Liver blood flow after partial hepatectomy in the pig

The role of liver blood flow in liver regeneration remains controversial. This study in 17 pigs documents the total hepatic blood flow, and portal and arterial components measured with an electromagnetic flowmeter, the portal pressure, and the cardiac output for 6 days after partial hepatectomy (PH) or sham operation. There was a twofold increase in total flow immediately after PH which rose to three- to fourfold by the second postoperative day. Thereafter values decreased but remained elevated above preoperative values; no similar increase was noted in sham animals. The increase in flow was both absolute as well as relative to the proportion of liver remnant remaining. The portal component increased from 74 +/- 3% preoperatively to 84 +/- 3% (P less than 0.05) on the second postoperative day, and portal pressure was apparently increased. These changes in flow precede the previously documented maximum regeneration response between Days 3 and 4. The factors resulting in the increased flow may be responsible in part, for regeneration.     

Liver regeneration and tumor growth in the rat after partial hepatectomy

Tumor growth of Yoshida sarcoma implanted in the remnant liver was studied in rats subjected to a hepatectomy. After 70 percent hepatectomy, the liver progressively regenerated and the total liver weight was reverted to by 10 days after the operation. Concomitantly with liver regeneration, tumor growth in the remnant liver was stimulated significantly, compared with that in the sham-operated liver. Incorporation of tritiated thymidine into tumor cells in the remnant liver was strikingly high and progressive, while that in the sham-operated liver was low and retained. Mitomycin C given to the hepatectomized rats was more effective against the tumor in the remnant liver than in the sham-operated liver. We conclude from this study that cancer cell proliferation in the remnant liver can be accelerated by the process of liver regeneration.     

N-acetylcysteine attenuates bacterial translocation after partial hepatectomy in rats

BACKGROUND: Translocating enteric bacteria have been suggested as playing a major role in the development of infections after partial hepatectomy. We investigated the effect of N-acetylcysteine (NAC) on bacterial translocation (BT) and intestinal mucosa as the first line of defense against BT. MATERIALS AND METHODS: We compared four groups of eight Sprague-Dawley male rats each: sham, control (partially hepatectomized), partial hepatectomy plus preoperative single-dose NAC, and a fourth that received partial hepatectomy with a preoperative single-dose NAC plus treatment with NAC for 2 days. Microorganism counts of tissues, lung injury score, lung tissue glutathione, and malondialdehyde levels and microscopy of intestinal mucosa were studied at the end of 48 h. RESULTS: Microorganism count in the lung and mesenteric lymph node cultures and lung injury score were significantly higher in the control group when compared with the sham, third, and fourth groups (lung: 9919.6 versus 0.0, 2912.9, 1550.0 cfu/g tissue; mesenteric lymph nodes: 8458.3 versus 0.0, 89.0, 88.9 cfu/g tissue; lung injury score: 3.25 versus 0.5, 1.13, 1.75). In the control group, the villous height of the distal ileal mucosa was significantly shorter than the sham group (65.25 versus 75.25 microm) and the difference from groups 3 and 4 was not statistically significant. Neutrophil infiltration in the distal ileal mucosa of the control group was significantly higher than the sham, third and fourth groups (3.13 versus 0.25, 0.38 and 1.0). CONCLUSIONS: The parenteral use of NAC attenuates bacterial translocation after partial hepatectomy in rats. Attenuation of the lung injury after partial hepatectomy in NAC-treated groups might be attributable to both anti-inflammatory effect and the effect on BT.     

Sildenafil accelerates liver regeneration after partial hepatectomy in rats

Objective

The regeneration process causes the liver to achieve an adequate volume and function after major hepatectomy or living donor liver transplantation. Sildenafil, a selective phosphodiesterase-5 inhibitor used for erectile dysfunction, impacts the liver by enhancing the effects of nitric oxide. The aim of this study was to investigate the influence of sildenafil on liver regeneration in rats after partial hepatectomy.

Methods

Sixty young female Wistar Albino rats were randomly divided into three equal groups before 70% hepatectomy. Thereafter, we administered intraperitoneal saline to the control group (G1); 10 μg/kg sildenafil to the low-dose group (G2) and 100 μg/kg to the high-dose sildenafil group (G3). Half of the rats per group were sacrificed on the first and the other half on the fifth postoperative day after partial hepatectomy. Regeneration was assessed using three methods: (1) the formula described by Kwon et al formula, (2) the average number of mitotic figures in 10 microscopic fields, and (3) the average of Ki-67-positive nuclei in 1000 cells using immunohistochemistry.

