失血性休克大鼠离体淋巴管对P物质的反应性

目的:应用离体淋巴管灌流技术,观察失血性休克(HS)发展进程中淋巴管对P物质(SP)的反应性。方法:Wistar雄性大鼠随机分为对照组(仅麻醉与手术)和HS组(通过股静脉放血至平均动脉血压为40 mmHg,复制HS模型,分为休克0h、0.5 h、1 h、2h、3 h五个亚组)。各组在相应时间点分离胸导管,制备淋巴管,3 cmH2O跨壁压下行离体灌流,分别给予从低到高浓度的SP,测量淋巴管收缩末期口径、舒张末期口径、收缩频率(CF)和被动管径,计算收缩幅度(CA)、泵流分数(FPF)和紧张指数(TI),以给予SP前后淋巴管的CF、TI、CA、FPF的差值△CF、△TI、△CA、△FPF作为评价淋巴管对SP反应性的指标。结果:Shock 0 h与shock 0.5 h大鼠淋巴管对多个或一个SP浓度的△CF、△TI、△CA、△FPF显著高于对照组,shock 2 h淋巴管对SP的△CF(3×10-7mol/L)、△TI(1×10-7mol/L)以及shock 3 h淋巴管对SP的△CF(1×10-7mol/L、3×10-7mol/L)、△TI(1×10-7mol/L)、△CA(1×10-7mol/L)均显著低于对照组。结论:休克淋巴管对SP反应性呈双相变化,即早期升高,晚期降低。     

超声心动图对慢性收缩性心力衰竭预后的预测价值分析

目的:探讨超声心动图对慢性收缩性心力衰竭(心衰)预后的预测价值。方法:选择2016年8月到2018年9月在南京医科大学附属脑科医院(胸科院区)医学影像二科(以我院代替)诊治的慢性收缩性心衰患者112例,均给予超声心动图检查并记录相关指标,随访患者的预后并进行相关性分析。结果:随访至今,112例患者的主要心血管不良事件(Major Adverse Cardiovascular Events,MACE)发生率为18.8%。MACE组患者的左室收缩末期容积(Left ventricular end systolic volume,LVESV)、左室舒张末期容积(Left ventricular end diastolic volume,LVEDV)值显著高于非MACE组患者(P0.05),两组患者左室收缩末期内径(Left ventricular end systolic diameter,LVDs)、左房内径(Left atrial diameter,LAD)、左心室舒张末期内径(Left ventricular end diastolic dimension,LVDd值无统计学差异(P0.05)。患者预后MACE与LVEDV、LVESV值呈显著相关性(P0.05)。LVEDV、LVESV为影响慢性收缩性心衰患者MACE的独立危险因素(P0.05)。结论:超声心动图用于慢性收缩性心衰患者可反映患者的心功能状况,且具有较高的预后预测价值。     

肠淋巴途径对休克大鼠心肌自由基、炎性介质的影响

目的：观察结扎肠系膜淋巴管对重症失血性休克大鼠不同时期心肌自由基、炎症介质的影响。方法：雄性Wistar大鼠78只,分为假手术组、休克组、结扎组。休克组与结扎组复制重症失血性休克模型,结扎组于休克复苏后行肠系膜淋巴管结扎术。于休克后90min、输液复苏后0h、1h、3h、6h、12h、24h等时间点处死大鼠,制备心肌组织匀浆,检测MDA、SOD、TNFα、IL-6、NO、NOS以及MPO水平,RT—PCR方法测定心肌组织iNOS mRNA表达。结果：休克组大鼠输液复苏后多个时间点心肌匀浆MDA、TNFα、IL-6、MPO、NO、NOS和iNOS mRNA表达均有不同程度的升高,3h-12h持续在较高水平,均显著高于假手术组,心肌匀浆SOD活性显著低于假手术组：结扎组多个时间点心肌匀浆MDA、TNFα、IL-6、MPO、NO、NOS以及iNOS mRNA显著低于休克组相应时间点,SOD活性高于休克组相应时间点。结论：肠系膜淋巴管结扎阻断肠淋巴液回流,可减少心肌PMN扣押、降低TNFα、IL-6的释放、抑制NO生成及iNOS mRNA表达、减少自由基释放与SOD消耗。     

