红花黄素对脊髓损伤大鼠的保护作用

目的探究红花黄素(SY)对脊髓损伤(SCI)的保护作用及其作用机制。方法将SCI模型大鼠分为模型(Model)组、重组高迁移率组蛋白(HMG)B1处理组(HMGB1组,8μg/kg)、SY干预组(SY组,40 mg/kg)、HMGB1+SY组(8μg/kg HMGB1+40 mg/kg SY),另设假手术(Control组),各组均12只,各组连续给药28 d。行为学运动(BBB)评分法评定运动行为;获取脊髓组织,采用苏木素-伊红(HE)染色观察脊髓组织病理形态学变化;免疫印迹法(WB)检测脊髓组织中HMG B1、Toll样受体(TLR)4、核转录因子(NF)-κB蛋白表达;制备脊髓组织匀浆液,采用酶联免疫吸附试验检测超氧化物歧化酶(SOD)、谷胱甘肽过氧化物酶(GSHP)、过氧化氢酶(CAT)、丙二醛(MDA)水平;Tunel染色观察脊髓组织中神经元细胞凋亡情况;Western印迹法检测B淋巴细胞瘤-2蛋白(Bcl-2)、Cleaved-caspase3、Bcl-2相关X蛋白(Bax)蛋白表达。结果与Control组相比,Model组BBB评分显著降低,SOD、GSHP、CAT水平显著降低,MDA水平显著升高,HMGB1、TLR4、NF-κB蛋白表达显著升高,脊髓组织神经细胞凋亡率显著升高,Bax、Cleaved-caspase3蛋白表达显著升高,Bcl-2蛋白表达显著降低(P<0.05)。与Model组相比,HMGB1组BBB评分显著降低,SOD、GSHP、CAT水平显著降低,MDA水平显著升高,HMGB1、TLR4、NF-κB蛋白表达显著升高,脊髓组织神经细胞凋亡率显著升高,Bax、Cleaved-caspase3蛋白表达显著升高,Bcl-2蛋白表达显著降低(P<0.05);SY组、HMGB1+SY组与Model组及HMGB1组比较BBB评分显著升高,SOD、GSHP、CAT水平显著升高,MDA水平显著降低,HMGB1、TLR4、NF-κB蛋白表达显著降低,脊髓组织神经细胞凋亡率显著降低,Bax、Cleaved-caspase3蛋白表达显著降低,Bcl-2蛋白表达升高(P<0.05)。结论 SY可能通过抑制HMGB1/TLR4/NF-κB信号通路,缓解SCI后氧化应激水平,减低脊髓组织神经元细胞凋亡,缓解脊髓组织、运动功能损伤。     

阿托伐他汀对糖尿病大鼠心肌组织NF-κB表达影响的研究

60只雄性大鼠,20只为对照组,余用链脲佐菌素(STZ)制备2型糖尿病大鼠模型。成模后,随机分成两组,糖尿病非药物干预组及阿托伐他汀干预组。干预组予阿托伐他汀(2mg/kg/day)灌胃,对照组及糖尿病非药物干预组予等量饮用水灌胃。3个月处死大鼠。取一部分心肌组织抽提RNA,另一部分心肌组织固定后做免疫组织化学观察。应用RT-PCR方法扩增NF-κB基因,比较3组大鼠的NF-κB在基因水平上的表达差异,RT-PCR方法检测心肌组织中NF-κB的mRNA表达水平,免疫组织化检测其蛋白表达。结果:糖尿病大鼠心肌组织中NF-κB在mRNA表达及蛋白表达比正常大鼠明显增高(P<0.05),给药3月NF-κB的mRNA表达及蛋白表达比糖尿病非药物干预组明显减少(P<0.05)。结论:阿托伐他汀能降低糖尿病大鼠心肌组织中NF-κB mRNA及NF-κB蛋白质的表达,减缓心肌组织病变进展。     