Results

Although, the hepatic regeneration and mitosis rates were similar in all three groups, Ki-67 levels were significantly higher in both G2 and G3 than the control group on the first postoperative day. Hepatic regeneration was significantly greater in G2 and G3 than the control group as was the mitosis rate in the G2 group versus the two groups. By the 5th postoperative day Ki-67 levels were similar in the three groups.

Conclusion

Sildenafil treatment accelerated hepatic regeneration after partial hepatectomy in rats.     

Effects of portal-systemic shunt following 90% partial hepatectomy in rats

We studied the effects of portal-systemic shunt after massive hepatectomy. Male Wistar rats were divided into two groups: one group underwent laparotomy alone (C group) and in the other group a portal-systemic shunt was placed through laparotomy (S group). After 90% hepatectomy was performed, 3-day and 1-week survival rates and histopathology were examined, and hepatic hemodynamics during the early stage after hepatectomy were measured using dye-containing microspheres. The 3-day survival rate in the S group was significantly higher, and the 1-week survival rate was slightly higher, than those in C group. Sinusoidal dilation 7 days after hepatectomy in the S group was significantly milder than that in the C group. Fatty degeneration of hepatocytes in the S group was significantly milder than that in the C group. With respect to hepatic hemodynamics during the early stage after hepatectomy, the rate of shunt (26.3%) in the S group was significantly higher than that (9.5%) in the C group. Portal pressure, total hepatic blood flow, and total hepatic blood flow per gram of liver in the S group were significantly lower than those in the C group. These results suggest that approximately 26% shunt after 90% hepatectomy in rats increases the early survival rate and improves histological changes in surviving rats 7 days after resection.     

Fibronectin protects endotoxin-induced liver injury after partial hepatectomy in rats

Endotoxemia following extended hepatectomy may be a cause of postoperative death. Multiple organ failure related to septemia is a common cause of early mortality after liver transplantation. Fibronectins (Fns) are involved in cellular adhesion, motility, differentiation, apoptosis, hemostasis, wound healing, and ischemic injury. Studies were performed to determine whether Fn influences the survival rate of rats subjected to endotoxin-induced liver injury after partial hepatectomy. Male Sprague-Dawley rats were intravenously administered lipopolysaccharide (LPS) 48 hours after 70% hepatectomy. Prior to LPS administration, plasma Fn or bovine serum albumin was given intravenously. The survival rate of the Fn-treated group was higher than that of the controls. Fn prevented increases in serum enzyme activity and total bilirubin related to liver injury. The levels of inflammatory cytokines including tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 interferon-gamma were also significantly lower in the Fn-treated than the control group. Furthermore, the number of apoptotic cells and the degree of necrosis in the remnant liver were significantly decreased in the Fn-treated rats compared with controls. These results indicate that Fn prevents endotoxin-induced liver injury after partial hepatectomy, at least in part through inhibiting the production of inflammatory cytokines, and the necrosis apoptosis in the remaining liver.     

Liver regeneration following partial hepatectomy is improved by enhancing the HGF/Met axis and Akt and Erk pathways after low-power laser irradiation in rats

A simple, easy, and safe procedure aiming to improve liver regeneration could be of great clinical benefit in critical situations such as major hepatectomy, trauma, or hemorrhage. Low-power laser irradiation (LPLI) has come into a wide range of use in clinical practice by inducing regeneration in healthy and injured tissues. However, the effect of LPLI on the process of liver regeneration, especially those related to the molecular mechanisms, is not fully understood. Thus, the aim of the present study was to investigate the main molecular mechanisms involved in liver regeneration of partially hepatectomized rats exposed to LPLI. We used Wistar male rats, which had their remaining liver irradiated or not with LPLI (wavelength of 632.8 nm and fluence of 65 mW/cm²) for 15 min after a 70 % hepatectomy. We subsequently investigated hepatocyte growth factor (HGF), Met, Akt, and Erk 1/2 signaling pathways through protein expression and phosphorylation analyses along with cell proliferation (proliferating cell nuclear antigen (PCNA) and Ki-67) using immunoblotting and histological studies. Our results show that LPLI can improve liver regeneration as shown by increased HGF protein expression and the phosphorylation levels of Met, Akt, and Erk 1/2 accompanied by higher levels of the PCNA and Ki-67 protein in the remnant livers. In summary, our results suggest that LPLI may play a clinical role as a simple, fast, and easy-to-perform strategy in order to enhance the liver regenerative capacity of a small liver remnant after hepatectomy.     

