骨形态发生蛋白4在肥胖小鼠心肌、动脉和脂肪组织的表达与炎症的相关性研究

目的:探讨肥胖老鼠体内心脏、动脉与脂肪组织中骨形态发生蛋白4(BMP4)的表达及其与炎症程度的相关性。方法:将ob/ob小鼠分为实验组与干扰组,以C57BL/6小鼠为对照组。每组各8只,普通饮食喂养,干扰组尾静脉注射BMP4shRNA腺病毒,每周1次,持续12周。12周后心脏采血处死,取心肌组织、腹主动脉及腹部脂肪组织。免疫组织化学染色定位半定量BMP4的表达水平。PCR荧光定量和免疫蛋白印迹法检测BMP4、白细胞介素(IL)-1β和IL-9mRNA与蛋白的表达水平。结果:实验组BMP4、IL-1β和IL-9的mRNA与蛋白在心肌组织和动脉血管的表达均显著高于干扰组和对照组,实验组和干扰组BMP4蛋白在脂肪组织中的表达要显著低于对照组(均P0.05)。结论:BMP4在肥胖小鼠体内心肌组织和动脉血管中明显高表达,是促进局部炎症反应发生的独立危险因子。     

Toll样受体2基因敲除通过myd88依赖的p38MAPK减轻高脂饮食诱导的肥胖小鼠脂肪组织氧化应激

目的探究Toll样受体(TLR)2基因敲除对高脂饮食诱导的肥胖小鼠脂肪组织氧化应激的影响。方法健康雄性C57BL/6小鼠和TLR2基因敲除小鼠随机分为正常对照组、肥胖组、TLR2基因敲除组和TLR2基因敲除肥胖组,高脂饮食或普通饮食16 w后Western印迹检测各组小鼠脂肪组织TLR2、myd88、p38MAPK蛋白相对表达量,专用试剂盒检测活性氧簇(ROS)、丙二醛(MDA)、超氧化物歧化酶(SOD)含量,荧光实时定量PCR检测肿瘤坏死因子(TNF)-αmRNA和白细胞介素(IL)-6 mRNA。结果与正常对照组小鼠相比,肥胖组小鼠脂肪组织TLR2、myd88、p38MAPK、TNF-αmRNA和IL-6 mRNA高表达,ROS和MDA含量明显增加,SOD含量明显减少,与肥胖组相比,TLR2基因敲除肥胖组小鼠脂肪组织myd88、p38MAPK、TNF-αmRNA和IL-6 mRNA表达减少,ROS和MDA含量明显减少,SOD含量明显增加。结论 TLR2基因敲除通过myd88依赖的p38MAPK减少了高脂饮食诱导的肥胖小鼠脂肪组织氧化应激。     

小鼠颈动脉损伤新生内膜增生与局部转录因子Id1的关系

目的研究转录因子Id1在小鼠颈动脉损伤后血管壁的动态表达及在损伤血管新生内膜增生中的作用。方法采用昆明小鼠颈动脉球囊损伤动物模型,随机均分为四组:正常对照组、血管损伤后7天、14天及28天组。HE染色评价血管内膜增生情况。逆转录聚合酶链反应、Western blotting及免疫组织化学染色等方法检测血管壁Id1的表达。结果正常对照组小鼠颈动脉内膜/中膜面积比值很小,损伤7天组颈动脉内膜/中膜面积比值显著高于正常对照组(P0.05),损伤14天组和28天组颈动脉内膜/中膜面积比值明显高于7天组(P0.05)。正常对照组小鼠颈动脉血管壁Id1 mRNA和蛋白表达很低,损伤后7天血管壁Id1 mRNA和蛋白表达水平明显增加,损伤14天Id1 mRNA和蛋白表达显著高于7天组(P0.05),但损伤28天组Id1 mRNA和蛋白表达较14天组有所降低(P0.05)。免疫组织化学显示正常血管壁Id1表达很弱;随血管损伤时间延长Id1表达逐渐增强,14天达到高峰,28天表达出现减弱。结论颈动脉损伤后局部Id1表达动态改变伴随血管损伤新生内膜增生的变化,提示转录因子Id1可能参与血管损伤后新生内膜增生的调控过程。     

