Deficiency of β1-6 N-Acetylglucosaminyltransferase Involved in the Biosynthesis of Blood Group I Antigen in the Liver of LEC Rats

The activities of the β1-6 and β1–3 N-acetylglucosaminyltransferases, which synthesize blood group I and i antigens, respectively, were measured in various tissues of hepatitis- and hepatoma-predisposed rats (LEC rats). In LEC rats the β1-6 N-acetylglucosaminyltransferase activity was barely detectable in the liver, while substantial enzyme activity was found in other tissues. In the control LEA rats the enzyme was expressed in most tissues, including the liver. Immunochemical studies using a monoclonal antibody which recognizes I antigen indicated that the expression of I antigen was less prominent in hepatocytes of LEC rats than in hepatocytes of LEA rats. The level of β1–3 N-acetylglucosaminyltransferase activity was constant in most of the tissues during the development. These results indicate that the biosynthesis of I antigen does not occur in the livers of the LEC rats.     

Comparison of disposition behavior and de-coppering effect of triethylenetetramine in animal model for Wilson's disease (Long-Evans Cinnamon rat) with normal Wistar rat.

The disposition behaviors and de-coppering effect of triethylenetetramine dihydrochloride (trientine), a selective chelating agent for copper and an 'orphan drug' for Wilson's disease, have been evaluated in an animal model, Long-Evans Cinnamon (LEC) rats, and normal rats (Wistar). In LEC rats, urinary excretion of trientine was remarkably lower than that of Wistar rats. The absorption rates from the jejunal loop and in vitro metabolism in the liver S9 fraction (supernatant of 9000 x g) were approximately the same for both strains. The decline of urinary excretion of trientine in LEC rats is thought to be due mainly to the lowering of the functional activity of the kidney, because urinary excretion of creatinine and phenolsulfonphthalein were significantly lower in LEC rats than those in Wistar rats. Both acceleration of urinary excretion of copper and reduction of hepatic copper levels were observed with treatment of trientine in LEC rats aged 6 weeks. In LEC rats aged 13 weeks, however, no de-coppering effect from the liver was observed, though urinary excretion of copper was increased. These results suggest that trientine has a pharmacological effect in disease state, especially in the early stages of hepatitis.     

PEDF对人晶状体上皮细胞生长调控的体内外研究

目的:探讨在体内及体外色素上皮衍生因子(PEDF)对人晶状体上皮细胞(LEC)生长的调节作用?方法:体内研究用ELISA法检测年龄相关性白内障患眼房水PEDF浓度,术中取前囊膜标本检测LEC密度,分析PEDF水平与LEC数量?白内障类型的关系;体外研究,加PEDF培养人晶状体上皮细胞株(HLE-B3),CCK8法检测细胞生长活性,流式细胞仪通过Annexin V-FITC/7-AAD双染法检测细胞周期和凋亡变化? 结果:120例白内障患眼房水PEDF浓度为(156.2 ± 41.2)ng/ml,中央区前囊下LEC密度随房水PEDF水平下降而降低(r = 0.556,P < 0.01),控制年龄因素后仍呈正相关(r = 0.387,P < 0.05),皮质型白内障房水PEDF浓度较核硬化型更低(P < 0.05);体外培养的LEC细胞株加入PEDF后,细胞生长明显加快(F = 187.33,P < 0.01),细胞凋亡被显著抑制,凋亡率从13.50%降为2.08%(t = 7.90,P < 0.01),细胞分裂活性增强,G2期 + S期细胞比例从28.54%升为54.05%(t = 6.32,P < 0.01)? 结论:人眼内PEDF可能作为LEC营养因子发挥细胞周期调控和抗凋亡的重要作用,参与晶状体生理性状维持和白内障发生发展?     

Lentiviral gene transfer ameliorates disease progression in Long-Evans cinnamon rats: An animal model for Wilson disease

