以线粒体通透性转换孔为靶点的脓毒症器官功能保护研究进展

脓毒症是由宿主对感染的反应失调引起的危及生命的器官功能障碍。对于脓毒症的治疗主要是抗感染、抗休克、维持机体组织器官灌注等。但近年来,在对脓毒症诱导的组织器官功能障碍的研究中发现,脓毒症时出现多器官功能障碍的原因不仅在于组织器官的缺血缺氧,而且与线粒体通透性转换孔(mitochondrial permeability transition pore, MPTP)异常开放等机制引起的线粒体功能障碍也有很大关系。本综述主要介绍了MPTP的组成、脓毒症时其异常开放对器官功能的影响,以及作为治疗靶点的应用前景。旨在为脓毒症的器官功能保护研究提供方向。     

高氧性细胞凋亡与急性肺损伤

自从Blodgett于120年前首次报道用持续给氧来辅助治疗肺炎以后,氧气已经成为了医学上最常用的药物之一[1]。作为一个有药理学定义的药物,临床医生大多对使用氧气的指征有普遍的认识,却往往对氧气尤其是过度氧疗的毒性作用认识不足[2]。事实上,高浓度的氧气对肺组织可造成明确的毒性作用,而最典型的就是急性肺损伤(acute lung     

人脐带间充质干细胞移植对脓毒症小鼠的保护作用研究

为了评价人脐带间充质干细胞(human umbilical cord mesenchymal stem cells,h UCMSCs)移植对脓毒症小鼠的疗效,作者将90只小鼠随机均分为3组:假手术(Sham)组、PBS治疗组和h UC-MSCs治疗组。治疗组小鼠采用盲肠结扎穿孔(cecal ligation and puncture,CLP)方式建立脓毒症模型;假手术组小鼠仅开腹探查盲肠,不行CLP。Sham组和PBS治疗组术后3h经尾静脉注射0.2mL PBS,hUC-MSCs治疗组注射等体积的h UC-MSCs悬液(含细胞7.5×10~5/mL)。术后24 h,流式细胞术检测各组小鼠外周血及腹腔灌洗液(peritoneal lavage fl uid,PLF)中的中性粒细胞数量,ELISA检测血清炎症因子水平,生化检验评价肝肾功,HE(hematoxylin and eosin)染色评估肝、肾、肺组织病理变化。观察术后小鼠一般情况,绘制120 h生存曲线。结果显示,hUC-MSCs可以显著改善脓毒症小鼠一般状况,减少中性粒细胞浸润,降低小鼠体内炎症水平,改善器官功能,减轻组织器官损伤,显著提高小鼠存活率。该研究显示了人脐带间充质干细胞移植对脓毒症小鼠的良好保护作用。     

S- 腺苷蛋氨酸在肝病患者中抗抑郁作用的研究进展

S-腺苷蛋氨酸(S-adenosyl-L-methionine,SAMe)是一种天然分子存在于人体所有细胞中,在肝脏、肾上腺以及松果体中具有较高浓度,在大脑中亦均匀分布。S-腺苷蛋氨酸通过抗氧化自由基及促进肝细胞再生等机制对肝细胞具有多重保护作用长久以来被广泛应用于肝病所致的肝内胆汁淤积、抗肝纤维化等治疗。近年来,研究亦发现S-腺苷蛋氨酸可增加患者脑中神经元膜的流动性及促进兴奋性神经递质的产生等对改善肝病患者情绪、治疗肝病患者抑郁症等方面具有重要的双重作用。通过静脉或口服用药,均可提高患者脑脊液中SAMe浓度,对于轻、中度抑郁患者的辅助治疗,更具安全性、有效性,这为人类的"生理-心理"疾病的治疗带来更广阔的应用前景。现将其对肝病患者抗抑郁的作用机制及临床应用综述如下。     

秀丽隐杆线虫对不同氧浓度的应答及其调控机制研究进展

不同地理位置的人类生活环境中氧气水平不同,与人体的正常生理功能密切相关。体内氧气的减少会引发多种疾病,如大脑缺血、缺氧导致的脑卒中。近年来利用秀丽隐杆线虫(Caenorhabditis elegans,简称线虫)作为模式生物研究机体对不同氧浓度应答和调控机制取得了长足进展。研究表明,线虫会逃避氧浓度过高或过低的环境,并对周围氧气浓度的变化有适应性,而且其在不同程度低氧环境中存在不同的应答与调控机制。本文综述了近年来线虫对不同氧气浓度的反应和调控机制研究进展。     

