从足细胞相关分子的研究认识足突融合现象

在伴有大量蛋白尿的人类肾病和肾病动物模型中，足突融合是最主要和最常见的形态改变，同时也是一些疾病（如微小病变肾病）的特征性形态改变。因此，早在1957年就关注对足突融合形态结构和足突融合机制的研究。一方面，一些免疫因素、生化因子以及血流动力学改变参与足突融合过程，另一方面，足突的负电荷屏障、足突与基膜之间的相互作用以及足突的细胞骨架改变可能与足突融合密切相关。     

嘌呤霉素肾病鼠尿蛋白量与足突形态改变的关系

目的 :研究嘌呤霉素肾病大鼠尿蛋白排出量与肾小球上皮细胞足突的形态变化之间的相互关系 ,初步探讨蛋白尿的发生机制。　 方法 :30只SD大鼠随机分为实验组和对照组 ,在 2天、5天、10天、15天、2 0天 5个不同时间点应用双缩脲法测定大鼠 2 4h尿蛋白排出量 ,并用透射电镜摄片 ,图像分析及形态计量学的方法 ,研究大鼠在不同时间点的足突形态变化 ,进而分析尿蛋白排出量与足突形态改变之间的相互关系。　 结果 :① 2 4h尿蛋白定量结果示 ,注药 5天后尿蛋白排出量逐渐增多 ,10天时尿蛋白排出量与对照组差异非常显著 (P <0 0 1) ,15天时尿蛋白排出量恢复 ,与 10天比差异亦非常显著 (P <0 0 1) ,且与对照组相比差异仍显著 (P <0 0 5 ) ,至 2 0天尿蛋白排出量与对照组无差别 (P >0 15 )。②注射嘌呤霉素后 ,足突形态呈现逐渐肿胀到融合以后又逐渐呈恢复的变化 ,其中 2～ 2 0天实验组足突宽度 ,体积密度 ,比表面与对照组相比差异有高度显著性 (P <0 0 1) ,表面积密度在2～ 15天与对照组差异显著 (P <0 0 5 ) ,各参数均于 10天达极值。③尿蛋白排出量与足突宽度正相关 (r =0 92 94,P =0 0 2 ) ,与体积密度成正相关 (r =0 95 5 9,P =0 0 11) ,而与比表面呈负相关 (r=- 0 9388,P =0 0 18)。　 结论 :尿     

氟伐他汀改善嘌呤霉素作用下足细胞β1整合素的表达

目的:探讨氟伐他汀(FLV)对嘌呤霉素(PAN)刺激下足细胞黏附分子β1整合素表达的影响及可能机制。方法:体外培养的永生化人足细胞分为以下四组:(1)正常对照组;(2)二甲基亚砜(DMSO,1mg/ml)对照组;(3)PAN(1.0μg/ml)组:PAN分别培养足细胞12h、24h、48h、72h;(4)PAN(1.0μg/ml)+FLV(1×10-8～1×10-5M)组,PAN分别与不同浓度FLV共同培养足细胞48h。用Western印迹和DCFHDA(2’,7’-二氯荧光素-3’,6’-二乙酸酯)分别检测以上四组足细胞β1整合素和活性氧簇(reactive oxygen species,ROS)的表达。噻唑蓝[3-(4,5-二甲基-2-噻唑)-2,5-二苯基溴化四唑,简称MTI]法检测足细胞活力。结果:与正常对照组相比,PAN分别作用24h、48h、72h后,β1整合素表达逐渐下降、ROS表达则明显升高(P<0.05)。FLV干预后,β1整合素表达水平升高、ROS表达水平下降,以FLV浓度为1×10-7M作用48h效果最明显(P<0.05)。相关性分析发现,PAN组以及PAN+FLV组足细胞β1整合素水平与细胞内ROS表达水平成负相关。MTT结果表明DMSO以及FLV浓度为1×10-8M和1×10-7M对足细胞的存活无明显影响(P>0.05),而FLV浓度为1×10-6M和1×10-5M、PAN组、PAN+FLV组,在24h均明显抑制足细胞的活力(P<0.05)。与PAN组相比,PAN与FLV1×10-7M共同作用48h足细胞活力有明显的改善(P<0.05)。结论:PAN可致体外培养足细胞的β1整合素表达下降,FLV上调β1整合素的表达,保护足细胞。此机制与FLV抑制足细胞内ROS的表达相关。     