miR-150及其靶基因IRAK2在变应性鼻炎小鼠模型中的表达

目的探讨miR-150及其靶基因IRAK2在变应性鼻炎小鼠鼻黏膜中的表达及其作用。方法SPF级Balb/c小鼠20只,随机分为两组,变应性鼻炎模型组(AR)、对照组(NC),每组10只。模型组用卵清蛋白(OVA)致敏建立变应性鼻炎小鼠模型;对照组使用生理盐水替代。每组随机取4只小鼠,病理检查;每组剩余6只小鼠取其鼻黏膜,实时定量PCR检测小鼠鼻黏膜中miR-150及IRAK2 mRNA表达水平,蛋白印迹法(Western blot)检测IRAK2蛋白的表达,采用酶联免疫吸附法(ELISA)测定血清中OVA特异性IgE、IL-4、IL-13的含量,模型组与对照组miR-150相对表达量与IRAK2 mRNA的相对表达量、OVA特异性IgE、IL-4、IL-13的相关性分析采用Pearson相关性分析。结果AR组小鼠动物行为学评分均大于5分;病理组织HE染色显示AR组鼻黏膜纤毛大量脱落,组织间质水肿、小血管扩张、腺体增生、炎性细胞浸润;血清OVA特异性IgE、IL-4、IL-13表达增加。AR组小鼠鼻黏膜miR-150表达较NC组降低(P<0.05);IRAK2 mRNA表达水平明显高于对照组(P<0.05);且AR组鼻黏膜IRAK2蛋白表达水平也比NC组增加(P<0.05)。AR组与NC组miR-150相对表达量与IRAK2 mRNA表达量和OVA特异性IgE、IL-4、IL-13的含量呈负相关(r=-0.841、-0.869、-0.834、-0.857,P<0.05)。结论miR-150在变应性鼻炎模型小鼠中表达降低且与IRAK2、OVA特异性IgE、IL-4、IL-13含量存在负相关,二者的表达差异可能在变应性鼻炎的发生发展中发挥作用。     

ApN/TNF-α信号途径在有氧运动防治ApoE-/-小鼠动脉粥样硬化过程中的抗炎症作用

目的观察有氧运动对ApoE-/-小鼠动脉粥样硬化(AS)的防治效果,探讨脂联素(ApN)/肿瘤坏死因子(TNF)-α信号途径的抗炎症作用。方法 8周龄雄性ApoE-/-小鼠随机分为对照组(C,10只)和运动组(E,10只)。14 w运动干预结束后取材观察主动脉管壁的病理变化,检测脂肪组织ApN mRNA表达和血清ApN水平及主动脉脂联素受体(AdipoR)1、TNF-α蛋白表达水平。结果 C组小鼠主动脉血管壁纤维板断裂,可见大量泡沫细胞浸润和纤维斑块,E组小鼠较C组主动脉病变有所延缓;E组小鼠ApN mRNA表达及血清水平显著高于C组(P0.05);E组小鼠主动脉AdipoR1蛋白表达显著高于C组(P0.05),主动脉TNF-α蛋白表达显著低于C组(P0.05)。结论有氧运动通过增强ApoE-/-小鼠ApN信号途径,抑制主动脉TNF-α蛋白表达,发挥防治AS的抗炎症作用。     

