Neuronal activation and corticotropin‐releasing hormone expression in the brain of obese (fa/fa) and lean (fa/?) Zucker rats in response to refeeding

The present study was conducted to investigate the pattern of neuronal activation and corticotropin‐releasing hormone (CRH) expression in fed, food deprived and refed lean (Fa/?) and obese (fa/fa) Zucker rats. The pattern of neuronal activation was studied by measuring the expression of the immediate‐early gene c‐fos. Expression of c‐fos and CRH mRNA was determined by in situ hybridization histochemistry. In both lean and obese rats, one hour of refeeding led to a transient increase in c‐fos mRNA levels which was detected in the paraventricular hypothalamic nucleus (PVH), the dorsomedial hypothalamic nucleus, the supraoptic nucleus, the paraventricular thalamic nucleus, the central nucleus of amygdala (CeA), the lateral and medial parabrachial nuclei, the nucleus of the solitary tract, and the area postrema. In addition, refeeding led to strong activation of the arginine‐vasopressin neurons located in the magnocellular part of the PVH. Following 24 h of food deprivation, CRH expression in the parvocellular division of the PVH was significantly higher in obese rats compared to lean animals. During refeeding, PVH CRH mRNA levels in obese rats decreased to reach control values. The decrease in CRH expression in obese rats was accompanied by the alleviation of the hypercorticosteronemia that characterized obese Zucker rats. CRH mRNA levels in the central nucleus of the amygdala were significantly higher in lean rats than in obese animals, when the rats were fed ad libitum During food deprivation, CeA CRH mRNA levels decreased in lean rats and gradually returned to predeprivation values during refeeding. In refed obese rats, CeA levels of CRH mRNA were higher than those of ad libitum fed or food‐deprived obese mutants. In the perifornical region of the lateral hypothalamic area (LHA), the expression of CRH mRNA rose significantly in response to refeeding in lean rats, but not in obese animals. Following the first hour of refeeding, the number of neurons expressing CRH mRNA in the LHA in lean rats almost doubled. The present results demonstrate that refeeding has a stimulating effect in obese Zucker rats in a pattern of activation similar to that seen in lean Fa/? rats. They also demonstrate differences in CRH expression between Fa/? and fa/fa rats after refeeding. The most apparent of these differences was seen in the lateral hypothalamus in which refeeding failed to up‐regulate CRH expression in obese rats.     

Endogenous histamine in the medial septum-diagonal band complex increases the release of acetylcholine from the hippocampus: a dual-probe microdialysis study in the freely moving rat

The effects of histaminergic ligands on both ACh spontaneous release from the hippocampus and the expression of c-fos in the medial septum-diagonal band (MSA-DB) of freely moving rats were investigated. Because the majority of cholinergic innervation to the hippocampus is provided by MSA-DB neurons, we used the dual-probe microdialysis technique to apply drugs to the MSA-DB and record the induced effects in the projection area. Perfusion of MSA-DB with high-KCl medium strongly stimulated hippocampal ACh release which, conversely, was significantly reduced by intra-MSA-DB administration of tetrodotoxin. Histamine or the H2 receptor agonist dimaprit, applied directly to the hippocampus, failed to alter ACh release. Conversely, perfusion of MSA-DB with these two compounds increased ACh release from the hippocampus. Also, thioperamide and ciproxifan, two H3 receptor antagonists, administered into MSA-DB, increased the release of hippocampal ACh, whereas R-alpha-methylhistamine, an H3 receptor agonist, produced the opposite effect. The blockade of MSA-DB H2 receptors, caused by local perfusion with the H2 receptor antagonist cimetidine, moderated the spontaneous release of hippocampal ACh and antagonized the facilitation produced by H3 receptor antagonists. Triprolidine, an H1 receptor antagonist, was without effect. Moreover, cells expressing c-fos immunoreactivity were significantly more numerous in ciproxifan- or thioperamide-treated rats than in controls, although no colocalization of anti-c-fos and anti-ChAT immunoreactivity was observed. These results indicate a role for endogenous histamine in modulating the cholinergic tone in the hippocampus.     

口服参芪扶正注射液对糖尿病大鼠肾脏的保护作用

 目的：探讨参芪扶正注射液对糖尿病大鼠肾脏的保护作用及其机制。方法：取60只健康雄性Sprague-Dawley种大鼠,腹腔内注射链脲佐菌素（60 mg·kg^-1）造成糖尿病模型,然后将其中32只大鼠给参芪扶正注射液200 mg·kg^-1·d^-1口服,共8周,同时取15只糖尿病大鼠和10只健康大鼠作对照。试验前后分别观察各组大鼠血压、尿蛋白、肾功能、血浆血管肾张素AngⅡ含量以及肾组织转化因子(TGF-β₁)、原癌基因c-fos的表达。结果：参芪扶正注射液可控制糖尿病肾脏体积的扩大、血压的升高,减少尿蛋白的排出,改善肾功能（BUN、Cr均下降）、降低血浆AngⅡ水平,与对照组相比差异均有显著或非常显著性。同时还可降低TGF-β₁、c-fos在肾组织中的表达,其灰度值测定与对照组相比差异具非常显著性(P＜0.01)。结论：参芪扶正注射液可通过改善血液循环,降低血浆AngⅡ水平,控制血压,改善肾小球的“三高状态”,从而抑制了ECM增生,以达保护肾功能,缓延肾小球硬化之目的。     

