健脾化湿解毒方对急性肝损伤小鼠肠屏障功能的影响

目的:探讨健脾解毒凉血方治疗肝损伤肠屏障功能障碍的作用靶点。方法:选取C57BL/6雄性小鼠32只,随机分为正常组、模型组、中药组、培菲康组,腹腔注射硫代乙酰胺100 mg/kg造模;中药组予以健脾解毒凉血方灌胃,培菲康组给予培菲康溶液灌胃;16 h后采集小鼠血清、肝组织、小肠组织,观察小鼠肝功能、肠道组织HE染色变化,免疫组织化学染色方法观察小肠闭锁小带蛋白-1表达。结果:模型组、中药组、培菲康组小鼠的ALT、AST均显著高于正常组,模型组、中药组、培菲康组比较差异无统计学意义(P0.05)。小肠组织在光镜和电镜下均可观察到中药组病变轻于模型组和培菲康组,免疫组织化学染色在小肠上皮细胞上可见闭锁小带蛋白-1棕黄色阳性标记,模型组、中药组、培菲康组阳性标记均显著少于正常组,中药组阳性标记显著多于模型组(P0.05)。结论:健脾解毒凉血方治疗硫代乙酰胺诱导急性肝损伤小鼠,可维护肠上皮细胞紧密连接部闭锁小带蛋白-1表达,修复肠屏障功能。     

Effects of fulminant hepatic encephalopathy on the adult rat brain antioxidant status and the activities of acetylcholinesterase, (Na+,K+)- and Mg2+-ATPase: comparison of the enzymes’ response to in vitro treatment with ammonia

Hepatic encephalopathy can be a life-threatening complication of fulminant hepatic failure. By understanding the pathophysiology involved in the induction of this neuropsychiatric disorder, future therapeutic and/or preventive attempts could be considered. In this study, an attempt has been made in order to shed more light on the mechanisms involved in the effects of thioacetamide (TAA)-induced fulminant hepatic encephalopathy on: (a) the adult rat brain total antioxidant status (TAS) and (b) the activities of acetylcholinesterase (AChE), (Na(+),K(+))-ATPase and Mg(2+)-ATPase. Moreover, in vitro experiments were conducted in order to evaluate the possible role of ammonia (incubated as NH(4)Cl, in a toxic concentration of 3mM) in the observed effects of TAA-induced fulminant hepatic encephalopathy on the examined adult rat brain enzyme activities. Fulminant hepatic encephalopathy caused a significant decrease in TAS (-22%, p < 0.001) and the activity of Na(+),K(+)-ATPase (-26%, p < 0.001), but had non-significant effects on the whole brain AChE and Mg(2+)-ATPase activities. The in vitro experiments (conducted through a 3h incubation with ammonia), showed no significant alterations in any of the examined parameters. Our in vitro and in vivo findings suggest that alterations in AChE and Mg(2+)-ATPase activities are not involved in the pathophysiology of the adult-onset fulminant hepatic encephalopathy, while the observed Na(+),K(+)-ATPase inhibition could be a result of the oxidative stress, neurotransmission deregulation, and/or of the presence of other toxic substances (that appear to act as direct or indirect inhibitors of the enzyme) and not due to the excess accumulation of ammonia in the brain.     

Contrasting effects of thioacetamide-induced liver damage on the brain uptake indices of ornithine,arginine and lysine: Modulation by treatment with ornithine aspartate

The dibasic amino acids arginine (ARG), ornithine (ORN) and lysine (LYS) are transported by a common saturable transporter (system ⁺) at the blood-brain barrier (BBB). In the present study we compared the brain uptake index (BUI) for radiolabelled ORN, ARG and LYS in control rats and in rats treated with thioacetamide (TAA) to induce hepatic encephalopathy (HE). Some animals received i.v. ornithine aspartate (OA), a drug structurally related to the ⁺ substrates that ameliorates neurological symptoms following liver damage by improving detoxification of ammonia in peripheral tissues: the compound was administered either by continuous infusion for 6h at a concentration of 2 g/kg (final blood concentration ranging from 0.19–0.5 mM), or as a 15 sec. bolus together with the radiolabelled amino acids, at a concentration of 0.35 mM. TAA treatment resulted in a delayed and progressive increase of BUI for ORN, to 186% of control at 7d post-treatment and to 345% of control at 21d post-treatment, when despite sustained liver damage, HE symptoms were already absent. In contrast, the BUI for ARG decreased to 30% of control at 7d post-treatment and remained low (42% of control) at 21d post-treatment. A 6h infusion of OA to untreated rats resulted in a reduction of the BUI for ARG and ORN to 51% and 62% of the control levels, respectively. Reductions of a similar magnitude were noted with both amino acids following the 15 sec OA bolus, indicating direct interaction of OA with the transport site in both cases. OA administered by either route abolished the enhancement of BUI for ORN, but did not further inhibit the BUI for ARG in the TAA-treated animals. The results indicate that some as yet unspecified factors released from damaged liver either modify the structure or conformation of the ⁺ transporter at the BBB from the normally ARG-preferring to the ORN-preferring state, or activate (induce) a different transporter specific for ORN which is normally latent.     