维吾尔族肥胖患者脂肪和血清内脂素、脂联素的改变及相关因素

目的 探讨维吾尔族肥胖患者内脂素、脂联素(APN)在腹部网膜、皮下脂肪组织的表达和血清水平改变及其与体重指数(BMI)、腰臀围比(WHR)和血脂的关系.方法 用半定量RT-PCR方法检测41例肥胖患者和20例非肥胖对照脂肪组织内脂素和APN mRNA表达水平,ELISA法检测血清内脂素和APN浓度,并测量腰围(WC)、臀围(HC)、血压(BP)、空腹血糖(FPG)和血脂等.结果 ① 网膜脂肪组织内脂素mRNA表达水平在肥胖组与非肥胖对照组之间差异无显著性,肥胖组APN mRNA表达水平显著低于非肥胖对照组(P<0.05);内脂素、APN在两组网膜和皮下脂肪组织mRNA的表达水平均无显著性部位差异;血清内脂素肥胖组显著高于非肥胖对照组(P<0.05),APN在两组之间比较差异无显著性.② 肥胖组舒张压(DBP)和收缩压(SBP)均显著高于非肥胖对照组(P<0.01和P<0.01),高密度脂蛋白(HDL-C)明显低于非肥胖对照组(P<0.05).③ 网膜脂肪组织内脂素mRNA表达量与血清内脂素、BMI和TG显著正相关,APN mRNA表达量与血清APN显著正相关,与BMI、LDL-C显著负相关.结论 维吾尔族肥胖患者血清内脂素水平升高,网膜和皮下脂肪组织内脂素mRNA表达水平无显著性部位差异;APN mRNA在网膜脂肪组织的表达显著降低,内脂素和脂联素可能在维吾尔人中心性肥胖相关的代谢紊乱性疾病中起一定作用.     

ob／ob小鼠脂肪组织中富含半胱氨酸的酸性分泌蛋白的表达及临床意义

目的观察富含半胱氨酸的酸性分泌蛋白（SPARC）在ob／ob小鼠脂肪组织中的表达情况。方法选择10周龄的ob／ob小鼠（C57BL／6J—Lepob／J）与其同窝野生对照型小鼠各6只,取其腹部皮下脂肪组织,RT-PCR方法检测脂肪组织中SPARC基因的表达,Westernblot法测定sPARC目的蛋白的表达水平,免疫荧光染色法对脂肪组织进行染色观察。结果SPARC在ob／ob小鼠脂肪组织中表达明显升高。结论SPARC在ob／ob小鼠脂肪组织中呈现高表达,可能参与肥胖和糖尿病的发生发展。     

前列腺癌骨转移患者血清白细胞介素-6、~(-1)0、转铁蛋白及转移灶中骨形成蛋白的表达变化及意义

目的探讨前列腺癌骨转移患者血清中白细胞介素(IL)-6、IL~(-1)0、转铁蛋白(sTfR)、骨形成蛋白(BMP)等指标的表达变化及其临床意义。方法选择86例前列腺癌患者作为研究对象,其中发生前列腺癌骨转移的患者有36例(骨转移组)、未发生转移的50例(前列腺癌组),选取前列腺良性增生患者50例(前列腺增生组),比较三组患者血清中IL-6、IL~(-1)0、sTfR的水平差异,同时分析前列腺癌组织中、转移病灶中BMP6、BMP4及BMP7的表达强度差异。结果骨转移组患者的IL-6、IL~(-1)0、sTfR、PSA水平显著高于前列腺癌组和前列腺增生组(P0.05);前列腺癌组患者的PSA水平显著高于前列腺良性增生组(P0.05)。前列腺癌骨转移患者的血清IL-6、IL~(-1)0、s Tfr值与PSA水平具有显著的相关性,相关系数分别为0.296、0.410、-0.337,P均0.005。免疫组化染色结果显示:骨转移组患者的BMP6、BMP4、BMP7评分〔(5.13±1.08)、(4.47±0.96)、(4.73±0.92)分〕均显著高于前列腺癌组〔(3.14±0.82)、(2.01±0.57)、(1.89±0.38)分〕(P0.05)。结论前列腺癌骨转移患者血清IL-6、IL~(-1)0、PSA水平显著增高,sTfR值显著降低,并与PSA呈相关性;前列腺癌骨转移患者的转移病灶组织中BMP6、BMP4及BMP7表达显著高于前列腺癌组织中的表达。     

