Effect of dihydromyricetin on hepatic encephalopathy associated with acute hepatic failure in mice

ContextHepatic encephalopathy (HE) is a complex neuropsychiatric disease caused by liver failure. Dihydromyricetin (DMY) is a traditional medicine used to treat liver injury.ObjectiveTo investigate the effects of dihydromyricetin (DMY) on hepatic encephalopathy associated with acute hepatic failure mice models established by thioacetamide (TAA) exposure.Materials and methodsFemale BALB/c mouse were randomly divided into control, DMY, TAA, and TAA + DMY groups (n = 8). The first two groups were intraperitoneally injected with saline or 5 mg/kg DMY, respectively. The last two groups were injected with 600 mg/kg TAA to establish HE models, and then the mice in the last group were treated with 5 mg/kg DMY. Neurological and cognition functions were evaluated 24 and 48 h after injection. Mice were sacrificed after which livers and brains were obtained for immunoblot and histopathological analysis, while blood was collected for the analysis of liver enzymes.ResultsIn the TAA + DMY group, ALT and AST decreased to 145.31 ± 12.88 U/L and 309.51 ± 25.92 U/L, respectively, whereas ammonia and TBIL decreased to 415.67 ± 41.91 μmol/L and 3.31 ± 0.35 μmol/L, respectively. Moreover, MDA decreased to 10.74 ± 3.97 nmol/g, while SOD and GST increased to 398.69 ± 231.30 U/g and 41.37 ± 21.84 U/g, respectively. The neurological score decreased to 2.87 ± 0.63, and the number of GFAP-positive cells decreased to 41.10 ± 1.66. Furthermore, the protein levels of TNF-α, IL-6, and GABA_A in the cortex decreased.ConclusionsWe speculate that DMY can serve as a novel treatment for HE.     

肠源性内毒素血症在硫代乙酰胺所致肝损伤发病中的作用

目的探讨肠源性内毒素血症在硫代乙酰胺（thioacetamide,TAA）所致肝损伤模型发病机制中的地位和作用。方法选用雄性Wistar大鼠26只,随机分为4组,即正常组（N）及结肠切除（C）对照组;TAA损伤组（T）和结肠切除+TAA组（C+T）。采用生化检测法测定血浆内毒素含量和ALT活性。结果单纯给予TAA组,血浆内毒素水平和ALT活性显著高于其它三个组;而结肠切除+TAA组的血浆内毒素水平与结肠切除对照组和正常对照组相比无明显升高,ALT活性结肠切除组+TAA组和正常对照组比较明显升高,但比TAA组却明显减低。T组与C+T组血浆内毒素水平与ALT活性变化之间呈正相关关系（r＝0.985,P＜0.01）。结论TAA所导致的内毒素血症是肠源性内毒素血症;TAA本身有直接致肝细胞损伤的作用,但其所形成的肠源性内毒素血症造成的肝损伤更为严重。     

