模拟失重对大鼠实验性胃溃疡愈合的影响

目的:探讨模拟失重对乙酸诱导的大鼠实验性胃溃疡愈合的影响及可能机制.方法:32只SD大鼠随机分为4组,即尾部悬吊7d组、尾部悬吊14d组和相应的同步对照组.采用乙酸烧灼法制备大鼠慢性胃溃疡模型,造模后第3天悬吊组大鼠采用尾悬吊法建立模拟失重动物模型.游标卡尺检测胃溃疡面积,电镜下观察再生黏膜结构,放免法检测胃液EGF含量,观察大鼠胃溃疡愈合分期.结果:与对照7d组相比,悬吊7d组大鼠溃疡面积明显增大(6.0mm2±1.7mm2vs2.2mm2±0.7mm2,t=5.661,P<0.01),溃疡分期明显降低(χ2=12.771,P<0.01);与对照14d组相比,悬吊14d组溃疡面积明显增大(3.0mm2±1.2mm2vs1.1mm2±0.4mm2,t=4.233,P<0.01),胃液EGF含量明显增高(0.155ng/mL±0.052ng/mLvs0.103ng/mL±0.019ng/mL,t=2.635,P<0.05);与悬吊7d组比较,悬吊14d组溃疡面积明显减小(3.0mm2±1.2mm2vs6.0mm2±1.7mm2,t=3.805,P<0.01),胃液EGF含量明显降低(0.155ng/mL±0.0...     

电针刺激内关穴对模拟失重大鼠心脑血管氧化应激的影响

目的 探讨电针刺激内关穴对模拟失重大鼠心脑血管氧化应激水平的影响。 方法 30只雄性SD大鼠随机分为尾吊组、穴位刺激尾悬吊组和对照组,尾吊组和穴位刺激尾吊组大鼠均头低位-30°尾吊7 d,穴位刺激尾吊组大鼠需进行每天30 min的电针刺激内关穴,对照组不做任何处理。三组均在7 d后测量血清、心脏组织、脑组织、颈动脉及股动脉的超氧化物歧化酶（SOD）和丙二醛（MDA）含量。 结果 尾悬吊后大鼠血清及各血管组织中SOD含量显著低于对照组,MDA含量则显著高于对照组（P<0.05）。给予电针刺激后,穴位刺激尾悬吊组大鼠SOD和MDA含量与对照组相比无显著差异。 结论 电针刺激大鼠内关穴可减轻7 d尾悬吊模拟失重效应所产生的心脑血管氧化应激。     

尾吊模拟失重大鼠胃肠道自介素2和生长抑素的表达

目的:研究尾吊模拟失重状态下大鼠胃窦和空肠黏膜白介素2(interleukin-2,IL-2)及生长抑素(somatostatin,SS)免疫反应细胞的变化. 方法:采用尾部悬吊模拟失重,将大鼠分为悬吊14 d组和28 d组及相应同步对照组.以免疫组织化学方法,观察大鼠胃窦和空肠黏膜IL-2及SS免疫反应细胞的变化. 结果:与正常对照组相比,在胃窦部黏膜14 d尾部悬吊大鼠IL-2免疫反应细胞有下降趋势,但统计学分析无明显差异,28 d悬吊组则明显减少(P<0.01);14 d和28 d悬吊组SS免疫反应细胞均明显减少(P<0.01).与正常对照相比, 在空肠黏膜14 d及28 d悬吊组IL-2免疫反应细胞无明显变化(P>0.05);14 d及28 d悬吊组SS免疫反应细胞减少(P<0.05及P<0.01). 结论:模拟失重状态下,IL-2在大鼠胃窦部的表达下降. 在空肠变化不明显;而SS在大鼠胃窦及空肠的表达均下降. 提示其免疫及内分泌功能发生了改变.     

