Experimental models of non-alcoholic fatty liver disease in rats

Non-alcoholic fatty liver disease(NAFLD)is the most common chronic liver disease in the Western world,and it persists at a high prevalence.NAFLD is characterised by the accumulation of triglycerides in the liver and includes a spectrum of histopathological findings,ranging from simple fatty liver through non-alcoholic steatohepatitis(NASH)to fibrosis and ultimately cirrhosis,which may progress to hepatocellular carcinoma.The pathogenesis of NAFLD is closely related to the metabolic syndrome and insulin resistance.Understanding the pathophysiology and treatment of NAFLD in humans has currently been limited by the lack of satisfactory animal models.The ideal animal model for NAFLD should reflect all aspects of the intricate etiopathogenesis of human NAFLD and the typical histological findings of its different stages.Within the past several years,great emphasis has been placed on the development of an appropriate model for human NASH.This paper reviews the widely used experimental models of NAFLD in rats.We discuss nutritional,genetic and combined models of NAFLD and their pros and cons.The choice of a suitable animal model for this disease while respecting its limitations may help to improve the understanding of its complex pathogenesis and to discover appropriate therapeutic strategies.Considering the legislative,ethical,economical and health factors of NAFLD,animal models are essential tools for the research of this disease.

Gastrin,somatostatin,G and D cells of gastric ulcer in rats

AIM: To investigate the relationship among gastrin, somatostatin, G and D cells in gastric ulcer and in its healing process in rats. METHODS: Fourty-nine Wistar rats were divided into 7 groups. The gastric ulcer model was induced by acetic acid successfully. The gastrin and the somatostatin in rat plasma, gastric fluid and antral tissue were measured by radioimmunoassay(RIA). G and D cells in antral mucosa were analyzed with polyclonal antibody of gastrin and somatostatin by immunohistochemical method and Quantimet 500 image analysis system. RESULTS: In gastric ulcer, the level of gastrin in plasma, gastric fluid, and antral tissue increased, that of somatostatin declined, and the disorder gradually recovered to the normal level in the healing process. Immunohistochemical technique of G and D cells in antral mucosa demonstrated that the number of G cells increased and that of D cells decreased, both areas of G and D cells declined, the ratio of number and area of G/D increased in gastric ulcer, and the disorder gradually recovered in the healing process. CONCLUSION: In gastric ulcer, the increased gastrin secreted by G cells, the declined somatostatin secreted by D cells, and the disordered G/D cell ratio can lead to gastrointestinal dysfunction.

刀豆蛋白A诱导Wistar大鼠肝纤维化模型的建立

目的:建立Wistar大鼠肝纤维化模型。方法:50只Wistar大鼠随机分成两组。实验组(E组)30只,经尾静脉注射12.5 mg/kg剂量的刀豆蛋白A(ConA),每周1次,10只大鼠在第4次注射1周后处死,其余20只8周后处死。正常对照组(N组)20只,大鼠经尾静脉注射300μl的PBS,第8次注射1周后处死。取大鼠肝脏计算肝脏指数并进行肝纤维化评分,做HE和Masson Trichrome染色,显微镜下观察肝脏的病理变化。取血清测ALT、AST、TP及ALB。结果:与对照组相比,实验组连续注射ConA 8周的大鼠ALT、AST显著升高,TP变化不明显,ALB及白球比显著降低。肝脏体积增大,肝脏指数增高,病理分析示明显纤维化。结论:反复尾静脉注射ConA可成功诱导Wistar大鼠肝脏纤维化模型的建立。

