animals were euthanised before PH or 2 or 5 d postPH. LRC was evaluated using: The total number of Ki-67 positive hepatocytes in the caudate lobe, N(Ki-67, lobe) evaluated in a stereology-based design, the regenerated protein ratio(RPR), prothrombin-proconvertin ratio(PP), and m RNA expression of genes related to regeneration.RESULTS The HFCD NASH model showed significant steatosis with ballooning and inflammation, while no fibrosis was present. Mortality was similar in HFCD and STD animals following PH. HFCD groups were compared to respective STD groups and HFCD animals had a significantly elevated alanine transaminase at baseline(P 0.001), as well as a significantly elevated bilirubin at day 2 after PH(P 0.05). HFCD animals had a higher N(Ki-67, lobe) at baseline,(P 0.0001), day 2 after PH(P = 0.06) and day 5 after PH(P 0.025). We found no significant difference in RPR or PP neither 2 or 5 d post-PH. Expression of liver regeneration genes(e.g., hepatic growth factor) was higher at both day 2 and 5 post-PH in HFCD groups(P 0.05).CONCLUSION NASH rats had a preserved LRC after hepatectomy when compared to STD rats. The methods and models of NASH are essential in understanding and evaluating LRC.     

Effects of streptococcal preparation OK-432 on liver regeneration and energy status after partial hepatectomy under ischemia/reperfusion in rats

BACKGROUND/AIMS: Activation of reticuloendothelial system functions by the treatment with OK-432 has been reported to enhance liver regeneration. However, its effect on liver regeneration has not been studied after hepatectomy under ischemia/reperfusion which is in clinical use. The aim was to examine the effect of OK-432 on regeneration and energy status of the liver after hepatectomy under ischemia/reperfusion in rats. METHODOLOGY: Rats were randomly divided into two groups; OK-432 pretreatment and saline treatment (control) group. In the OK-432 group, OK-432 (2.5 mg/kg body weight) was administered intraperitoneally 24 hours before hepatectomy. In the control group, the same volume of physiological saline was administered in the same manner. Seventy percent hepatectomy was performed in both groups during the second 15-minute ischemia period after an initial 15-minute ischemia and 15-minute reperfusion periods. The survival after hepatectomy, relative liver weight, deoxyribonucleic acid synthesis rate, and hepatic adenine nucleotide and energy charge levels were examined immediately after hepatectomy and on postoperative days 1, 2, 3, and 7. Serum levels of total bilirubin, glutamic pyruvic transaminase, and hyaluronic acid were also measured. RESULTS: All rats survived and the relative liver weight and deoxyribonucleic acid synthesis rate were not significantly different in the two groups. Serum total bilirubin and glutamic pyruvic transaminase levels were not significantly different in both groups. The serum concentration of hyaluronic acid immediately after hepatectomy was significantly higher in the OK-432 group than in the control group. The pretreatment with OK-432 had no significant effect on the levels of adenine nucleotides and energy charge in the liver. CONCLUSIONS: Under ischemia/reperfusion, pretreatment with OK-432 has no significant effect on regeneration and energy status of the liver after hepatectomy.     

Kinetic changes of liver regeneration and hepatocellular carcinoma cells after partial hepatectomy in rats

We investigated, using rats, the effect of partial hepatectomy (PH) on hepatocellular carcinoma (HCC, KDH-8 and AH-66) cells, and the effect of HCC cells on the regeneration of remaining hepatocytes after PH. Our results showed that PH significantly enhanced the growth of HCC cells in rats. Tumor volume increased more significantly in the partially hepatectomized group (H-group) than in the control group, and the tumor wet weights on the 14th postoperative day were significantly higher in the H-group than in the control group. Such an enhanced growth effect of PH on the injected (s.c) HCC cells was related to an abrupt increase of tumor volume within 24 hours after operation, which was supported by the mitotic indices (MI) of the KDH-8 cells. These phenomena of the enhanced growth of the HCC cells following PH were not observed at all in rats injected with estrogen receptor (ER)-negative mammary carcinoma (SST-2) or nonepithelial fibrosarcoma (KMT-75) cells. The MIs of the remaining hepatocytes after PH increased abruptly at the 30th postoperative hour and reached a maximum at the 36th postoperative hour, and the MIs were significantly higher in the H-group with the KDH-8 cells than in the H-group without them from the 42th to the 60th postoperative hour. In the control group, the MIs of hepatocytes were not regardless of the presence of KDH-8 cells. From these results, we speculate that some growth factor(s) induced by PH may act on injected (s.c.) HCC cells, and that the other growth factor(s) secreted by HCC cells may act on the regenerating hepatocytes after PH. This work was supported in part by a grant from the Japanese Ministry of Education. Science and Culture.     