黄芩素对胃溃疡大鼠胃黏膜损伤及炎症反应的影响

目的探讨黄芩素(BAI)对胃溃疡大鼠胃黏膜损伤及炎症反应的影响。方法选取成年Wistar大鼠,采用乙酸烧灼法制备胃溃疡模型,造模次日选取40只成模大鼠随机分为模型组和BAI组(n=20),BAI组接受20 mg/kg的BAI灌胃处理,1次/d,连续2 w。同时选取20只正常Wistar大鼠作对照。实验结束后取出胃组织并检测黏膜肌层缺损宽度、溃疡面积及溃疡指数,留取血清标本用于检测血清氧化应激指标[丙二醛(MDA)、谷胱甘肽过氧化物酶(GSH-Px)和超氧化物歧化酶(SOD)]、三叶因子(TFF)1和TFF2及炎症因子[肿瘤坏死因子(TNF)-α、白细胞介素(IL)-6和IL-2],比较各组大鼠胃黏膜组织中前列腺素(PG)E2和表皮生长因子(EGF)水平。结果与对照组比较,模型组的黏膜肌层缺损宽度、溃疡面积及溃疡指数均升高(P<0.05),提示胃溃疡模型制备成功。与对照组比较,模型组的血清MDA、TFF1、TFF2、胃黏膜PGE2、EGF及血清TNF-α、IL-2和IL-6水平均升高,GSH-Px和SOD活性均降低(P<0.05)。BAI组的血清MDA、TFF1、TFF2及血清TNF-α、IL-2和IL-6水平均低于模型组;而血清TFF1、TFF2水平,胃黏膜PGE2、EGF水平及血清GSH-Px和SOD活性均高于模型组(P<0.05)。除IL-6外,BAI组的其余指标与对照组的差异仍有统计学意义(P<0.05)。结论 BAI改善胃溃疡大鼠胃黏膜损伤、氧化应激及炎症反应,可能与其通过上调TFF、PGE2和EGF水平以促进胃黏膜修复有关。     

间断人工重力在模拟失重所致胸主动脉炎症反应中的对抗作用

目的 观察模拟失重大鼠胸主动脉炎症反应变化以及间断人工重力对抗模拟失重所致变化的作用.方法 采用尾部悬吊方法建立模拟失重大鼠模型,将45只雄性Sprague-Dawley大鼠随机分为3组,每组15只(n=15).即对照(CON)组、4周尾部悬吊(HU)组和1 h/d间断人工重力(IAG)组.建模成功后,分离大鼠胸主动脉...     

损毁孤束核对电针足三里穴抗大鼠应激性胃溃疡作用的影响

目的:探讨孤束核(NTS)在电针(EA)足三里穴抗大鼠应激性胃溃疡中的作用.方法:健康♂SD大白鼠56只随机分为应激组、EA 应激组、NTS电损毁组、NTS假损毁组.通过脑立体定向仪电损毁大鼠孤束核,采用束缚-浸水制备大鼠应激性胃溃疡模型,分别测定各组胃黏膜损伤指数(UI)、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量.结果:与应激组比较,EA 应激组UI明显减少(t=9.5071,P<0.01),SOD活性升高(t=3.8729,P<0.01),MDA降低(t=2.3578,P<0.05).NTS电损毁组分别与假损毁组和EA 应激组比较UI提高(t=4.4223,7.2579,均P<0.01),SOD活性降低(t=3.5625,3.7242,均P<0.01),MDA含量升高(t=2.9045,2.4960,均P<0.05).结论:电损毁孤束核后,电针足三里穴对应激性胃黏膜损伤的保护作用减弱.     

尾悬吊模拟失重对大鼠血清GAS含量和胃黏膜Hsp70及其基因表达的影响

目的研究尾悬吊模拟失重对大鼠血清GAS含量和腺胃区黏膜组织中Hsp70及其基因表达的影响。方法健康雄性Wistar大鼠64只,随机分成8组(n=8),按模拟失重时相分别为6h、12h、1d、2d、3d、5d、7d和0h(地面对照组)。采用尾吊法建立模拟失重动物模型。应用放免法检测各组大鼠血清GAS含量,免疫组化法和RT-PCR技术分别检测大鼠胃黏膜组织中Hsp70蛋白及Hsp70mRNA表达。结果与对照组相比,实验组大鼠血清GAS含量在模拟失重早期(6～12h)明显升高(P<0.05),随着尾悬吊时相的延长,血清GAS含量呈逐渐下降趋势。免疫组化染色结果显示,实验各组大鼠胃黏膜组织中均有Hsp70阳性表达;悬吊6h～2d各组大鼠胃黏膜组织中着色明显变深,尤其胞核在模拟失重早期即深染,期间胞浆染色亦增强;悬吊3～7d组大鼠的胞核染色逐渐变浅,部分胞核中染色消失,但细胞浆内仍有比较明显的Hsp70染色。RT-PCR结果显示,模拟失重6h大鼠胃黏膜组织中Hsp70mRNA表达水平即明显上调(P<0.05)。12h、1d、2d各组的Hsp70mRNA表达逐渐回落,3d组降至接近对照组水平,其后又出现一短时相升高现象。结论尾悬吊模拟失重可导致大鼠血清GAS含量波动和腺胃区胃黏膜组织中Hsp70及其基因表达明显改变,提示GAS和Hsp70在失重条件下胃黏膜应激反应及适应耐受过程中可能发挥重要作用。     