胆管结扎和四氯化碳诱导Wistar大鼠肝纤维化模型的建立及相关指标的对比分析

目的比较胆管结扎(BDL)、四氯化碳(CCl4)诱导大鼠肝纤维化的生化指标、肝脏病理学及纤维连接蛋白(FN)的表达。方法 90只健康雄性Wistar大鼠,分为CCl4肝纤维化模型组(44只)及其对照组(6只)和BDL肝纤维化模型组(30只)及其对照组(10只)。CCl4肝纤维化模型组是采用50%的CCl4橄榄油溶液对大鼠进行腹腔注射的方法来制备模型,而BDL肝纤维化模型组则采用结扎大鼠胆总管的方法来制备。观察大鼠一般情况,生化方法测血清ALT、AST、TBil、DBil;ELISA法测血清透明质酸(HA)和层黏连蛋白(LN)水平。HE和Masson染色观察肝组织的病理学变化,免疫组织化学染色观察肝组织FN表达。计量资料组间比较采用t检验。结果血清生化学结果显示,BDL组大鼠自胆管结扎术后第7天开始,TBil及DBil即上升到较高水平且随后一直保持此水平,CCl4肝纤维化模型组大鼠2周始逐渐升高,至8周达高峰;BDL大鼠纤维化指标HA、LN水平显著高于同期CCl4模型组;CCl4模型组大鼠可见肝细胞弥漫性脂肪变性,汇管区-汇管区或汇管区-中央静脉间纤维间隔形成极为显著,BDL大鼠则表现为肝内胆管显著增生,炎性细胞浸润及纤维间隔形成同时存在;BDL组中FN的表达呈分散无规则型,且纤维组织细小,而CCl4组的FN多集中表达于小叶之间的间隔处,纤维组织粗大。结论 BDL和CCl4均可诱导大鼠肝纤维化,BDL较早引起肝功能及肝纤维化指标升高,可见明显胆管增生,CCl4则以脂肪变性为主;FN在两种模型中表达分布不同。

Wistar大鼠插线法局灶性脑缺血/再灌注模型的实验研究

目的：局灶性脑缺血／再灌注模型是研究缺血性脑血管病的重要模型。本文介绍一种简便易行的插线法Ｗｉｓｔａｒ 大鼠局灶性脑缺血／再灌注模型的制备方法，并通过神经病学评分、ＴＴＣ染色、病理形态学变化的观察，对该模型的可靠性进行评价。方法：用头端处理过的尼龙钓丝，从颈外动脉向颈内动脉插入，可逆性阻断大鼠一侧大脑中动脉（ＭＣＡ）。结果：大鼠ＭＣＡ阻断后１．５ｈ，同时出现Ｈｏｒｎｅｒ＇ｓ征阳性、提尾悬空时梗塞对侧前肢屈曲、内收、自主运动时身体向偏瘫侧划圈的动物，ＴＴＣ染色能清楚地显示梗塞范围，且相对较稳定，光镜下可见脑缺血后的病理改变。阻断后３ｈ及再灌注３、６ｈ时的病理改变加重，神经病学评分同前。结论：该改良法制备的模型简便易行、稳定性好、结果可靠，是用于研究局灶性脑缺血／再灌注的较为理想的实验动物模型。

SD大鼠与Wistar大鼠脑胶质瘤动物模型的建立及比较

目的比较利用SD大鼠、Wistar大鼠建立脑胶质瘤动物模型的不同,为研究脑胶质瘤的发病机制及治疗方法提供操作平台。方法利用立体定向仪建立SD大鼠、Wistar大鼠大脑皮层接种C6细胞(2.5×105个细胞/只),建立脑胶质瘤动物模型,利用组织病理学、免疫组织化学以及核磁共振成像等技术,比较两种动物模型在成瘤率、肿瘤生长状况、死亡率以及动物一般情况等方面的异同。结果SD大鼠组、Wistar大鼠组的成瘤率均为100%,两组均未见转移;但SD大鼠组肿瘤成瘤时间较长,且部分肿瘤有自愈倾向,而Wistar大鼠组则未出现类似情况。结论Wistar大鼠大脑皮层脑胶质瘤动物模型的肿瘤性状更接近于人的脑胶质瘤,因此更适合探索和研究脑胶质瘤的发病机制和治疗方法;而SD大鼠的肿瘤由于性状类似转移瘤,且有自愈倾向,不适合作为上述相关研究的动物模型。