白细胞介素-23/-17轴在小鼠急性实验性结肠炎中的表达及作用

目的 研究白细胞介素(IL)-23/IL-17轴在小鼠实验性结肠炎结肠组织中的表达和作用.方法 将64只小鼠分为对照组24只、模型组24只、抗体组8只、正常血清组8只.除对照组外,其余各组建立小鼠急性实验性结肠炎模型.对照组和模型组小鼠分别于造模后24 h、48 h、7 d处死.抗体组和正常血清组小鼠分别于造模前2 h腹腔内注射多克隆大鼠抗小鼠IL-17中和抗体和正常大鼠血清,于造模48 h后处死.检测各组小鼠组织学损伤评分、肠组织髓过氧化物酶(MPO)活性;酶联免疫吸附试验检测结肠组织IL-23p19、IL-17含量;免疫组化染色检测核因子(NF)-κB p65在结肠组织中的表达;实时荧光定量(RT)PCR检测IL-23p19、IL-17、IL-12p35的mRNA表达水平.结果 模型组24 h、48 h、7 d时IL-23p19蛋白表达水平和mRNA表达水平[分别为(15.53±3.32)、(31.16±4.98)、(14.03±3.56)ng/mg蛋白和4.09±0.34、3.39±0.46、6.54±1.82]、IL-17的蛋白表达水平和mRNA表达水平[分别为(0.35±0.06)、(0.38±0.08)、(0.26±0.05)ng/mg蛋白和4.21±2.61、2.65±0.91、5.63±1.43]均显著高于正常对照组(P值均＜0.05),48 h时达高峰.IL-23与IL-17蛋白表达水平和mRNA表达水平呈正相关(r值分别为0.745和0.793,P＜0.05).抗体组IL-23p19和IL-12p35高水平表达,但NF-κB p65阳性细胞率、组织学评分及MPO活性[分别为1.86%±0.36%、0.63±0.52、(0.40±0.03)U/g]明显低于48 h模型组[分别为4.35%±0.37%、5.13±0.64、(2.29±0.40)U/g],说明中和IL-17后能明显减轻结肠炎症,抑制NF-κB活性.结论 IL-23/IL-17轴在急性实验性结肠炎早期阶段起关键作用.IL-17有望成为炎症性肠病治疗的新靶标.     

核转录因子κB、Toll样受体和炎性细胞因子在颅内动脉瘤破裂中的表达及相关性

目的探究核转录因子κB(NF-κB)、Toll样受体(TLR)和炎性细胞因子在颅内动脉瘤(IA)破裂中的表达及相关性。方法通过手术收集IA以及IA破裂的动脉瘤组织作为IA组和IA破裂组,同时收集健康血管组织作为对照组。通过qPCR检测动脉瘤组织中NF-κB、TLR4、白细胞介素1β(IL-1β)以及超敏C反应蛋白(hs-CRP)mRNA水平,通过Western blot检测NF-κB和TLR4蛋白水平。酶联免疫吸附法检测各组血清中IL-1β和hs-CRP的水平。结果 IA组和IA破裂组动脉瘤组织中的NF-κB、TLR4、IL-1β、hs-CRP mRNA和NF-κB、TLR4蛋白水平显著高于对照组(P0.05),此外,IA破裂组动脉瘤组织中的NF-κB、TLR4、IL-1β、hs-CRP mRNA和NF-κB、TLR4蛋白水平显著高于IA组(P0.05)。IA组和IA破裂组血清IL-1β和hs-CRP显著高于对照组(P0.05),IA破裂组血清IL-1β和hs-CRP水平显著高于IA组(P0.05)。结论与IA患者相比,IA破裂患者的动脉瘤组织中具有更高水平的NF-κB、TLR4、IL-1β以及hs-CRP mRNA和蛋白的表达,并且血清中IL-1β和hs-CRP的水平也更高,这说明NF-κB、TLR4、IL-1β以及hs-CRP可能与IA破裂有关。     