Heme Oxygenase-1对乙酸诱导大鼠胃溃疡的保护作用

目的研究血红蛋白氧化酶一1(Heme oxygenase-1,HO-1)在乙酸诱导大鼠胃溃疡模型中所起的作用及可能的机制.方法雄性Sprague-Dawley大鼠,体质量160 g～180 g,每组8只,乙酸诱导大鼠胃溃疡1,3,7 d后用RT-PCR,Westernblotting和免疫组织化学分别检测胃粘膜中HO-1和诱导型一氧化氮合酶(inducible nitric oxide Synthase,iNCS;)的表达.同时研究HO-1抑制剂tin mesoporphyrin(SnMP)对iNOS表达、活性及胃粘膜损伤的影响.结果 RT-PCR结果显示正常大鼠胃粘膜HO-1仅轻度表达,乙酸诱导大鼠胃溃疡后,胃粘膜内HO-1表达明显增强.HO抑制剂SnMP处理组大鼠溃疡面积1 d为(72±6)mm2,明显大于对照组(51±4)mm2,(P＜0.01);3 d为(51±4)mm2,明显大于对照组(35±4)mm2,(P＜0.01);7 d时(27±4)mm2和对照组(24±3)mm2无显著差异.同时SnMP能显著增强胃粘膜iNOS的表达及iNOS的活性,溃疡诱导1 d SnMP组iNOS的活性为5.6±0.3,对照组3.2±0.3(P＜0.01);3 d SnMP组6.4±0.6,对照组4.0±0.3(P＜0.01);7 d SnMP组0.6±0.1,对照组0.5±0.1无显著差异(单位,pmol[3H]瓜氨酸@min-1@g-1蛋白).结论在乙酸诱导的大鼠胃溃疡模型中,HO-1对胃粘膜具有一定的保护作用,抑制HO-1后加重胃粘膜损伤,同时伴iNOS表达和活性的增强.提示HO-1的粘膜保护作用可能通过抑制iNOS功能,减少一氧化氮产生所介导的.沈锡中.Heme Oxygenase-1对乙酸诱导大鼠胃溃疡的保护作用.     

血红蛋白氧化酶诱导剂Hemin在乙酸诱导大鼠胃溃疡中的作用

目的众多研究表明血红蛋白氧化酶(Heme Oxygenase,HO)具有内源性组织细胞保护作用,诱导HO表达能减轻和限制炎症引起的组织损伤.本研究目的旨在研究HO诱导剂Hemin在乙酸诱导大鼠胃溃疡模型中所起的作用及可能的机制.方法用RT-PCR,Western blotting分别检测乙酸诱导大鼠胃溃疡1,3,7 d后胃粘膜中两种诱导型酶,HO-1和一氧化氮合酶(inducible nitric oxide synthase,iNOS)的表达.以溃疡面积判断胃粘膜损伤程度,研究HO-1诱导剂Hemin对乙酸诱导胃溃疡形成过程中胃粘膜损伤的影响,同时研究Hemin对胃粘膜iNOS表达及活性的影响以探讨其可能的作用机制.结果乙酸诱导大鼠胃溃疡后,胃粘膜HO-1和iNOS表达明显增强.HO诱导剂Hemin能显著增强HO-1 mRNA和蛋白质表达,但溃疡面积反而增大,炎症加重.处理组大鼠溃疡面积1 d为(77±5)mm2,明显大于对照的(51±3)mm2(P＜0.01,n=10);3 d为(53±4)mm2,明显大于对照(36±3)mm2(P＜0.01,n=10).同时Hemin能显著增强胃粘膜iNOS的表达及iNOS的活性,溃疡诱导1 d Hemin组iNOS的活性为5.3±0.3,对照3.1±0.3(P＜0.01,n=10);3 d Hemin组5.7±0.5,对照3.8±0.4(P＜0.01,n=10,单位为pmol[3H]瓜氨酸·min-1·g蛋白-1).结论在乙酸诱导的胃溃疡模型中,HO-1表达增加对胃粘膜可能存在一定程度的保护作用,但这一保护作用不足于抵消其他损害因素如NO过度产生所导致的粘膜损伤.HO代谢产物可能尚具有双向作用,即生理性产生增加具有粘膜保护作用,过度产生可能存在细胞毒性作用.     