Wistar大鼠C_6胶质瘤动物模型的肿瘤生长特点

目的 :探讨Wistar大鼠颅内及皮下接种C6胶质瘤细胞的肿瘤生长特点及病理特征。方法 :第一组Wistar大鼠及SD大鼠各 5 0只 ,应用立体定向方法将 10 6的C6细胞接种于大鼠脑尾状核 ,对比观察接种后不同大鼠生存时间及病理特征。第二组 140只Wistar大鼠于颅内接种后 3d、5d、7d、9d、11d、13d和 15d各处死 2 0只 ,观察肿瘤大小及病理学变化。第三组 5 0只Wistar大鼠皮下接种 2× 10 6的C6细胞 ,观察皮下肿瘤生长特点及病理特征。结果 :Wistar大鼠颅内接种后平均生存期为 (15 9± 1 2 )d ,瘤组织向正常脑组织浸润生长 ,无明显分界 ,有肿瘤血管 ,坏死 ,卒中发生 ,S 10 0及GFAP染色阳性。SD大鼠平均生存期为 (18 9± 1 8)d ,瘤组织与正常脑组织有明显分界。Wistar大鼠颅内接种后第 5～ 11d肿瘤生长最为迅速。Wistar大鼠皮下接种后肿瘤生长稳定 ,但接种后 2 5d停止生长并逐渐缩小。结论 :Wistar大鼠颅内C6胶质瘤模型特征更加接近于人恶性脑胶质瘤 。

Animal experiment and clinical study of effect of gamma-interferon on hepatic fibrosis

AIM: To evaluate the antifibrotic effect of different doses of recombinant human Gamma-Interferon (IFN-gamma) in two rat models of hepatic fibrosis, and to observe its effect on moderate chronic hepatitis B virus fibrosis. METHODS: Hepatic fibrosis was successfully induced in 150 and 196 rats by subcutaneous injection of carbon tetrachloride (CCl4) and intraperitoneal injection of dimethylnitrosamine (DMN), respectively. Each of the two model groups was divided into: (1) fibrotic model group; (2) colchicine treatment group (0.1 mg/kg/day, gastrogavage for 8 weeks); (3) high-dose IFN-gamma group (15 MU/kg per day, i.m. for 8 weeks); (4) medium-dose IFN-gamma group (5 MU/kg daily, i.m. for 8 weeks); and (5) Y low-dose IFN-gamma group (1.67 MU/kg daily, i.m. for 8 weeks). Another group of 10 rats without any treatment was used as normal controls. At the end of the experiment, semi-quantitative histopathological scores of inflammation and fibrosis, liver alpha smooth muscle actin (alpha-SMA) expression level, liver hydroxyl proline content and serum hyaluronic acid levels were compared. And 47 medium chronic hepatitis B viral fibrosis patients were studied. They were given IFN-gamma treatment, 100 MU/day i.m. for the first three months and 100 MU qod i.m. for the next six months. Semi-quantitative pathological scores of inflammation and fibrosis and serum hepatic fibrosis indices were compared within the 9 months. RESULTS: In animal experiment, the pathological fibrosis scores and liver hydroxyl proline content were found to be significantly lower in rats treated with different doses of IFN-gamma as compared with rats in fibrotic model group induced by either CCl4 or DMN, in a dose-dependent manner. For CCl4-induced model, pathological fibrosis scores in high, medium and low doses IFN-gamma groups were 5.10 +/- 2.88, 7.70 +/- 3.53 and 8.00 +/- 3.30, respectively, but the score was 14.60 +/- 7.82 in fibrotic model group. Hydroxyl proline contents were 2.83 +/- 1.18, 3.59 +/- 1.22 and 4.80 +/- 1.62, in the three IFN-gamma groups, and 10.01 +/- 3.23 in fibrotic model group. The difference was statistically significant (P【0.01). Similar results were found in DMN-induced model. Pathological fibrosis scores were 6.30 +/- 0.48, 8.10 +/- 2.72 and 8.30 +/- 2.58, in high, medium and low doses IFN-gamma groups, and 12.60 +/- 3.57 in fibrotic model group. Hydroxyl proline contents were 2.72 +/- 0.58, 3.14 +/- 0.71 and 3.62 +/- 1.02, in the three IFN-gamma groups, and 12.79 +/- 1.54 in fibrotic model group. The difference was statistically significant (P【0.01).Serum hepatic fibrosis indices decreased significantly in the 47 patients after IFN-gamma treatment (HA: 433.38 +/- 373.00 vs 281.57 +/- 220.48; LN: 161.22 +/- 41.02 vs 146 +/- 35 +/- 44. 67; PC III: 192.59 +/- 89.95 vs 156.98 +/- 49.22; C-I: 156.30 +/- 44.01 vs 139.14 +/- 34.47) and the differences between the four indices were significant (P 【0.05). Thirty-three patients received two liver biopsies, one before and one after IFN-gamma treatment. In thirty of 33 patients IFN-gamma had better effects according to semi-quantitative pathological scores (8.40 +/- 5.83 vs 5.30 +/- 4.05, P【0.05). CONCLUSION: All the three doses of IFN-gamma are effective in treating rat liver fibrosis induced by either CCl4 or DMN, the higher the dose, the better the effect. And IFN-gamma is effective for patients with moderate chronic hepatitis B viral fibrosis.