豚鼠形觉剥夺性近视视网膜早基因c-fos的动态表达

目的建立豚鼠形觉剥夺性近视(form-deprivationmyopia,FDM)动物模型,并对豚鼠形觉剥夺性近视形成及恢复过程中视网膜早基因c-fos的动态变化进行观察,研究豚鼠FDM中视网膜信号转导及抑制近视的可能分子机制。方法3周三色豚鼠40只,随机均分为4组:遮盖前组、单眼遮盖1周组、单眼遮盖2周组及去遮盖组。对各组进行视网膜检影和A超测眼轴,分别运用免疫组化和RT-PCR观察各组视网膜c-fos蛋白及mRNA的表达和变化。结果遮盖2周后,遮盖眼较对照眼呈高度相对近视(-8.8 D),视网膜c-fos表达明显下调,双眼屈光度、眼轴和视网膜c-fos的表达差异均有显著性(P<0.05);遮盖2周后,去遮盖1周,去遮盖眼较对照眼呈中度相对近视(-5.9 D),但去遮盖前后屈光度及眼轴差异无显著性(P>0.05),去遮盖眼较对照眼视网膜c-fos的表达明显上调,差异有非常显著性(P<0.01)。结论形觉剥夺能成功诱导豚鼠近视的发生及发展,并抑制视网膜c-fos的表达,而去除形觉剥夺可抑制近视的发展,并诱导视网膜c-fos的表达上调,证明c-fos的表达规律不仅反映外界视觉环境对眼的刺激,并与近视发展规律呈负相关,可能参与视网膜的信号转导和近视的抑制机制。     

haFGF和nm-haFGF过表达对乳腺肿瘤细胞增殖及c-fos、c-jun mRNA表达的影响

目的研究非促分裂人酸性成纤维细胞生长因子(non-mitogenetic human acidic fibroblast growth factor,nm-haF-GF)和人酸性成纤维细胞生长因子(haFGF)对恶性肿瘤细胞的增殖作用及其与对c-fos、c-jun mRNA表达的影响,探讨nm-haFGF在治疗神经系统疾病和心血管疾病等方面的临床应用安全性。方法构建细胞内真核表达载体pIRES/haF-GF、pIRES/nm-haFGF,分泌型真核表达载体pSectag/haFGF、pSectag/nm-haFGF。转染乳腺癌细胞MCF-7,Western blot鉴定细胞内及上清中aFGF的表达。用流式细胞技术分析细胞周期(G0/G1,S期,G2/M)。用半定量RT-PCR检测立早基因c-fos、c-jun mRNA的表达。结果nm-haFGF和haFGF在MCF-7细胞中能够过量表达。转染nm-haFGF组的S期和G2/M细胞比率与对照组差异无显著性,而转染haFGF组差异有显著性。转染haFGF后,c-fos、c-jun mRNA的表达明显升高,转染nm-aFGF后却与未转染组无差别。结论与haFGF相比,nm-haFGF消除了促肿瘤细胞增殖活性,基本不会诱导细胞c-fos、c-jun原癌基因的转录与表达。     

大鼠肝缺血/再灌注损伤时c-fos、Bcl-2在肝组织的表达及与肝细胞凋亡的关系

目的:观察大鼠肝缺血/再灌注损伤时c-fos、Bcl-2在肝组织中的表达及与肝细胞凋亡的关系,并探讨可能的机制。方法:选健康雄性Wistar大鼠48只,随机分为对照组、缺血30min组(I组)、缺血30min即刻再灌注组(I/R组)、缺血30min再灌注1h组(I/R1h组)、缺血30min再灌注2h组(I/R2h组)、缺血30min再灌注后4h组(I/R4h组),每组8只。应用免疫组化法分别测定各组大鼠肝组织c-fos、Bcl-2的表达,应用原位细胞凋亡法测定肝细胞凋亡的情况,同时观察肝脏组织病理变化。结果:肝脏I/R可出现肝细胞明显损伤、肝细胞水肿、炎性细胞浸润,甚至有细胞坏死。与对照组比较,cfos在I组表达就有增高(P<0.01),I/R4h组达到高峰。I/R组与I组、I/R4h组与I/R2h组相比差异有统计学意义(P<0.01)。肝组织Bcl2在I组表达增高(P<0.01),I/R2～4h达到高峰。I/R4h组与I/R2h组相比差异无统计学意义(P>0.01)。细胞凋亡指数:I组、I/R组与对照组比较明显增加(P<0.01),随着时间的延长细胞凋亡指数逐渐增加。c-fos与细胞凋亡指数呈正相关(r=0.889,P<0.01),Bcl-2与细胞凋亡指数呈正相关(r=0.901,P<0.01)。结论:肝缺血/再灌注损伤可引起肝组织的损伤及肝细胞凋亡。肝细胞凋亡与cfos的表达有关。Bcl2在缺血期发挥了其抑凋亡作用,随着再灌注时间的延长,其抑凋亡作     

