A fatal and metabolic experimental hemorrhagic shock in immature swine

Abstract Purpose: To use blood lactate (BL) as an end-point metabolic marker for the begin resuscitation of volume replacement in experimental hemorrhagic shock. Methods: Group I (n=7) was not bled (Control). Animals in Group II (n=7) were bled to a MAP of 30mmHg in thirty minutes. Hemodynamic and metabolic data were recorded at Baseline, at 30, 60 and 120 minutes after Baseline. The animals were intubated in spontaneous breathing (FIO2=0.21) with halothane. Results: Group I all survived. In Group II all died; no mortality occurred before a BL<10mM/L. Beyond the end-point all animals exhibited severe acidemia, hyperventilation and clinical signs of shock. Without treatment all animals died within 70.43±24.51 min of hypotension shortly after reaching an average level of BL 17.01±3.20mM/L. Conclusions: Swine's breathing room air spontaneously in hemorrhagic shock not treated a blood lactate over 10mM/L results fatal. The predictable outcome of this shock model is expected to produce consistent information based on possible different metabolic and hemodynamic patterns as far as the type of fluid and the timing of resuscitation in near fatal hemorrhagic shock.

Serum concentrations and renal expressions of IL-1 and TNF-a early after hemorrhage in rats under the effect of glibenclamide

ABSTRACT PURPOSE: To investigate changes in the serum concentration and renal expression of IL-1 and TNF-α cytokines in rats that received sevoflurane and glibenclamide prior to hemorrhage. METHODS: Two groups of sevoflurane-anesthetized Wistar rats (n=10): G1 (control) and G2 (glibenclamide, 1 µg/g i.v.); hemorrhage of 30% blood volume (10% every 10 min), with replacement using Ringer solution, 5 ml/kg/h. Serum concentrations of IL-1 and TNF-α were studied in the first hemorrhage (T1) and 50 min later (T2), renal expression, at T2. RESULTS: In serum, G1 TNF-α (pg/mL) was T1=178.6±33.5, T2=509.2±118.8 (p<0.05); IL-1 (pg/mL) was T1=148.8±31.3, T2=322.6±115.4 (p<0.05); in G2, TNF-α was T1=486.2±83.6, T2=261.8±79.5 (p<0.05); IL-1 was T1=347.0±72.0, T2= 327.3±90.9 (p>0.05). The expression of TNF-α and IL-1 in the glomerular and tubular cells was significantly higher in the G2 group. CONCLUSIONS: Hemorrhage and glibenclamide elevated TNF-α and IL-1 concentrations in serum and kidneys. High levels of TNF-α already present before the hemorrhage in the glibenclamide group may have attenuated the damages found in the kidneys after the ischemia event.

Effect of volume replacement during combined experimental hemorrhagic shock and traumatic brain injury in prostanoids, brain pathology and pupil status / Efeito da reposição volêmica durante o choque hemorrágico combinado com traumatismo craniencefálico sobre prostanóides, patologia cerebral e status pupilar

Traumatic brain injury (TBI) is the main cause of trauma-related deaths. Systemic hypotension and intracranial hypertension causes cerebral ischemia by altering metabolism of prostanoids. We describe prostanoid, pupilar and pathological response during resuscitation with hypertonic saline solution (HSS) in TBI. Method Fifteen dogs were randomized in three groups according to resuscitation after TBI (control group; lactated Ringer’s (LR) group and HSS group), with measurement of thromboxane, prostaglandin, macroscopic and microscopic pathological evaluation and pupil evaluation.Result Concentration of prostaglandin is greater in the cerebral venous blood than in plasma and the opposite happens with concentration of thromboxane. Pathology revealed edema in groups with the exception of group treated with HSS.Discussion and conclusion There is a balance between the concentrations of prostaglandin and thromboxane. HSS prevented the formation of cerebral edema macroscopically detectable. Pupillary reversal occurred earlier in HSS group than in LR group.