大鼠运动应激性胃溃疡模型的建立以及苦苣总黄酮的预防作用

背景:近年运动应激性胃溃疡受到广泛关注,有研究证实苦苣总黄酮有抗炎、抗氧化作用。目的:建立快速、稳定、可重复的大鼠运动应激性胃溃疡模型,并探讨苦苣总黄酮对运动应激性胃溃疡的干预作用。方法:100只Wistar大鼠随机分为安静对照组、1 h无负荷运动组、1 h负荷运动组、2 h无负荷运动组和2 h负荷运动组,每组20只,雌雄各半。采用游泳方式建立大鼠运动应激性胃溃疡模型,观察胃黏膜溃疡指数(UI)和病理学改变。40只雄性Wistar大鼠随机分空白对照组、1 h负荷运动模型组、大剂量苦苣总黄酮组(生药3.2 g/kg)和小剂量苦苣总黄酮组(生药1.6 g/kg),观察胃黏膜病理学改变,检测胃黏膜SOD以及胃黏膜和血清MDA含量。结果:与1 h负荷运动组相比,1 h无负荷运动组UI显著降低(P<0.01),2 h负荷运动组显著升高(P<0.01),2 h无负荷运动组无明显差异(P>0.05)。1 h、2 h无负荷运动组和1 h负荷运动组雄性大鼠UI明显高于雌性大鼠(P<0.05)。与空白对照组相比,1 h负荷运动后大鼠胃黏膜SOD含量明显降低(P<0.01),胃黏膜和血清中MDA含量明显上升(P<0.05),大剂量苦苣总黄酮可明显改善上述指标(P<0.05)。结论:1 h负荷游泳运动可有效快速地建立大鼠运动应激性胃溃疡模型。大剂量苦苣总黄酮对运动引起的大鼠应激性胃溃疡有明显预防作用。     

Effects of ursodeoxycholic acid and／or low-calorie diet on steatohepatitis in rats with obesity and hyperlipidemia

AIM: To evaluate the effects of ursodeoxycholic acid (UDCA) and/or low-calorie diet (LCD) on a rat model of nonalcoholic steatohepatitis (NASH). METHODS: Fifty-five Sprague-Dawley rats were divided into five groups. The control group (n = 9) was fed with standard rat diet for 12 wk, NASH group (n = 10) was fed with high-fat diet consisted of normal diet, 10% lard oil and 2% cholesterol for 12 wk, UDCA group (n = 10) was fed with high-fat diet supplemented with UDCA at a dose of 25 mg/(kg · d) in drinking water for 12 wk, LCD group (n = 10) was fed with high-fat diet for 10 wk and then LCD for 2 wk, and UDCA+LCD group (n = 15) was fed with high-fat diet for 10 wk, followed by LCD+UDCA for 2 wk. At the end of the experiment, body weight, serum biochemical index, and hepatopathologic changes were examined. RESULTS: Compared with the control group, rats in the NASH group had significantly increased body weight, liver weight, and serum lipid and aminotransferase levels. All rats in the NASH group developed steatohepatitis, as determined by their liver histology. Compared with the NASH group, there were no significant changes in body weight, liver weight, blood biochemical index, the degree of hepatic steatosis, and histological activity index (HAI) score in the UDCA group; however, body and liver weights were significantly decreased, and the degree of steatosis was markedly improved in rats of both the LCD group and the UDCA+LCD group, but significant improvement with regard to serum lipid variables and hepatic inflammatory changes were seen only in rats of the UDCA+LCD group, and not in the LCD group. CONCLUSION: LCD might play a role in the treatment of obesity and hepatic steatosis in rats, but it exerts no significant effect on both serum lipid disorders and hepatic inflammatory changes. UDCA may enhance the therapeutic effects of LCD on steatohepatitis accompanied by obesity and hyperlipidemia. However, UDCA alone is not effective in the prevention of steatohepatitis induced by high-fat diet.     