Liver structural transformation after partial hepatectomy and repeated partial hepatectomy in rats: A renewed view on liver regeneration

BACKGROUND The phenomenon of liver regeneration after partial hepatectomy(PH) is still a subject of considerable interest due to the increasing frequency of half liver transplantation on the one hand, and on the other hand, new surgical approaches which allow removal of massive space-occupying hepatic tumors, which earlier was considered as inoperable. Interestingly, the mechanisms of liver regeneration are extensively studied after PH but less attention is paid to the architectonics of the regenerated organ. Because of this, the question "How does the structure of regenerated liver differ from normal, regular liver?" has not been fully answered yet. Furthermore, almost without any attention is left the liver's structural transformation after repeated hepatectomy(of the re-regenereted liver).To compare the architectonics of the lobules and circulatory bed of normal, regenerated and re-regenerated livers.METHODS The livers of 40 adult, male, albino Wistar rats were studied. 14 rats were subjected to PH-the 1st study group(SG_1); 10 rats underwent repeated PH – the 2nd study group(SG2); 16 rats were subjected to sham operation-control group(CG); The livers were studied after 9 months from PH, and after 6 months from repeated PH. Cytological(Schiff reaction for the determination of DNA concentration), histological(HE, Masson trichrome, CK8 Immunohistochemical marker, transparent slides after Indian Ink injection,), morphometrical(hepatocytes areas, perimeters and ploidy) and Electron Microscopical(Scanning Electron Microscopy of corrosion casts) methods were used.RESULTS In the SG_1 and SG_2, the area of hepatocytes and their perimeter are increased compared to the CG(P 0.05). However, the areas and perimeters of the hepatocytes of the SG_1 and SG_2 groups reveal a lesser difference. In regenerated(SG_1) and re-regenerated(SG_2) livers, the hepatocytes form the remodeled lobules, which size(300-1200 μm) exceeds the sizes of the lobules from CG(300-600 μm). The remodeled lobules(especially the "mega-lobules" with the sizes 1000-1200 μm) contain the transformed meshworks of the sinusoids, the part of which is dilated asymmetrically. This meshwork might have originated from the several portal venules(interlobular and/or inlet). The boundaries between the adjacent lobules(including mega-lobules) are widened and filled by connective tissue fibers, which gives the liver parenchyma a nodular look. In SG_2 the unevenness of sinusoid diameters, as well as the boundaries between the lobules(including the mega-lobules) are more vividly expressed in comparison with SG_1. The liver tissue of both SG_1 and SG_2 is featured by the slightly expressed ductular reaction.CONCLUSION Regenerated and re-regenerated livers in comparison with normal liver contain hypertrophied hepatocytes with increased ploidy which together with transformed sinusoidal and biliary meshworks form the remodeled lobulli.     

Plasma-kallikrein clearance during liver regeneration after partial hepatectomy in the rat

