实验性鸡脂肪肝出血综合征模型的建立与评价

目的 建立一种造模时间较短、成本较低,成功率更高的鸡脂肪肝出血综合征动物模型.方法 320只14日龄青脚麻鸡随机分为对照组、高脂模型组、雌激素模型组和高脂结合雌激素模型组,每组设4个重复,每个重复20只,共处理28 d.期间每天观察记录鸡的临床状况,并于实验14、28 d测定血清生化指标、肝脏相关参数以及腹腔脂肪重、肝脏病理形态学变化.结果 对照组在28 d内未发生脂肪肝出血综合征,而高脂结合雌激素模型组在实验14 d发生了脂肪肝出血综合征.临床观察见10d后部分鸡开始出现张口呼吸、嗜睡、腹部大而下垂等临床表现.14 d及28 d后,剖检见腹腔脂肪过度沉积,肝脏明显肿大、黄染、质脆、边缘钝厚、表面可见散在点状或斑状出血;14 d后,显微镜下可见肝细胞轻度变性,胞质内出现较小的脂肪空泡.28 d后,可观察到大量肝细胞体积极度肿大,胞质内充满较大的脂肪空泡,肝脏结构紊乱等病理学变化;28 d后FLHS发生率高于14 d.血清甘油三酯浓度、总胆固醇浓度、肝脏相对重、腹脂相对重、肝脂率、肝出血分数与对照组相比,差异皆有显著性(P＜0.05或P＜0.01).雌激素模型组和高脂模型组的临床症状、剖检特征、病理组织学变化及血液生化指标的变化趋势与高脂结合雌激素模型组相似,但程度稍轻、发生时间较晚.结论 通过28 d的高脂日粮与雌激素复合诱导,可成功建立鸡脂肪肝出血综合征模型.     

Brain cholecystokinin-8 immunoreactivity in rats with experimental liver cirrhosis

Cholecystokinin-8 like immunoreactivity (CCK-8 IR) was measured in different brain regions of rats with experimental liver cirrhosis. A statistically significant reduction of CCK-8 content was observed in the hypothalamus of cirrhotic rats. No significant modification of brain CCK fractionation pattern was observed in treated animals as compared to controls. The decrease of CCK-8 IR parallels the recently reported hypothalamic depletion of beta endorphin in cirrhotic rats confirming that central neuropeptides are affected by chronic liver failure.     

Lipotoxicity and steatohepatitis in an overfed mouse model for non-alcoholic fatty liver disease

The major risk factors for non-alcoholic fatty liver disease (NAFLD) are obesity, insulin resistance and dyslipidemia. The cause for progression from the steatosis stage to the inflammatory condition (non-alcoholic steatohepatitis (NASH)) remains elusive at present. Aim of this study was to test whether the different stages of NAFLD as well as the associated metabolic abnormalities can be recreated in time in an overfed mouse model and study the mechanisms underlying the transition from steatosis to NASH.Male C57Bl/6J mice were subjected to continuous intragastric overfeeding with a high-fat liquid diet (HFLD) for different time periods. Mice fed a solid high-fat diet (HFD) ad libitum served as controls. Liver histology and metabolic characteristics of liver, white adipose tisue (WAT) and plasma were studied.Both HFD-fed and HFLD-overfed mice initially developed liver steatosis, but only the latter progressed in time to NASH. NASH coincided with obesity, hyperinsulinemia, loss of liver glycogen and hepatic endoplasmatic reticulum stress. Peroxisome proliferator-activated receptor γ (Pparγ), fibroblast growth factor 21 (Fgf21), fatty acid binding protein (Fabp) and fatty acid translocase (CD36) were induced exclusively in the livers of the HFLD-overfed mice. Inflammation, reduced adiponectin expression and altered expression of genes that influence adipogenic capacity were only observed in WAT of HFLD-overfed mice.In conclusion: this dietary mouse model displays the different stages and the metabolic settings often found in human NAFLD. Lipotoxicity due to compromised adipose tissue function is likely associated with the progression to NASH, but whether this is cause or consequence remains to be established.     