甲状腺癌组织中HMGB1、NF-κB p50的表达及相关性

目的探讨甲状腺癌组织中高迁移率族蛋白(HMG)B1、核因子(NF)-κB p50的表达及相关性。方法选择该院甲状腺乳腺外科2014年3月至2016年3月收集的100例甲状腺癌组织标本,另选择同期该院收集的腺瘤组织20例、甲状腺肿组织20例、正常组织20例作为对照,应用免疫组织化学SP法检测各组织HMGB1、NF-κB p50的表达情况及相关性。结果甲状腺癌组织HMGB1、NF-κB p50阳性表达显著高于腺瘤组织、甲状腺肿组织和正常组织(P<0.05)。甲状腺癌组织中HMGB1、NF-κB p50阳性表达与性别、年龄、组织类型无关(P>0.05),与肿瘤直径、淋巴结转移有关(P<0.05)。甲状腺癌组织中HMGB1表达与NF-κB p50表达呈正相关(Rs=0.743,P=0.000)。结论甲状腺癌组织中HMGB1、NF-κB p50呈异常表达,其表达水平与肿瘤直径、淋巴结转移有关,HMGB1、NF-κB p50高表达可能与甲状腺癌的发病有关。     

压力超负荷对大鼠左室心肌牵张敏感性钾通道TREK-1 mRNA和蛋白表达的影响

目的探讨压力超负荷状态下左室心肌牵张敏感性钾通道TREK-1mRNA及其蛋白表达的变化。方法雄性W istar大鼠被随机分为腹主动脉缩窄组(n=30)和假手术组。腹主动脉缩窄组依观察时间随机分为2,4,8周组各10只。每组观察期结束后,计算左右室肥厚指数(LVM I、RVM I)。HE染色观察压力超负荷对心肌组织结构的影响。采用RT-PCR和免疫组织化学SABC法分别检测牵张敏感性钾通道TREK-1mRNA与蛋白水平表达的改变。结果腹主动脉缩窄术后2周,出现左室肥厚,但无统计学意义。腹主动脉缩窄术后4,8周,左室肥厚指数较正常组明显增加(P<0.05),光镜下显示心肌肥厚。术后2,4,8周组左室心肌牵张敏感性钾通道TREK-1mRNA上调(P<0.05),心肌细胞内TREK-1蛋白表达明显增加(P<0.05)。结论压力超负荷致大鼠左室肥厚的同时可诱导牵张敏感性钾通道TREK-1的表达增加。     

牛蒡子苷元抑制HMGB1/TLR4/NF-κB信号通路对肺炎链球菌脑膜炎大鼠神经元凋亡的影响北大核心CSCD

目的探讨牛蒡子苷元(ATG)抑制HMGB1/TLR4/NF-κB信号通路对肺炎链球菌脑膜炎大鼠神经元凋亡的影响。方法通过脑内注射Ⅲ型肺炎链球菌建立脑膜炎大鼠模型,并随机分为模型组、ATG低(ATG-L)、中(ATG-M)、高(ATG-H)剂量组以及ATG-H+重组高迁移率组蛋白B1(rHMGB1)组,另取正常大鼠为对照组,10只/组。治疗结束后,对各组大鼠进行神经系统评分;分离大鼠脑组织,检测其病理变化、含水量、IL-1β、IL-6、TNF-α水平以及神经元细胞凋亡,同时检测HMGB1/TLR4/NF-κB信号通路蛋白表达水平。结果与对照组比较,模型组大鼠神经系统评分显著下降(P<0.05),脑组织含水量、IL-1β、IL-6、TNF-α、HMGB1、TLR4、p-NF-κB p65/NF-κB p65水平及TUNEL荧光染色阳性细胞数量均显著增加(均P<0.05);ATG-L组、ATG-M组、ATG-H组小鼠神经系统评分均较模型组显著增加(均P<0.05),脑组织含水量、IL-1β、IL-6、TNF-α水平、TUNEL荧光染色阳性细胞数量、HMGB1、TLR4、p-NF-κB p65/NF-κB p65均较对照组显著下降(均P<0.05);ATG-H+rHMGB1组较ATG-H组神经系统评分显著下降(P<0.05),脑组织含水量、IL-1β、IL-6、TNF-α、HMGB1、TLR4、p-NF-κB p65/NF-κB p65水平及TUNEL荧光染色阳性细胞数量均显著增加(均P<0.05)。结论ATG可抑制肺炎链球菌脑膜炎大鼠神经元凋亡,减轻炎症反应,其机制可能与抑制HMGB1/TLR4/NF-κB信号通路有关。     