高强度间歇训练后高低氧恢复对于糖代谢的影响

为探究高强度间歇训练后于90 min恢复期内吸入高浓度氧气与常氧浓度对于机体糖代谢的影响,本研究选取40名大学男子篮球代表队队员作为研究对象,接受单次高强度间歇训练(high-intensity interval training, HIIT)。以120%～140%无氧阈值速度作为运动强度,运动2 min,间隔休息1 min,重复7次,之后吸入高浓度氧气(90%O2)恢复90 min,隔天更换为常氧(21%O2)恢复90 min,运动前后分别进行口服葡萄糖耐量测试并分析血糖、胰岛素、皮质醇浓度。研究结果显示,高强度间歇运动后,高氧恢复后的血糖值显著低于常氧恢复后的血糖值,并呈显著性差异(p0.05);运动前后以及运动后高氧、常氧状态下恢复后的胰岛素敏感度均未呈显著性差异(p0.05);高氧恢复后第60分钟、90分钟后的皮质醇浓度明显低于训练后常氧状态下恢复后的皮质醇浓度,并呈显著性差异(p0.05)。研究结果表明,高强度间歇训练后的90 min高氧恢复有助于减缓运动后的生理压力和提升运动后肌肉细胞对葡萄糖吸收能力,促进机体糖代谢。     

用于脑缺血小鼠海马SOD1表达的改进灌注固定法

常规灌注固定法多用于兔和大鼠等较大动物,并存在一些不足。改进了灌注固定法流程、灌注溶液的配方、流速、用量以及灌注装置,将其用于在显微操作下制备的缺血再灌注C57BL/6N小鼠模型,并对其海马进行H.E染色和免疫组织化学SOD1基因表达。结果显示,改进的灌注固定法使组织切片结构更加清晰,海马免疫阳性神经元定位于胞浆。缺血再灌注组(24hI/R)海马神经元SOD1表达比假手术对照组(sham-o)减少,而高压氧治疗组(24hHBO)SOD1表达有所恢复。表明改进的灌注固定法用于缺血再灌注C57BL/6N小鼠海马SOD1基因表达效果良好,结果可靠。实验结果提示,高压氧的治疗机制之一可能是通过增加SOD1基因表达而实现的。     

转基因动物的组织缺血再灌注损伤较非转基因动物轻

近年来,缺血再灌注损伤中氧自由基的作用已被许多直接或间接证据所证实,并得到公认。目前直接测定氧自由基的方法是用电子自旋共振仪(ESR);间接的方法是使用外源性氧自由基清除剂如超氧化物歧化酶(SOD)、过氧化氢酶(CAT)观察其对组织缺血再灌注损伤的保护作用。最近Kinouchi等用携带人SOD 1基因的转基因小鼠(Tg)观察了处于高表达状态的铜锌超氧化物歧化酶(CuZn SOD,其SOD的活力是非转基因小鼠nTg的3.1倍)对小鼠大脑局部缺血再灌注损伤的保护作用,结果发现,缺血24h后,转     

急性ST段抬高心肌梗死治疗新进展

<正>在临床各类急性病症中,急性ST段抬高心肌梗死(ST segment elevation acute myocardial infarction,STEMI)是其中较为常见的一种。早期再灌注治疗是临床用于挽救STEMI患者生命、改善其预后及生存质量的有效手段。再灌注治疗主要包括经皮冠状动脉腔内成形术(PTCA)、溶栓治疗以及支架置入术。国内外大量临床研究表明,对于STEMI患者实施早期再灌注治疗可使病人死亡率大幅度降低,幸存者心功能也可得到显著改善[1]。本文就急性ST段抬高心肌     

黑茶提取物对脓毒症模型小鼠的保护作用

研究黑茶提取物对脓毒症模型小鼠的保护作用。本实验采用腹腔注射高浓度40 mg/kg脂多糖(LPS)和盲肠结扎穿孔术(CLP)两种不同的方式建立小鼠脓毒症模型,考察黑茶提取物对脓毒症小鼠7 d存活率的影响;利用LPS诱导巨噬细胞程序性坏死实验研究黑茶提取物对小鼠脓毒症治疗作用的机制。结果显示,黑茶水提物可提高LPS和CLP诱导的脓毒症小鼠的7 d存活率,提高幅度达40%;黑茶多糖可对LPS诱导的巨噬细胞程序性坏死有一定的抑制作用,与LPS对照组相比,差异具有显著性(P0.05)。提示黑茶提取物对脓毒症模型小鼠有一定的治疗作用,其作用的机制可能与黑茶多糖抑制LPS诱导的巨噬细胞程序性坏死有关,更深入的作用机制有待进一步研究。     