交感神经对大鼠失血性休克过程中淋巴微循环的调控

为了探讨交感神经对失血性休克过程中淋巴微循环变化的影响,应用显微电视录像技术,观察了切断内脏大神经的大鼠在失血性休克及输血、补液过程中肠中系膜微淋巴管（ＭＬ）收缩性的变化。结果表明,去神经后ＭＬ自主收缩频率及总收缩活性旨数（ＩｎｄｅｘⅡ）、淋巴管力学指数（Ｌ．Ｋ－Ｉｎｄｅｘ）显著降低,失血性休克时神经完整组及去神经组ＭＬ的自主收缩性均降低,神经完整组在回输血液及输液期,ＭＬ自主收缩性显著高于休克前     

淋巴液的抗休克作用

目的和方法：应用显微电视录象设备和活体大鼠肠系膜微循环观察技术,观察胸导管淋巴液对重症失血性休克大鼠血压和微循环障碍的影响,以探讨淋巴液的抗休克作用及其机制。结果：淋巴液治疗组大鼠存活时间（７０３ｈ）显著高于白蛋白对照组（２０５ｈ）。治疗组输入胸导管淋巴液后血压显著回升,血液流态改善,有效地解除肠系膜细动、静脉和微淋巴管（ＭＬ）静态口径的病理性收缩,ＭＬ收缩分数、总收缩活性指数及淋巴管动力学指数恢复正常,而白蛋白对照组的微血管口径及三个ＭＬ收缩性指数仍处于休克时水平,且明显低于治疗组（Ｐ＜０．０１）。结论：淋巴液具有良好的抗休克作用,其机制可能与显著改善休克时的微循环障碍和提升血压有关     

牛磺酸对失血性休克复苏家兔血浆和心肌NOS活性影响

目的:探讨牛磺酸对失血性休克复苏后血浆和心肌一氧化氮合酶(NOS)活性、一氧化氮(NO)含量变化的影响.方法:新西兰种兔24只随机分为3组(n=8):对照组、休克组、牛磺酸治疗组.采用失血性休克复苏动物模型.连续观察休克前、休克1.5 h、复苏后1 h、2 h、3 h血浆一氧化氮合酶(NOS)活性、一氧化氮代谢产物(NO-2/NO-3)含量、乳酸脱氢酶(LDH)活性的动态变化.测定复苏后3 h心肌一氧化氮合酶(NOS)活性、一氧化氮代谢产物(NO-2/NO-3)含量的变化,并常规留取心肌标本观察形态学改变.结果:①休克组复苏后各时限血浆NOS活性、NO-2/NO-3含量、LDH活性显著高于休克前及休克1.5 h;②休克组复苏后3 h心肌NOS活性、NO-2/NO-3含量显著高于对照组,心肌出现明显水肿和脂肪变性;③牛磺酸(40 mg·kg-1 iv)可显著缓解上述变化.结论:失血性休克复苏后NOS的激活和NO的大量释放,可能介导了休克复苏所致心肌损伤,牛磺酸可减少NO的生成使心肌损伤减轻.     

失血性休克大鼠淋巴管及血管压力对去甲肾上腺素反应的相关性研究

目的:观察失血性休克(HS)大鼠淋巴管与血管对去甲肾上腺素(NE)反应性的变化,探讨淋巴管与血管反应性的关系。方法:大鼠行左侧腹部手术,分离胸导管,测量淋巴管压力(LP);股部手术,经股动脉测量平均动脉血压(MAP)。休克组经股动脉放血复制HS模型(维持MAP40mmHg左右,3h),假手术(sham)组仅手术。在休克不同时间点(或相当),股静脉注射NE(5μg/kg.bw),观察给予NE前后两组大鼠LP以及MAP的变化。结果:休克即刻淋巴管对NE的反应性与sham组无明显差异,到休克0.5h时淋巴管对NE的升压反应开始减弱,至休克3h依然维持低反应性;与sham组相比,休克组血管对NE反应性呈双相表现,休克即刻血管高反应性,休克1h后对NE的升压作用开始减弱,表现为血管低反应性;休克后二者的反应性相关。结论:大鼠HS后淋巴管出现低反应性,且出现在血管低反应性之前;休克发展进程中淋巴管与血管对NE的低反应性呈正相关。     