O traumatismo cranioencefálico (TCE) é a principal causa de morte relacionada ao trauma. O choque hemorrágico e hipertensão intracraniana causam isquemia cerebral alterando o metabolismo de prostanóides. Neste estudo, relatamos o comportamento dos prostanóides, resposta pupilar e patologia durante a reposição volêmica com solução salina hipertônica (SSH) no TCE. Método Quinze cachorros foram randomizados em três grupos (controle, grupo de Ringer lactato e grupo de SSH) e foram avaliados tromboxane, prostaglandina, avaliação patológica macroscópica e microscópica e status pupilar.Resultado A concentração de prostaglandina é maior no sangue cerebral em comparação ao plasma, e o inverso ocorre com o tromboxane. A patologia revelou edema em todos os grupos, com exceção do grupo tratado com SSH.Discussão e conclusão Existe um equilíbrio entre concentrações cerebrais e plasmáticas de prostaglandina e tromboxane. A SSH protegeu o cérebro da formação de edema pós traumático.

Effect of N-acetylcysteine in hearts of rats submitted to controlled hemorrhagic shock / Efeito da N-acetilcisteína em corações de ratos submetidos ao choque hemorrágico controlado

Abstract Introduction: Pharmacological therapy is a strategy for the prevention of complications associated with ischemia and reperfusion injury that occurs after volume replacement in the treatment of hemorrhagic shock. Objective: The aim of this study was to evaluate the effect of N-acetylcysteine associated with fluid resuscitation in cardiac injury in a rat hemorrhagic shock model. Methods: Mice Wister male rats were randomly and subjected to controlled hemorrhagic shock for 60 min. and then, subjected to resuscitation with Ringer lactate. In a group of six animals, 150mg/kg of N-acetylcysteine were added to fluid volume replacement. The animals were observed for 120 min and after this period, were euthanized and cardiac tissue was collected for histopathological analysis and measurement of thiobarbituric acid reactive substances and pro-and anti-inflammatory interleukin. Results: Cardiac tissue of the group treated with N-acetylcysteine showed lower concentrations of thiobarbituric acid reactive substances (0.20±0.05 vs. 0.27±0.05, P=0.014) and reduced histopathological damage and edema when compared to the group whose volume replacement occurred only with Ringer lactate. There was no difference in the expression of cytokines interleukin 6 (2,138.29±316.89 vs. 1,870.16±303.68, P=0.091) and interleukin 10 (1.019,83±262,50 vs. 848.60±106.5, P=0.169) between the treated groups. Conclusion: The association of N-acetylcysteine on volume replacement attenuates oxidative stress in the heart, as well myocardial damage and edema, but does not modify the expression of inflammatory cytokines. .

Resumo Introdução: A terapia farmacológica é uma estratégia de prevenção das complicações associadas à lesão de isquemia e reperfusão tecidual que ocorre após a reposição volêmica no tratamento do choque hemorrágico. Objetivo: O objetivo deste estudo foi avaliar a repercussão da N-acetilcisteína associada à reposição volêmica na lesão cardíaca em modelo de choque hemorrágico em ratos. Métodos: Ratos Wistar, machos, foram randomizados e submetidos ao choque hemorrágico controlado por 60 minutos e, depois, submetidos à reposição volêmica com Ringer Lactato. Em um grupo de seis animais, foram adicionados 150 mg/Kg de N-acetilcisteína ao fluido de reposição volêmica. Os animais foram observados por 120 minutos e após este período foram submetidos à eutanásia e coleta do tecido cardíaco para análise histopatológica e dosagem de substâncias reativas ao ácido tiobarbitúrico e interleucinas pró e anti-inflamatórias. Resultados: Foi observada menor concentração de substâncias reativas ao ácido tiobarbitúrico (0,20±0,05 vs. 0,27±0,05, P=0,014) e menor dano histopatológico e edema no tecido cardíaco do grupo tratado com N-acetilcisteína em relação ao grupo cuja reposição volêmica ocorreu somente com Ringer Lactato. Não foi observada diferença da expressão das citocinas interleucina 6 (2.138,29±316,89 vs. 1.870,16±303,68, P=0,091) e interleucina 10 (1.019,83±262,50 vs. 848,60±106,5, P=0,169) entre os grupos tratados. Conclusão: A associação da N-acetilcisteína na reposição volêmica atenua o estresse oxidativo no coração, assim como dano e edema miocárdicos, porém, não modifica a expressão de citocinas inflamatórias. .

