Acute treatment with bone marrow-derived mononuclear cells attenuates the organ injury/dysfunction induced by hemorrhagic shock in the rat

Recent evidence suggests that cell therapy such as the injection of bone marrow-derived mononuclear cells (BMMNCs) can exert protective effects in various conditions associated with ischemia-reperfusion injury. Here, we investigate the effects of BMMNCs on the organ injury/dysfunction induced by hemorrhagic shock (HS). Thirty-seven anesthetized male Wistar rats were subjected to hemorrhage by reducing mean arterial pressure to 35 ± 5 mmHg for 90 min, followed by resuscitation with 20 mL/kg Ringer's lactate administered over 10 min and 50% of the shed blood over 50 min. Rats were killed 4 h after the onset of resuscitation. Bone marrow-derived mononuclear cells were freshly isolated from rat tibias and femurs using Percoll density gradient centrifugation, and BMMNCs (1 × 10 cells per rat in 1 mL/kg phosphate-buffered saline, i.v.) were administered on resuscitation. Hemorrhagic shock resulted in significant organ injury/dysfunction (renal, hepatic, neuromuscular) and inflammation (hepatic, lung). In rats subjected to HS, administration of BMMNCs significantly attenuated (i) organ injury/dysfunction (renal, hepatic, neuromuscular) and inflammation (hepatic, lung), (ii) increased the phosphorylation of Akt and glycogen synthase kinase-3β, (iii) attenuated the activation of nuclear factor-κB, (iv) attenuated the increase in extracellular signal-regulated kinase 1/2 phosphorylation, and (v) attenuated the increase in expression of intercellular adhesion molecule-1. Our findings suggest that administration of BMMNCs protects against the induction of early organ injury/dysfunction caused by severe HS by a mechanism that may involve activation of Akt and the inhibition of glycogen synthase kinase-3β and nuclear factor-κB.     

Superoxide dismutase mimetics with catalase activity reduce the organ injury in hemorrhagic shock

Reactive oxygen species (ROS) contribute to the multiple organ failure (MOF) in hemorrhagic shock. Here we investigate the effects of two superoxide dismutase (SOD) mimetics with catalase activity (EUK-8 and EUK-134) on the circulatory failure and the organ injury and dysfunction associated with hemorrhagic shock in the anesthetised rat. Hemorrhage (sufficient to lower mean arterial blood pressure to 45 mmHg for 90 min) and subsequent resuscitation with shed blood resulted (within 4 h after resuscitation) in a delayed fall in blood pressure, liver injury and renal dysfunction as well as pancreatic injury. Treatment of rats on resuscitation with EUK-8 (3 mg/kg i.v. bolus followed by 3 mg/kg/h i.v. infusion) significantly attenuated liver injury, renal dysfunction and pancreatic injury caused by hemorrhage and resuscitation. Administration of EUK-134 (3 mg/kg i.v. bolus followed by 3 mg/kg/h) reduced the liver injury and renal dysfunction (but not the pancreatic injury) caused by hemorrhagic shock. However, neither EUK-8 nor EUK-134 reduced the delayed circulatory failure associated with hemorrhagic shock. Thus, we propose that an enhanced formation of ROS contributes to the MOF in hemorrhagic shock, and that membrane-permeable SOD-mimetics with catalase activity, such as EUK-8 or EUK-134, may represent a novel therapeutic approach for the therapy of hemorrhagic shock.     

Adenosine A2A receptor activation reduces lung injury in trauma/hemorrhagic shock

OBJECTIVE: Hemorrhagic shock and resuscitation trigger a global ischemia/reperfusion phenomenon, in which various inflammatory processes critically contribute to the ensuing tissue damage. Adenosine is an endogenous nucleoside that is released during shock. Activation of adenosine A(2A) receptors can broadly inactivate inflammatory cascades. The current study was designed to evaluate the effect of A(2A) receptor activation on organ injury and inflammation in the setting of global ischemia/reperfusion elicited by trauma/hemorrhagic shock and resuscitation. DESIGN: Prospective animal study with concurrent control. SETTING: Small animal laboratory. SUBJECTS: Adult male Sprague-Dawley rats. INTERVENTIONS: The rats were subjected to a laparotomy (trauma) and 90 mins of hemorrhagic shock or trauma/sham shock. The selective A(2A) receptor agonist CGS-21680 (2-p-(2-carboxyethyl) phenethylamino-5'-N-ethyl-carboxamidoadenosine; 0.5 mg/kg) or its vehicle was injected 30 mins before shock or immediately after resuscitation. At 3 hrs following resuscitation, animals were killed and tissue was harvested for analysis. Lung permeability and pulmonary myeloperoxidase levels were used to quantitate lung injury. Intestinal injury was determined by histologic analysis of terminal ileum. Red blood cell deformability was measured by a laser-assisted ektacytometer. In this assay, a decrease in the elongation index is a marker of decreased red blood cell deformability. MEASUREMENTS AND MAIN RESULTS: Pretreatment with CGS-21680 protected the lung but not the gut against shock-induced injury and prevented the shock-induced decrease in red blood cell deformability. Posttreatment with CGS-21680 ameliorated shock-induced lung injury but failed to prevent gut injury and preserve red blood cell deformability. CONCLUSION: A(2A) receptor agonists may represent a novel therapeutic approach in preventing organ injury following trauma/hemorrhagic shock.     