一氧化氮在淋巴管收缩中的作用

淋巴管收缩是淋巴循环的动力学基础,对于维持循环系统稳态发挥重要作用.生物活性分子一氧化氮(NO)的周期性变化参与了淋巴管生理状态下的收缩、舒张以及张力调节.NO通过提高cAMP、cGMP水平激活PKA和PKG,既可引起淋巴管平滑肌细胞(LSMC)膜超极化、降低肌浆网IP3活性,从而降低LSMC细胞内Ca2+浓度;亦可通过活化肌球蛋白轻链磷酸酶降低LSMC的钙敏感性,最终降低淋巴管收缩性.通过调控淋巴管收缩过程中NO的生成与释放,有可能成为治疗或干预淋巴障碍性疾病的新靶点之一.     

牛磺酸对失血性休克再灌注肺损伤的防护作用及其机制探讨

目的:探讨失血性休克再灌注肺损伤与一氧化氮的关系及牛磺酸对其的影响.方法:健康家兔24只随机分为三组:对照组、单纯休克组、牛磺酸治疗组.采用失血性休克再灌注后肺损伤模型.测定肺组织及血浆中一氧化氮合酶(NOS)活性、一氧化氮代谢产物(NO2-/NO3-)含量、超氧化物歧化酶(SOD)活性、丙二醛(MDA)含量、肺湿重/肺干重、肺水含量、肺通透指数(LPI)、肺泡灌洗液(PALF)中蛋白含量等指标的变化,并常规留取肺标本进行病理形态观察.结果:①再灌注3 h时肺组织及血浆中SOD活性显著下降,而上述其它指标均显著升高,与对照组相比差异有显著性(均P<0.01).②血浆、肺组织中NO2-/NO3-含量与MDA含量均呈正相关,且肺组织中NO2-/NO3-含量和肺损伤指标呈显著正相关.③牛磺酸(40 mg*kg-1,iv)可减轻上述指标的变化.结论:NO在休克再灌注肺损伤中起重要作用,牛磺酸可减少NO的生成、增强自由基的清除从而使肺组织损伤减轻.     

纳豆枯草杆菌培养滤液对家兔离体肠平滑肌的作用

目的观察纳豆枯草杆菌培养滤液（culture filtrate,CF）对家兔离体肠平滑肌的作用,并初步探讨其作用机制。方法制备兔离体回肠标本,分别记录肠平滑肌的正常收缩张力和收缩频率作为给药前对照,然后按累积剂量分别加入CF小剂量（每次0．2mL）、CF大剂量（每次0．5mL）、肉汤（每次0．5mL）,给药间隔3min,共给药8次,并描记收缩曲线。观察不同剂量cF对肠平滑肌的作用。另取肠段按毛果芸香碱、CF或阿托品、再毛果芸香碱的顺序给药,观察CF对M胆碱受体的作用。结果CF小剂量组在累积给药达1．6mL时,CF大剂量组在累积给药达3．5mL和4．0mL时,兔离体肠平滑肌收缩张力下降,与给药前比较差异有统计学意义（P〈0．05）,其余各点差异均无统计学意义（P〉0．05）。CF小剂量组在累积给药达1．2、1．4、1．6mL时,CF大剂量组在累积给药达4．0mL时,兔离体肠平滑肌收缩频率明显降低,与给药前比较差异有统计学意义（P〈0．05或P〈0．01）,其余各点差异均无统计学意义（P〉0．05）。CF或阿托品可明显对抗毛果芸香碱引起的兔离体肠平滑肌收缩张力的增加（P〈0．05或P〈0．01）,同时CF还能使其收缩频率明显减少（P〈0．01）。结论纳豆枯草杆菌CF能明显抑制兔离体肠平滑肌蠕动,其作用机制可能与阻断M胆碱受体有关。     

Sensitivity to endotoxin in rabbits is increased after hemorrhagic shock.