Heparin improves organ microcirculatory disturbances in caerulein-induced acute pancreatitis in rats

AIM:Microcirculatory disturbances are important early pathophysiological events in various organs during acute pancreatitis.The aim of the study was to evaluate changes in microperfusion of the pancreas,liver,kidney,stomach, colon,skeletal muscle,and to investigate the influence of heparin on the organ microcirculation in caerulein-induced experimental acute pancreatitis. METHODS:Acute pancreatitis was induced by 4 intraperitoneal injections of caerulein(Cn)(15 μg/kg).The organ microcirculation was measured by laser Doppler flowmetry.Serum interleukin 6 and hematocrit levels were analysed. RESULTS:Acute pancreatitis resulted in a significant drop of microperfusion in all examined organs.Heparin administration(2×2.5 mg/kg)improved the microcirculation in pancreas(36.9±4% vs 75.9±10%),liver(56.6±6% vs 75.2±16%),kidney (45.1±6% vs 79.3±5%),stomach (65.2±8% vs 78.1±19%),colon(69.8±6% vs 102.5±19%), and skeletal muscle (59.2±6% vs 77.9±13%).Heparin treatment lowered IL-6(359.0±66 U/mL vs 288.5±58 U/mL) and hematocrit level(53±4% vs 46±3%). CONCLUSION:Heparin administration has a positive influence on organ microcirculatory disturbances accompanying experimental Cn-induced acute pancreatitis.

SD大鼠和Wistar大鼠实验性自身免疫性脑脊髓炎发病情况比较

目的比较Wistar大鼠和Sprague-Dawley(SD)大鼠实验性自身免疫性脑脊髓炎(EAE)发病情况。方法注射以豚鼠脊髓匀浆-完全福氏佐剂制备的完全抗原,辅以百日咳疫苗加强诱导,复制Wistar大鼠和SD大鼠EAE模型,比较两组大鼠EAE的神经症状及中枢神经不同部位病理学改变。结果Wistar大鼠组发病数、潜伏期、发病达峰时间以及神经症状最高评分分别为9/12、12.33±1.37、15.17±3.19、1.33±0.41;SD大鼠组分别为11/12、15.88±0.64、18.63±1.52、3.13±1.89;两组大鼠相比,SD大鼠EAE潜伏期延长(P<0.01),达峰时间相应推迟(P<0.05),但神经症状较Wistar大鼠严重(P<0.05);病理结果显示,两组大鼠CNS均以脑干病理改变最为严重,而大脑病变最轻,SD大鼠总体中枢系统炎症改变较Wistar大鼠严重(标准评分P<0.01,血管套计数P<0.05)。结论SD大鼠EAE与Wistar大鼠EAE比较,发病过程很相似:发病率接近,中枢炎症病理改变相仿,两者均以脑干炎症变化最严重;略有不同点是:SD大鼠EAE发病潜伏期较长(P<0.01),神经症状较严重(P<0.05),总体中枢炎症改变较为严重。故SD大鼠也是制备EAE模型的理想实验动物。