竹节参总皂苷通过HMGB1/TLR4/NF-κB信号通路改善游离脂肪酸诱导肝细胞脂肪变性的实验研究

目的:通过HMGB1/TLR4/NF-κB信号通路探讨竹节参总皂苷(TSPJ)改善游离脂肪酸(FFA)诱导的肝癌细胞HepG2脂肪变性的作用机制。方法:体外培养HepG2细胞，随机分成对照组、FFA组、FFA+高迁移率族蛋白1(HMGB1) p-NC组、FFA+HMGB1 siRNA组、FFA+TSPJ组、FFA+pcDNA+TSPJ组、FFA+HMGB1 pcDNA+TSPJ组、FFA+HMGB1 p-NC+TSPJ组、FFA+HMGB1 siRNA+TSPJ组。RT-qPCR和Western blot检测HMGB1 siRNA干扰效率；油红O染色观察TSPJ对细胞脂质蓄积的影响；检测TSPJ对甘油三酯(TG)的作用。RT-qPCR和Western blot检测各组细胞HMGB1、蛋白Toll样受体4(TLR4)和核因子κB(NF-κB)表达水平。结果:HepG2细胞经0.5 mmol/L FFA处理后，脂质水平及TG含量升高(P<0.05);TSPJ干预使肝细胞脂质水平及TG含量降低(P<0.05);干扰HMGB1表达后，肝细胞脂质水平及TG含量降低(P<0.05...     

HMGB1和NF-κB p65在非小细胞肺癌组织中的表达及意义

目的探讨高迁移率族蛋白B1（HMGB1）与核转录因子（NF-κB）p65在非小细胞肺癌（NSCLC）组织中的表达及意义。方法采用免疫组织化学法检测95例NSCLC（NSCLC组）和27例癌旁正常肺组织（对照组）中HMGB1、NF-κB p65蛋白的表达水平,并分析其临床意义。结果 HMGB1蛋白在NSCLC组织中的阳性表达（48.4%）明显高于癌旁正常肺组织（P〈0.01）;NF-κB p65蛋白在NSCLC癌组织中的阳性表达（44.2%）高于癌旁正常肺组织（22.2%）（P〈0.05）。HMGB1和NF-κB p65在转移组的表达显著高于非转移组（P〈0.01）。HMGB1和NF-κB p65蛋白在肺癌组织中的表达呈正相关（P〈0.05）,两者的表达均与NSCLC淋巴结转移有关。结论 HMGB1与NF-κB p65的高表达可能与NSCLC的转移有关。     

急性坏死性胰腺炎大鼠心肌核因子-κB激活及重组葡激酶的干预作用

目的 研究重症急性胰腺炎(SAP)心肌功能损害时心肌核因子-κB (NF-κB)的活化及葡激酶的干预作用.方法 63只SD大鼠随机分为假手术组(n = 9)、ANP组(n = 27)、葡激酶干预组(n = 27),ANP模型采用5%的牛磺胆酸钠胰胆管逆行注射方法建立.干预自造模前2 d腹腔注射葡激酶1.5 mg/kg体重,一天2次,共4次.ELISA法测定制模后6 h、12 h、24 h各时点血TNF-α、IL-6含量;RT-PCR检测心肌NF-κB mRNA的表达;免疫组化法检测心肌NF-κB蛋白的表达,常规观察胰腺及心肌组织的病理变化.结果 ANP组术后6 h大鼠心肌NF-κB mRNA及NF-κB蛋白表达异常增高,TNF-α、IL-6呈进行性升高,干预组胰腺及心肌组织的病理变化减轻.心肌NF-κB mRNA及蛋白表达下调,血TNF-α、IL-6明显下降,与ANP组比较,差异均显著(P＜0.05).结论 ANP大鼠的心肌损伤可能与循环中TNF-α、IL-6水平升高导致的心肌NF-κB活化有关.葡激酶对SAP并发的心肌损伤具有防治作用.     