Role of protein kinase G on the post-shock mesenteric lymph blockage ameliorating vascular calcium sensitivity

PURPOSE: To investigate the role of protein kinase G (PKG) in blocking post-shock mesenteric lymph (PSML) return ameliorating the calcium sensitivity in hemorrhagic shock rats. METHODS: Male Wistar rats were randomly divided into sham, shock, shock+ligation (shock plus mesenteric lymph duct ligation (MLDL)), shock+drainage (shock plus PSML drainage) groups. After shock (hypotension 40mmHg) for three hours or corresponding times, the superior mesenteric artery (SMA) was taken out for detecting the PKG and phospho PKG (p-PKG) contents, and the vascular rings of SMA were prepared for assaying the calcium sensitivity using an isolated organ perfusion system. RESULTS: The PKG and p-PKG contents of SMA in shock group were significantly increased than that of sham group, and MLDL or PSML drainage reducing the levels of PKG and p-PKG. Meanwhile, the vascular calcium sensitivity in shock group was significantly lower than that of sham group, MLDL or PSML drainage enhanced the calcium sensitivity. After incubating with PKG regulators in shock+ligation and shock+drainage groups, the PKG agonist 8Br-cGMP reduced the contractility of vascular rings to gradient calcium ions and Emax and the PKG inhibitor agonist KT5823 elevated the calcium sensitivity significantly. CONCLUSION: Protein kinase G plays an important role in post-shock mesenteric lymph blockage improving vascular calcium sensitivity.

Fisiopatología del shock: Nuevas perspectivas / Pathophysiology of shock: New perspectives

La actividad metabólica puede modificarse mediante la regulación de la población mitocondrial en distintas enfermedades críticas. A través de observaciones y ensayos clínicos examinamos esta adaptación metabólica en el shock cardiogénico, hemorrágico y séptico. La caída de la disponibilidad de O2 (DO2) llevaría a una reducción de la población mitocondrial y consecuentemente a una disminución del consumo de O2 (VO2). Esta secuencia permite atenuar y aun evitar la adquisición de una deuda de O2, considerada hasta hoy base fundamental de la fisiopatología del shock. El costo de esta adaptación mitocondrial es menor energía disponible y el déficit energético resultante ha sido relacionado con la falla orgánica múltiple (FOM), importante complicación de diversos procesos inflamatorios agudos y estados de shock. La FOM es mejor tolerada que el metabolismo anaeróbico y es potencialmente reversible si se revierten las causas desencadenantes y se reestablece el nivel energético por medio de la biogénesis mitocondrial.El desacople de la fosforilación oxidativa mitocondrial ocurre tanto en diversos modelos experimentales de shock como así también en el shock séptico en el hombre. Esta alteración mitocondrial puede ser detectada por un aumento desmesurado del VO2 en respuesta al incremento terapéutico de la DO2. Este aumento de la actividad metabólica puede ser equívocamente interpretado como la fase de repago de una deuda de O2.