Effect of endotoxin on portal hemodynamic in rats

AIM: To study the effects of endotoxin on portal hemodynamic of normal and noncirrhotic portal hypertensive rats. METHODS: Normal rats were intraperitoneally injected with 0.1, 0.25, 0.5, 1.0, 2.0, 4.0mg.kg(-1) of lipopolysaccharide(LPS) respectively, portal vein ligation(PVL) and intrahepatic portal occlusion (IPO) rats as well as sham-operated rats were treated with an intraperitoneal injection of 1.0mg.kg(-1) of LPS, the portal vein pressure(PVP), portal venous flow(PVF), inferior vena cava pressure(IVCP) and portal vein resistance(PVR) were detected 4 hours after injection. RESULTS: PVF of the 5 groups of rats accepting intraperitoneal injection of LPS were increased from 14.0 to 18.0, 22.2, 26.2, 34.8, 39.6, 38.8 mL.min(-1) 4 hours after injection of LPS(P【0.01). PVP of the 4 groups of rats accepting more than 0.1mg/kg.b.w of LPS was increased from 1.04 to 1.25, 1.50, 1.80, 1.95, 2.05 kPa(P【0.01). The increments of PVF and PVP were in a dose-dependent manner of LPS. PVR of the 5 groups of rats was decreased from 51 to 42,44,48,45,44,47 kPa.min.L(-1) (P【0.05) and no dose-dependent manner was observed. PVF of PVL, IPO and sham-operated rats increased from 22.6 to 32.8, 22.0 to 28.0, 14.0 to 34.8 mL.min(-1) (P【0.01), and PVP increased from 1.86 to 2.24, 1.74 to 1.95, 1.04 to 1.80 kPa(P【0.01), PVR decreased from 71 to 61, 67 to 61, 52 to 44 kPa.min.L(-1) after intraperitoneal injection of 1mg.kg(-1) of LPS. The increments of PVF and PVP of PVL and IPO rats were significantly less than the sham-operated rats(P【0.01), There was no significant difference between the amounts of PVR decreased in the two groups of PHT model rats and sham-operated rats(P】0.05) after intraperitoneal injection 1mg.kg(-1) of LPS. CONCLUSION: Endotoxin could prompt portal hypertension of the normal and noncirrhotic portal hypertensive rats by increasing portal blood flow mainly.

Effects of glycyrrhetinic acid on collagen metabolism of hepatic stellate cells at different stages of liver fibrosis in rats

INTRODUCTIONLiver fibrosis is a dynamic course leading tocirrhosis from a various chronic liver diseases. Thepathological basis of fibrosis is the disturbance ofproduction and degradation of the extracellularmatrix (ECM), which causes accumulation of ECMin the liver[1,2].

Epidemiological and histopathological study of relevance of Guizhou Maotai liquor and liver diseases

AIM: To explore the relevance of Maotai liquor and liver diseases. METHODS: Epidemiological study was conducted on groups of subjects, each consisting of 3 subjects from the Maotai liquor group consisting of 99 individuals and one from the non-alcoholic control group consisting of 33 individuals. Liver biopsy was performed on 23 volunteers from Guizhou Maotai Distillery who had a constant and long history of drinking Maotai liquor. Experimental histopathological study was conducted as follows: sixty male Wistar rats were divided into 3 groups randomly and fed with Maotai liquor, ordinary white wine, and physiological saline respectively for a period of 8 and 12 weeks. The rats were sacrificed in batches, then serum ALT, AST, TBil, and AKP were measured. Rat livers were harvested to measure the liver indexes, GSH, and MDA. Histopathological examinations were also performed. Another eighty mice were randomly divided into 4 groups and fed with Maotai (at different dosages of 10 ml.kg(-1) and 20 ml.kg(-1)), ethanol, and physiological saline. The animals were sacrificed after 4 weeks and serum ALT was determined. Then the livers were harvested and liver indexes and MDA were measured. RESULTS: The incidence rate of hepatic symptoms, splenomegaly, liver function impairment, reversal of Albumin/Globulin and increased diameter of portal veins in the Maotai liquor group were 1.0% 1/99 , 1.0% 1/99 , 1.0% 1/99 , 1.0% 1/99 , 0 0/99 and 0 0/99 , 0 0/99 ,0 0/99 , 0 0/99 , 0 0/99 , respectively. There was no significant difference between the Maotai group and the non-alcoholic control group P】0.05 . Various degree of fatty infiltration of hepatocytes was found in the 23 volunteers receiving liver biopsy, but there was no obvious hepatic fibrosis or cirrhosis. A comparison was made between the Maotai liquor group and the ordinary white wine group. It was found that hepatic MDA in rats and mice were 0.33+/-0.10 and 0.49+/-0.23 respectively in Maotai group and 0.61+/-0.22 and 0.66+/-0.32 in the ordinary white wine group; MDA had an obvious decrease in the Maotai liquor group (P【0.05); hepatic GSH were 0.12 mg.g(-1)+/-0.06 mg.g(-1) in rats of the Maotai liquor group and (0.08+/-0.02)mg.g(-1) in white wine group, it was obviously increased in the Maotai liquor group (P【0.05). After the 20 rats had been fed with ordinary white wine for 8 weeks consecutively, disarranged hepatocyte cords, fatty infiltration of hepatocytes, and fibrous septa of varying widths due to hepatic connective tissues proliferation were observed; after 12 weeks, the fibrous tissue proliferation continued and early cirrhosis appeared. Compared with the ordinary white wine group, fatty infiltration was observed in the 8-week and 12-week groups, but no necrosis or fibrosis or cirrhosis was found in the Maotai liquor group (P【0.05). CONCLUSION: Maotai liquor may cause fatty liver but not hepatic fibrosis or cirrhosis, and it can strengthen lipid peroxidation in the liver.

