Pancreatic trophism in experimental liver cirrhosis

Summary Pancreatic trophism and pancreatic enzyme composition, and plasma levels of cholecystokinin, insulin, glucagon, and glucose in liver cirrhosis induced by chronic thioacetamide administration (0.02% in the drinking water for 12 mo) were studied in rats. Advanced liver cirrhosis was evident in all thioacetamide-treated rats. The weight of the pancreas and its contents of DNA, protein, trypsinogen, chymotrypsinogen, proelastase, secretory trypsin inhibitor, and amylase were significantly increased as compared to the controls. The pancreatic secretory enzyme content changes showed a nonparallelism, characteristic of a cholecystokinin effect. Light and electron microscopy revealed a normal pancreatic architecture. Bioassayed plasma cholecystokinin levels in both fed and 24-h-fasted cirrhotic rats were significantly higher than in the corresponding controls. The plasma glucose, insulin, and glucagon levels demonstrated hypoglycemic tendencies with a glucagon predominance. These findings indicate that advanced liver cirrhosis in the rat is accompanied by pancreatic hypertrophy and hyperplasia, which might be attributed, at least in part, to elevated circulating cholecystokinin levels. Some parts of this work were presented at the 21 st Meeting of the European Pancreatic Club, Glasgow, UK, September 20–23, 1989.     

慢病毒介导脯氨酰寡肽酶过表达抑制硫代乙酰胺诱导的大鼠肝纤维化

目的探讨慢病毒介导的脯氨酰寡肽酶(POP)过表达对硫代乙酰胺(TAA)诱导的大鼠肝纤维化模型的影响。方法 40只雄性SD大鼠被随机分为4组,采用5%TAA诱导大鼠肝纤维化模型,各组分别在造模第1 w末门静脉注射生理盐水(正常对照组和TAA模型组)、空病毒(TAA模型+空病毒组)或携POP慢病毒(TAA模型+POP慢病毒组),在造模第4 w末处死动物,留取肝脏组织;采用苏木素-伊红(HE)染色及Masson染色观察肝脏病理形态学变化,采用化学比色法测定肝组织内羟脯氨酸含量,分别采用实时定量PCR或Western blot法检测POP m RNA表达或蛋白水平。结果模型组POP蛋白相对表达量较正常对照组水平显著降低(P0.05),而POP转基因组POP蛋白水平较其余三组均显著升高(P0.01);POP m RNA相对表达变化与POP蛋白相一致。TAA模型组和空病毒组的纤维化评分多为Ⅱ级,肝纤维化半定量积分分别为(15.2±1.69)和(15.3±4.62),显著高于正常对照组(1.75土0.63)和POP慢病毒过表达载体组(7.75±2.71)(P0.05);模型组和空病毒组肝组织羟脯氨酸含量分别为(504.47±111.15)μg/g肝质量和(498.32±90.87)μg/g肝质量,均显著高于正常对照组[(298.20±47.47)μg/g肝质量,P0.05],而POP转基因组大鼠肝组织中羟脯氨酸含量为(383.52±43.49)μg/g肝质量,显著低于模型组和空病毒组(P0.05)。结论肝纤维化时肝组织内POP水平下调,慢病毒载体可成功介导POP在大鼠肝组织内过表达,抑制TAA诱导的大鼠肝纤维化,降低肝组织羟脯氨酸水平。     

The Ras antagonist, farnesylthiosalicylic acid (FTS), inhibits experimentally-induced liver cirrhosis in rats

BACKGROUND/AIMS: Protooncogenes may play an important role, not only in carcinogenesis, but also in the regulation of normal cellular proliferation and differentiation. Several studies have indicated increased expression of the Ras protooncogenes in the liver in animal models and in patients with liver cirrhosis. The aim of the present study was to examine whether a synthetic Ras antagonist, S-farnesylthiosalicylic acid (FTS), which specifically dislodges Ras from the membrane of Ras-transformed fibroblasts (EJ cells), can prevent experimentally-induced liver cirrhosis in rats. METHODS: Cirrhosis was induced in male Wistar rats by intraperitoneal administration of thioacetamide (200 mg/kg twice weekly for 12 weeks). The Ras antagonist, farnesylthiosalicylic acid (FTS, 5 mg/kg), was administered during the study period 3 times a week. Ras expression in the liver was determined by Western blot analysis with pan anti-Ras antibodies and by immunohistochemistry. RESULTS: Rats treated with thioacetamide and the Ras antagonist, farnesylthiosalicylic acid (FTS), for 12 weeks had lower histopathologic scores of fibrosis and inflammation (p-values of 0.003 and 0.008, respectively) than those treated with thioacetamide only. There were no differences between the histopathologic scores in vehicle (control) and in Ras-antagonist (FTS) only treatments. Analysis of hepatic hydroxyproline levels from the two thioacetamide-treated groups and controls confirmed the histopathologic scores (7.7+/-0.9 mg/g protein in the TAA-treated vs. 3.8+/-0.5 mg/g protein in the TAA+FTS treated group, p = 0.007). Ras levels, determined by Western blot analysis, were markedly increased in the livers treated with TAA (17-fold over control) and significantly decreased (by about 70%) in the livers of rats treated with TAA and FTS. Studies in isolated human hepatic stellate cells demonstrated that FTS inhibited both DNA synthesis and migration of those cells (p<0.05). CONCLUSION: These results indicate that inhibition of Ras expression in the liver during fibrogenesis, prevents the development of experimentally-induced hepatic cirrhosis.     