肝切除术后肝再生对大鼠结肠癌肝转移灶生长的影响

目的 探讨肝再牛进程触发大鼠结肠痛肝转移残肝内隐性转移灶进展的发生机制.方法 采用肝包膜下种植建立结肠癌肝转移大鼠模型,随机分为假手术组、37%肝切除组和70%肝切除组;采用腹膜后注射建市结肠癌腹膜后转移模型,随机分为假手术组和70%肝切除组.手术后3周处死动物,测定肝内转移瘤量、再生肝重及腹膜后瘤结节重.在含有肝切除后24 h和14 d的门静脉血清培养基中进行结肠癌细胞Lovo体外培养,5.溴脱氧尿核苷(5-BrdU)DNA掺入法检测细胞增殖反应.结果 手术切除明显促进70%肝切除组肝内残留癌牛长(P<0.05),对37%肝切除组肝内残留癌和结肠癌腹膜后转移瘤牛长无促进作用(P>0.05);肝切后24 h门静脉血清组5-BrdU DNA掺人率从第72小时开始增加,至第120小时呈持续增加趋势(P<0.05);肝切后14 d门静脉血清对结肠癌细胞生长无明显刺激作用(P>0.05).结论 结肠癌肝转移切除术后可诱发肝内微小残留灶的进展,并不通过血液循环全身性释放,对肝外转移瘤并不发挥作用.肝切除范围与诱发肿瘤生长有关,只有肝切除达到一定程度时,才足以刺激肿瘤生长.     

Effect of fish oil, olive oil, and vitamin E on liver pathology, cell proliferation, and antioxidant defense system in rats subjected to partial hepatectomy

The high capacity of liver regeneration after partial hepatectomy (PH) is well known. This study investigated the role of the antioxidant defense system in regeneration among Wistar-albino male rats subjected to 70% partial hepatectomy after a pretreatment period of 2 weeks with eicosapentanoic acid (EPA) rich fish oil (FO), first pressed virgin olive oil (OO), or vitamin E. The control group of 10 rats underwent PH only. On postoperative day 3, all rats were humanely killed. Liver sections of animals treated with FO or vitamin E showed significant increases in regeneration within both liver parenchyma and cut surface compared with the control group (P < .05). Liver sections of OO displayed an insignificant increase in liver regeneration (P > .05), with less increase in parenchyma than of the cut surface. The enhancement of the liver parenchymal regeneration in the FO group was significantly greater than that of the vitamin E group. Concerning liver function tests (LFT), there was no significant difference among the groups. When the treatment groups were compared to the control group glutathione (GSH) levels were increased and content of malondialdehyde (MDA), nitric oxide (NO), and superoxide dismutase (SOD) were decreased. Based on these results, we concluded that after 70% PH in rats, the liver parenchyma and cut surface regeneration were greatest with FO and least with OO treatment. Both FO and vitamin E served to improve the antioxidant defense system more than OO treatment.     

大鼠肝切除后肝再生期间细胞周期调控下细胞增殖与凋亡的关系

目的探讨正常组织增生过程中,细胞周期调控下细胞增殖与凋亡之间的关系。方法以大鼠肝切除后肝再生为模型,以Ｋｉ６７抗原的检测和ＳｕｂＧ１法分别为细胞增殖与细胞凋亡的定量分析方法。结果肝切除术后３６小时,Ｋｉ６７阳性细胞比例（Ｋｉ）达峰值;术后２４小时,凋亡细胞比例（Ａｐ）达峰值;各实验组的Ａｐ／Ｋｉ比值与对照组相比差异有显著性（Ｐ＜０．０１）,其峰值位于术后１２小时。结论（１）正常组织增生中,细胞凋亡不但存在,而且和细胞增殖一样重要。机体通过细胞周期,以细胞凋亡形式,调控着组织增生的速度和规模;（２）应以Ａｐ／Ｋｉ衡量细胞凋亡在各时期所具作用之重要性;（３）细胞凋亡所具作用相对最大时,是在组织增生开始后的早期,先于细胞增殖最活跃期,表明机体对组织增生的反应谨慎而严格。     