足细胞与糖尿病肾病关系的若干研究进展

足细胞在维持肾小球滤过屏障完整性及限制血浆蛋白的滤出方面发挥重要作用,足细胞的损伤可部分解释肾小球滤过屏障结构及功能的改变的原因。在糖尿病肾病早期,足细胞损伤已出现,并可进一步导致。肾脏损伤。本文就足细胞与糖尿病肾病中若干研究进展作简要综述。     

雷公藤甲素对嘌呤霉素模型足细胞病变的影响

目的：研究雷公藤甲素对非免疫因素介导的、单纯足细胞病变模型——嘌呤霉素氨基核苷（PAN）肾病模型的疗效及其对足细胞病变的影响。方法：采用PAN单次颈静脉注射法建立PAN肾病模型。大鼠分为正常对照组，模型组，雷公藤甲素预防组和治疗组。分别在1天、3天、5天、10天、14天和21天收集血尿标本，并处死大鼠留取肾组织标本。检测24h尿蛋白排泄量、血生化指标，行肾组织光镜和电镜观察肾小球病变和足突超微结构。采用定量学方法测定足突宽度。免疫荧光染色观察足细胞裂孔膜分子Nephrin和Podocin表达和分布变化。结果：雷公藤甲素无论是预防还是治疗性用药均能明显改善PAN肾病大鼠的肾病综合征状况，明显减少尿蛋白，加快血清白蛋白回升和血脂水平恢复。与此同时，雷公藤甲素预防组和治疗组大鼠在各观察点足突融合程度和范围均比PAN肾病大鼠明显减轻，至第14天仅见少数足突融合，第21天足突形态已基本恢复正常。雷公藤甲素预防性和治疗性用药均能够增加足细胞裂孔膜分子Nephrin和Podocin表达，促进其分布异常的修复。在第10天，Nephrin和Podocin不仅表达较PAN肾病大鼠明显增多，而且大部分血管袢已开始呈现连续的线状分布，以Podocin更为明显；两者的表达和分布在第14天已基本恢复，至第21天已完全恢复正常。结论：雷公藤甲素对PAN导致的足细胞损伤模型具有明显的预防和治疗作用，表现为减少蛋白尿，改善足突融合，恢复足细胞相关蛋白的表达及其分布，逆转足细胞病变。     

山茱萸颗粒对糖尿病肾病大鼠足细胞podocin表达的影响

利用单侧肾切除加STZ注射法改良复制糖尿病肾病大鼠模型,分为正常组、模型组、治疗组(山茱萸颗粒高、中、低剂量组及缬沙坦对照组),RT-PCR法检及免疫组化法检测podocin mRNA及蛋白的表达。结果:治疗组肾组织podocinmRNA含量显著升高,podocin蛋白的表达有一定程度提高。与模型对照组相比,差异有显著统计学意义(P<0.05或P<0.01)。结论:山茱萸颗粒可用于治疗早期糖尿病肾病,其机制可能与其调节肾脏足细胞podocin蛋白表达有关。     

尿足细胞相关标记物在糖尿病肾病领域的研究进展

足细胞是一种高度特异性终末分化细胞,其损伤与糖尿病肾病(DN)进展密切相关,尿足细胞相关标记物检测有望成为一项DN早期诊断的无创伤性指标。尿液中完整足细胞以及足细胞碎片的定量主要是通过标记足细胞特异蛋白、mRNA及mi-RNA,其检出的阳性率及准确性有赖于各种定量方法的完善。探寻一种灵敏度高、操作简便且成本低廉的检测方法是目前尿足细胞标记物检测应用于DN早期临床诊断所亟待解决的问题。本文重点介绍了尿足细胞相关标志蛋白、mRNA、mi-RNA及胞外体等在该研究领域的新进展,并分析目前存在的问题及发展前景。     