Protective action of glutamine in rats with severe acute liver failure

BACKGROUND Severe acute liver failure(SALF) is a rare, but high-mortality, rapidly evolving syndrome that leads to hepatocyte degeneration with impaired liver function.Thioacetamide(TAA) is a known xenobiotic, which promotes the increase of the formation of reactive oxygen species. Erythroid 2-related factor 2(Nrf2) activates the antioxidant protection of cells. Studies have evidenced the involvement of inflammatory mediators in conditions of oxidative stress.AIM To evaluate the antioxidant effects of glutamine on Nrf2 activation and NFκBmediated inflammation in rats with TAA-induced IHAG.METHODS Male Wistar rats(n = 28) were divided into four groups: control,control+glutamine, TAA, and TAA + glutamine. Two TAA doses(400 mg/kg)were administered intraperitoneally, 8 h apart. Glutamine(25 mg/kg) was administered at 30 min, 24 h, and 36 h. At 48 h, blood was collected for liver integrity analysis [aspartate aminotransferase(AST), alanine aminotransferase(ALT), and alkaline phosphatase(ALP)]. The liver was harvested for histology and assessment of oxidative stress [thiobarbituric acid-reactive substances(TBARS), catalase(CAT), glutathione peroxidase(GPx), glutathione S-transferase(GST), glutathione(GSH), Nrf2, Kelch-like ECH-associated protein 1(Keap1),NADPH quinone oxidoreductase1(NQO1), superoxide dismutase(SOD)] and inflammatory process.RESULTS TAA caused disruption of the hepatic parenchyma, with inflammatoryinfiltration, massive necrosis, and ballooning degeneration. Glutamine mitigated this tissue damage, with visible regeneration of hepatic parenchyma; decreased TBARS(P 0.001), GSH(P 0.01), IL-1β, IL6, and TNFα levels(P 0.01) in hepatic tissue; and decreased blood levels of AST, ALT, and ALP(P 0.05). In addition, CAT, GPx, and GST activities were restored in the glutamine group(P0.01, P 0.01, and P 0.001, respectively vs TAA alone). Glutamine increased expression of Nrf2(P 0.05), NQO1, and SOD(P 0.01), as well as levels of IL-10(P 0.001), while decreasing expression of Keap1, TLR4, NFκB(P 0.001), COX-2 and iNOS,(P 0.01), and reducing NO_2 and NO_3 levels(P 0.05).CONCLUSION In the TAA experimental model of IHAG, glutamine activated the Nrf2 pathway,thus promoting antioxidant protection, and blunted the NFκB-mediated pathway, reducing inflammation.     

水飞蓟宾对硫代乙酰胺所致肝损伤状态下CYP3A的调节作用及机制

目的：水飞蓟宾（sB）是植物奶蓟的主要成分,长期以来被用于治疗各种肝脏疾病。由于肝病往往伴随有CYP450酶的功能失调,因此本文以硫代乙酰胺（TAA）引起的大鼠肝损伤为模型,研究水飞蓟宾的肝保护作用和对CYP3A的调控作用之间的关系。方法：血清生化指标检测和肝脏病理切片实验评价水飞蓟宾的保肝作用。免疫组化实验测定0【一SMA的表达,ELISA试剂盒测定大鼠肝脏炎症因子的表达。实时定量PCR和westernblot实验考察CYP3A和PXR的mRNA和蛋白表达水平变化,咪达唑仑4一羟基化反应测定CYP3A的活性。siRNA转染实验沉默PXR后考察PXR在硫代乙酰胺细胞毒和CYP3A调节中的作用。结果：水飞蓟宾表现出明显的保肝、抗炎、抗纤维化作用,并能有效逆转硫代乙酰胺导致的大鼠肝脏CYP3A和PXR表达减少以及PXR的入核减少。PXR沉默实验显示PXR参与了水飞蓟宾的细胞保护和CYP3A调控过程。结论：PXR是参与CYP3A调控的重要因子,很可能是水飞蓟宾在硫代乙酰胺导致的大鼠肝损伤模型中的作用靶点,同时也提示在治疗肝脏疾病时要注意与水飞蓟宾合用的药物可能与水飞蓟宾之间存在潜在的药物相互作用。     

内毒素血症在肝癌发生发展中的作用

目的:探讨内毒素血症在肝癌发生发展中作用。方法:利用饮水中加入0.03%TAA,4个月形成肝硬化,6个月形成肝癌动物的模型。TAA+LPS组从第5个月开始皮下注射内毒素,至实验结束。在肝癌发生发展过程中进行血浆内毒素水平、γ-GT活性、DNA指数、增殖指数,并对N-ras、p53基因点突变进行分析。结果:内毒素可增加bcl-2与p53蛋白过度表达与增加N-ras、p53基因的点突变,增加自由基生成与降低抗氧化酶活性,加重DNA损伤。结论:内毒素能够促进TAA诱发肝癌变的过程。     

Evaluation of hepatoprotective activity of aerial parts of Tephrosia purpurea L. and stem bark of Tecomella undulata

Ethnopharmacological relevance

The aerial parts of Tephrosia purpurea (L.) pers. (Fabaceae) and stem bark of Tecomella undulata seem. (Bignoniaceae) are used for liver disorders in the traditional system of medicine.