内毒素血症对部分肝切除大鼠的肝损伤机制探讨

目的 探讨内毒素(LPS)血症对部分肝切除大鼠的肝损伤作用及其可能机制.方法 54只大鼠随机分为假手术组(S组)、对照组(H组)及模型组(I组),每组各18只大鼠.假手术组仅行开关腹.模型组大鼠行70%肝切除,术后24 h静脉注射LPS(0.5 mg/kg).对照组大鼠70%肝切除后24 h静脉注射等量生理盐水替代LPS.在既定时点,测血清AST与ALT;Western blot法测定肝组织TNF-α表达;ELISA法测定血清TNF-α水平;化学比色法测定肝组织髓过氧化物酶(MPO)水平;同步切取肝组织行HE染色;免疫组化法测定肝组织增殖细胞核抗原(PCNA)指数.结果 模型组大鼠血清AST、ALT在LPS注射后1 h即升高,随时间递增明显,各时点上述指标均显著高于对照组(P＜0.01).模型组肝组织MPO活性随时间增高,各时点均显著高于对照组(P＜0.01).注射LPS后6 h肝组织出现片状坏死区,伴明显炎症细胞浸润.模型组1 h肝组织TNF-α表达及各时点血清TNF-α均较对照组显著升高(P＜0.01).模型组各时点肝PCNA指数均显著低于对照组(P＜0.01).结论 内毒素血症能引起部分肝切除大鼠出现急性肝损伤;肝细胞坏死伴中性粒细胞浸润是这种损伤的重要形态学改变,可能与内毒素诱导肝脏TNF-α产生增加及肝组织MPO活性增高有关;内毒素还损害肝细胞增殖,不利于肝再生.     

Increased intraabdominal pressure impairs liver regeneration after partial hepatectomy in rats

BACKGROUND: There are many experimental studies showing that increased intraabdominal pressure (IAP) reduces liver blood flow, leading to ischemia and portal venous congestion. But, there is no study evaluating the effect of increased IAP on liver regeneration. It is well known that acute liver ischemia and portal venous congestion impair liver regeneration. We, therefore, aimed to determine the effect of increased IAP on liver regeneration in this study. METHODS: Sprague-Dawley rats underwent partial hepatectomy with or without IAP of 12-14 mm Hg for 24 h or sham operation. Rats were randomly divided into six groups: two sham-operated groups, two hepatectomy groups, and two hepatectomy with increased IAP groups. Mitotic index, proliferating cell nuclear antigen (PCNA)-labeling index, and liver regeneration rate as liver regeneration parameters were studied on day 1 or on day 4 after operation. Additionally, serum aspartate transaminase (AST) level and histopathological changes in intestinal mucosa were studied. RESULTS: Hepatectomy with/without increased IAP groups had significantly higher serum AST levels than the sham-operated group on day 1. Serum AST level was found to be significantly higher in the hepatectomy with increased IAP group than in the other groups on day 4. Intestinal mucosal injury was found in the hepatectomy with increased IAP groups on days 1 and 4. Mitotic index and PCNA-labeling index were markedly higher in all hepatectomy with/without increased IAP groups than in the sham-operated groups. However, together with liver regeneration rate, both indices were significantly less in the hepatectomy with increased IAP groups than in the hepatectomy groups both on day 1 and on day 4. CONCLUSION: Maintenance of IAP between 12 and 14 mm Hg for 24 h impaired liver regeneration after partial hepatectomy in rats.     

Changes of gluconeogenesis and alanine metabolism following partial hepatectomy in normal and cirrhotic rats

Gluconeogenesis and alanine metabolism of normal and cirrhotic rats were studied in view of partial hepatectomy. Liver cirrhosis was made by repeated injection of thioacetamide in rat. Partial hepatectomy was performed by modified method of Higgins-Anderson. Liver glycogen and fructose-2, 6-bisphosphate were decreased after hepatectomy and recovered within 7 days in normal groups, while those of cirrhotic group reduced even in preoperative state were further decreased and hardly recovered after hepatectomy. Gluconeogenesis of perfused liver in cirrhosis was increased from both lactate and alanine preoperatively, but gluconeogenesis from alanine was not increased in both hepatectomized rats. ATP and energy charge were decreased after hepatectomy and recovered within two weeks. These level were lower in cirrhotic group, and decreased further and hardly recovered after hepatectomy. Alanine utilization to CO2 in vivo was not impaired in cirrhotic group either preoperatively or postoperatively. ATP and energy charge were increased by alanine injection in hepatectomized rats of both normal and cirrhotic group. In conclusion, glucose-insulin therapy of sufficient amounts is important to improve decreased glycolysis and abnormal gluconeogenesis on both post-hepatectomy period of normal and pre and post-hepatectomy period of cirrhosis. Also alanine is effective for stimulating decreased energy production.     