cFLIP在压力超负荷诱导的心肌肥厚及纤维化中的作用

目的利用基因工程小鼠研究细胞型Fas相关死亡区域蛋白样β白介素-1转换酶抑制蛋白基因(cFLIP)在压力超负荷诱导的心肌肥厚及心肌纤维化中的作用。方法 cFLIP杂合子小鼠(heterozygote,HZ)和cFLIP野生型小鼠(wild type,WT)各20只分别随机分为模型组和假手术组,每组10只。主动脉缩窄术建立小鼠心肌肥厚模型,术后4周超声检测小鼠心室腔大小及左室短轴缩短率,组织病理学方法评价心肌肥厚及纤维化程度,实时定量聚合酶链式反应在mRNA水平检测心肌肥厚标志物心钠肽,脑钠肽,β-MHC以及心肌纤维化标志物结缔组织生长因子(CTGF),Ⅰ、Ⅳ型胶原(collagenⅠ,Ⅳ),TGF-β1。结果术后4周,HZ模型组较WT模型组和HZ假手术组心室腔增大,左室短轴缩短率下降(P<0.05,n=10);心肌肥厚及纤维化组织病理学检测及相关标志物表达水平模型组较假手术组升高(P<0.05,n=10),而HZ模型组表达增加程度较WT模型组更为显著(P<0.05,n=10)。结论cFLIP可抑制心肌肥厚及纤维化,对心功能起保护作用。     

N-乙酰半胱氨酸对阿霉素致心力衰竭兔心肌细胞凋亡的作用

目的:探讨慢性心力衰竭(HF)兔心肌核因子-κB(NF-κB)活化、诱生型一氧化氮合酶(iNOS)与心肌细胞凋亡的关系以及N-乙酰半胱氨酸(NAC)对心肌细胞凋亡的作用。方法:设立对照组,剩余动物以阿霉素复制HF模型,随机分为HF组和NAC组,药物干预4周。观测3组心肌细胞凋亡指数、血清和心肌一氧化氮(NO)浓度、iNOS蛋白在心肌细胞中表达的水平,以及NF-κB p65的核表达和结合活性的改变,观察NAC对上述指标的影响。结果:与对照组比较,HF组心肌细胞凋亡指数增高,iNOS蛋白表达增多,NF-κB p65易位和核内表达增多,血清和心肌NO浓度升高(P<0.001),NF-κB p65活化与iNOS表达呈直线相关(r=0.973,P<0.001)。NAC组结果示NAC可显著减少NF-κB p65核内表达及iNOS蛋白的表达,降低血清和心肌NO水平,降低心肌细胞凋亡指数(P<0.01～0.001)。结论:HF时心肌细胞中NF-κB的活化及其促进iNOS的转录合成导致NO大量生成,参与了心肌凋亡的发生。NAC可显著拮抗NF-κB的大量活化核表达,减弱iNOS的表达上调,抑制NO的生成,减少心肌细胞凋亡。NF-κB的活化可能是iNOS表达的重要调控机制之一。     

Betaine Protects Against High-Fat-Diet-Induced Liver Injury by Inhibition of High-Mobility Group Box 1 and Toll-Like Receptor 4 Expression in Rats

Background and Objectives

Previous studies have shown that betaine prevents alcohol-induced liver injury and improves liver function. The purpose of this study was to investigate the hepatoprotective effects of betaine on nonalcoholic fatty liver disease (NAFLD) and to observe changes of HMGB1/TLR4 signaling.

Methods

Thirty rats were randomly divided into control, model, and betaine groups. The rats in the model and betaine groups were fed a high-fat diet for 12 weeks to induce an animal model of NAFLD. The rats in the betaine group were then intragastrically administered betaine solution at a dose of 400 mg/kg per day for four weeks. Liver histology was examined. Serum levels of ALT, AST, TC, TG, HDL-C, LDL-C, FFA, HMGB1, NF-κB, TLR4, and tHcy were determined and intrahepatic TC, TG, and Hcy levels were assayed. mRNA expression and protein levels of HMGB1, NF-κB, and TLR4 in liver tissue were also determined.