The immunoinflammatory response following trauma and hemorrhage may predispose to the development of sepsis and multiple-organ failure syndrome. Cardiac output (CO), arterial pressure, arterial PO2, and pulmonary permeability index were measured. We examined the sensitivity of rabbits to infusions of lipopolysaccharide (LPS) after hemorrhagic shock. Shock was produced by reducing CO to 40% of baseline for 90 min, followed by resuscitation with shed blood and then with lactated Ringer solution to maintain CO near baseline. Animals were assigned to three groups: 1) hemorrhagic shock only, 2) LPS only, and 3) hemorrhagic shock + LPS. Groups 1 and 3 were subjected to hemorrhagic shock on day 1. Escherichia coli LPS was infused (1.0 microgram/kg i.v.) into groups 2 and 3 on day 2. Fluid resuscitation with lactated Ringer solution was continued in an effort to maintain CO at baseline. Five hours after LPS infusion, 125I-albumin was injected intravenously, and rabbits were killed 1 h later for measurement of pulmonary permeability index. LPS infusion after shock (group 3) caused significant decreases in CO, arterial pressure, and PO2 and an increase in pulmonary permeability. These changes were not seen in the groups 1 and 2. We conclude that hemorrhagic shock and resuscitation result in a proinflammatory state, leading to increased sensitivity to subsequent exposure to LPS.     

Dexmedetomidine suppresses serum syndecan-1 elevation and improves survival in a rat hemorrhagic shock model

Hemorrhagic shock causes vascular endothelial glycocalyx (EGCX) damage and systemic inflammation. Dexmedetomidine (DEX) has anti-inflammatory and EGCX-protective effects, but its effect on hemorrhagic shock has not been investigated. Therefore, we investigated whether DEX reduces inflammation and protects EGCX during hemorrhagic shock. Anesthetized Sprague-Dawley rats were randomly assigned to five groups (n=7 per group): no shock (SHAM), hemorrhagic shock (HS), hemorrhagic shock with DEX (HS+DEX), hemorrhagic shock with DEX and the α7 nicotinic type acetylcholine receptor antagonist methyllycaconitine citrate (HS+DEX/MLA), and hemorrhagic shock with MLA (HS+MLA). HS was induced by shedding blood to a mean blood pressure of 25–30 mmHg, which was maintained for 30 min, after which rats were resuscitated with Ringer’s lactate solution at three times the bleeding volume. The survival rate was assessed up to 3 h after the start of fluid resuscitation. Serum tumor necrosis factor-alpha (TNF-α) and syndecan-1 concentrations, and wet-to-dry ratio of the heart were measured 90 min after the start of fluid resuscitation. The survival rate after 3 h was significantly higher in the HS+DEX group than in the HS group. Serum TNF-α and syndecan-1 concentrations, and the wet-to-dry ratio of heart were elevated by HS, but significantly decreased by DEX. These effects were antagonized by MLA. DEX suppressed the inflammatory response and serum syndecan-1 elevation, and prolonged survival in rats with HS.     

Microarray analysis of differentially expressed background genes in rats following hemorrhagic shock

To uncover the contribution of the diversity of the genetic backgrounds to the pathogenesis of hemorrhagic shock, we employed male Sprague-Dawley rats to establish a controlled 2.5 ml/100 g total body weight fixed-volume hemorrhagic shock and left lobular hepatectomy model. RNA was isolated from the liver samples taken from the rats (survival group: rats survived over 24 h after shock; and dead group: rats died within 1 h after shock, n = 3 per group), and subjected to microarray using the illumina^TM chips for rat cDNA (27,342 genes, >700,000 probes). The results demonstrated that the rats had about 50% survival rate and 100 genes were identified differentially expressed in the two groups. Of these genes, 47 genes were up-regulated and 53 genes down-regulated. Real-time PCR confirmed the differential expression for Aldh1a1, Aldh1a7, Aoc3, Cyp26al, Hdc and Ephx2 genes. Pathway analysis revealed that these genes are involved in circadian rhythm, beta-Alanine metabolism, histidine metabolism, biosynthesis of unsaturated fatty acids, glycine, serine and threonine metabolism, vitamin B6 metabolism, as well as arginine and proline metabolism. Therefore, our study provided a global molecular view on the contribution of genetic backgrounds to the response to hemorrhagic shock.     