Metabolic activity can be down-regulated throughout the reduction of mitochondrial population. Lowering O2 demand in cardiogenic, hemorrhagic and septic shock is here examined through clinical observations and trials. A decrease in the availability of O2 will be followed by reductions in mitochondrial population and, therefore, in a decrease in O2 demand. This response may lessen or prevent the acquisition of an O2 debt; until now, cornerstone in the pathophysiology of shock. The cost of this adaptation is less energy production, and the resulting energy deficit has been linked to multiple organ failure (MOF), a complication of acute inflammatory processes and shock. MOF is better tolerated than anaerobic metabolism and is potentially reversible if the triggering causes are reversed and the energy level is re-established through mitochondrial biogenesis.Decoupling of mitochondrial oxidative phosphorylation occurs in both experimental models and in clinical septic shock. In critical patients this phenomenon may be detected by an inordinate increase in VO2 in response to a therapeutically increased DO2. This hipermetabolic stage can be mistakenly interpreted as the repayment phase of an O2 debt.

A novel fluid resuscitation strategy modulates pulmonary transcription factor activation in a murine model of hemorrhagic shock

INTRODUCTION: Combining the hemodynamic and immune benefits of hypertonic saline with the anti-inflammatory effects of the phosphodiesterase inhibitor pentoxifylline (HSPTX) as a hemorrhagic shock resuscitation strategy reduces lung injury when compared with the effects of Ringer's lactate (RL). We hypothesized that HSPTX exerts its anti-inflammatory effects by interfering with nuclear factor kappa B/cAMP response element-binding protein (NF-êB-CREB) competition for the coactivator CREB-binding protein (CBP) in lung tissue, thus affecting pro-inflammatory mediator production. METHODS: Male Sprague-Dawley rats underwent 60 minutes of hemorrhagic shock to reach a mean arterial blood pressure of 35 mmHg followed by resuscitation with either RL or HSPTX (7.5 percent HS + 25 mg/kg PTX). After four hours, lung samples were collected. NF-êB activation was assessed by measuring the levels of phosphorylated cytoplasmic inhibitor of kappa B (I-êB) and nuclear NF-êB p65 by western blot. NF-êB and CREB DNA-binding activity were measured by electrophoretic mobility shift assay (EMSA). Competition between NF-êB and CREB for the coactivator CBP was determined by immunoprecipitation. Interleukin-8 (IL-8) levels in the lung were measured by ELISA. RESULTS: RL resuscitation produced significantly higher levels of lung IL-8 levels, I-êB phosphorylation, p65 phosphorylation, and NF-êB DNA binding compared with HSPTX. NF-êB-CBP-binding activity was similar in both groups, whereas CREB-CBP-binding activity was significantly increased with HSPTX. CREB-DNA binding-activity increased to a greater level with HSPTX compared with RL. DISCUSSION: HSPTX decreases lung inflammation following hemorrhagic shock compared with conventional resuscitation using RL through attenuation of NF-êB signaling and increased CREB-DNA binding activity. HSPTX may have therapeutic potential in the attenuation of ischemia-reperfusion...

High mobility group box 1 as a mediator of endotoxin administration after hemorrhagic shock-primed lung injury

High mobility group box 1 (HMGB1) was discovered as a novel late-acting cytokine that contributes to acute lung injury (ALI). However, the contribution of HMGB1 to two-hit-induced ALI has not been investigated. To examine the participation of HMGB1 in the pathogenesis of ALI caused by the two-hit hypothesis, endotoxin was injected intratracheally in a hemorrhagic shock-primed ALI mouse model. Concentrations of HMGB1 in the lung of the shock group were markedly increased at 16 h (1.63 ± 0.05, compared to the control group: 1.02 ± 0.03; P < 0.05), with the highest concentration being observed at 24 h. In the sham/lipopolysaccharide group, lung HMGB1 concentrations were found to be markedly increased at 24 h (1.98 ± 0.08, compared to the control group: 1.07 ± 0.03; P < 0.05). Administration of lipopolysaccharide to the hemorrhagic shock group resulted in a notable HMGB1 increase by 4 h, with a further increase by 16 h. Intratracheal lipopolysaccharide injection after hemorrhagic shock resulted in the highest lung leak at 16 h (2.68 ± 0.08, compared to the control group: 1.05 ± 0.04; P < 0.05). Compared to the hemorrhagic shock/lipopolysaccharide mice, blockade of HMGB1 at the same time as lipopolysaccharide injection prevented significantly pulmonary tumor necrosis factor-alpha, interleukin-1beta and myeloperoxidase. Lung leak was also markedly reduced at 16 h; blockade of HMGB1 24 h after lipopolysaccharide injection failed to alter lung leak or myeloperoxidase at 48 h. Our observations suggest that HMGB1 plays a key role as a late mediator when lipopolysaccharide is injected after hemorrhagic shock-primed ALI and the kinetics of its release differs from that of one-hit ALI. The therapeutic window to suppress HMGB1 activity should not be delayed to 24 h after the disease onset.