Results

Compared with the control group, rats in the model group developed severe liver injury, accompanied by significant increases in serum levels of ALT, AST, TC, TG, LDL-C, FFA, HMGB1, NF-κB, and TLR4, intrahepatic TC, TG, and Hcy content, histological scores for steatosis, inflammation, and necrosis, and mRNA expression and protein levels of HMGB1, NF-κB, and TLR4, and a significant decrease in serum HDL-C (P < 0.05). Compared with the model group, all these indicators were significantly improved by administration of betaine (P < 0.05).

Conclusions

Betaine effectively protects against high-fat-diet-induced NAFLD and improves liver function; the mechanism is probably related to inhibition of HMGB1/TLR4 signaling pathways.     

Increased collagen deposition and diastolic dysfunction but preserved myocardial hypertrophy after pressure overload in mice lacking PKCepsilon

Overexpression and activation of protein kinase C-epsilon (PKCepsilon) results in myocardial hypertrophy. However, these observations do not establish that PKCepsilon is required for the development of myocardial hypertrophy. Thus, we subjected PKCepsilon-knockout (KO) mice to a hypertrophic stimulus by transverse aortic constriction (TAC). KO mice show normal cardiac morphology and function. TAC caused similar cardiac hypertrophy in KO and wild-type (WT) mice. However, KO mice developed more interstitial fibrosis and showed enhanced expression of collagen Ialpha1 and collagen III after TAC associated with diastolic dysfunction, as assessed by tissue Doppler echocardiography (Ea/Aa after TAC: WT 2.1+/-0.3 versus KO 1.0+/-0.2; P<0.05). To explore underlying mechanisms, we analyzed the left ventricular (LV) expression pattern of additional PKC isoforms (ie, PKCalpha, PKCbeta, and PKCdelta). After TAC, expression and activation of PKCdelta protein was increased in KO LVs. Moreover, KO LVs displayed enhanced activation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK), whereas p42/p44-MAPK activation was attenuated. Under stretch, cultured KO fibroblasts showed a 2-fold increased collagen Ialpha1 (col Ialpha1) expression, which was prevented by PKCdelta inhibitor rottlerin or by p38 MAPK inhibitor SB 203580. In conclusion, PKCepsilon is not required for the development of a pressure overload-induced myocardial hypertrophy. Lack of PKCepsilon results in upregulation of PKCdelta and promotes activation of p38 MAPK and JNK, which appears to compensate for cardiac hypertrophy, but in turn, is associated with increased collagen deposition and impaired diastolic function.     

奥美沙坦不依赖血管紧张素Ⅱ改善压力超负荷诱发的小鼠心脏肥大

目的探讨奥美沙坦在无内源性血管紧张素II(AngII)情况下能否抑制压力超负荷导致的小鼠心脏肥厚。方法通过缩窄升主动脉(TAC)构建小鼠压力超负荷心脏肥大模型。8-10周龄野生型(WT)和血管紧张素原基因敲除(ATGKO)小鼠各随机分为3组:假手术组,生理盐水组和奥美沙坦组。TAC两周后,对小鼠心脏进行超声及病理形态学检测,同时测量左心室压力、全心/体重比值以及相关肥大基因检测。结果相对于假手术组,生理盐水组心脏肥厚各项指标值明显变大(P0.05)。奥美沙坦组心脏肥厚的各项指标值均显著低于生理盐水组(P0.05);在WT小鼠和ATGKO小鼠可见相似结果。结论奥美沙坦在无内源性AngII的条件下也能有效抑制压力超负荷所致心肌肥厚,其作用机制可能是不依赖于AngII而直接抑制压力超负荷触发的AT1受体的活化。     