Expression of lipopolysaccharide binding protein and its receptor CD14 in experimental alcoholic liver disease

AIM: To evaluate the relationship between the expression of lipopolysaccharides (LPS) binding protein (LBP) and CD14 mRNA and the severity of liver injury in alcohol-fed rats. METHODS: Twenty Wistar rats were divided into two groups:ethanol-fed group (group E) and control group (group C). Group E was fed with ethanol(5-12 g x kg(-1) x d(-1)) and group C received dextrose instead of ethanol. Rats of the two groups were sacrificed at 4 weeks and 8 weeks. Levels of endotoxin and alanine transaminase (ALT) in blood were measured, and liver pathology was observed under light and electronic microscopy. Expressions of LBP and CD14 mRNA in liver tissues were determined by RT-PCR analysis. RESULTS: Plasma endotoxin levels were increased more significantly in group E(129+/-21) ng x L(-1) and (187+/-35) ng x L(-1) at 4 and 8 wk than in control rats(48+/-9) ng x L(-1) and (53+/-11) ng x L(-1), respectively (P【0.05). Mean values of plasma ALT levels were (1867+/-250) nkat x L(-1) and (2450+/-367) nkat x L(-1) in Group E. The values were increased more dramatically in ethanol-fed rats than in Group C after 4 and 8 weeks. In liver section from ethanol-fed rats, there were marked pathological changes (steatosis, cell infiltration and necrosis). In ethanol-fed rats, ethanol administration led to a significant increase in LBP and CD14 mRNA levels compared with the control group (P【0.05). CONCLUSION: Ethanol administration led to a significant increase in endotoxin levels in serum and LBP and CD14 mRNA expressions in liver tissues. The increase of LBP and CD14 mRNA expression might wake the liver more sensitive to endotoxin and liver injury.

Transplantation of human hepatocytes into tolerized genetically immunocompetent rats

AIM: To determine whether normal genetically immunocompetent rodent hosts could be manipulated to accept human hepatocyte transplants with long term survival without immunosuppression. METHODS: Tolerance towards human hepatocytes was established by injection of primary human hepatocytes or Huh7 human hepatoma cells into the peritoneal cavities of fetal rats. Corresponding cells were subsequently transplanted into newborn rats via intrasplenic injection within 24h after birth. RESULTS: Mixed lymphocyte assays showed that spleen cells from non-tolerized rats were stimulated to proliferate when exposed to human hepatocytes, while cells from tolerized rats were not. Injections made between 15 d and 17 d of gestation produced optimal tolerization. Transplanted human hepatocytes in rat livers were visualized by immunohistochemical staining of human albumin. By dot blotting of genomic DNA in livers of tolerized rats 16 weeks after hepatocyte transplantation, it was found that approximately 2.5 X 10(5) human hepatocytes survived per rat liver. Human albumin mRNA was detected in rat livers by RT-PCR for 15 wk, and human albumin protein was also detectable in rat serum. CONCLUSION: Tolerization of an immuno-competent rat can permit transplantation, and survival of functional human hepatocytes.

Safe upper limit of intermittent hepatic inflow occlusion for liver resection in cirrhotic rats