Abstract: Aims/Background: The liver clears circulating plasma-kallikrein through a receptor-mediated endocytosis process: an initial fast phase is followed by a slow exponential phase. Methods: To determine whether the clearance rate of plasma-kallikrein is affected during liver regeneration, we perfused isolated rat livers with rat plasma-kallikrein (rPK) at 0, 1, 2, 3 and 7 days after partial hepatectomy or sham operation. Results: Liver regeneration was followed by the expression of the proliferating-cell nuclear antigen (PCNA) labeling index. The serum concentration of α₂-macroglobulin, an acute phase protein in rats, was measured. At day 1, the fast phase of rPK clearance rate increased in hepatectomized rats when compared with day 0 (4.9±0.4 and 3.7±0.4 mU/g liver · min, p<0.05). However, at day 2, the rPK fast phase clearance rate dropped significantly (2.6±0.2, p<0.05), when compared with day 1. No difference was found among the sham groups at different days of hepatectomy. These changes seem to be independent of the acute phase reaction. The regenerative liver weight increased continuously during the observation period. PCNA expression increased significantly after hepatectomy, with maximal PCNA-labeling indices at days 1 and 2, declining thereafter. Conclusion: The rPK fast phase clearance rate changes during liver regeneration, with a zenith occurring when PCNA labeling index is maximal (day 1) and a nadir occurring at the mitotic phase (day 2).     

Insulin addition after ischemia improves recovery of function equal to ischemic preconditioning in rat heart

Background Ischemic preconditioning (IPC) is considered the most potent mechanism to improve ischemia tolerance. We have demonstrated that insulin addition during reperfusion improves recovery of function in the isolated working rat heart. We herein compare the relative importance of these two mechanisms in improving recovery of postischemic function.Methods Isolated working rat hearts were perfused with Krebs-Henseleit buffer containing glucose (5 mmol/l) plus oleate (0.4 mmol/l) for 20 min and were then subjected to 15 min of ischemia followed by 35 min of reperfusion. IPC was achieved by an ischemic period of ve minutes followed by 10 minutes of reperfusion before ischemia. Insulin (1 mU/ml) was or was not added at the beginning of reperfusion. Wortmannin (WM, 3 µmol/l), an inhibitor of phosphatidylinositol 3-kinase, was or was not present in the perfusate from the beginning of the experiments. We measured glucose uptake with [2-³H]glucose, cardiac power and tissue metabolite content at the end of the experiments.Results Cardiac power before ischemia ranged from 7.17 to 10.4 mW. After ischemia, cardiac power recovered to 65.7 ± 3.8% (Control). Insulin signicantly improved recovery (96.3 ± 10.8%, p < 0.05 vs. Control). This effect was also achieved by IPC (recovery 86.2 ± 6.2%, p < 0.05). The effects of insulin and IPC were not additive (recovery 83.4 ± 6.2%, p < 0.05). WM fully inihibited the effects of both insulin and IPC (69.5 ± 3.3, 72.0 ± 6.9, respectively). Basal glucose uptake ranged from 2.53 to 3.46 µmol/gdry, and was signicantly lower after ischemia in the presence of WM.Conclusions Insulin is a potent tool to improve postischemic contractile function. The improvement of recovery afforded by insulin added after ischemia may be mediated through a similar mechanism as ischemic preconditioning.     

Functional regeneration in liver of old rats after partial hepatectomy

This study suggests that changes in liver protein metabolism occurring with age are not due to changes in the genome. Regenerating rat liver in old animals has regained functional properties of young rat liver.Specifically albumin synthesis, which is elevated in old animals, returns to young rat levels in old rats for several weeks after partial hepatectomy. Both in vivo and in vitro studies support this evidence. Old rat liver ferritin also undergoes changes in regenerating liver. The amount of ferritin iron/g liver falls to one half, the amount of iron/mg ferritin protein drops, but the amount of ferritin protein/g liver remains constant in regenerated old rat liver. The half-life of ferritin in regenerated old rat liver (2·3 days) is much shorter than in old rat liver controls (3·9 days) and approaches that of young rat liver ferritin (2·1 days).Determinations were done at a time when liver weight had been fully restored following removal of 67 per cent of the liver. Functional properties of old rat liver are restored by 12 weeks after partial hepatectomy.     