黄芪多糖对大鼠缺氧/复氧诱导的心肌细胞自噬及凋亡抑制作用的机制探讨

目的：探究黄芪多糖（APS）通过调控高迁移率族蛋白1/Toll样受体4/核转录因子-κB(HMGB1/TLR4/NF-κB)信号通路对大鼠缺氧/复氧（H/R）诱导的心肌细胞自噬及凋亡的抑制作用。方法：建立H9C2心肌细胞H/R损伤模型并分为4组：对照组、H/R组、APS组和HMGB1抑制剂组。CCK-8法和EdU染色法检测细胞增殖能力;酶联免疫吸附试验检测细胞肿瘤坏死因子（TNF）-α、白细胞介素（IL）-1β、IL-6含量;透射电镜观察细胞自噬小体的形成;膜联蛋白V-异硫氰酸荧光素/碘化丙啶（AnnexinV-FITC/PI）双染法检测细胞凋亡;实时定量PCR检测细胞HMGB1、TLR4、NF-κB p65 mRNA表达水平;蛋白免疫印迹法检测细胞HMGB1、TLR4、NF-κB p65、B细胞淋巴瘤-2(Bcl-2)、Bcl-2相关X蛋白（Bax）、含半胱氨酸的天冬氨酸蛋白水解酶-3(caspase-3)、P62、微管相关蛋白1A/1B-轻链3(MAP1LC3,缩写为LC3)-Ⅱ蛋白表达水平。结果：与对照组相比,H/R组细胞增殖能力明显减弱,凋亡及自噬水平明显增加,细胞内可见大量自...     

C-reactive protein overexpression exacerbates pressure overload-induced cardiac remodeling through enhanced inflammatory response

Serum C-reactive protein (CRP) elevation predicts the development of heart failure in patients with hypertension. CRP activates macrophages and enhances oxidative stress. We hypothesize that CRP itself has a pathogenic role in the development of pressure overload-induced cardiac remodeling. Transgenic mice with human CRP overexpression (CRPtg) and nontransgenic littermates (CON) were subjected to transverse aortic constriction (TAC/CRPtg and TAC/CON) or sham operation (Sham/CRPtg and Sham/CON). One week after operation, in TAC/CRPtg, myocardial mRNA levels of interleukin (IL)-6, CD68, glutathione peroxidase-3 (GPx3), 47-kDa α-subunit of nicotinamide adenine dinucleotide phosphate oxidase (p47(phox)), and collagen-I, the number of infiltrating Mac-2-positive macrophages, nuclear localization of phosphorylated NF-κB/p65 (p-p65) in cardiomyocytes, nuclear NF-κB-DNA-binding activity, and reactive oxygen species (ROS) content were increased compared to those in TAC/CON. Cardiac fibrosis was more prominent in TAC/CRPtg compared to TAC/CON. Four weeks after operation, heart and lung weights, cardiomyocyte cross-sectional area, and the extent of cardiac fibrosis were greater in TAC/CON than in Sham/CON, and these differences were further augmented in TAC/CRPtg compared to TAC/CON. Left ventricular (LV) fractional shortening was less and LV end-diastolic pressure was higher in TAC/CRPtg than in TAC/CON. Myocardial mRNA levels of angiotensin type 1 receptor, atrial natriuretic factor, IL-6, GPx3, p47(phox), collagen-I, and transforming growth factor (TGF)-β1, the protein level of TGF-β1, and the numbers of Mac-2-positive macrophages and p-p65-positive cells were higher in TAC/CRPtg than in TAC/CON. In conclusion, CRP itself may have a pathogenic role in the development of pressure overload-induced cardiac remodeling, possibly through enhanced inflammation and oxidative stress.     

The TIR/BB-loop mimetic AS-1 prevents cardiac hypertrophy by inhibiting IL-1R-mediated MyD88-dependent signaling

Activation of NF-κB contributes to cardiac hypertrophy and the interleukin-1 receptor (IL-1R)-mediated MyD88-dependent signaling pathway predominately activates NF-κB. Recent studies have shown that the TIR/BB-Loop mimetic (AS-1) disrupted the interaction of MyD88 with the IL-1R, resulting in blunting of NF-κB activation. We have examined the effects of AS-1 on the IL-1β-induced hypertrophic response using cultured neonatal cardiac myocytes in vitro and transverse aortic constriction (TAC) pressure overload-induced cardiac hypertrophy in vivo. Neonatal cardiac myocytes were treated with AS-1 15?min prior to IL-1β stimulation for 24?h. AS-1 treatment significantly attenuated IL-1β-induced hypertrophic responses of cardiac myocytes. In vivo experiments showed that AS-1 administration prevented cardiac hypertrophy and dysfunction induced by pressure overload. AS-1 administration disrupted the interaction of IL-1R with MyD88 in the pressure overloaded hearts and prevented activation of NF-κB. In addition, AS-1 prevented increases in activation of the MAPK pathway (p38 and p-ERK) in TAC-induced hypertrophic hearts. Our data suggest that the IL-1R-mediated MyD88-dependent signaling pathway plays a role in the development of cardiac hypertrophy and AS-1 attenuation of cardiac hypertrophy is mediated by blocking the interaction between IL-1R and MyD88, resulting in decreased NF-κB binding activity and decreased MAPK activation.     