肾小球足细胞synaptopodin和WT-1表达水平与糖尿病肾病患者肾脏损害的关系

目的 观察synaptopodin和WT-1在糖尿病肾病患者肾脏组织内的表达水平,探讨其对糖尿病肾病进展的影响.方法 选取1998年1月至2005年9月经解放军二八一医院确诊的35例糖尿病肾病患者,收集肾脏组织标本,根据病理变化分为弥漫性系膜硬化组(n=20)和结节性硬化组(n=15),另以7例肾脏肿瘤患者瘤旁肾脏组织为对照.应用间接免疫荧光双标记和激光共聚焦显微镜技术检测肾脏组织内synaptopodin和WT-1表达水平.收集患者肾脏活检前24h尿蛋白定量、血肌酐、评估的肾小球滤过率等临床资料.采用单因素方差分析、q检验、t检验、直线相关分析进行数据统计.结果 结节性硬化组与弥漫性系膜硬化组比较,24 h尿蛋白定量和血肌酐升高[24 h尿蛋白定量分别为(3.7±0.9)、(5.6 ±1.6)g,/24 h,t=4.177,P<0.05;血肌酐分别为(92±20)、(135±45)vmol/L,t=10.455,P<0.05] ,评估的肾小球滤过率降低[分别为(65±19)、(53±24)ml/min,t=8.921,P<0.05] .与对照组相比,糖尿病肾病患者肾组织内足细胞数量(F=4.06,P<0.05)、synaptopodin(F=3.79,P<0.05)、WT-1表达显著减少(F=5.68,P<0.05),结节性硬化组较弥漫性系膜硬化组减少更为显著(q值分别为5.80、6.42、5.35,均P<0.05).糖尿病肾病患者synaptopodin 和WT-1表达与24 h尿蛋白定量呈负相关(相关系数分别为-0.64、-0.71,均P<0.05),与评估的肾小球滤过率呈正相关(相关系数分别为0.57、0.62,均P<0.05).结论 糖尿病肾病患者肾小球内synaptopodin和WT-1表达降低,并且与肾脏损害临床指标存在相关性,提示足细胞损伤可能为糖尿病肾病进展的原因之一.     

足细胞损伤与糖尿病肾病

糖尿病肾病(diabetic nephropathy,DN)是糖尿病的主要并发症。1936年Kimmelstiel等[1]第一次描述DN时,系膜基质增多和肾小球基底膜(glomerular basement mem-brane,GBM)增厚就被描述为DN的主要病理表现。研究也证实,系膜增生与蛋白尿、肾功能恶化密切相关。但是,系膜增生并不能解释蛋白尿的发生,因为由肾小球内皮细胞、GBM、足细胞构成的肾小球滤过屏障的损伤才是蛋白尿的根源。事实上,肾小球内皮细胞和GBM参与了DN蛋白尿的发生,但两者均是有孔的,均允许某些蛋白通过[2]。因此,足细胞构成了蛋白滤过的最后一道屏障,但其在DN中的生物…     