Intestinal ischemia-reperfusion impairs liver regeneration after partial hepatectomy in rats

BACKGROUND/AIMS: The deleterious effects of intestinal ischemia-reperfusion on liver are realized, but its effect on the regenerative capacity of the liver has not been studied. Our aim in this study was to determine the effect of intestinal ischemia-reperfusion on liver regeneration. METHODOLOGY: Sprague-Dawley rats were randomly divided into six groups; two sham-operated, two hepatectomy, and two hepatectomy with intestinal ischemia-reperfusion groups. To create intestinal ischemia-reperfusion, the superior mesenteric artery and collateral arteries supplying the small intestine were occluded for 20 minutes. Partial hepatectomy was performed during the period of ischemia. Ischemia-reperfusion injury in the mucosal layer of the small intestine was scored in light microscopy. Liver regeneration parameters (proliferating cell nuclear antigen labeling index for hepatocytes and liver regeneration rate), and serum levels of aspartate aminotransferase and alanine aminotransferase were studied on day 1 or 4 after operation. RESULTS: Mucosal injury score was high in the hepatectomy with intestinal ischemia-reperfusion groups. Liver regeneration rate and proliferating cell nuclear antigen labeling index were less in these groups than the hepatectomy groups on day 1 and 4. There were no differences in the serum levels of aspartate aminotransferase and alanine aminotransferase between hepatectomy and hepatectomy with intestinal ischemia-reperfusion groups. The mortality rate was higher in the hepatectomy with intestinal ischemia-reperfusion groups than the other groups. CONCLUSIONS: Ischemia and reperfusion of the small intestine impaired liver regeneration with high mortality after partial hepatectomy in the rats.     

The effect of ursodeoxycholic acid on liver regeneration after partial hepatectomy in rats with non-alcoholic fatty liver disease

Aim:  To investigate the effect of ursodeoxycholic acid (UDCA) on liver regeneration following partial hepatectomy in rats with non-alcoholic fatty liver disease (NAFLD).
Methods:  UDCA was administered to seven rats (group 1) and physiological saline was administered both to seven rats (group 2) with NAFLD and to seven rats with normal livers (group 3). All rats underwent two-thirds hepatectomy and the remnant liver tissues were removed 48 h later. Mitotic index (MI) and levels of proliferating cell nuclear antigen (PCNA), glutathione (GSH) and malondialdehyde (MDA) were assayed.
Results:  MI and PCNA levels in group 2 were significantly lower than in groups 1 and 3, but the values in groups 1 and 3 were similar. The GSH levels of group 2 were significantly lower than those of group 3 in the hepatectomy tissues, and lower than those of groups 1 and 3 in the remnant tissues. The differences between GSH levels in groups 1 and 3 were not significant. MDA levels in hepatectomy and remnant tissues were significantly higher in group 2 compared to groups 1 and 3; values in groups 1 and 3 were similar.
Conclusion:  UDCA increases regeneration after partial hepatectomy in rats with NAFLD, possibly due to an attenuating effect on oxidative stress.     

Ischemic preconditioning improves stability of intestinal anastomoses in rats

Background  The aim of our study was to establish whether ischemic preconditioning (IPC) directly before performing a small bowel anastomosis has an effect on anastomotic stability and healing. Material and methods  Forty male Wistar rats were randomized to five groups: control (CO, n = 8) with preparation of the superior mesenteric artery (SMA) but without IPC. IPC groups had different intervals of ischemia (occlusion of the SMA) and reperfusion: 10 min ischemia and 20 min reperfusion (IPC10/20, n = 7), 10 min ischemia and 30 min reperfusion (IPC10/30, n = 8), 15 min ischemia and 20 min reperfusion (IPC15/20, n = 8), and 15 min ischemia and 30 min reperfusion (IPC15/30, n = 9). On the fourth postoperative day, the animals were relaparotomized: bursting pressure, hydroxyproline concentration, and histological ischemia mucosal injury scale of the anastomosis were assessed. Results  Four days after operation, the mean bursting pressure was 73 ± 6 mmHg in the control group, whereas it was significantly higher in IPC10/20 (113 ± 11 mmHg; p = 0.018), IPC10/30 (110 ± 13 mmHg; p = 0.001), and IPC15/30 (124 ± 9 mmHg; p = 0.003). IPC15/20 did not show a significant difference (63 ± 2 mmHg; p = 0.4). We did not find a significant effect regarding hydroxyproline concentration, but IPC diminished mucosal injury. Conclusions  IPC directly before performing a small bowel anastomosis has a time-dependent beneficial effect on anastomotic stability, thus indicating a new clinical approach to improve the healing process of intestinal anastomosis.     

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.