Immunotherapy for nonalcoholic steatohepatitis using the multiple cytokine production modulator Y-40138

AIM: To investigate the possible use of the multiple cytokine production modulator, Y-40138, as a novel immunotherapy in the rat nonalcoholic steatohepatitis(NASH) model.METHODS: We allocated 6-wk-old male F344 rats to choline-supplemented, L-amino acid-defined (CSAA) diet (control group), CSAA diet + Y-40138 (control +Y-40138 group), choline-deficient, L-amino acid-defined (CDAA) diet (NASH group), or CDAA diet + Y-40138 (NASH + Y-40138 group). In each group, we measured the plasma alanine aminotransferase (ALT) levels, and the plasma and liver levels of tumor necrosis factor-α (TNF-α), interferon-γ (IFN-γ), and interleukin-10 (IL-10). Tissue specimens of phosphate buffered saline-perfused liver were subjected to hematoxylin and eosin staining, Azan staining, Sirius red staining, and immunohistochemical staining (for Kupffer cells and TNF-α). We then extracted Kupffer cells from the collagenase-perfused livers using the Percoll gradient centrifugation method, and measured the TNF-α levels in the supernatant ( in vitro TNF-α production by Kupffer cells) using an enzyme-linked immunosorbent assay kit. RESULTS: In comparison to the NASH group, serum ALT elevation was mild, production of serum and liver TNF-α and IFN-γ was inhibited, and IL-10 production was increased in the NASH + Y-40138 group. Amelioration of liver histology was also noted in the NASH + Y-40138 group. Kupffer cell immunohistochemical staining revealed no differences between groups, whereas TNF-α immunohistochemical staining showed fewer stained cells in the NASH + Y-40138 group than in the NASH group. The TNF-α levels in the in-vitro Kupffer cell culture supernatant were lower in the NASH + Y-40138 group than in the NASH group.CONCLUSION: Administration of Y-40138 to NASH model rats reduced hepatic inflammation and suppressed fibrosis. These results indicate that the multiple cytokine production modulator, Y-40138, is promising as a novel treatment for NASH.     

茴三硫防治非酒精性脂肪性肝炎的实验研究

目的 非酒精性脂肪性肝炎（NASH）可发展为纤维化、肝硬化、目前尚缺乏有效防治药物。研究茴三硫对大鼠NASH模型形成的影响，为临床防治NASH提供新方法。方法 60只SD大鼠随机平均分为6组，每组10只：正常组喂普通饲料；模型组高脂饲料；茴三硫预防组喂高脂饲料同时，加用茴三硫。余30只大鼠在高脂饮食12周后复分为：茴三硫治疗组，喂高脂饲料同时加用茴三硫；饮食治疗组即恢复正常饲料喂养；茴三硫＋饮食治疗组，恢复正常饮食同时予茴三硫治疗。16周后处死动物。称动物体重、肝脏湿重、检测血清转氨酶，光镜下评估肝脂肪变性和炎症活动程度。结果 茴三硫治疗、饮食治疗、茴三硫＋饮食治疗能显著降低造模大鼠的体重（P＜0．05）、肝指数（P＜0．05）、转氨酶（P＜0．01），还能改善肝脏指肪变性和炎症坏死的程度（P分别＜0．05和＜0．01）。茴三硫预防组的上述各项指标则与无显著差异。结论 茴三硫、饮食治疗NASH有效，两种方法联用可增强疗效。预防性应用茴三硫并无必要。     