Objective. Wilson disease is a copper storage disorder caused by mutations in the ATP7B gene leading to liver cirrhosis. It has previously been shown that lentiviral vectors can govern an efficient delivery and stable expression of a transgene. The aim of this pilot study was to prove the principle of a lentiviral gene transfer in the Long-Evans cinnamon (LEC) rat, an animal model of Wilson disease. Material and methods. LEC rats were treated either by systemic application of lentiviral vectors or by intrasplenic transplantation of LEC-rat hepatocytes lentivirally transduced with ATP7B. The ATP7B gene expression was analyzed by RT-PCR and immunofluorescence analysis. The therapeutic effect was assessed by analysis of liver histology, serum ceruloplasmin oxidase activity, and liver copper content. Results, Hepatic expression of the transgene was detected at different time-points post-treatment and lasted for up to 24 weeks (end of experiment). Liver copper levels were lowered in all treatment groups compared to untreated LEC rats. Twenty-four weeks after treatment, the area of the examined liver-tissue sections occupied by fibrosis was 48.3–57.9% in untreated LEC rats and 10.7–19.8% in rats treated with cell therapy. In systemically treated rats, only small fibrous septa could be observed. Conclusions. These data prove for the first time that lentiviral ATP7B gene transfer is feasible in Wilson disease. In our pilot study the systemic approach was more promising in ameliorating disease progression than the transplantation of lentivirally transduced hepatocytes.     

Differing Distribution of Hepatocyte Growth Factor-positive Cells in the Liver of LEC Rats with Acute Hepatitis, Chronic Hepatitis and Hepatoma

Using anti-rat hepatocyte growth factor (HGF) antibody, we investigated the distribution of HGF-positive cells in the liver tissues of LEC rats at various phases of liver diseases. During the phase of fulminant hepatitis, HGF-positive cells increased remarkably, and many of them were localized at the portal triads; these cells were identified from their shape as non-epithelial cells. A reduced number of HGF-positive cells was observed during the phase of chronic hepatitis, while no HGF-positive cells were seen in the tissue of cholangiofibrosis. During the phase of carcinoma, staining revealed that both the hepatocellular carcinoma cells and the non-epithelial cells in cancerous liver tissue were HGF-positive. These results suggest that, in LEC rats, HGF may play an important role in the regeneration of hepatocytes as well as in the development of hepatocellular carcinoma.     

Lateral entorhinal cortical kindling can be established without potentiation of the entorhinal-granule cell synapse

Kindling is an animal model of epilepsy which involves a permanently enhanced neuronal response to an electrical stimulus. It has been proposed that long-term potentiation (LTP) of excitatory synaptic transmission is the cellular basis of kindling. Therefore, LTP was examined in the monosynaptic projections from the lateral entorhinal cortex (LEC) to dentate granule cells (DG) in unrestrained, unanesthetized rats kindled via the LEC. Population excitatory postsynaptic potentials (pEPSPs) were recorded from the granule cells before, during, and after kindling of the LEC. Controls were unkindled rats recorded during the same time period as the experimental rats. No consistent changes were found in plateau pEPSP amplitudes or initial slopes although kindling via the LEC proceeded through the typical stages. There was also no significant change in the stimulus intensity needed to elicit a 50% maximal or "plateau" pEPSP. Thus, whereas kindling was indeed established by stimulation of the LEC, there was no evidence of LTP detected in the granule cell response either during the development or after completion of kindling. Either LTP does not underlie the mechanism of kindling via this pathway or it occurs in different brain regions receiving LEC input.     

Contribution of Va24Vb11 natural killer T cells in Wilsonian hepatitis

Wilson disease (WD) is an autosomal recessive disorder of copper transport, resulting in copper accumulation and toxicity to the liver and brain. There is no evidence that the WD patient's immune system attacks copper accumulated hepatocytes. Here we describe that the frequency and absolute number of Valpha24+Vbeta11+ natural killer T (NKT) cells were significantly increased in 3 cases of WD, whereas those of CD3+CD161+ NKT cells were within the normal range. Patients no. 1 and 2 had a presymptomatic form of WD. Their tissue specimens showed pathological changes of mild degeneration of hepatocytes with a few infiltrating mononuclear cells and a low degree of fatty change. Patient no. 3 displayed fulminant hepatitis with Coombs-negative haemolytic anaemia. The tissue specimens of patient no. 3 showed macronodular cirrhosis with thick fibrosis, inflammatory infiltrates and spotty necrosis. Human Valpha24+Vbeta11+ NKT cells are almost equal to CD1d-restricted NKT cells. Therefore we investigated CD1d-restricted NKT cells in the LEC rat as an animal model of WD. In LEC rats before hepatitis onset, the number and phenotype of liver NKT cells were normal. At about 4 months of age all LEC rats developed acute hepatitis accompanied by acute jaundice, and CD161high NKT cells developed in their livers. CD161highalphabetaTCRbright NKT cells developed in some of them. Their hepatitis was severe. CD161highalphabetaTCRbright NKT cells expressed an invariant rat Valpha14-Jalpha281 chain, which is CD1d-restricted. Furthermore, liver lymphocytes in the acute jaundiced LEC rats with CD161highalphabetaTCRbright NKT cells had significant and CD1d-specific cytotoxic activity.     