AIM: To evaluate the effects of varying ischemic durations on cirrhotic liver and to determine the safe upper limit of repeated intermittent hepatic inflow occlusion. METHODS: Hepatic ischemia in cirrhotic rats was induced by clamping the common pedicle of left and median lobes after non-ischemic lobes resection. The cirrhotic rats were divided into six groups according to the duration and form of vascular clamping: sham occlusion (SO), intermittent occlusion for 10 (IO-10), 15(IO-15), 20(IO-20) and 30(IO-30) minutes with 5 minutes of reflow and continuous occlusion for 60 minutes (CO-60). All animals received a total duration of 60 minutes of hepatic inflow occlusion. Liver viability was investigated in relation of hepatic adenylate energy charge (EC). Triphenyltetrazollum chloride (TTC) reduction activities were assayed to qualitatively evaluate the degree of irreversible hepatocellular injury. The biochemical and morphological changes were also assessed and a 7-day mortality was observed. RESULTS: At 60 minutes after reperfusion following a total of 60 minutes of hepatic inflow occlusion, EC values in IO-10 (0.749 +/- 0.012) and IO-15 (0.699 +/- 0.002) groups were rapidly restored to that in SO group (0.748 +/- 0.016), TTC reduction activities remained in high levels (0.144 +/- 0.002 mg/mg protein, 0.139 +/- 0.003 mg/mg protein and 0.121 +/- 0.003 mg/mg protein in SO, IO-10 and IO-15 groups, respectively). But in IO-20 and IO-30 groups, EC levels were partly restored (0.457 +/- 0.023 and 0.534 +/- 0.027) accompanying with a significantly decreased TTC reduction activities (0.070 +/- 0.005 mg/mg protein and 0.061 +/- 0.003 mg/mg protein). No recovery in EC values (0.228 +/- 0.004) and a progressive decrease in TTC reduction activities (0.033 +/- 0.002 mg/mg protein) were shown in CO-60 group. Although not significantly different, the activities of the serum aspartate aminotransferase (AST) on the third postoperative day (POD(3)) and POD(7) and of the serum alanine aminotransferase (ALT) on POD(3) in CO-60 group remained higher than that in intermittent occlusion groups. Moreover, a 60% animal mortality rate and more severe morphological alterations were also shown in CO-60 group. CONCLUSION: Hepatic inflow occlusion during 60 minutes for liver resection in cirrhotic rats resulted in less hepatocellular injury when occlusion was intermittent rather than continuous. Each period of 15 minutes was the safe upper limit of repeated intermittent vascular occlusion that the cirrhotic liver could tolerate without undergoing irreversible hepatocellular injury.

Fe_3O_4磁纳米介导磁感应治疗Wistar大鼠Walker-256肿瘤

目的探讨Fe3O4磁性纳米微球磁感应对Wistar大鼠Walker-256肿瘤的治疗作用。方法荷瘤鼠随机分为NS组(注入生理盐水而不接受磁场处理)、MF组(注入磁流体而不接受磁场处理)、MFH1组(注入磁流体在交变磁场中治疗1次)、MFH2组(治疗2次)和MFH3组(治疗3次),共5组。治疗温度控制在50～55℃,分别观察肿瘤体积抑制率和生存期,以及肿瘤的病理改变。结果MFH2组和MFH3组的肿瘤在2周内有明显的肿瘤体积抑制作用,肿瘤体积抑制率分别为(65.0±3.5)%、(71.6±4.2)%。与NS组(35.5±5.6)d比较,MFH3组(41.9±6.5)d和MFH2组(42.1±5.0)d的生存期延长,差异有统计学意义(q=4.386,P<0.05;q=4.558,P<0.05);MFH1组(39.0±5.3)d和MF组(36.1±6.6)d的生存期差异无统计学意义(q=2.406,P>0.05)。NS、MF组肿瘤表面光滑,小灶性坏死区;癌细胞密度大,核仁明显,易见核分裂相。MFH2和MFH3组瘤内大片坏死残留的无结构红染物质,或空洞,部分胞核有固缩、碎裂及崩解。结论Fe3O4纳米磁流体介导的磁热疗能抑制大鼠Walker-256皮下肿瘤增殖。

Transretinoic acid inhibits rats gastric epithelial dysplasia induced by N-methyi-N-nitro-N-nitrosoguanidine:influences on cell apoptosis and expression of its regulatory genes

INTRODUCTIONGastric epithelial dysplasia (GED) hypothetically is a straight-forward concept: dysplastic epithelium replacing the normal gastric epithelium of the stomach [1].In the stomach ,like any other segment of the gut ,it is defined as an unequivocal non-invasive epithelial change[2,3].The observation of gastric dysplasia as a cancerous lesion was recognized over a century ago ,but it is only after the advent of gastroscopy that its clinical significance has been stressed[4-7].