acute inflammatory response in trauma / hemorrhage and traumatic brain injury: current state and emerging prospects

Traumatic injury/hemorrhagic shock [T/HS] elicits an acute inflammatory response that may result in death. Inflammation describes a coordinated series of molecular, cellular, tissue, organ, and systemic responses that drive the pathology of various diseases including T/HS and traumatic brain injury [TBI]. Inflammation is a finely tuned, dynamic, highly-regulated process that is not inherently detrimental, but rather required for immune surveillance, optimal post-injury tissue repair, and regeneration. The inflammatory response is driven by cytokines and chemokines and is partially propagated by damaged tissue-derived products [Damage-associated Molecular Patterns; DAMP's]. DAMPs perpetuate inflammation through the release of pro-inflammatory cytokines, but may also inhibit anti-inflammatory cytokines. Various animal models of T/HS in mice, rats, pigs, dogs, and non-human primates have been utilized in an attempt to move from bench to bedside. Novel approaches, including those from the field of systems biology, may yield therapeutic breakthroughs in T/HS and TBI in the near future

Postmortem changes of liver phosphofructokinase-2 level in rats following different causes of death / 法医学杂志

OBJECTIVE@#To study the changes of liver phosphofructokinase-2 (PFK-2) level at different postmortem intervals as well as due to different causes of death.@*METHODS@#One hundred and five rats were randomly divided into 3 groups and the rats were sacrificed by either bleeding, suffocating, and neck breaking, respectively. The content of liver PFK-2 at 0, 1, 2, 4, 8, 12 and 24 hours following death were studied using immunohistochemishtry and image analysis.@*RESULTS@#PFK-2 content of the rat's liver in all 3 groups showed a linear decrease at different postmortem intervals with no significant statistical differences found between the different groups.@*CONCLUSION@#PFK-2 level in rat liver appears to decrease linearly in correlation with prolonged PMI.

Comparison of the contents of ATP, ADP, and AMP in the cardiac muscle of rat killed by different manners / 法医学杂志

OBJECTIVE@#The content changes of energy substances in the cardiac muscle of rat killed by different manners were investigated to elucidate evidence that can be used to determine the modes of death and postmortem interval.@*METHODS@#One hundred and eighty rats were randomly allocated into 3 groups and killed by bleeding, suffocating, and neck breaking, respectively. The contents of ATP, ADP, and AMP in the cardiac muscle of rats killed by the different manners at different death intervals (0, 0.5, 1, 1.5, 2, 3, 4, 6, 8, 12, 18, and 24 h) were measured by HPLC.@*RESULTS@#There were significant differences observed in the contents of ATP and AMP in the rats' cardiac muscle in different groups at most of the intervals (P < 0.05) and at all of the intervals within the same group (P < 0.01), but no differences were found in the ADP contents in any of the group at most of the intervals.@*CONCLUSION@#The content changes of energy substances (ATP and AMP) in the cardiac muscle of dead rats may provide a basis for determination of the death manners and postmortem intervals.