硫代乙酰胺致大鼠肠源性内毒素血症模型探讨

目的 探讨不同剂量硫代乙酰胺(TAA)所制备的大鼠肠源性内毒素血症(IETM)模型的量效关系.方法 将40只大鼠分为4组,每组10只.TAA组分别以200、400、600mg/kg剂量的TAA灌胃,24h后相同剂量TAA重复灌胃一次,建立不同剂量TAA致大鼠IETM的动物模型;健康对照组以等体积0.9%氯化钠溶液灌胃.观察造模后24、48h大鼠死亡情况,48h后采集存活大鼠腹主动脉血,检测血浆内毒素、血清ALT和AST,观察肝组织病理变化.采用单因素方差分析,组间比较采用t检验.结果 造模48h后,健康对照组无大鼠死亡,200mg/kgTAA模型组死亡2只,400mg/kg TAA模型组死亡5只,600mg/kg TAA模型组死亡8只.200、400、600mg/kg TAA模型组大鼠血清ALT水平分别为(305.09±116.78)、(901.67±274.31)和(1454.84±473.49)U/L,明显高于健康对照组的(47.81±22.61)U/L(t=14.583、25.896、20.596,均P＜0.05);200、400、600mg/kg TAA模型组大鼠血清AST水平分别为(465.88±139.96)、(884.37±250.90)和(1889.23±159.67)U/L,明显高于健康对照组的(69.33±22.04)U/L(t=12.988、18.455、13.542,均P＜0.05);200、400、600mg/kg TAA模型组大鼠血浆内毒素水平分别为(0.436±0.110)、(0.550±0.095)和(0.620±0.057)EU/mL,明显高于健康对照组的(0.103±0.056)EU/mL(t=7.335、5.260、8.191,均P＜0.05).病理学显示不同剂量TAA模型组有不同程度的肝细胞变性坏死.结论 TAA剂量为200～600mg/kg时可成功制作IETM模型,200mg/kg TAA模型组大鼠死亡率较低,适于进一步的实验研究.     

Atorvastatin and rosuvastatin do not prevent thioacetamide induced liver cirrhosis in rats

AIM:To examine whether the administration of atorvastatin and rosuvastatin would prevent experimentallyinduced hepatic cirrhosis in rats.METHODS:Liver cirrhosis was induced by injections of thioacetamide(TAA).Rats were treated concurrently with TAA alone or TAA and either atorvastatin(1,10 and 20 mg/kg) or rosuvastatin(1,2.5,5,10 and 20 mg/kg) given daily by nasogastric gavage.RESULTS:Liver fibrosis and hepatic hydroxyproline content,in the TAA-treated group was significantly higher than those of the controls [11.5 ± 3.2 vs 2.6 ± 0.6 mg/g protein(P = 0.02)].There were no differences in serum aminotransferase levels in the TAA controls compared to all the groups treated concomitantly by statins.Both statins used in our study did not prevent liver fibrosis or reduce portal hypertension,and had no effect on hepatic oxidative stress.Accordingly,the hepatic level of malondialdehyde was not lower in those groups treated by TAA + statins compared to TAA only.In vitro studies,using the BrdU method have shown that atorvastatin had no effect of hepatic stellate cells proliferation.Nevertheless,statin treatment was not associated with worsening of liver damage,portal hypertension or survival rate.CONCLUSION:Atorvastatin or rosuvastatin did not inhibit TAA-induced liver cirrhosis or oxidative stress in rats.Whether statins may have therapeutic applications in hepatic fibrosis due to other etiologies deserve further investigation.     