Wistar大鼠肾结石形成过程的动态观察研究

目的观察Wistar大鼠肾结石形成的动态过程。方法 2016年3月选取6周龄左右SPF级雄性Wistar大鼠60只,适应性饲养1周后随机分为空白对照组(NC组,n=30)和乙二醇组(EG组,n=30)。NC组大鼠正常饮水,2 ml 0.9%氯化钠溶液灌胃2周;EG组大鼠饮用1%EG溶液,2 ml 2%氯化铵溶液灌胃2周。连续10周观察两组大鼠一般情况,每周处死3只,每周检测两组大鼠血、尿生化指标,肉眼及解剖显微镜下观察大鼠肾脏解剖情况,并分析两组大鼠肾脏结晶分级及结石形成情况。结果观察期间EG组大鼠垫料有血尿,造模期间于第8周死亡1只,第9周死亡1只。造模1~2周时两组大鼠进食良好、安静温顺。造模3~8周时,NC组大鼠无特殊表现,EG组大鼠表现为烦躁兴奋、活泼好动。造模9~10周EG组大鼠表现为精神疲倦,针刺反应迟钝,活动度减少,食量减少;NC组大鼠无特殊表现。EG组大鼠造模第2~10周血肌酐、血尿酸均高于NC组(P<0.05)。EG组大鼠第3~8周尿素氮高于NC组(P<0.05)。EG组大鼠第2周、第4~10周尿钙高于NC组(P<0.05)。EG组大鼠第5~10周血钙高于NC组(P<0.05)。EG组大鼠第6~10周血磷、血镁高于NC组(P<0.05)。EG组大鼠第2~8周尿p H值低于NC组(P<0.05)。两组大鼠第1~10周尿比重、尿量比较,差异无统计学意义(P>0.05)。EG组大鼠第3~10周肾体比高于NC组(P<0.05)。造模第1~2周,肉眼观察两组大鼠肾脏无明显差异。造模第3周开始,肉眼观察EG组大鼠部分肾脏较NC组略有增大。造模第6周以后,肉眼观察EG组大鼠肾脏肿大;解剖显微镜下可见晶体以肾盂为中心呈扇形分布。造模第6周以后,肉眼观察NC组大鼠肾脏表面光滑,解剖显微镜下亦未见明显结晶。EG组大鼠肾脏结晶分级高于NC组(Z=-5.195,P<0.001)。EG组大鼠结石检出率高于NC组(χ~2=21.172,P<0.001)。结论采用EG加氯化铵法建立的肾结石模型大鼠在造模第3周开始形成结石,肾结石模型大鼠明显较空白对照大鼠精神疲倦,活动度及饮食量减少,血、尿生化指标明显改变,肾体比明显升高。

HFJ和Wistar大鼠脂肪肝及胰岛素抵抗动物模型的比较

目的建立近交系HFJ大鼠和封闭群Wistar大鼠脂肪肝胰岛素抵抗动物模型及比较其生物学特性。方法雄性HFJ大鼠和Wistar大鼠,分别随机分为模型组和正常组,模型组喂养高脂饮食,正常组喂养普通饮食,两组脂肪分别占摄入能量的44.2%和19.2%,共饲养12周。每周称体质量,测定血糖、甘油三酯、胆固醇、ALT、AST、HDLC、LDLC和血胰岛素水平。实验期末处死动物摘取肝脏并称质量,计算肝指数;鼠肝脏用10%甲醛固定,石蜡包埋切片,HE染色,光镜下评估肝脂肪变性和炎症活动情况。结果镜下可见,HFJ和Wistar大鼠模型组肝细胞均呈现弥漫性脂肪变性,小叶内可见炎症细胞浸润,HFJ比Wistar脂肪变性较重,对照组肝脏均未见异常。两种动物的模型组ALT、AST、肝指数、HOMA-IR指数均显著高于其正常组,HFJ和Wistar种系间各指标的差异无显著性;HFJ大鼠模型组体重和正常组体重具有显著性差异(P<0.01),而Wistar大鼠模型组体重与正常组体重间无显著差异(P>0.05);HFJ大鼠TG和TC含量均显著高于Wistar大鼠。结论通过高脂饮食喂养成功建立了HFJ大鼠和Wistar大鼠脂肪肝与胰岛素抵抗疾病动物模型,与Wistar大鼠比较,HFJ大鼠具有自发性高血脂特征,造模更易成功,可为胰岛素抵抗和脂肪肝的发病机制研究、防治高血脂药物筛选提供一种新的实验动物。