A murine model of sepsis following smoke inhalation injury

Acute lung injury (ALI) by smoke inhalation with subsequent pneumonia and sepsis represents a major cause of morbidity and mortality in burn patients. The aim of the present study was to develop a murine model of ALI and sepsis to enhance the knowledge of mechanistic aspects and pathophysiological changes in patients with these injuries. In deeply anesthetized female C57BL/6 mice, injury was induced by four sets of cotton smoke using an inhalation chamber. Afterward, live Pseudomonas aeruginosa (3.2 × 10⁷ colony-forming units) was administered intranasally. The indicated dose of bacteria was determined based on the results of a dose-response study (n = 47). The following study groups were monitored for survival over 96 h: (1) sham injury group, (2) only smoke inhalation group, (3) only bacteria group, and (4) smoke inhalation plus bacteria group. Each group included 10 mice. The survival rates were 100%, 90%, 30%, and 10%, respectively. The double hit injury was associated with excessive releases of pro-inflammatory cytokines in the plasma, and enhanced neutrophil accumulation, increased lipid peroxidation, and excessive formation of reactive nitrogen species in the lung. In mice receiving only smoke inhalation injury, no systemic cytokine release and increased lung tissue lipid peroxidation were observed. However, smoke alone significantly increased neutrophil accumulation and formation of reactive nitrogen species in lung tissue. In conclusion, bacterial pneumonia is predominantly responsible for mortality and morbidity in this novel murine model of smoke inhalation and pulmonary sepsis. Reactive oxygen and nitrogen species mediate the severity of lung injury.     

Sepsis,complement and the dysregulated inflammatory response

Sepsis in human beings is a major problem involving many individuals and with a high death rate. Except for a single drug (recombinant activated protein C) that has been approved for treatment of septic patients, supportive measures represent the main clinical approach. There are many models of experimental sepsis, mostly in rodents. A commonly used model is cecal ligation and puncture (CLP). In this model, robust activation of complement occurs together with up-regulation of C5a receptors (C5aR, C5L2) in a variety of different organs (lungs, kidneys, liver, heart). In septic human beings there is abundant evidence for complement activation. Interception of C5a or its receptors in the CLP model greatly improves survival in septic rodents. There is compelling evidence that CLP causes an intense pro-inflammatory state and that C5a interaction with its receptors can be linked to apoptosis of the lymphoid system and cells of the adrenal medulla, loss of innate immune functions of blood neutrophils, consumptive coagulopathy and cardiac dysfunction. These findings may have implications for therapeutic interventions in human beings with sepsis.     

The Effect of Ghrelin upon the Early Immune Response in Lean and Obese Mice during Sepsis

Introduction

It is well established that obesity-related hormones can have modulatory effects associated with the immune response. Ghrelin, a hormone mainly derived from endocrine cells of the gastric mucosa, regulates appetite, energy expenditure and body weight counteracting leptin, a hormone mainly derived from adipocytes. Additionally, receptors of both have been detected on immune cells and demonstrated an immune regulatory function during sepsis.

Methods

In the present study, the effect of peripheral ghrelin administration on early immune response and survival was investigated with lean mice and mice with diet-induced obesity using cecal ligation and puncture to induce sepsis.

Results

In the obese group, we found that ghrelin treatment improved survival, ameliorated hypothermia, and increased hyperleptinemia as compared to the lean controls. We also observed that ghrelin treatment divergently regulated serum IL-1ß and TNF-α concentrations in both lean and obese septic mice. Ghrelin treatment initially decreased but later resulted in increased bacteriaemia in lean mice while having no impact upon obese mice. Similarly, ghrelin treatment increased early neutrophil oxidative burst while causing a decrease 48 hours after sepsis inducement.

Conclusion

In conclusion, as the immune response to sepsis temporally changes, ghrelin treatment differentially mediates this response. Specifically, we observed that ghrelin conferred protective effects during the early phase of sepsis, but during the later phase deteriorated immune response and outcome. These adverse effects were more pronounced upon lean mice as compared to obese mice.     