姜黄素与吡格列酮对大鼠非酒精性脂肪性肝炎作用的对照研究

目的 比较姜黄素和吡格列酮对高脂饮食诱导的大鼠非酒精性脂肪性肝炎（NASH）的作用并探讨其机制.方法 48只SD大鼠随机分为正常组、模型组、姜黄素组和吡格列酮组（每组各12只）.正常组全程饲以普通饲料,另外三组均给予高脂饮食.6周末,每组各处死2只大鼠.验证非酒精性脂肪肝病造模成功后,姜黄素组和吡格列酮组每日分别给予姜黄素50 mg/kg和吡格列酮10 mg/kg灌胃,正常组、模型组给予相应体积的0.5%的羧甲基纤维素钠灌胃.6周治疗结束后,留取血样和肝组织.统计体/肝质量,计算肝指数和胰岛素抵抗指数（HOMA-IR）;进行肝功能检测及病理组织学检查;并检测血清FFA、TNF-α和IL-6水平及肝组织FFA、TNF-α、IL-6、MDA、GSH含量和SOD的活性.结果 与模型组相比,姜黄素组和吡格列酮组大鼠NAS评分及血清ALT、AST水平均降低（P均〈0.05）.模型组较正常组大鼠血清HOMA-IR、FFA、TNF-α、IL-6水平及肝组织TNF-α、IL-6、MDA含量均明显升高（P均〈0.01）,而姜黄素组、吡格列酮组与模型组大鼠相比,上述指标均降低（P均〈0.05）,且以姜黄素组大鼠体质量、血清AST、NAS积分及肝组织FFA、MDA下降最为显著（P均〈0.01）.结论 姜黄素与吡格列酮均可通过调脂、改善IR、抗炎及抗氧化作用防治NASH,但前者的作用更强,且不增加大鼠的体质量.     

饮食调整治疗大鼠非酒精性脂肪性肝炎

目的:观察单纯饮食改变治疗大鼠非酒精性脂肪性肝炎(NASH)的作用。方法:30只SD大鼠随机分为3组(每组n=10):正常组喂普通饲料;模型组喂高脂饲料;饮食治疗组在高脂饮食12周后恢复正常饲料喂养。16周后处死动物。结果:正常饮食能显著降低造模大鼠的体重、肝指数、转氨酶,还能改善肝脏脂肪变性和炎症坏死的程度。结论:单纯恢复正常饮食即可治疗大鼠NASH。     

疏肝祛瘀通络降浊法对大鼠非酒精性脂肪性肝炎的保护作用

目的探讨非酒精性脂肪性肝炎大鼠内毒素性肝损伤机制及中药对其影响。方法用喂饲高脂饮食的方法建立非酒精性脂肪性肝炎大鼠模型。4周后用疏肝祛瘀通络降浊法分小、中、大剂量进行治疗,12周后处死测定血脂、ALT、内毒素(ET)、肿瘤坏死因子(TNF-α)和白细胞介素(IL-1β)的含量;免疫组化法观察肝组织CD14和核转录因子(NF-κB)的表达;RT-PCR检测脂多糖结合蛋白(LBP)和4型Toll样受体(TLR-4)mRNA的表达。同期正常饮食饲养大鼠作对照。结果第12周时,模型组大鼠腹主动脉血清内毒素水平较正常组明显升高,有显著性差异;中剂量治疗组大鼠血清ET、TNF-α、IL-1β水平明显低于模型组,差异有显著意义。模型组大鼠肝组织CD14阳性细胞数量明显增多,主要分布于肝窦内,部分呈灶型聚集;与模型组相比,中剂量治疗组大鼠肝组织CD14阳性细胞数量明显减少。模型组可见少量细胞核染色的NF-κB阳性细胞散在分布于汇管区。模型组肝组织LBPmRNA和TLR-4mRNA表达均明显上调,与正常组比较差异均有显著意义;中剂量治疗组大鼠肝组织LBPmRNA和TLR-4mRNA表达均较模型组明显下调,且有显著性差异。结论疏肝祛瘀通络降浊法对非酒精性脂肪肝有疗效,可能与其降低血清内毒素水平和下调肝组织内毒素相关受体表达继而减轻炎症性肝损害有关。     