Sublethal hemorrhagic shock reduces tumor necrosis factor-alpha-producing capacity in different cell compartments

Hemorrhagic shock results in a severe impairment of the immune response. Immunological alterations after hemorrhagic shock thus appear to be responsible for reduced resistance to infectious agents commonly observed after shock and severe injury. In the present study we examined the TNF-alpha-producing capacity of immune cells derived from different organs after sublethal shock in rats. Hemorrhagic shock was established by pressure controlled bleeding to a mean arterial pressure of 35 mm Hg for 35-40 min and consecutive resuscitation in male Sprague-Dawley rats. Twenty four hours after shock, TNF-a production in response to lipopolysaccharide (LPS, Salmonella friedenau) stimulation was measured in isolated spleen, bone marrow and blood cells. TNF-a production could be induced by stimulation with 1 ng/ml, in blood, spleen and bone marrow cells collected from sham-operated animals. A maximal stimulation was observed in all cell types after stimulation with 10 ng/ml LPS and could not be further increased with LPS doses of 100 ng/ml. Hemorrhagic shock of 35 mm Hg for 35-40 min, with consecutive resuscitation did not result in mortality, in contrast to a 4 hours lasting hemorrhagic shock resulting in 80% mortality. Blood, spleen or bone marrow cells, harvested from animals 24 hours after sublethal hemorrhagic shock, showed a significantly reduced TNF-alpha production in all cell populations after LPS stimulation. Serum collected from animals 2 hours after sublethal hemorrhagic shock contained an activity not present either before or 24 hours after shock, that downregulated LPS-induced TNF-alpha production in rat whole blood cultures and the murine macrophage cell line J774. The inhibitory activity present in serum, 2 hours after shock is not IL-10 since this mediator was not detectable in any serum sample. However, in the serum samples with TNF-alpha-inhibitory activity, elevated levels of PGE2 metabolites were found, which suggests the involvement of prostaglandins in trauma-induced immunosuppression. Altered TNF-a expression might be partially explained by an inhibitory activity in the serum already present 2 hours after shock. Since adequate, but not overwhelming TNF-alpha production is essential for host response, the altered cytokine formation might explain local and systemic susceptibility to infections after hemorrhagic shock.     

Role of oxygen-derived free radicals on rat splanchnic eicosanoid production during acute hemorrhage.

The effect of superoxide dismutase (SOD), an oxygen-derived free radical scavenger, on rat splanchnic eicosanoid synthesis was examined following hemorrhagic shock. Anesthetized male rats were hemorrhaged to 30 mm Hg for 30 minutes (Shock), killed, or treated with the shed blood (Shock plus reperfusion). The Shock plus reperfusion group was treated with saline vehicle or SOD (2500, 5000, 7500, 10,000 or 15,000 U/Kg, i.v.) 15 minutes prior to the reperfusion of the shed blood. The superior mesenteric artery was removed in continuity with the end organ intestine (SV+SI) and perfused in vitro with oxygenated Krebs-Henseleit buffer (3 ml/min at 37 degrees C). Venous effluent was measured for basal release of 6-keto-PGF1 alpha, PGE2 and thromboxane B2 at 15, 30, 60 and 90 minutes of perfusion. The SV+SI compensated for acute shock by increased release of 6-keto-PGF1 alpha (300%) (and not PGE2 or thromboxane B2) which was abolished by reperfusion of the shed blood following shock. Prior treatment of the Shock plus reperfusion group with 7500 U/Kg or more of SOD restored the increased release of SV+SI 6-keto-PGF1 alpha found following shock alone (p less than 0.05). These data provided indirect evidence that ODFRs contributed to endogenous SV+SI regulation of PGI2 synthesis and release during hemorrhagic shock and reperfusion of shed blood.     

