Role of nitric oxide in the regulation of fibrogenic factors in experimental liver fibrosis in mice

Previously, we have shown that an increased expression level of iNOS but a reduction in the expression of eNOS is associated with increased oxidative stress markers in CCl?-induced experimental liver fibrosis. The present study aimed to investigate the effect of L-arginine and 5-methylisothiourea hemisulfate (SMT) in the expression of profibrogenic factors in chronic liver injury. ICR mice were treated with CCl? with or without treatment of L-arginine, an NO donor, or SMT, an iNOS inhibitor. The expression of matrix metalloptroteinases (MMPs), tissue inhibitors of metalloproteinases (TIMPs), α-smooth muscle actin (α-SMA), tumor necrosis factor-α (TNF-α) and cyclooxygenase-2 (COX-2) were investigated by RT-PCR. The activity of the MMP-2 and MMP-9 were measured by zymography. Our results showed that CCl?-treated mice showed significant up-regulation of expression of pro-fibrogenic factors, TNF-α and COX-2. Treatment with L-arginine or SMT showed a significant reduction in CCl?-induced expression of these pro-fibrogenic factors, TNF-α and COX-2. In conclusion, both SMT and L-arginine effectively attenuated the progression of CCl?-induced liver fibrosis. SMT suppresses iNOS mediated NO production. However, L-arginine augments NO production. The similar effect of the two drugs on liver fibrosis indicates that there may be two distinct pathways of NOS mediated fibrogenesis in chronic liver injury by iNOS and eNOS. Our results suggest that eNOS-mediated liver fibrogenesis may play a more important role than that of iNOS in chronic liver injury. Taken together, these results support the contention that NO plays an active role in the progression of liver fibrosis and hepatocellular damage.     

肝硬化患者术后感染的危险因素及干预措施

目的:感染是肝硬化患者肝移植术后常见的并发症之一,影响患者的治疗效果和生存质量。本文针对肝硬化患者术后感染的危险因素进行分析,探讨有效的干预措施以提高临床疗效,为肝硬化术后并发症的预防提供可借鉴的方法。方法:对2008年10月-2013年9月在我院接受手术治疗的120例肝硬化患者的临床资料进行回顾性分析。根据术后并发症的发生情况选择其中60例发生感染的患者作为感染组,另外60例未发生感染的患者作为对照组。观察两组患者的年龄、肝硬化分期及用药情况等,对比不同的干预措施产生的临床效果。结果:感染组患者的平均年龄、肝功能障碍、抗生素使用量及术前合并感染的比率均显著高于正常对照组,差异具有统计学意义(P0.05)。两组患者进行针对性的护理干预均获得良好的治疗效果,未发生死亡病例。结论:患者的年龄、肝功能分级、用药及合并症等均为肝硬化术后感染的危险因素,临床中应实施针对性的干预措施以提高疗效。     

A comparative study of the action of liver extracts from C57Bl and CBA mice on hepatocyte adhesion

The adhesiometric methods were used for the investigation of influence of the preparations extracted from liver of CBA mice, predisposed to spontaneous blastomogenesis, and stable C57BL mice on cell adhesion. The extraction was carried out at 4 degrees C or 20 degrees C under condition of Ca2(+)-deficiency, so four preparations were investigated. The differences in adhesive activity between these liver preparations of two mouse lines were determined. The influence of the liver extracts (20 degrees C) from C57BL and CBA mice on cell adhesion was different. These preparations from C57BL mice contained the cell surface and membrane connected adhesion factors. The liver extracts (4 degrees C) from C57BL mice contained the cell surface adhesion factors influenced adhesive properties of hepatocytes under condition of cell surface preservation, and acted only on hepatocytes of C57BL mice. Our results concluded that, first, there were different adhesion factors extracted at 4 degrees C and 20 degrees C in liver preparations from C57BL mice; second, there was the strong change in cell surface of CBA mouse hepatocytes.     

Liver regeneration: molecular mechanisms of growth control

The molecular signals controlling liver regeneration are becoming rapidly defined. Control of growth in regenerating liver has advanced from elusive serum factors and nutrient effects to identification of entirely new growth factors with apparent liver specificity as well as establishment of meaningful gene expression patterns for growth factors already known. Based on studies with hepatocyte cultures and gene expression in regenerating liver, the substances EGF, TGF alpha, HBGF-1 (aFGF), and two new substances (HPTA/HGF and Hepatopoietin B) have been defined as complete mitogens for hepatocytes and implicated in control of liver growth. The amino acid sequence of HPTA/HGF recently became clear and revealed interesting structural homologies in a molecule that might become the largest known growth factor. The plasticity of growth responses seen in liver may be controlled by these factors as well as by comitogenic substances such as norepinephrine which, although nonmitogenic per se, can initiate growth in hepatocytes exposed to the above mitogenic growth factors or mitogenic inhibitors such as TGF beta. The role of the latter in cessation of DNA synthesis in liver regeneration will be discussed, presenting the positive and negative evidence that constitutes the TGF beta paradox of liver regeneration.     