猪神经干细胞分离培养研究进展

神经干细胞用于神经学临床修复和基础理论研究的前提是首先完成神经干细胞的体外分离、培养、纯化并大量扩增。鼠、人、猪中都已成功分离出神经干细胞并已尝试用于动物神经系统损伤等疾病的治疗,尽管在鼠和人上的研究很多,相对于鼠神经干细胞在神经学临床应用上的局限和人神经干细胞在材料来源上的不便,猪作为神经干细胞临床应用和基础研究的模式动物有很大的潜力。但关于猪神经干细胞体外分离培养的研究非常少,本文对这方面的研究进展做一综述。     

Increased natural CD4+CD25+ regulatory T cells and their suppressor activity do not contribute to mortality in murine polymicrobial sepsis

Regulatory T cells (Tregs), including natural CD4+CD25+ Tregs and inducible IL-10 producing T regulatory type 1 (T(R)1) cells, maintain tolerance and inhibit autoimmunity. Recently, increased percentages of Tregs have been observed in the blood of septic patients, and ex vivo-activated Tregs were shown to prevent polymicrobial sepsis mortality. Whether endogenous Tregs contribute to sepsis outcome remains unclear. Polymicrobial sepsis, induced by cecal ligation and puncture, caused an increased number of splenic Tregs compared with sham-treated mice. Splenic CD4+CD25+ T cells from septic mice expressed higher levels of Foxp3 mRNA and were more efficient suppressors of CD4+CD25- T effector cell proliferation. Isolated CD4+ T cells from septic mice displayed increased intracellular IL-10 staining following stimulation, indicating that T(R)1 cells may also be elevated in sepsis. Surprisingly, Ab depletion of total CD4+ or CD4+CD25+ populations did not affect mortality. Furthermore, no difference in survival outcome was found between CD25 or IL-10 null mice and wild-type littermates, indicating that Treg or T(R)1-generated IL-10 are not required for survival. These results demonstrate that, although sepsis causes a relative increase in Treg number and increases their suppressive function, their presence does not contribute significantly to overall survival in this model.     

The sepsis model: an emerging hypothesis for the lethality of inhalation anthrax

Inhalation anthrax is often described as a toxin‐mediated disease. However, the toxaemia model does not account for the high mortality of inhalation anthrax relative to other forms of the disease or for the pathology present in inhalation anthrax. Patients with inhalation anthrax consistently show extreme bacteraemia and, in contrast to animals challenged with toxin, signs of sepsis. Rather than toxaemia, we propose that death in inhalation anthrax results from an overwhelming bacteraemia that leads to severe sepsis. According to our model, the central role of anthrax toxin is to permit the vegetative bacteria to escape immune detection. Other forms of B. anthracis infection have lower mortality because their overt symptoms early in the course of disease cause patients to seek medical care at a time when the infection and its sequelae can still be reversed by antibiotics. Thus, the sepsis model explains key features of inhalation anthrax and may offer a more complete understanding of disease pathology for researchers as well as those involved in the care of patients.     

Quantitative trait loci modulate neutrophil infiltration in the liver during LPS-induced inflammation.

A crucial aspect of the inflammatory response is the recruitment of activated neutrophils (PMN) to the site of damage. Lytic enzymes and oxygen radicals released by PMN are important in clearing an infection or cellular debris, but can also produce host tissue damage. Failure to properly regulate the inflammatory response contributes to a variety of human diseases like sepsis and multiple organ dysfunction syndrome, the leading cause of morbidity and mortality in surgical intensive care units. Many aspects of human disease pathology, including hepatic PMN infiltration, can be recapitulated in mice using an endotoxic shock model. Six quantitative trait loci that predispose to high infiltration of PMN in hepatic sinusoids after high-dose endotoxin administration were provisionally identified. Two of these loci, Hpi1 and Hpi2 on mouse chromosomes 5 and 13, were mapped to the significant and highly significant level using a low-resolution genome scan on 122 intercross animals. These loci interact epistatically to produce a high degree of PMN infiltration. Intercross and recombinant inbred strain mice with a specific genotype at these loci always had a high infiltration response, indicating that genotype analysis at just these two loci can accurately predict a high PMN infiltration response. Genetic predisposition to the degree of PMN infiltration in the inflammatory response in mice suggests that analogous genetic mechanisms occur in human beings that could be used for diagnostic purposes.     