肠淋巴液引流对失血性休克小鼠心肌组织ACE/ACE2的作用

目的：观察失血性休克后小鼠心肌组织血管紧张素转换酶（ACE）/ACE2平衡的变化及肠淋巴液引流（PHSML）的作用。方法：BALB/c雄性小鼠24只,随机分为对照组、假手术组、休克组、休克+引流组（n=6）。建立失血性休克模型,行液体复苏;休克+引流组液体复苏后,引流肠淋巴液。在液体复苏后6 h或假手术组相应时间点、对照组于麻醉后,留取心肌组织,qRT-PCR法检测ACE、ACE2、血管紧张素Ⅱ （Ang Ⅱ）1型受体（AT1R）、Mas相关G蛋白偶联受体（Mas1R）的mRNA表达,ELISA方法检测Ang Ⅱ和Ang （1-7）含量。结果：休克组小鼠心肌组织ACE与AT1R mRNA表达、Ang Ⅱ水平均显著高于对照组与假手术组,ACE2与Mas1R mRNA表达显著低于对照组与假手术组、Ang （1-7）含量显著低于对照组,ACE/ACE2、Ang Ⅱ/Ang （1-7）、AT1R/Mas1R显著高于对照组与假手术组;PHSML引流显著抑制了失血性休克对这些指标的作用。结论：失血性休克上调心肌ACE-Ang Ⅱ-AT1R轴、下调ACE2-Ang （1-7）-Mas1R轴表达,引起ACE/ACE2失衡;PHSML引流下调ACE-Ang Ⅱ-AT1R轴、上调ACE2-Ang （1-7）-Mas1R轴表达,在一定程度上维持了ACE/ACE2平衡。     

Heart Rate Variability Analysis in an Experimental Model of Hemorrhagic Shock and Resuscitation in Pigs

Background

The analysis of heart rate variability (HRV) has been shown as a promising non-invasive technique for assessing the cardiac autonomic modulation in trauma. The aim of this study was to evaluate HRV during hemorrhagic shock and fluid resuscitation, comparing to traditional hemodynamic and metabolic parameters.

Methods

Twenty anesthetized and mechanically ventilated pigs were submitted to hemorrhagic shock (60% of estimated blood volume) and evaluated for 60 minutes without fluid replacement. Surviving animals were treated with Ringer solution and evaluated for an additional period of 180 minutes. HRV metrics (time and frequency domain) as well as hemodynamic and metabolic parameters were evaluated in survivors and non-survivors animals.

Results

Seven of the 20 animals died during hemorrhage and initial fluid resuscitation. All animals presented an increase in time-domain HRV measures during haemorrhage and fluid resuscitation restored baseline values. Although not significantly, normalized low-frequency and LF/HF ratio decreased during early stages of haemorrhage, recovering baseline values later during hemorrhagic shock, and increased after fluid resuscitation. Non-surviving animals presented significantly lower mean arterial pressure (43±7vs57±9 mmHg, P<0.05) and cardiac index (1.7±0.2vs2.6±0.5 L/min/m², P<0.05), and higher levels of plasma lactate (7.2±2.4vs3.7±1.4 mmol/L, P<0.05), base excess (-6.8±3.3vs-2.3±2.8 mmol/L, P<0.05) and potassium (5.3±0.6vs4.2±0.3 mmol/L, P<0.05) at 30 minutes after hemorrhagic shock compared with surviving animals.

Conclusions

The HRV increased early during hemorrhage but none of the evaluated HRV metrics was able to discriminate survivors from non-survivors during hemorrhagic shock. Moreover, metabolic and hemodynamic variables were more reliable to reflect hemorrhagic shock severity than HRV metrics.     

Assessing hemorrhagic shock: Feasibility of using an ultracompact photoacoustic microscope

Hemorrhagic shock, as an important clinical issue, is regarding as a critical disease with a high mortality rate. Unfortunately, existing clinical technologies are inaccessible to assess the hemorrhagic shock via hemodynamics in microcirculation. Here, we propose an ultracompact photoacoustic microscope to assess hemorrhagic shock using a rat model and demonstrate its clinical feasibility by visualizing buccal microcirculation of healthy volunteers. Both functional and morphological features of the microvascular network including concentration of total hemoglobin (C_HbT), number of blood vessels (VN), small vascular density (SVD) and vascular diameter (VD) were derived to assess the microvascular hemodynamics of different organs. Animal studies show the feasibility of the proposed tool to assess and stage the hemorrhagic shock via microcirculation. in vivo oral imaging of healthy volunteers indicates the translational possibility of this technique for clinical evaluation of hemorrhagic shock.