艾灸对实验性类风湿关节炎滑膜细胞原癌基因 c-fos和c-myc mRNA表达的影响

目的观察艾灸对实验性类风湿关节炎滑膜细胞原癌基因c-fos、c-myc mRNA表达的影响,初步探讨艾灸对RA滑膜细胞内分子信号传导的调控.方法在日本大耳白兔右后足踝关节部皮内注射福氏完全佐剂造模,经过艾灸治疗,通过半定量RT-PCR测定c-fos和c-myc mRNA的表达量.结果治疗组c-fos和c-myc mRNA表达量显著低于造模组(P＜0.01).结论艾灸治疗能够降低c-fos和c-myc mRNA的表达,影响生长因子信号传导系统.     

缺血预处理对大鼠肝缺血再灌注后即早基因c-fos、c-jun表达的影响

目的观察缺血预处理对大鼠肝缺血再灌注后即早基因c-fos、c-jun表达的影响。方法采用大鼠原位部分缺血再灌注模型,96只SD大鼠随机分为缺血再灌注组(IR),缺血预处理组(IPC),每组又分为8个亚组(n=6),于复灌后0、0.5、1、2、4、8、12和24h取材,应用RT-PCR法检测各组c-fos、c-junmRNA的表达,流式细胞仪检测Ki67和Sub-G1。结果与IR组相比,IPC组血清ALT、AST在复灌后的0.5￣8h组明显降低(P<0.05);Ki67在复灌后的0.5、1和2h明显升高,24h明显降低(P<0.05);Ap指数在复灌后的1h以上明显降低(P<0.05);IPC组c-fos和c-junmRNA的表达较IR组低,其中c-jun在0.5、1和2h组明显降低(P<0.05)。结论缺血预处理能有效地保护肝脏免受缺血再灌注造成的损伤,这种保护效应的机制可能与影响即早基因的转录有关。     

星状神经节阻滞后福尔马林诱导的伤害行为反应和间脑c-fos表达

目的　研究星状神经节阻滞 (SGB)后福尔马林诱导的家兔伤害行为反应和间脑c -fos表达。方法　在家兔星状神经节附近置入导管 ,一周后 ,选择恢复健康者 2 4只随机分为三组 :假手术组 (A组 )、SGB组 (B组 )和对照组 (C组 ) ,每组 8只。B和C组在右前肢足底皮下注射 3 %福尔马林 0 5ml致痛 ,A组同样部位注射等量生理盐水。致痛前 10min ,B组经导管给 0 2 5 %布比卡因0 5ml ,A和C组给等量生理盐水。致痛 2h ,灌注固定 ,取左右侧间脑。采用加权法对伤害行为反应评分 ,免疫组化法测间脑c -fos表达。结果　SGB后福尔马林诱导的Ⅱ期伤害行为反应明显缓解 ;B组下丘脑c -fos表达明显少于C组 (P <0 0 1) ,而B组与C组丘脑c -fos表达无显著性差异 (P >0 0 5 )。结论　SGB可减轻福尔马林诱导的Ⅱ期伤害行为反应 ,降低下丘脑c -fos表达 ,这可能与其治疗炎症痛的机制有关。     

应激启动下丘脑-垂体-肾上腺轴信号转导机制的实验研究

目的以束缚应激大鼠作为应激研究模型,探讨应激后下丘脑内信号转导分子的变化。方法用Western印迹杂交法研究了应激大鼠下丘脑内c-fos的蛋白表达和p38MAPK的磷酸化情况。结果Western印迹杂交结果显示束缚应激后鼠下丘脑内磷酸化的p38MAPK明显增加,与对照组相比具有非常显著性差异(P<0.01),应激解除后1、3h磷酸化的p38MAPK仍然保持较高的水平(P<0.05),但是应激解除后3h较应激刚结束时下丘脑内磷酸化p38MAPK的水平明显回落(P<0.05);应激后下丘脑内c-fos蛋白表达同样明显增加,与对照组相比具有显著性差异(P<0.01)。应激解除后0、1、3h,c-fos蛋白的表达仍然保持较高的水平(P<0.05)。结论应激发生后,其下丘脑内p38MAPK磷酸化的时相、c-fos蛋白表达时相以及血浆内皮质酮浓度时相具有类似之处,p38MAPK磷酸化、c-fos蛋白很可能是HPA轴活动的上游分子信号。