依普利酮对急性肾病大鼠尿蛋白含量及肾小球足细胞标记蛋白表达的影响

目的：观察依普利酮对急性肾病大鼠尿蛋白含量及肾小球足细胞标记蛋白表达的影响,探讨其肾脏保护机制。方法采用随机数字表法将32只SD大鼠分为对照组（C组）、模型组（M组）和干预组（E组）,后两组均单次腹腔注射嘌呤霉素氨基核苷（ PAN）制备急性肾病模型,C组注射等体积生理盐水。造模后第3天开始,E组予依普利酮灌胃,余两组给予等量蒸馏水灌胃,均连续2周。期间每天测定24 h尿蛋白定量;实验结束后麻醉大鼠,自心脏抽取血液检测血清白蛋白（Alb）、总胆固醇（TC）及尿素氮（BUN）、肌酐（Cr）;大鼠左心室灌注生理盐水,留取肾组织于光镜和电镜下观察形态学改变,实时定量PCR法和Western blotting法检测Nephrin蛋白和mRNA,免疫荧光法检测Podocin、Podocalyxin蛋白表达。结果实验第7～14天,M组和E组24 h尿蛋白定量均高于C组,但E组低于M组（P均＜0．05）;M组和E组血清Alb均显著低于C组,TC、BUN、Cr均高于C组（P均＜0．05）。光镜下M组和E组符合微小病变肾病（ MCD）病理表现;电镜下M组足突广泛融合、消失,局部基底膜裸露,E组较之超微结构改善、仍有足突融合。 M组、E组的Podocin及Podocalyxin 蛋白、Nephrin蛋白及mRNA表达均明显低于C组,尤以M组为著（ P均＜0．05）。结论依普利酮能够明显减少PAN肾病大鼠的尿蛋白,可能机制为上调足细胞标记蛋白表达和活性。     

雷公藤甲素干预足细胞病变的体外观察

目的：雷公藤甲素对Heymann肾炎和嘌呤霉素肾病大鼠的疗效及其对足细胞病变的影响提示，雷公藤甲素有可能直接作用于足细胞，从而改善其病变状况。本研究借助小鼠足细胞系，体外观察了雷公藤甲素对足细胞损伤的保护和修复作用，并对其作用机制进行了研究。方法：体外采用氨基核苷嘌呤霉素（puromycin aminonucleoside，PAN）致足细胞损伤模型。观察雷公藤甲素对足细胞损伤的保护作用研究中，雷公藤甲素与足细胞预孵育30min后，再加入含PAN的培养基，继续作用24h；观察雷公藤甲素对足细胞损伤的修复作用研究中，PAN作用足细胞24h，造成足细胞明显损伤后，再加入含或不含雷公藤甲素的培养基，继续培养3天。免疫荧光法和流式细胞仪分析足细胞骨架相关蛋白F-actin和Synaptopodin的变化，并进一步观察了细胞内调节骨架装配的Rho／ROCK信号通路的活性，即采用Western Blot检测ROCK-Ⅰ底物——肌球蛋白磷酸酶结合亚单位（MBS）磷酸化水平，以及Rho／ROCK信号通路选择性阻断剂Y-27632对雷公藤甲素作用的影响。同时采用免疫荧光法和流式细胞仪分析足细胞裂孔膜相关分子Nephrin和Podocin在足细胞的分布及表达量的变化。结果：正常分化足细胞F—actin呈丝状结构，密度大，丝强劲有力，沿细胞极性分布；Synaptopodin呈颗粒状沿细胞骨架分布。裂孔膜蛋白Nephrin沿足细胞膜和细胞骨架分布，Podocin呈线状均匀分布于胞浆内，PAN作用24h后，细胞足突回缩，F—actin几乎完全解聚，Synaptopodin表达消失。Nephrin和Podocin表达减弱，正常丝状结构消失。而经过雷公藤甲素的预处理，PAN诱导的足细胞损伤明显减弱，足细胞未表现出上述骨架结构的改变，Synaptopodin表达没有明显减弱。同时我们的结果显示，在PAN造成足细胞明显损伤后再加入雷公藤甲素，足细胞损伤能够得到一定修复，细胞内重新出现极性分布的微丝，同时，Synaptopodin的表达也得以修复。Rho／ROCK信号通路研究显示，100μg／ml PAN明显降低Rho／ROCK通路活性。雷公藤甲素能有效遏制MBS磷酸化水平的降低，维持足细胞Rho／ROCK通路的活性状态。Rho／ROCK信号通路选择性抑制剂Y-27632可阻断雷公藤对足细胞骨架结构的保护作用。此外，对裂孔膜蛋白Nephrin，Podocin的研究表明，不论是在预防组和治疗组，PAN对Nephrin和Podocin的损伤可在一定程度上被雷公藤甲素预防和修复。结论：雷公藤甲素可稳定足细胞的细胞骨架，拮抗PAN对足细胞的损伤。在足细胞损伤已经发生后，雷公藤甲素可逆转足细胞的损伤，修复足细胞骨架结构和相关分子的表达。雷公藤甲素的上述作用与细胞内Rho／ROCK信号通路密切相关。雷公藤甲素对足细胞的影响可能是其降低肾小球肾炎患者尿蛋白的重要机制之一。     