两种急性免疫性肝损伤小鼠模型的对比研究

目的比较两种急性免疫性肝损伤小鼠模型的肝功能及淋巴因子变化特点和规律,为研究抗肝炎药物提供理想的动物模型。方法选用BCG＋LPS和Con-a建立两种免疫性肝损伤模型。以小鼠血清转氨酶水平变化及肝脏病理学检查作为肝损伤判断标准,以ELISA法测定血清中IL-2、IL-4、IL-10、TNF-α、IFN-r的变化。结果与正常对照组相比,两组模型ALT、AST的活性均显著升高（P〈0.01）;BCG＋LPS组IL-2、IFN-r、TNF-α的含量明显高于正常对照组（P〈0.01）,但IL-4、IL-10的含量无明显变化;Con-a组IL-2、IL-4、IL-10、TNF-α、IFN-r的含量均高于正常对照组（P〈0.01）。两组模型均出现严重的肝组织病理改变。结论Con-a建立的免疫性肝损伤模型更适用于防治免疫性肝损伤药物的筛选和研究。     

Purification and characterization of the enzymes of bile acid conjugation from fish liver

1. The two steps in bile acid conjugation have been studied in subcellular fractions of liver from three species of fish; vermillion rockfish, canary rockfish and ling codfish. 2. The bile acid: coenzyme A (CoA) ligase activity in homogenates and isolated microsomes is undetectable due to indeterminate factors. 3. A purification scheme is presented which eliminates the interfering factors. The purified ligase was found to have a lower affinity for bile acids as compared to the mammalian form and to be present in much lower titer. 4. Since it appears to be the rate controlling enzyme in all species, it is expected that the rate of bile acid conjugation is much slower in non-mammalian liver as compared to mammalian liver. 5. The bile acid-CoA:taurine N-acyltransferase was found to exist as a dimer of molecular weight 100,000, in contrast to the monomeric mammalian forms. 6. The only major kinetic difference is that the fish liver forms have rates of glycine conjugation which are only 1-2% of the rate with taurine, in part due to a very high Km for glycine.     

Fatty acid synthesis in the regenerating liver of the rat.

1. Synthesis de novo of fatty acids in the rat liver, measured per g wet wt. of tissue, was increased by a factor of about two, between 1 and 4 days after partial hepatectomy, compared with rates in sham-operated control rat livers. 2. There were no associated changes in the rates of liver cholesterol synthesis or of adipose-tissue fatty acid synthesis in rats after partial hepatectomy, compared with rates in sham-operated rats. 3. In regenerating livers, perfused under three different conditions, there was no alteration in the capacity for fatty acid synthesis compared with that of control rats. 4. The increased synthesis of fatty acids in regenerating liver was associated with insignificant increases in plasma concentrations of tricylglycerols and free fatty acids, with a decrease in content of liver glycogen, and with no change in hepatic activity of acetyl-CoA carboxylase. 5. The accelerated rate of synthesis of fatty adids in regenerating liver appears not to be due to any intrinsic alteration in hepatic capacity for fatty acid synthesis, but it may be caused by the continuous action on liver of unidentified circulating factors.     

Demonstration of two subtypes of insulin-like growth factor receptors by affinity cross-linking

The structure of receptors for insulin-like growth factors in rat liver plasma membranes and the BRL 3A2 rat liver cell line has been examined by chemical cross-linking with disuccinimidyl suberate and sodium dodecyl sulfate-polyacrylamide gel electrophoresis under reducing and nonreducing conditions. Two receptor subtypes have been identified: (i) 125I multiplication-stimulating activity cross-linked to liver membranes or intact cells appeared in a complex of Mr = 260,000 (reduced) and 220,000 (nonreduced) and (ii) 125I-insulin-like growth factor I cross-linked to BRL 3A2 cells appeared predominantly in two bands of Mr greater than 300,000 without disulfide reduction and in a Mr = 130,000 complex following reduction. The two subtypes of insulin-like growth factor receptors identified by structural analysis correspond to previously observed differences in their specificity for insulin and insulin-like growth factors.     

Improving effects obtained by the ovariectomy or treatment with tamoxifen of female diabetic rats over the function and enzyme activities of liver mitochondria.

In the present work we studied, in female chronic diabetic rats the effect of either the parenteral administration of tamoxifen (TAM) (500 micrograms.kg-1.day-1) for 15 days or the ovariectomy upon the respiration and oscillatory behaviour of intact mitochondria and the activities of 3-hydroxybutyrate dehydrogenase (HBD) and cytochrome c oxidase (Cox) of disrupted liver mitochondria. The treatment with TAM as well as the ovariectomy of diabetic animals significantly increased the respiratory control (RC) and the state 3 (S3) of respiration of intact liver mitochondria with the three substrates assayed (3-hydroxybutyrate, malate-glutamate and succinate). Both treatments also lowered significantly the damped factors of the oscillatory variation of liver intact mitochondria of diabetic rats. Moreover, the two above-mentioned treatments restored the activities of HBD and Cox of liver disrupted mitochondria to normal values. The effect of estrogens at level of its receptors in the modulation of liver mitochondrial function and liver HBD and Cox activities in chronic diabetes is discussed.     

Activity of cytochromes P-450p and P-450h in liver microsomes and blood corticosteroid levels in experimental animals under the action of physical factors]

In experiments on male Wistar rats it has been found that physical factors applied in medicine (laser radiation of low intensity with wave length 0.89 microns, microwaves of centimeter range of 2450 MHz, and ultrasound of low intensity 880 KHz) changed catalytic activity of liver microsomal and rostenedione 16 alpha- and 6 beta-hydroxylating cytochromes P-450h and P-450p and blood corticosteroids level. Activities of these two steroid-metabolizing cytochromes decreased under ultrasonic skin application on liver region and increased under microwave and laser action. Contents of physiologically inactive form of corticosterone were not changed by the physical factors action while level of active hormone was increased under ultrasonic and microwave action. These findings suggest association of the activity of liver steroid-metabolizing cytochromes P-450 and level of physiologically active form of corticosterone in blood under physical factors skin application on liver region.