A membrane-permeable radical scavenger reduces the organ injury in hemorrhagic shock.

Reactive oxygen species (ROS) contribute to the multiple organ failure (MOF) in hemorrhagic shock. Here we investigate the effects of a membrane-permeable radical scavenger (tempol) on the circulatory failure and the organ injury and dysfunction (kidney, liver, lung, intestine) associated with hemorrhagic shock in the anesthetized rat. Hemorrhage (sufficient to lower mean arterial blood pressure to 500 mmHg for 90 min) and subsequent resuscitation with shed blood resulted (within 4 h after resuscitation) in a delayed fall in blood pressure, renal and liver injury and dysfunction as well as lung and gut injury. In all organs, hemorrhage and resuscitation resulted in the nitrosylation of proteins (determined by immunohistochemistry for nitrotyrosine) suggesting the formation of peroxynitrite and/or reactive oxygen species. Treatment of rats upon resuscitation with the membrane-permeable radical scavenger tempol (30 mg/kg bolus injection followed by an infusion of 30 mg/kg/h i.v.) attenuated the delayed circulatory failure as well as the multiple organ injury and dysfunction associated with hemorrhagic shock. Thus, we propose that an enhanced formation of ROS and/or peroxynitrite importantly contributes to the MOF in hemorrhagic shock, and that membrane-permeable radical scavengers, such as tempol, may represent a novel therapeutic approach for the therapy of hemorrhagic shock.     

Effects of albumin and Ringer's lactate on production of lung cytokines and hydrogen peroxide after resuscitated hemorrhage and endotoxemia in rats

RATIONALE AND HYPOTHESIS: Acute lung injury is a frequent complication of severe sepsis or blood loss and is often associated with an excessive inflammatory response requiring mechanical ventilation. We tested the hypothesis that the types of fluids used during early resuscitation have an important effect on the evolution of lung injury. METHODS: Rats were subjected to either hemorrhage or endotoxemia for 1 hr, followed by resuscitation to a controlled mean blood pressure with Ringer's lactate, 5% albumin, or 25% albumin for 1 hr. After resuscitation, blood cytokine levels were measured. The lung was then excised and ventilated with a tidal volume of 30 mL/kg for 2 hrs. RESULTS: The volume of fluids required was significantly smaller in the albumin-treated groups than in the Ringer's lactate groups. In the hemorrhagic shock model, plasma concentrations of tumor necrosis factor-alpha, interleukin-6, and macrophage inflammatory protein-2 were significantly lower and interleukin-10 was significantly higher in the albumin-treated groups compared with the Ringer's lactate-treated group. The levels of tumor necrosis factor-alpha and macrophage inflammatory protein-2 in bronchoalveolar lavage fluid were lower and interleukin-10 was higher in the albumin-treated groups than in the Ringer's lactate group. The decreased cytokine production was associated with a reduction of hydrogen peroxide formation with albumin resuscitation. The lung wet/dry ratio was lower in the 5% albumin (0.54 +/- 0.01) and 25% albumin (0.55 +/- 0.02) groups than in the Ringer's lactate group (0.62 +/- 0.02; both p <.05). These effects of albumin seen in the hemorrhagic shock model were not observed in the endotoxic shock model. CONCLUSIONS: We conclude that resuscitation with albumin may have utility in reducing ventilator-induced lung injury after hemorrhagic shock, but not after endotoxic shock. These findings suggest that the mechanisms leading to ventilator-induced lung injury after hemorrhage differ from those after endotoxemia.     

高渗氯化钠溶液复苏抑制失血性休克大鼠肺细胞凋亡的初步研究

目的 探讨高渗氯化钠溶液(HS)复苏对失血性休克大鼠肺细胞凋亡的影响及其意义. 方法 将23只SD大鼠制作成重度失血性休克模型,随机分为假手术组(Sham组,8只)、高渗氯化钠溶液复苏组(HS组,9只)和等渗盐水复苏组(NS组,6只),采用流式细胞仪FITC-AnnexinV/PI荧光染色法定量测定休克/复苏后各组大鼠肺组织细胞的凋亡情况,并加以比较和分析. 结果 在失血性休克/复苏后的早期阶段,HS组和NS组大鼠的肺组织细胞即有大量凋亡发生,其肺细胞凋亡率均明显高于Sham组,差异有统计学意义(P＜0.01).同时,NS组大鼠的肺细胞凋亡率则显著高于HS组,差异有统计学意义(P＜0.01). 结论 在重度失血性休克大鼠模型中,与等渗盐水复苏相比较,高渗氯化钠溶液复苏能显著抑制失血/复苏后肺细胞的凋亡,有助于减轻休克后急性肺损伤,这可能也是高渗氯化钠溶液复苏肺保护作用的重要机制之一.     