不规则趋化蛋白在嘌呤霉素氨基核苷肾病模型中的表达

目的：检测CX3C族趋化因子不规则趋化蛋白(fractalkine,Fkn)在嘌呤霉素氨基核苷(puromycin aminonucleoside，PAN)肾病中的表达，进一步阐明肾病的发病机制，为肾病的治疗提供新的靶点。方法：从Wistar大鼠的颈静脉给予PAN，对照组给予等量生理盐水，在不同的时间点观察PAN引起的尿蛋白改变和肾脏炎性细胞浸润情况，并于第l、3、5、7、10天处死动物，制作肾组织匀浆和冰冻切片，分别用于RT-PCR和免疫组化研究，观察在：PAN注射的不同时间点肾组织中Fkn mRNA和蛋白质的表达情况；同时在体外用白介素-1β（IL-1β）刺激培养的肾小管上皮细胞观察Fkn的表达。结果：：PAN注射后第5天尿蛋白开始升高，持续增加直至第10天，同时伴有肾间质中CD4^ T细胞，CD8^ T细胞和单核／巨噬细胞的增加。RT-PCR和免疫组化均显示Fkn在第7、第10天表达升高，第3天主要分布在肾小球，以后主要在肾小管上皮细胞表达。用IL-1β刺激后1h体外培养的肾小管上皮细胞即开始表达FknmRNA，在4～6h达到高峰。结论：本文首次观察到Fkn在PAN肾病模型中表达增高，其特征为先出现于肾小球，后移行至肾小管，并早于肾组织中白细胞浸润及蛋白尿的发生。提示：Fkn可能是肾病发病和进展过程中的另一重要的相关分子。     

Costimulatory and coinhibitory molecules of B7-CD28 family in cardiovascular atherosclerosis: A review

Accumulating evidence supports the active involvement of vascular inflammation in atherosclerosis pathogenesis. Vascular inflammatory events within atherosclerotic plaques are predominated by innate antigen-presenting cells (APCs), including dendritic cells, macrophages, and adaptive immune cells such as T lymphocytes. The interaction between APCs and T cells is essential for the initiation and progression of vascular inflammation during atherosclerosis formation. B7-CD28 family members that provide either costimulatory or coinhibitory signals to T cells are important mediators of the cross-talk between APCs and T cells. The balance of different functional members of the B7-CD28 family shapes T cell responses during inflammation. Recent studies from both mouse and preclinical models have shown that targeting costimulatory molecules on APCs and T cells may be effective in treating vascular inflammatory diseases, especially atherosclerosis. In this review, we summarize recent advances in understanding how APC and T cells are involved in the pathogenesis of atherosclerosis by focusing on B7-CD28 family members and provide insight into the immunotherapeutic potential of targeting B7-CD28 family members in atherosclerosis.     

Proton-coupled electron transfer and the role of water molecules in proton pumping by cytochrome c oxidase