TAT-BH4 and TAT-Bcl-xL peptides protect against sepsis-induced lymphocyte apoptosis in vivo

Apoptosis is a key pathogenic mechanism in sepsis that induces extensive death of lymphocytes and dendritic cells, thereby contributing to the immunosuppression that characterizes the septic disorder. Numerous animal studies indicate that prevention of apoptosis in sepsis improves survival and may represent a potential therapy for this highly lethal disorder. Recently, novel cell-penetrating peptide constructs such as HIV-1 TAT basic domain and related peptides have been developed to deliver bioactive cargoes and peptides into cells. In the present study, we investigated the effects of sepsis-induced apoptosis in Bcl-x(L) transgenic mice and in wild-type mice treated with an antiapoptotic TAT-Bcl-x(L) fusion protein and TAT-BH4 peptide. Lymphocytes from Bcl-x(L) transgenic mice were resistant to sepsis-induced apoptosis, and these mice had a approximately 3-fold improvement in survival. TAT-Bcl-x(L) and TAT-BH4 prevented Escherichia coli-induced human lymphocyte apoptosis ex vivo and markedly decreased lymphocyte apoptosis in an in vivo mouse model of sepsis. In conclusion, TAT-conjugated antiapoptotic Bcl-2-like peptides may offer a novel therapy to prevent apoptosis in sepsis and improve survival.     

巴马小型猪在医学研究中的应用进展简

广西巴马小型猪作为国内小型猪主要品种之一,具有遗传性稳定、多产、体重较小、体表多覆白毛等特征,组织器官及生化指标与人类相似,已越来越广泛地应用于医学研究领域：猪的心脏解剖与生理特点与人类高度相似,已被广泛应用于心血管系统研究中,在我国,巴马小型猪被用来构建心肌缺血、卵圆孔未闭等心血管疾病模型;猪具有杂食性及与人相似的脂质代谢,可用于研究内分泌疾病,巴马小型猪已用于糖尿病动物模型建立及其遗传易感性、并发症的防治研究等;巴马小型猪的消化系统与人类相似,利用此特点已建立阻塞性慢性胰腺炎、结肠穿孔、胆肠吻合等消化系统疾病模型;巴马小型猪除头、尾外,体表覆以白毛,这一特点使其成为研究皮肤创伤、烧伤修复等的理想动物;小型猪的牙齿解剖结构与人类相似,口裂大,可作为口腔医学研究中的理想动物,巴马小型猪已用来建立牙髓坏死模型及对上颌扩弓方式的研究;类似人的解剖、生理、病理使其成为较为适合的异种移植供体.在中医药研究方面,已用巴马小型猪分别建立了肝脏、脾脏、股动、静脉出血及头颈恶性肿瘤放疗后的腮腺损伤动物模型以研究中药制剂的疗效及机制.     

Disruption of Calcium Homeostasis in Cardiomyocytes Underlies Cardiac Structural and Functional Changes in Severe Sepsis

Sepsis, a major cause of morbidity/mortality in intensive care units worldwide, is commonly associated with cardiac dysfunction, which worsens the prognosis dramatically for patients. Although in recent years the concept of septic cardiomyopathy has evolved, the importance of myocardial structural alterations in sepsis has not been fully explored. This study offers novel and mechanistic data to clarify subcellular events that occur in the pathogenesis of septic cardiomyopathy and myocardial dysfunction in severe sepsis. Cultured neonatal mice cardiomyocytes subjected to serum obtained from mice with severe sepsis presented striking increment of [Ca²⁺]_i and calpain-1 levels associated with decreased expression of dystrophin and disruption and derangement of F-actin filaments and cytoplasmic bleb formation. Severe sepsis induced in mice led to an increased expression of calpain-1 in cardiomyocytes. Moreover, decreased myocardial amounts of dystrophin, sarcomeric actin, and myosin heavy chain were observed in septic hearts associated with depressed cardiac contractile dysfunction and a very low survival rate. Actin and myosin from the sarcomere are first disassembled by calpain and then ubiquitinated and degraded by proteasome or sequestered inside specialized vacuoles called autophagosomes, delivered to the lysosome for degradation forming autophagolysosomes. Verapamil and dantrolene prevented the increase of calpain-1 levels and preserved dystrophin, actin, and myosin loss/reduction as well cardiac contractile dysfunction associated with strikingly improved survival rate. These abnormal parameters emerge as therapeutic targets, which modulation may provide beneficial effects on future vascular outcomes and mortality in sepsis. Further studies are needed to shed light on this mechanism, mainly regarding specific calpain inhibitors.