健肝灵胶囊对小鼠肝损伤模型的保护作用

目的探讨健肝灵胶囊对小鼠免疫性肝炎及急性肝损伤保护作用。方法小鼠静脉注射卡介苗5×10^6个菌／鼠,11天后再静脉注射脂多糖7．5汕g／鼠,造成免疫性肝炎模型;另分别用四氯化碳和硫代乙酰胺造成小鼠急性中毒模型;观察小鼠血清谷雨转氨酶、谷草转氨酶、超氧化物歧化酶、丙二醛和一氧化氮的变化,评价健肝灵胶囊对免疫性肝炎及四氯化碳和硫代乙酰胺致急性肝损伤小鼠的保护作用。结果健肝灵胶囊能明显降低免疫性肝炎及急性肝损伤模型小鼠血清谷丙转氨酶、谷草转氨酶（P〈0．01）,超氧化物歧化酶的活性升高,丙二醛和一氧化氮含量明显降低。结论健肝灵胶囊对小鼠免疫性肝炎及急性肝损伤有保护作用。     

Tetrandrine stimulates the apoptosis of hepatic stellate cells and ameliorates development of fibrosis in a thioacetamide rat model

AIM To investigate the therapeutic effect of tetrandrine on liver fibrosis induced by thioacetamide in rats in vivo and in vitro.METHODS In vitro study we investigated the effect of tetrandrine on the apoptosis of rat hepatic stellate cells transformed by simian virus 40 (T-HSC/Cl-6), which retains the features of activated cells. In vivo studyhepatic fibrosis was induced in rats by thioacetamide.Tetrandrine was given orally to rats at doses of 5, 10 or 20 mg/kg for 4 wk compared with intraperitoneal injection of interferon-r.RESULTS In vitro study 5, 10 or 25 μg/mL of tetrandrine-induced activation of caspase-3 in t-HSC/Cl-6 cells occurred dose-depenclently. In vivo study tetrandrine treatment as well as interferon-r significantly ameliorated the development of fibrosis as determined by lowered serum levels of aspartate aminotransferase (AST),alanine aminotransferase (ALT), total bilirubin (T-Bil)and the levels of liver hydroxyproline (Hyp), hyaluronic acid (HA), laminin (LN) and also improved histological findings. The effects of tetrandrine at the concentration of 20 mg/kg were better than the other concentration groups.CONCLUSION Tetrandrine promotes the apoptosis of activated HSCs in vitro. Tetrandrine administration can prevent liver fibrosis and liver damage induced by thioacetamide in rats in vivo, indicating that it might exert a direct effect on rat HSCs.     

Animal PET for Thioacetamide-Induced Rat Cholangiocarcinoma: A Novel and Reliable Platform

PURPOSE: Cholangiocarcinoma (CCA) is a lethal disease afflicting many thousands of patients worldwide. We have previously developed an oral thioacetamide (TAA)-induced model of rat CCA that recapitulates the histologic progression of human CCA. Our objective was to evaluate the feasibility of animal PET in detecting CCA in the setting of the TAA rat model. PROCEDURES: Male Sprague-Dawley rats (n = 30) were used in this study. Drinking water with TAA 300 mg/l was administered orally in 26 rats, and animal PET was performed at 20 weeks after initiation of TAA. A total of four rats served as controls. Animal PET images were acquired sequentially using both C-11 acetate and 2-deoxy-2-[F-18]fluoro-D-glucose (FDG) to determine the optimal tracer. Dynamic animal PET images were collected to assess the optimal scan time based on the highest tumor-to-liver (T/L) ratio using time-activity curves. Animal PET findings were compared lesion by lesion with the results of autoradiography and the histological data. RESULTS: FDG animal PET images had a higher T/L ratio compared to images obtained with C-11 acetate as a marker. The optimal scan time for FDG animal PET was determined as 90 min postinjection of the tracer. This was when the T/L ratio reached its peak. Necropsy and histology confirmed the presence of TAA-induced CCA in 22 rats (84.6 %). Static animal PET images showed intense FDG uptake in 17 of the 22 tumor-bearing animals (77.3%). The average T/L ratio was 1.60 +/- 0.09. The sensitivity and specificity of animal PET in the detection of CCA were 77% (17/22) and 100% (4/4), respectively. CONCLUSIONS: We conclude that animal PET in the setting of the TAA rat model seems to be feasible for the detection of CCA. Future translational studies are needed to confirm and expand our findings.