Dietary fatty acids modulate liver mitochondrial cardiolipin content and its fatty acid composition in rats with non alcoholic fatty liver disease

No data are reported on changes in mitochondrial membrane phospholipids in non-alcoholic fatty liver disease. We determined the content of mitochondrial membrane phospholipids from rats with non alcoholic liver steatosis, with a particular attention for cardiolipin (CL) content and its fatty acid composition, and their relation with the activity of the mitochondrial respiratory chain complexes. Different dietary fatty acid patterns leading to steatosis were explored. With high-fat diet, moderate macrosteatosis was observed and the liver mitochondrial phospholipid class distribution and CL fatty acids composition were modified. Indeed, both CL content and its C18:2n-6 content were increased with liver steatosis. Moreover, mitochondrial ATP synthase activity was positively correlated to the total CL content in liver phospholipid and to CL C18:2n-6 content while other complexes activity were negatively correlated to total CL content and/or CL C18:2n-6 content of liver mitochondria. The lard-rich diet increased liver CL synthase gene expression while the fish oil-rich diet increased the (n-3) polyunsaturated fatty acids content in CL. Thus, the diet may be a significant determinant of both the phospholipid class content and the fatty acid composition of liver mitochondrial membrane, and the activities of some of the respiratory chain complex enzymes may be influenced by dietary lipid amount in particular via modification of the CL content and fatty acid composition in phospholipid.     

The function of the liver mitochondria in rats with experimental cirrhosis undergoing an organ-preserving operation on the spleen]

The effect of splenectomy and of spleen-preserving operation with suture ligation of the left gastric artery on the functional status of liver mitochondria was studied by using 102 white male-rats of mixed population with experimental cirrhosis. The obtained data made it evident that in the immediate postoperative period (from 1 to 3 weeks after the procedure) in the animals of both the first and the second series, the disorder of energetic regulation of mitochondria hepatocytes respiration and the decrease in phosphorylation efficiency had the same tendency, which were seemingly caused by stress-action of the operative trauma. The data accumulated in the more distant postoperative period (8 weeks after the procedure) indicated that the resection of the lower splenic pole in combination with supplementary liver arterialization improved essentially the functional status of mitochondria hepatocytes and was more beneficial in contradistinction to splenectomy.     

Bradykinin release and inactivation in brain of rats submitted to an experimental model of Alzheimer's disease

The kallikrein-kinin system is involved in a variety of physiological and pathological processes. Components of this system, identified in rat and human brains, can be altered in neurodegenerative processes such as Alzheimer's disease. Here, we studied kinin release and its inactivation in rats submitted to chronic cerebroventricular infusion of β-amyloid (Aβ) peptide. Neurodegeneration was confirmed by histological analysis of brain samples. In cerebrospinal fluid of animals infused with Aβ, bradykinin concentration was increased, as determined by radioimmunoassay. However, in the brain of Aβ group, we only detected the tripeptide Arg-Pro-Pro, purified by reversed-phase chromatography and characterized by liquid chromatography-electrospray ionization mass spectrometry. This fragment of bradykinin indicated the possible participation of kinin-processing enzymes in the brain such as a prolyl oligopeptidase.     

Hongjam prevents hepatic damage against ethanol-induced fatty liver disease in rats

Silkworm, Bombyx mori, contains beneficial components such as protein, minerals, amino acids and omega-3. We previously reported a technique to produce silkworms in an easy to eat Hongjam. In this study, the inhibitory effect of Hongjam (50, 100, and 300 mg/kg body weight) on ethanol liver damage was investigated. Normal diet, ethanol, ethanol with Hongjam were administered to male Sprague-Dawley rats for 4 weeks. Administration of Hongjam reduced triglyceride levels in plasma and liver. In addition, plasma concentrations of alanine transaminase, aspartate aminotransferase and gamma glutamyl transpeptidase were significantly decreased in the Hongjam administered group. Moreover, Hongjam administration effectively reduced the plasma level of interleukin-1 beta, a pro-inflammatory cytokine. These results suggest that dietary intake of Hongjam can prevent alcoholic liver disease.     

Antioxidant system activation in rats with experimental cirrhosis after injection of cryopreserved fetal liver cells

The possibility to recover the antioxidant system in rats with experimental liver cirrhosis (LC) after allo- and xenotransplantation of cryopreserved fetal liver cells (FLC) was investigated. It was shown that the content of lipid peroxidation products in the blood serum of animals with LC four weeks after FLC transplantation decreased significantly as compared to control group. Such changes were accompanied by a significant increase of catalase (CAT), glutathione reductase (GR), Se-dependent glutathione peroxidase (GP) activity in the liver and total anti-oxidative activity (AOA) of blood. Obtained results demonstrate that the main direction of FLC effects in animals with LC agree with that we observed previously in other experimental models (partial hepatectomy, chronic alcohol poisoning and hypercholesterolemia). In conclusion, cell therapy may be considered as the universal method for correction of disorders in regulation of free-radical processes in various experimental pathologies.     