电针对高脂饮食小鼠中枢及外周急性炎症的影响

目的探讨电针对肥胖小鼠中枢及外周急性炎症的影响。方法将100只C57BL/6J雄性小鼠随机分为正常组、对照组、模型组,予以普通饲料或高脂饲料喂养2 w,模型组除高脂饲养外还予以电针治疗。各组小鼠均在第1、3、7、14天脱颈处死,取脑组织、附睾脂肪组织,采用RT-PCR检测下丘脑、脂肪组织中肿瘤坏死因子(TNF)-α、白细胞介素(IL)-6、IL-1β基因的表达情况。结果模型组、对照组体重增加,与正常组相比差异有统计学意义(P<0.05);模型组、对照组附睾脂肪组织炎症因子表达增加,与正常组相比差异有统计学意义(P<0.05);模型组表达量低于对照组,差异有统计学意义(P<0.05);模型组、对照组下丘脑炎症因子表达增加,与正常组相比差异有统计学意义(P<0.05);除IL-1β外,模型组TNF-α、IL-6表达量低于对照组,差异有统计学意义(P<0.05)。结论高脂饮食可引起小鼠下丘脑及附睾脂肪组织炎症因子在短期内增多,天枢穴、足三里穴、三阴交穴、关元穴电针治疗可以改善高脂饮食导致的炎症因子增多,减轻炎症反映。     

Regulated expression of the obese gene product (leptin) in white adipose tissue and 3T3-L1 adipocytes.

A mutation within the obese gene was recently identified as the genetic basis for obesity in the ob/ob mouse. The obese gene product, leptin, is a 16-kDa protein expressed predominantly in adipose tissue. Consistent with leptin's postulated role as an extracellular signaling protein, human embryonic kidney 293 cells transfected with the obese gene secreted leptin with minimal intracellular accumulation. Upon differentiation of 3T3-L1 preadipocytes into adipocytes, the leptin mRNA was expressed concomitant with mRNAs encoding adipocyte marker proteins. A factor(s) present in calf serum markedly activated expression of leptin by fully differentiated 3T3-L1 adipocytes. A 16-hr fast decreased (by approximately 85%) the leptin mRNA level of adipose tissue of lean (ob/+ or +/+) mice but had no effect on the approximately 4-fold higher level in obese (ob/ob) littermates. Since the mutation at the ob locus fails to produce the functional protein, yet its cognate mRNA is overproduced, it appears that leptin is necessary for its own downregulation. Leptin mRNA was also suppressed in adipose tissue of rats during a 16-hr fast and was rapidly induced during a 4-hr refeeding period. Insulin deficiency provoked by streptozotocin also markedly down-regulated leptin mRNA and this suppression was rapidly reversed by insulin. These results suggest that insulin may regulate the expression of leptin.     

Anti-inflammatory effect of atorvastatin ameliorates insulin resistance in monosodium glutamate-treated obese mice

Considering that inflammation contributes to obesity-induced insulin resistance and that statins have been reported to have other effects beyond cholesterol lowering, the present study aimed to investigate whether atorvastatin treatment has anti-inflammatory action in white adipose tissue of obese mice, consequently improving insulin sensitivity. Insulin sensitivity in vivo (by insulin tolerance test); metabolic-hormonal profile; plasma tumor necrosis factor (TNF)-α, interleukin (IL)-6, and adiponectin; adipose tissue immunohistochemistry; glucose transporter (GLUT) 4; adiponectin; TNF-α; IL-1β; and IL-6 gene expression; and IκB kinase (IKK)-α/β activity were assessed in 23-week-old monosodium glutamate-induced obese mice untreated or treated with atorvastatin for 4 weeks. Insulin-resistant obese mice had increased plasma triglyceride, insulin, TNF-α, and IL-6 plasma levels. Adipose tissue of obese animals showed increased macrophage infiltration, IKK-α (42%, P < .05) and IKK-β (73%, P < .05) phosphorylation, and TNF-α and IL-6 messenger RNA (mRNA) (∼15%, P < .05) levels, and decreased GLUT4 mRNA and protein (30%, P < .05) levels. Atorvastatin treatment lowered cholesterol, triglyceride, insulin, TNF-α, and IL-6 plasma levels, and restored whole-body insulin sensitivity. In adipose tissue, atorvastatin decreased macrophage infiltration and normalized IKK-α/β phosphorylation; TNF-α, IL-6, and GLUT4 mRNA; and GLUT4 protein to control levels. The present findings demonstrate that atorvastatin has anti-inflammatory effects on adipose tissue of obese mice, which may be important to its local and whole-body insulin-sensitization effects.     