Molecular oxygen acts as the terminal electron sink in the respiratory chains of aerobic organisms. Cytochrome c oxidase in the inner membrane of mitochondria and the plasma membrane of bacteria catalyzes the reduction of oxygen to water, and couples the free energy of the reaction to proton pumping across the membrane. The proton-pumping activity contributes to the proton electrochemical gradient, which drives the synthesis of ATP. Based on kinetic experiments on the O–O bond splitting transition of the catalytic cycle (A → P_R), it has been proposed that the electron transfer to the binuclear iron–copper center of O₂ reduction initiates the proton pump mechanism. This key electron transfer event is coupled to an internal proton transfer from a conserved glutamic acid to the proton-loading site of the pump. However, the proton may instead be transferred to the binuclear center to complete the oxygen reduction chemistry, which would constitute a short-circuit. Based on atomistic molecular dynamics simulations of cytochrome c oxidase in an explicit membrane–solvent environment, complemented by related free-energy calculations, we propose that this short-circuit is effectively prevented by a redox-state–dependent organization of water molecules within the protein structure that gates the proton transfer pathway.Life on Earth is supported by a constant supply of energy in the form of ATP. Cytochrome c oxidase (CcO) in the respiratory chains of mitochondria and bacteria catalyzes the exergonic reduction of molecular oxygen (O₂) to water and uses the free energy of the reaction to pump protons across the membrane (1–3). The oxygen reduction reaction takes place at a highly conserved active site formed by two metal sites, heme a₃ and Cu_B (Fig. 1 A and B), called the binuclear center (BNC). The electrons donated by the mobile electron carrier cytochrome c reach the BNC via two other conserved metal centers, Cu_A and heme a (Fig. 1A). The protons required for the chemistry of O₂ reduction to water, and for proton pumping, are transported with the assistance of side chains of polar amino acids and conserved water molecules in the protein interior (4–6) (Fig. 1A). Two such proton transfer pathways have been described in the mitochondrial and bacterial A-type oxidases (to distinguish between different types of oxidases, see ref. 7), namely, the D and K channels (8, 9), the names of which are based on the conserved amino acid residues Asp91 and Lys319, respectively (Fig. 1A, amino acid numbering based on the bovine heart CcO). The D channel is responsible for the translocation of all of the pumped protons, and for the transfer of at least two of the four protons required for oxygen reduction chemistry, whereas the K channel supplies one or two protons to the BNC during the reductive phase of the catalytic cycle (8, 9). The D channel terminates at a highly conserved glutamic acid residue, Glu242, from where the protons are either transferred to the BNC for consumption, or to the proton-loading site (PLS) for pumping across the membrane (Fig. 1A). In 2003, Wikström et al. postulated a molecular mechanism in which water molecules in the nonpolar cavity above Glu242 would form proton-transferring chains, the orientation of which depends upon the redox state of the enzyme (10). They proposed that the reduction of the low-spin heme would result in transfer of a proton via a preorganized water chain from Glu242 to the d-propionate (Dprp) of the high-spin heme, whereas in the case when the electron has moved to the BNC, the water chain would reorientate and conduct protons from Glu242 to the BNC (Fig. 1A, and see below). Even though there is little direct experimental support available for such a water-gated mechanism, a recent FTIR study indeed suggests changes in water organization upon changes in the redox state of the enzyme (11). Many of the elementary steps that were postulated in the water-gated mechanism have gained support from experiments in the recent past (12, 13).Open in a separate windowFig. 1.(A) A three-subunit (SU) CcO. SU I (blue), II (red), and III (orange) are displayed as transparent ribbons. The D and K channels of proton transfer are marked with blue arrows. Crystallographic water molecules present in these proton channels are shown in purple. Electron transfer (red arrow) takes place from Cu_A (orange) via heme a (yellow) to the binuclear center comprising heme a₃ (yellow)–Cu_B (orange). Protons are transferred from Glu242 (E242) either to the PLS or to the binuclear center (black arrows). Lipid bilayer (silver lines), water (gray dots), and sodium (light yellow) and chloride (cyan) ions are also displayed. (B) The catalytic cycle of CcO. The states of heme a₃, Cu_B, and the cross-linked tyrosine are displayed. Each light orange rectangle corresponds to a state of the BNC, the name of which is displayed in red (Upper Right). Pumped protons are shown in blue, black H⁺ indicates uptake of a proton for water formation, and e⁻ indicates transfer of an electron from the low-spin heme a. Catalysis of O₂ reduction occurs clockwise.It is generally thought that the proton pump of CcO operates via the same mechanism in each of the 4 one-electron reduction steps of the catalytic cycle (Fig. 1B). However, kinetic data on two different transitions (A → P_R and O_H → E_H) have suggested dissimilarities in some of the elementary steps (12, 13). Fully reduced enzyme reacts with oxygen and forms an oxygenated adduct A in ca. 10 µs, followed by splitting of the O–O bond leading to formation of the P_R intermediate (in ∼25 μs) that is linked to loading of the PLS with a proton (3, 12). O–O bond splitting from state A in the absence of electrons in heme a or Cu_A yields the stable state P_M without proton transfer to the PLS (3, 12). Therefore, it is the electron transfer from heme a into the BNC accompanying O–O bond scission during A → P_R that is linked to the proton transfer to the PLS. The structure of the P_R intermediate is well characterized with ferryl heme a₃, cupric hydroxide, and tyrosinate (3, 14). In P_M the tyrosine is almost certainly in the form of a neutral radical (3, 14), so the reaction P_M → P_R is a proton-coupled electron transfer reaction (PCET) that initiates the reactions of the proton pump (3, 12). Note that in the state P_R the proton at the PLS partially neutralizes the electron in the BNC (3) in accordance with the charge-neutralization principle of the BNC (15). However, an important question arises: how can proton transfer from Glu242 to the BNC be prevented, which would short-circuit one step of proton pumping and form the next stable intermediate F? In the O_H → E_H transition of the catalytic cycle this short-circuit is minimized because reduction of the low-spin heme is thought to raise the pK_a of the PLS sufficiently to lead to its protonation before transfer of the electron to the BNC (3, 10, 13, 16–18), and uncompensated proton transfer to the BNC is endergonic in nature (refs. 13,16,17; cf. ref. 19). In contrast, the likelihood of a proton leak in the A → P_R transition increases manifold because the electron transfer from heme a to the BNC is required for loading of the PLS with a proton (3, 12). This facet is analyzed in the current work, and it is proposed that it is the orientation of the water molecules in the nonpolar cavity above Glu242 that effectively gates the pump and minimizes such a short-circuit.     