Aim of the study

To evaluate the hepatoprotective activity of aerial parts of Tephrosia purpurea and stem bark of Tecomella undulata against thioacetamide-induced hepatotoxicity.

Materials and methods

Hepatotoxicity was induced in albino rats of either sex by subcutaneous injection of thioacetamide. Aqueous–ethanolic extract of aerial parts of Tephrosia purpurea (100, 300 and 500 mg/kg/day and ethanolic extract of stem bark of Tecomella undulata (200, 500 and 1000 mg/kg/day were evaluated.

Results

Oral administration of Tephrosia purpurea at 500 mg/kg and Tecomella undulata at 1000 mg/kg resulted in a significant reduction in serum aspartate aminotransaminase (35% and 31%, respectively), alanine aminotransaminase (50% and 42%, respectively), gamma glutamyl transpeptidase (56% and 49%, respectively), alkaline phosphatase (46% and 37%, respectively), total bilirubin (61% and 48%, respectively) and liver MDA levels (65% and 50%, respectively), and significant improvement in liver glutathione (73% and 68%, respectively) when compared with thioacetamide damaged rats. Histology of the liver sections of the animals treated with the extracts also showed dose-dependent reduction of necrosis.

Conclusions

The present study demonstrates the hepatoprotective activity of the aerial parts of Tephrosia purpurea and stem bark of Tecomella undulata against thioacetamide-induced hepatotoxicity.     

暴发性肝损伤肝性脑病大鼠脑糖胺多糖含量的变化

本文应用硫代乙酰胺灌胃复制暴发性肝损伤肝性脑病大鼠模型,检测了实验大鼠大脑、脑干、小脑糖胺多糖含量的变化。结果表明肝性脑病发生时大脑、脑干糖胺多糖含量较正常大鼠显著降低,而小脑糖胺多糖含量并无变化。说明肝性脑病发生时大脑及脑干部位伴有糖胺多糖的变化,提示肝性脑病的发生与脑内神经细胞外基质成份糖胺多糖等的变化有关。     

酒制大黄、乳酸菌素及复方乳黄制剂对急性肝性脑病大鼠防治的研究

目的探讨酒制大黄、乳酸菌素及其复方乳黄制剂对硫代乙酰胺(TAA)引起的大鼠急性肝性脑病的不同防治作用。方法用TAA灌胃建立大鼠急性肝性脑病模型,观察酒制大黄、乳酸菌素及其复方乳黄制剂对肝性脑病大鼠行为神经学、脑电图、肝功能、血氨浓度、血浆γ氨基丁酸(GABA)浓度和肝脏病理损伤的不同影响。结果乳黄制剂、酒制大黄、乳酸菌素均能不同程度地改善肝性脑病大鼠行为活动、神经反射和脑电图情况,恢复肝脏功能,降低肝性脑病级别、血氨和血浆GABA浓度,减轻肝脏病理损伤。其疗效大小依次为乳黄制剂>酒制大黄>乳酸菌素。结论酒制大黄与乳酸菌素有协同作用,两者组成的复方乳黄制剂对TAA引起的大鼠急性肝性脑病有显著防治作用。     

Synaptosomal Uptake of Alpha-Ketoglutarate and Glutamine in Thioacetamide-Induced Hepatic Encephalopathy in Rats

The kinetics of uptake of two astroglia-derived glutamate (GLU) precursors, α-ketoglutarate (α-KG) and glutamine (GLN) were determined in synaptosomes derived from rats with acute hepatic encephalopathy (HE) induced with a hepatotoxin, thioacetamide (TAA). TAA treatment increased by 33% Vmax for high affinity, low capacity α-KG uptake, without influencing its Km. The increase of the uptake capacity for α-KG may represent a response of the GLUergic nerve terminals to the decreased cerebral α-KG content, which during HE is associated with depressed activity of pyruvate carboxylase, an enzyme that replenishes α-KG in astrocytes. The result is thus consistent with the notion that HE affects the astroglial control of GLUergic neurotransmission. The Km and Vmax for the low affinity, high capacity GLN uptake was not affected by TAA treatment.