Therapeutic effect of oxyberberine on obese non-alcoholic fatty liver disease rats

BackgroundBerberine (BBR) has been widely used to treat non-alcoholic fatty liver disease (NAFLD). The metabolites of BBR were believed to contribute significantly to its pharmacological effects. Oxyberberine (OBB), a gut microbiota-mediated oxidative metabolite of BBR, has been firstly identified in our recent work.PurposeHere, we aimed to comparatively investigate the anti-NAFLD properties of OBB and BBR.MethodsThe anti-NAFLD effect was evaluated in high-fat diet-induced obese NAFLD rats with biochemical/ELISA tests and histological staining. The related gene and protein expressions were detected by qRT-PCR and Western blotting respectively. Molecular docking and dynamic simulation were also performed to provide further insight.ResultsResults indicated OBB remarkably and dose-dependently attenuated the clinical manifestations of NAFLD, which (100 mg/kg) achieved similar therapeutic effect to metformin (300 mg/kg) and was superior to BBR of the same dose. OBB significantly inhibited aberrant phosphorylation of IRS-1 and up-regulated the downstream protein expression and phosphorylation (PI3K, p-Akt/Akt and p-GSK-3β/GSK-3β) to improve hepatic insulin signal transduction. Meanwhile, OBB treatment remarkably alleviated inflammation via down-regulating the mRNA expression of MCP-1, Cd68, Nos2, Cd11c, while enhancing Arg1 mRNA expression in white adipose tissue. Moreover, OBB exhibited closer affinity with AMPK in silicon and superior hyperphosphorylation of AMPK in vivo, leading to increased ACC mRNA expression in liver and UCP-1 protein expression in adipose tissue.ConclusionTaken together, compared with BBR, OBB was more capable of maintaining lipid homeostasis between liver and WAT via attenuating hepatic insulin pathway and adipocyte inflammation, which was associated with its property of superior AMPK activator.     

莪术醇对非酒精性脂肪性肝大鼠肝功能和肝纤维化的影响及机制*

目的:探讨莪术醇(CC)对非酒精性脂肪性肝(NAFLD)大鼠模型肝功能和肝纤维化的影响及机制。方法:采用高脂饮食构建非酒精脂肪肝炎(NASH)伴肝纤维化的大鼠模型,将60只SD大鼠随机分为:空白对照组、模型组(NASH)、NASH+复方鳖甲软肝片(CBT)组(阳性对照组)、NASH+CC组(25、50、100 mg/kg),每组10只。测量大鼠肝脏占体重的百分比,测量大鼠高密度脂蛋白(HDL)、甘油三酯(TG)、谷丙转氨酶(ALT)、谷草转氨酶(AST)水平,HE染色观察肝纤维化情况,免疫组化检测鼠肝组织α-平滑肌肌动蛋白(α-SMA)表达及肝组织核因子κB p65(NF-κB p65)的阳性染色情况,蛋白印迹(Western blot)检测α-SMA、基质金属蛋白酶-1(MMP-1)、基质金属蛋白酶抑制剂-1(TIMP-1)蛋白表达及Toll样受体-4(TLR4)、转化生长因子激活激酶-1(TAK1)、NF-κB p65、血管细胞粘附分子-1(VCAM-1)蛋白的表达情况,酶联免疫吸附法(ELISA)检测肝组织中白介素(IL-6、IL-10、IL-1β)、肿瘤坏死因子-α(TNF-α)的表达。结果:与空白对照组相比,模型组大鼠HDL、 IL-10含量、MMP-1蛋白表达量显著降低(P＜0.05),TG、ALT、AST、肝组织P65阳性率,α-SMA、TIMP-1、TLR4、TAK1、NF-κB p65、VCAM-1表达、IL-6、TNF-α及IL-1β含量显著升高(P＜0.05)。与模型组相比,CBT和CC处理后大鼠HDL、 IL-10含量、MMP-1蛋白表达量显著升高(P＜0.05),TG、ALT、AST、肝组织P65阳性率,α-SMA、TIMP-1、TLR4、TAK1、NF-κB p65、VCAM-1表达、IL-6、TNF-α及IL-1β含量显著降低(P＜0.05),其中模型+CC组以高浓度组改善最显著(P＜0.05),但各剂量改善幅度均低于模型+CBT组(P＜0.05)。结论:莪术醇通过调节TLR4、TAK1、NF-κB p65信号通路,减轻炎症反应,改善肝功能,从而缓解非酒精性脂肪肝肝肝纤维化,且在一定范围内呈浓度依赖性。