Exacerbation of heart failure in adiponectin-deficient mice due to impaired regulation of AMPK and glucose metabolism

OBJECTIVE: Insulin resistance (IR) was reported to be associated with chronic heart failure (CHF). Adiponectin, an insulin-sensitizing hormone with anti-inflammatory activity, improves energy metabolism via AMP-activated protein kinase (AMPK). AMPK deficiency is associated with depressed cardiac function under stress conditions. However, it is not clear whether adiponectin plays an important role in CHF. We hypothesize that deficiency of adiponectin might result in deterioration of heart failure. METHODS: Using adiponectin null mice and their littermates, we examined the effects of adiponectin on LV pressure overload-induced cardiac hypertrophy and failure, and investigated the mechanisms involved. RESULTS: Three weeks after transverse aortic constriction (TAC), cardiac hypertrophy (evaluated from the heart-to-body weight ratio: 7.62+/-0.27 in wild-type (WT) mice, 9.97+/-1.13 in knockout (KO) mice, P<0.05) and pulmonary congestion (lung-to-body weight ratio: 9.05+/-1.49 in WT mice, 14.95+/-2.36 in KO mice, P<0.05) were significantly greater in adiponectin KO mice than WT mice. LV dimensions were also increased in KO mice. Compared with WT TAC mice, expression of AMPKalpha protein was lower, while IR was higher in KO TAC mice. CONCLUSION: These findings indicate that adiponectin deficiency leads to progressive cardiac remodeling in pressure overloaded condition mediated via lowing AMPK signaling and impaired glucose metabolism.     

Abnormal Expression of Toll-Like Receptor 4 Is Associated with Susceptibility to Ethanol-Induced Gastric Mucosal Injury in Mice

Background and Aims

Toll-like receptor 4 (TLR4) contributes to ethanol-induced gastric mucosal injury. This study aimed to determine its precise role in this pathogenic state and the related signaling pathway.

Methods

Ethanol-induced gastric mucosal injury models were generated in TLR4^?/? mice (C3H/HeJ: point mutation; C57BL/10ScNJ: gene deletion), their respective TLR4^+/+ wild-type counterparts, and heterozygous TLR4^+/? mice. Lipopolysaccharide (LPS) or pyrrolidine dithiocarbamate (PDTC) was injected intraperitoneally 1 h or 30 min before ethanol administration. At 1 h post-ethanol treatment, gastric or serum specimens were evaluated.

Results

Ethanol intra-gastric administration induced significant gastric mucosal injury in all mice, but the damaged area was larger in TLR4^?/? mice. LPS preconditioning and up-regulated TLR4 expression led to significantly larger areas of gastric mucosal damage. Upon ethanol administration, TLR4^+/+, and not TLR4^?/?, mice showed significant increases in TLR4, myeloid differentiation factor 88 (MyD88), cytoplasmic high mobility group box 1 (HMGB1), and nuclear factor-kappa B p65 (NF-κB p65). PDTC pretreatment significantly attenuated the ethanol-induced gastric mucosal damaged areas, inhibited nuclear NF-κB p65 expression, and suppressed HMGB1 translocation out of the nucleus. In addition, PDTC pretreatment reduced ethanol-stimulated expression of the inflammatory modulators, interleukin-1β (IL-1β) and tumor necrosis factor-alpha (TNF-α), in serum.

Conclusions

Both deficient and excessive expression of TLR4 promotes ethanol-induced gastric mucosal injury. The underlying mechanism involves the MyD88/NF-κB signaling pathway and the HMGB1, TLR4 activator ligand. The increased expression of HMGB1 may lead to increased secretion and binding to TLR4, further stimulating the TLR4/MyD88/NF-κB signaling pathway and aggravating the ethanol-induced gastric mucosal injury.