Possible carcinogenic risks of copper gluconate and their prevention by co-administered green tea catechins evaluated by a rat medium-term multi-organ carcinogenicity bioassay protocol

Carcinogenic risks of copper gluconate, green tea catechins and their combined exposure were evaluated using a rat medium-term multi-organ carcinogenicity bioassay protocol. Male BrlHan:WIST@Jcl (GALAS) rats were given N-nitrosodiethylamine (DEN), N-methylnitrosourea (MNU), 1,2-dimethylhydrazine (DMH), N-butyl-N-(4-hydroxybutyl)nitrosamine (BBN) and 2,2'-dihydroxy-di-n-propylnitrosamine (DHPN) for a total multiple initiation period of 4 weeks (DMBDD treatment). Rats were then given a diet containing copper gluconate at a concentration of 0, 10, 300, 3000 or 6000 ppm with or without a co-administration of catechins starting 1 week later by admixing in the drinking water at a concentration of 5000 ppm. All survivors were sacrificed at the end of week 29. Number of putatively preneoplastic, glutathione S-transferase placental form-positive, liver lesions significantly increased by copper gluconate of 300 ppm or greater. In addition, both incidence and grade of hyperplasia in the forestomach significantly increased by copper gluconate of 6000 ppm. Catechins, exerting no effects by themselves, inhibited these effects of copper gluconate. The present results indicate that copper gluconate may possess carcinogenic risks for the liver and forestomach at its high dose level, and that co-administered green tea catechins may exert preventive effects.     

Low Susceptibility of Long-Evans Cinnamon Rats to N-Butyl-N-(4-hydroxybutyl)-nitrosamine-induced Urinary Bladder Carcinogenesis and Inhibitory Effect of Urinary Copper

We studied the susceptibilities to N -butyl- N -(4-hydroxybutyl)nitrosamine (BBN)-induced urinary bladder carcinogenesis of male Long-Evans Cinnamon (LEC), F344 and Long-Evans Agouti (LEA) rats. Male rats ( n =21) were given 0.1% BBN in their drinking water from week 6, 8 and 10 for one week, and killed in week 56. The incidences of transitional cell tumors (papillomas plus carcinomas) in BBN-treated LEC and F344 rats were 12% and 76%, respectively ( P < 0.001, experiment 1), and those in LEC and LEA rats were 11% and 95%, respectively ( P < 0.001, experiment 2). When male LEC and F344 rats were given 0.1% BBN in their drinking water for 7 days, the intake of BBN and the urinary concentration of its active metabolite, N -butyl- N -(3-carboxypropyl)nitrosamine (BCPN), were higher in the LEC rats ( P < 0.01). The urinary pHs of untreated LEC and F344 rats were similar between week 6 and 30. The urinary copper concentration was lower in LEC rats before jaundice than in F344 rats, but its concentrations in 28- and 50-week-old LEC rats were 1.7 and 2.3 times those in F344 rats. In a two-stage carcinogenesis study using F344 rats, i.p. injections of cupric nitrilotriacetate increased urinary copper excretion, and inhibited BBN induced bladder carcinogenesis. In a two-stage carcinogenesis study using LEC rats, oral administration of D-penicillamine decreased urinary copper excretion, and increased BBN-induced bladder cancer, although the difference was not significant. These data show that LEC rats are resistant to bladder carcinogenesis and suggest that urinary copper has a significant role in their resistance.     

年龄相关性白内障晶状体上皮细胞中hTERT的活性表达

目的：探讨hTERT在年龄相关性白内障晶状体上皮细胞（lens epithelial cells,LEC）中的活性表达及在白内障形成中的作用。方法：对40例年龄相关性白内障患者和10例正常LEC中的hTERT进行原位杂交技术检测,并进行比较。结果：年龄相关性白内障LEC中hTERT的阳性表达率明显增高,与正常晶状体组相比,有显著性差异（P〈0.01）。结论：LEC中hTERT活性的变化与年龄相关性白内障的形成密切相关,随着年龄的增长,hTERT的表达活性升高,使LEC发生衰老,从而形成白内障。