肝移植治疗肝硬化肝癌切除后肝功能衰竭

目的　评估肝硬化肝癌局部切除后肝功能衰竭 (肝衰 )行肝移植的疗效。方法　 1例重度肝硬化肝癌病人行局部切除后肝衰 ,行原位肝移植术 ;术后尽早予足量化疗 ;免疫抑制剂予最低有效剂量。结果　肝移植术使肝衰、门静脉高压症得到有效治疗 ,肿瘤得到根治性切除 ,术后 6个月未见复发征象。结论　肝硬化肝癌切除后肝衰行肝移植疗效较好。合并重度肝硬化的大肝癌可能是肝移植的手术指征     

BCL-2 and BAX expression and cell proliferation,after partial hepatectomy with and without ischemia,on cholestatic liver in rats: an experimental study

BACKGROUND: Liver regeneration after partial hepatectomy (PHx) is regulated by several factors that activate or inhibit hepatocyte proliferation. Apoptosis seems to play an important role in cellular proliferation and liver regeneration. This study investigates the expression apoptosis-associated genes bcl-2 and bax, and the presence of apoptosis and cell proliferation after PHx, in normal and jaundiced rats with or without superimposed ischemia. MATERIALS AND METHODS: The study included 50 male Wistar rats assigned into; five groups (10 rats each). On day 0, rats of groups II, IV, and V underwent common bile duct ligation (BDL). On day 10, total liver ischemia (TLI) (occlusion of hepatic artery and portal vein-TLI) for 30 min was performed on animals of group V. When TLI was completed, all 30 animals (of groups I, IV, and V) underwent PHx (68%). Animals of group III underwent only TLI for 30 min. Rats of groups I, IV, and V were sacrificed 24 and 48 h after PHx was completed. Rats of group II were sacrificed 10, 11, and 12 days after BDL. Rats of group III were sacrificed immediately, 24 and 48 h after TLI completion. Liver tissue was obtained and pathologic examination included: (a) H&E stain, (b) in situ hybridization (detection of bcl-2 and bax mRNA) in paraffin sections, (c) Western blot analysis for the evaluation of bcl-2 and bax protein levels, (d) in situ hybridization (TUNEL) for the detection of apoptotic bodies, and (e) immunohistochemical stains (streptavidin-biotin method) in paraffin sections to detect cells that (i) express bcl-2 and bax proteins and (ii) undergo proliferation (Ki67+ cells). Results were expressed following morphometric analysis. RESULTS: Before hepatectomy, bcl-2 (protein or mRNA) levels were higher in jaundiced rats vs controls. Furthermore, bax (protein or mRNA) levels and apoptotic body index (ABI) were higher in cholestatic livers. After hepatectomy, there was an early decrease in the protein and mRNA levels of antiapoptotic gene bcl-2 and a late increase of proapoptotic gene bax and the ABI, compared to controls. Cell proliferation of hepatocytes was lower in group V (BDL + TLI) compared to that of groups II and IV (BDL). CONCLUSIONS: This study shows that apoptosis takes place in cholestatic livers with or without superimposed ischemia and may contribute in the impaired regenerative response observed in livers of jaundiced rats after partial hepatectomy.     

Changes of serum and urinary neopterin concentrations in rats after partial hepatectomy.

OBJECTIVE: To investigate the changes in serum and urinary neopterin concentrations over time after partial hepatectomy in rats, and to find out if neopterin can be used as a marker of immunological response during the regulation of liver regeneration. DESIGN: Randomised experiment. SETTING: University hospital, Taiwan, R.O.C. SUBJECTS: 84 male Wistar rats weighing about 200g. INTERVENTIONS: Partial hepatectomy (67%) or sham operation (n = 42 in each group). MAIN OUTCOME MEASURES: Serum and urinary neopterin concentrations measured by radioimmunoassay preoperatively and on days 1, 2, 3, 5, 7, and 10 postoperatively. RESULTS: Serum neopterin concentrations increased and reached their peak on days 5 and 7 after partial hepatectomy. The urinary neopterin concentration showed a similar trend, but with a more pronounced increase on days 5 and 7. CONCLUSIONS: Serum and urinary neopterin concentrations can be used as markers of activated cell-mediated immunity in rats after partial hepatectomy.