理气化痰祛瘀法对非酒精性脂肪性肝炎大鼠脂肪细胞因子表达的影响

[目的]观察理气化痰祛瘀中药对高脂饮食诱导的非酒精性脂肪性肝炎（NASH）大鼠肿瘤坏死因子α（TNF-α）、白细胞介素6（IL-6）、瘦素（1eptin）及其肝组织mRNA水平的影响，探讨其防治NASH的作用机制。[方法]以高脂饮食喂养Wistar大鼠12周，建立大鼠NASH模型，同时以不同剂量的理气化痰祛瘀法中药干预12周，测定大鼠血清丙氨酸氨基转移酶（ALT）、天冬氨酸转氨酶（AST）及游离脂肪酸（FFA）水平，观察肝组织的病理改变，原位杂交技术检测肝组织TNF-α、IL-6、leptinmRNA表达，放免法测定血清TNF-α、IL-6、leptin水平。[结果]NASH大鼠血清ALT、AST、FFA、TNF-α、IL-6、leptin水平较正常大鼠显著升高，肝组织TNF-α、IL-6和leptinmRNA表达显著增强，理气化痰祛瘀法中药能显著改善NASH大鼠肝组织炎症活动程度，显著降低ALT、AST、FFA、TNF-a、IL-6、leptin水平和肝组织TNF-α、IL-6、leptinmRNA表达。[结论]TNF-α、IL-6、leptin参与高脂饮食诱导的大鼠NASH的发生，理气化痰祛瘀中药能调节TNF-α、IL-6、leptin的分泌，防止NASH的进一步发展。     

Cyclooxygenase-2 Promotes Hepatocellular Apoptosis by Interacting with TNF-α and IL-6 in the Pathogenesis of Nonalcoholic Steatohepatitis in Rats

Background and Purpose

The underlying mechanisms of nonalcoholic steatohepatitis (NASH) are poorly understood, and little is known about hepatocellular apoptosis in NASH. Cyclooxygenase (COX)-2, the key enzyme in eicosanoid metabolism, is highly expressed in NASH. COX-2 can also regulate the release of mediators of inflammation, such as tumor necrosis factor (TNF)-α and interleukin (IL)-6. The aim of our study was to evaluate the effects of COX-2 on hepatocellular apoptosis and the mechanism of the action in the pathogenesis of NASH in rats.

Methods

Sprague-Dawley rats were fed a high-fat diet (HFD) or standard diet for 8 and 12 weeks. COX-2 and cytokines expression in hepatic tissue and TNF-α and IL-6 levels in serum were measured at 8 and 12 weeks. Moreover, celecoxib (10 mg/kg body weight once a day) was administered to rats for 4 weeks to inhibit the expression of COX-2. Liver pathology was assessed by hematoxylin and eosin (H&E) stain and electron microscopy. Hepatocyte apoptosis was evaluated by TUNEL staining.

Results

COX-2 messenger RNA and protein were highly expressed in livers of HFD rats and were correlated with the severity of steatohepatitis (R = 0.82, p < 0.01). COX-2 upregulation was preceded by increases in TNF-α and IL-6. The level of hepatocellular apoptosis was significantly higher in HFD rats than in the control rats. The hepatocellular apoptosis was suppressed by the inhibition of COX-2.

Conclusions

COX-2 may promote hepatocellular apoptosis by interacting with TNF-α and IL-6 in NASH in rats.     

Characterization of High-Fat,Diet-Induced,Non-alcoholic Steatohepatitis with Fibrosis in Rats

An ideal animal model is necessary for a clear understanding of the etiology, pathogenesis, and mechanisms of human non-alcoholic steatohepatitis (NASH) and for facilitating the design of effective therapy for this condition. We aimed to establish a rat model of NASH with fibrosis by using a high-fat diet (HFD). Male Sprague–Dawley (SD) rats were fed a HFD consisting of 88 g normal diet, 10 g lard oil, and 2 g cholesterol. Control rats were fed normal diet. Rats were killed at 4, 8, 12, 16, 24, 36, and 48 weeks after HFD exposure. Body weight, liver weight, and epididymal fat weight were measured. Serum levels of fasting glucose, triglyceride, cholesterol, alanine aminotransferase (ALT), free fatty acids (FFA), insulin, and tumor necrosis factor-alpha (TNF-α) were determined. Hepatic histology was examined by H&E stain. Hepatic fibrosis was assessed by VG stain and immunohistochemical staining for transforming growth factor beta 1 (TGF-β1), and alpha-smooth-muscle actin (α-SMA). The liver weight and liver index increased from week 4, when hepatic steatosis was also observed. By week 8, the body weight and epididymal fat weight started increasing, which was associated with increased serum levels of FFA, cholesterol, and TNF-α, as well as development of simple fatty liver. The serum ALT level increased from week 12. Steatohepatitis occurred from weeks 12 through 48. Apparent hepatic perisinosodial fibrosis did not occur until week 24, and progressed from week 36 to 48 with insulin resistance. Therefore, this novel model may be potentially useful in NASH study.