肥胖小鼠脂肪组织缺氧对脂联素表达的转录抑制作用

目的观察缺氧对脂肪细胞脂联素mRNA和蛋白表达的影响,探讨肥胖小鼠脂肪组织缺氧导致脂肪组织脂联素表达下降的机制。方法采用实时定量聚合酶链反应（qRT—PCR）和蛋白免疫印迹法（Western blotting）检测遗传型肥胖小鼠（ob／ob,12周）和高脂饮食肥胖小鼠（HFD,53周）的附睾旁脂肪中脂联素mRNA和蛋白的表达;用小鼠3T3-L1脂肪细胞系为模型,采用RT—PCR和荧光素酶报告基因方法检测缺氧处理后脂联素和过氧化物酶体增殖物激活受体（PPAR）-mRNA的表达和稳定性、脂联素启动子的活性;用Western blotting和荧光素酶报告基因检测缺氧对PPAR-γ在核蛋白中集聚以及PPAR-γ转录因子活性的影响。组间数据比较采用t检验。结果（1）缺氧时两种肥胖小鼠的脂肪组织中脂联素mRNA和蛋白的表达均显著下降（P〈0．01）;333-L1脂肪细胞系在缺氧8h和24h后,脂联素mRNA表达量分别下降至0．65±0．05和0．29±0．05,较对照组（1．00±0．04）明显降低,差异有统计学意义（t=11．548、24．893,均P〈0．01）,但缺氧对脂联素mRNA的稳定性并没有影响;荧光素酶报告基因方法表明,脂联素启动子的活性受到缺氧的抑制。（2）在两种肥胖小鼠的脂肪组织中,PPAR-γmRNA和蛋白的表达均明显下降（P〈0．01）;小鼠333-L1脂肪细胞系在缺氧8h和24h后,PPAR- γmRNA的表达量分别下降至0．72±0．09和0．54±0．07,与对照组（1．00±0．09）相比,差异有统计学意义（t：5．134、9．876,均P〈0．01）;PPAR一1蛋白的核转位以及PPAR一^y转录因子活性也受到缺氧的抑制。结论肥胖小鼠脂肪组织缺氧抑制了脂联素的表达,抑制作用可能发生在转录水平;其机制可能是通过抑制PPAR-γmRNA的表达和PPAR-γ转录因子的活性而实现的。     

脱氧胆酸在酸性环境下促进正常食管鳞状上皮细胞表达BMP4

背景：骨形态发生蛋白4（BMP4）是Barrett食管（BE）上皮的标记性蛋白,可调节CDX2表达以及促进肠化生,但其在BE中表达上调的机制尚不明。脱氧胆酸（DCA）是BE发生的重要环境因素。目的：探讨DCA对正常食管鳞状上皮细胞BMP4及其第二信使Smad1表达的影响。方法：培养原代正常食管鳞状上皮细胞．采用不同浓度DCA与pH值酸处理细胞。分别以实时荧光定量聚合酶链反应（PCR）和蛋白质印迹法检测BMP4、Smad1 mRNA和蛋白表达。结果：DCA在酸性环境下可呈浓度依赖性地增强正常食管鳞状上皮细胞表达BMP4．同时100μmol／LDCA可促进Smad1表达,200μmol／LDCA的作用则相反。结论：DCA可能通过促进BMP4和BMP信号通路相关蛋白表达而参与BE的发生.     