Investigating the relationship between hemodynamic and metabolic parameters in portal triade occlusion following hemorrhagic shock

OBJETIVO: com a utilização de um modelo experimental, determinar se as alterações hemodinâmicas e metabólicas estão "matematicamente" relacionadas em ratos submetidos a estado de choque hemorrágico controlado seguido de isquemia hepática total. MÉTODOS: O coeficiente de correlação de Pearson (valor r) foi utilizado para determinação das fórmulas matemáticas. Diferenças foram consideradas significativas com p<0,05 e -0,50>r>0.50. RESULTADOS: Encontrou-se uma relação diretamente proporcional para o HCO3- quando comparado com pCO2 (r=0,66) e com o déficit de base (r=0,87); e inversamente proporcional quando comparado com o lactato sérico (r=-0,54). O pCO2 esteve diretamente relacionado com a PAM (r=0,51) e inversamente com o pH (r=-0,64). O hematócrito esteve diretamente associado com a freqüência cardíaca (r=0,72) e, também, com o índice cardíaco (r=0,70). O lactato sérico esteve inversamente associado com o déficit de base (r=-0,61). CONCLUSAO: Em ratos submetidos ao estado de choque hemorrágico controlado, por 20 minutos, seguido de manobra de Pringle, por 15 minutos, diversas variáveis hemodinâmicas e metabólicas estão matematicamente associadas.

Lipid peroxidation in haemorrhagic shock and after transfusion of blood in dogs.

The present study was carried out on mongrel dogs. Haemorrhagic shock of different severities and duration was produced by exsanguination from an artery. After the required duration of shock, two third of the volume of blood withdrawn was transfused back into the animal. Effect of haemorrhage and reperfusion of blood after haemorrhagic shock on lipid peroxidation was assessed by measuring plasma malondialdehyde (MDA). Severity of shock was assessed from the haematocrit values. There was a significant increase (P < 0.05) in plasma MDA level after blood transfusion in a group having 40 mm Hg blood pressure as magnitude of shock and one hour as duration of shock (Group II) only. Haemotocrit value was also significantly low (P < 0.05) in this group after haemorrhagic shock. Results are suggestive of lipid peroxidation with ischaemic reperfusion in severe and long duration of shock.

Blood glucose and lactate levels during hemorrhagic shock reversion by hypertonic NaCl solution

1. Several studies have shown that in irreversible hemorrhagic shock the liver is one of the first vital organs to present metabolic alterations accompanied by an increase in lacticemia. Intravenous infusion of hypertonic solutions increases mesenteric flow as well as liver perfusion, an effect which can be blocked by vagotomy. 2. In the present study we investigate the possible role of the increase in mesenteric flow in the prevention of hepatic failure evaluated by the arterial-venous difference in the generation of glucose from lactate during the reversal of hemorrhagic shock with hypertonic NaCl solution and the possible blockage of this response by bilateral vagotomy. 3. Twenty-eight male dogs, weighing 14-20 kg, were submitted to severe hemorrhagic shock. The animals were then divided into four groups: a) HYPER, 2400 mosm/l NaCl; b) SALINE, 300 mosm/l NaCl; c) HYPERVg, 2400 mosm/l NaCl immediately after bilateral vagotomy; d) SALINEVg, 300 mosm/l NaCl immediately after bilateral vagotomy. Each group received an intravenous infusion of 10 of the shed blood volume of NaCl infusion. 4. Arterial and venous samples were collected to monitor the levels of lactate, glucose and insulin. During hemorrhage, arterial and venous lactate concentrations increased. After infusion, arterial lactate levels decreased from 332 +/- 23 to 115 +/- 12 in the HYPER group in contrast to the SALINE group where it increased from 327 +/- 20 to 422 +/- 19. 5. The decrease in arterial lactate observed after hypertonic solution infusion (2400 mosm/l), in dogs with intact vagus, suggests an increase of lactate uptake by heart and liver. Thus the beneficial effect of hypertonic solution in the reversal of hemorrhagic shock may be to enhance blood flow and oxygen delivery to the liver which would maintain glucose production and prevent hepatic failure. All the metabolic effects of hypertonic solution were abolished by vagotomy.