胰岛素抵抗大鼠血清淀粉样蛋白A、主动脉抵抗素样分子α的表达及运动干预作用

目的观察胰岛素抵抗（IR）大鼠血清淀粉样蛋白A（SAA）含量、主动脉抵抗素样分子α（RELMα）表达情况以及游泳运动干预后上述指标的变化。方法6～8周龄体重160—200gWistar雄性大鼠30只,采用随机数字表法分为正常对照组（A组）和IR组（B组）、运动组（C组）各10只,正常对照组给予普通饲料喂养,后两组大鼠均给予高脂高糖饮食喂养,8周后经计算稳态模型IR指数（HOMA-IR）确认IR大鼠造模成功后,继续给予原饮食喂养8周,C组同时进行8周游泳运动。16周末测量各组大鼠体重、空腹血糖（FBG）、空腹胰岛素（FINS）、甘油三酯（TG）、总胆固醇（Tc）、高密度脂蛋白胆固醇（HDL—C）及低密度脂蛋白胆固醇（LDL-C）、RELMα、血清淀粉样蛋白A（SAA）、HOMA-IR;苏木精一伊红（HE）染色观察各组主动脉形态学变化。各组间计量资料比较采用单因素方差分析。结果与正常对照组相比,IR组大鼠体重、FBG、FINS、HOMA—IR、TC、TG、LDL—C、SAA、RELM（x水平均明显升高,差异均有统计学意义（t=-20．666～-3．681,均P〈0．05）,HDL—C明显降低,泡沫细胞数明显增多,差异有统计学意义（t=8．950、-20．596,P〈0．05）,IR组主动脉内皮排列紊乱、内膜增厚;运动组干预后SAA、RELMα、体重、FBG、FINS、HOMA．IR、TC、TG、LDL—C均较IR组明显下降,差异均有统计学意义（t=2．524～8．640,均P〈0．05）,相应泡沫细胞聚集程度减轻（t=11．520,P〈0．05）。结论RELMα、SAA与IR、主动脉炎症关系密切;运动能降低SAA、RELMα水平及泡沫细胞聚集程度,对改善IR、减轻IR大鼠主动脉炎症反应具有重要意义。