The effect of limit feeding on thermogenesis and thermoregulation in genetically obese (ob/ob) mice during cold exposure

Thermogenesis and thermoregulation in ad-lib-fed and limit-fed lean (+/ob or +/+) and obese (ob/ob) mice during acute cold exposure were studied by measuring oxygen consumption and body temperature. No significant differences in oxygen consumption were found between the lean ad-lib, obese ad-lib- or obese limit-fed groups. The oxygen consumption of the lean-limit-fed group was decreased by 25-30 per cent compared with the other groups. The body temperature of the obese ad-lib-fed group fell at a rate of at least twice that of any other group. The weight, total cytochrome c oxidase activity and protein content of the brown adipose tissue (BAT) of the lean groups was similar, and there appeared to be little difference in cell size or fat content. The BAT of both obese groups showed a several-fold increase in weight, and a 50 per cent increase in total protein, compared with the lean groups. The limit-fed obese group showed a significant increase in cytochrome c oxidase activity compared with all other groups. The BAT cells of both obese groups were much enlarged and contained considerable amounts of fat. These observations indicate that the susceptibility of obese mice to hypothermia is not due to a reduced capacity for thermogenesis, but to a failure to conserve heat. Failure of thermoregulation in obese animals may be due to postural constraints that result in increased heat loss by radiation. The results are discussed in relation to the accredited role of BAT thermogenesis in rodents exposed to the cold.     

Acute and chronic regulation of ob mRNA levels by beta3-adrenoceptor agonists in obese Yellow KK mice.

The inhibitory effect of beta3-adrenoceptor agonists on the ob gene in brown adipose tissue (BAT) and white adipose tissue (WAT) is now well documented both in vivo in lean animals and in vitro, but the reported effects of beta3-adrenoceptor agonists on ob gene expression in obese animals remain controversial. We investigated whether ob gene expression in BAT and WAT is reduced by acute and chronic administrations of a beta3-adrenoceptor agonist, CL316,243 (CL). The ob gene mRNA levels in BAT, perimetric and inguinal WAT of obese Yellow KK mice were about 4-fold higher than those of lean controls. Acute exposure (6 h) to CL decreased ob gene mRNA levels in three fat depots in both animals. Chronic exposure (10 days) to CL also decreased ob gene mRNA levels in BAT, perimetric, and inguinal WAT in both animals. We concluded that acute and chronic regulation by a beta3-adrenoceptor agonist suppressed ob gene expression in obese Yellow KK mice and lean controls.     

Down-regulated STAT3 messenger ribonucleic acid and STAT3 protein in the hypothalamic arcuate nucleus of the obese leptin-deficient (ob/ob) mouse

Leptin is a weight-reducing hormone produced by adipose tissue, which reduces food intake via hypothalamic leptin receptors and the JAK-STAT signaling pathway. In vivo studies have shown that leptin activates specifically STAT3 in the hypothalamus. We have studied the cellular localization of STAT3 messenger RNA (mRNA) and STAT3 protein in the mouse mediobasal hypothalamus using, respectively, in situ hybridization and immunohistochemistry. Strong STAT3 mRNA and STAT3 immunoreactivity was demonstrated in neurons located in the ventral part of the mouse arcuate nucleus. Comparison of STAT3 mRNA levels in the arcuate nucleus of lean control mice and obese leptin-deficient ob/ob mice showed that the levels of STAT3 mRNA in the arcuate nucleus were significantly lower (31% less in ob/ob mice), compared with control mice. Hybridization with a probe specific for STAT3alpha mRNA showed that the down-regulated STAT3 expression in the arcuate nucleus of ob/ob mice is represented by STAT3alpha. There was a marked difference in numbers and intensity of STAT3-immunoreactive cell bodies, with virtually no STAT3-immunoreactive cell bodies in the mediobasal hypothalamus of ob/ob mice, compared with control mice. Direct double-labeling immunofluorescence histochemistry of sections from control mice, combining a goat antiserum raised against a peptide sequence present in all leptin receptor isoforms (Ob-R) or a guinea pig anti-serum generated to a peptide sequence specific for Ob-Rb with rabbit STAT3 antiserum, demonstrated colocalization of STAT3 and Ob-R as well as colocalization of STAT3 and Ob-Rb, in many cell bodies of the arcuate nucleus. The results suggest that circulating leptin acts via leptin receptor-/STAT3-containing neurons in the ventral arcuate nucleus and that congenital leptin deficiency, as seen in obese ob/ob mice, results in a down-regulation of STAT3 mRNA and protein levels.