解毒口服液对大鼠实验性肝损伤内毒素血症的防护作用

目的:探讨中医药对肝损伤大鼠内毒素血症的防治作用。方法:应用硫代乙酰胺灌胃建立暴发性肝衰竭大鼠模型,观察解毒口服液对实验性肝损伤大鼠血浆内毒素、肝功能及肝组织病理学指标的影响。结果:解毒口服液组在降低血浆内毒素、缩短凝血酶原时间、改善肝脏病理损伤程度方面,与损伤组比较均有非常显著的差异(P<0.01);解毒护肝口服液组次之(P<0.05)。在改善肝功酶系指标方面,解毒口服液与损伤组比较亦有显著差异(P<0.05),略差于解毒护肝口服液组。结论:解毒口服液有较好改善肝脏功能、防治内毒素血症的功效。     

丹参注射液对肝性脑病的的防治作用及机制研究

目的：探讨丹参注射液对肝性脑病（hepatic encephalopathy,HE）的防治作用及其作用的初步机制。方法：通过急性氨中毒动物模型和四氯化碳（CCl4）致肝损伤合并硫代乙酰胺（TAA）诱导髙血氨的大鼠肝性脑病模型,对氨中毒死亡时相、血氨、脑氨水平、肝脏功能以及肝脏病理组织学改变等指标进行了评价。结果：在急性氨中毒实验中,丹参注射液能使急性氨中毒小鼠存活时间明显延长;在CCL4和TAA诱导的肝性脑病大鼠模型中,丹参注射液能明显降低肝性脑病大鼠血氨和脑氨水平,并可在一定程度上降低肝性脑病大鼠血清ALT、AST、ALP、总胆红素（Tbil）含量,改善肝功能,从而防治肝性脑病。结论：丹参注射液对肝性脑病有较好的防治作用,可能与降低血氨和脑氨水平有关。     

Microwave-assisted conditions for the green synthesis of thioacetamide. Optimization of reaction parameters using response surface methodology

An optimized method for the synthesis of thioacetamide (TA) in relation to the consumption of materials and energy, which reduces the production of waste and minimizes costs, is hitherto presented. The most important highlight of this work is the use of an inexpensive and readily accessible reactant for the thionation process (i.e. phosphorus pentasulfide, P₄S₁₀), combined with both alumina as solid support and a non-conventional microwave (MW) irradiation technique. In addition to this, Response Surface Methodology (RSM) was used to optimize the entire procedure of the synthesis for simultaneous tripled-maximization of Yield (ε), Mass Intensity (MI) and Mass Productivity (MP). Acetamide (AC)/P₄S₁₀ molar ratio, time and temperature of reaction were chosen as independent variables; while ε, MI and MP were chosen as responses. The determination of these green metrics parameters allow to evaluate the sustainability of the reaction and compare with other methodologies. A quadratic regression model was derived with satisfactory prediction. Tripled optimization with desirability function predicts a maximum ε of 100%, maximum MI of 29.00 kg/kg and a maximum MP of 3.45% under the following experimental conditions: AC/P₄S₁₀ molar ratio of 2.10, time of irradiation of 14 min and a temperature 140 °C.     

硫代乙酰胺诱导大鼠肝纤维化的研究

目的研究硫代乙酰胺对大鼠肝纤维化模型的诱导作用。方法采用0．03％的硫代乙酰胺腹腔注射,每周2次,构建大鼠肝纤维化模型;观察大鼠肝纤维化形成情况。结果与空白组比较,模型组大鼠血清谷丙转氨酶（ALT）、谷草转氨酶（AST）、透明质酸（HA）明显升高（P〈0．01）;层粘连蛋白（LN）升高（P〈0．05）。组织病理提示模型组大鼠肝细胞大量坏死,假小叶形成。结论硫代乙酰胺能诱导大鼠形成肝纤维化。     

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。