高压氧防止创伤/失血性休克复苏后大鼠肠道缺血-再灌注损伤

目的 观察高压氧(HBO)对创伤/失血性休克复苏后大鼠肠道缺血-再灌注损伤的保护作用并探讨其作用机制.方法Wistar大鼠用铁块砸击左侧股骨并同时通过右颈动脉放血建立创伤/失血性休克模型,随后进行自体血和液体复苏.大鼠随机分成对照组、休克组、HBO一次和三次治疗组.结果 复苏24 h后HBO一次和三次组大鼠肠道组织乳酸含量、诱生型一氧化氮合成酶(iN0s)活性、一氧化氮(NO)和肿瘤坏死因子-α(TNF-α)水平均明显低于休克组(P<0.05);HBO一次和三次组中肠组织病理损伤评分明显低于休克组(P<0.05).电镜显示休克组肠黏膜上皮细胞肿胀,微绒毛广泛脱落;线粒体肿胀,嵴消失,形成空泡,广泛线粒体溶解;桥粒连接稀疏,细胞间紧密连接开放.HBO一次和三次组上述改变明显减轻:线粒体部分溶解,嵴部分消失,紧密连接得以保存.HBO三次组在以上所有的指标中均要好于HBO一次组,但差异无统计学意义(P>0.05).结论HBO可以减少创伤性休克后肠道组织炎性细胞因子的产生,减轻炎症反应,保护肠道组织和黏膜屏障免受创伤/失血性休克后缺血/再灌注的损伤.     

Limb ischemic preconditioning mitigates lung injury induced by haemorrhagic shock/resuscitation in rats

Aim of the study

Haemorrhagic shock and subsequent resuscitation induce acute lung injury. We elucidated whether bilateral lower limb ischemic pre-conditioning (IP) could mitigate lung injury in haemorrhagic shock/resuscitation rats. The role of heme oxygenase-1 (HO-1) was also elucidated.

Method

Adult male rats were randomized to receive haemorrhagic shock/resuscitation (HS), HS plus IP, or HS plus IP plus the HO-1 inhibitor tin protoporphyrin (SnPP) (n = 12 in each group). Sham groups were employed simultaneously. For pre-conditioning, 3 cycles of limb IP (10 min ischemia followed by 10 min reperfusion) were performed immediately before haemorrhagic shock. Haemorrhagic shock (mean arterial pressure: 40-45 mmHg) was induced by blood drawing and maintained for 120 min. SnPP was injected 5 min before resuscitation. Shed blood/saline mixtures were re-infused to achieve resuscitation. After monitoring for another 8 h, rats were sacrificed. Arterial blood gas and alveolar-arterial oxygen difference (lung function index), histology, polymorphonuclear leukocytes/alveoli ratio (leukocyte infiltration index), wet/dry weight ratio (water content index), inflammatory molecules (e.g., chemokine, cytokine, prostaglandin E₂), and malondialdehyde (lipid peroxidation index) assays were preformed.

Results

Haemorrhagic shock/resuscitation induced significant lung function alterations and significant increases in leukocyte infiltration, water content, inflammation, and lipid peroxidation in lungs. Histological analysis confirmed that haemorrhagic shock/resuscitation caused marked lung injury. Limb IP significantly mitigated the adverse effects of haemorrhagic shock/resuscitation. Moreover, the protective effects of limb IP were reversed by SnPP.

Conclusions

Limb IP mitigates lung injury in haemorrhagic shock/resuscitation rats. The mechanisms may involve HO-1.     

Glycogen synthase kinase-3beta inhibitors protect against the organ injury and dysfunction caused by hemorrhage and resuscitation

Glycogen synthase kinase 3beta (GSK-3beta) is a serine/threonine protein kinase that has recently emerged as a key regulatory switch in the modulation of the inflammatory response. Dysregulation of GSK-3beta has been implicated in the pathogenesis of several diseases including sepsis. Here we investigate the effects of 2 chemically distinct inhibitors of GSK-3beta, TDZD-8 and SB216763, on the circulatory failure and the organ injury and dysfunction associated with hemorrhagic shock. Male Wistar rats were subjected to hemorrhage (sufficient to lower mean arterial blood pressure to 35 mmHg for 90 min) and subsequently resuscitated with shed blood for 4 h. Hemorrhage and resuscitation resulted in an increase in serum levels of (a) creatinine and, hence, renal dysfunction, and (b) alanine aminotransferase and aspartate aminotransferase and, hence, hepatic injury. Treatment of rats with either TDZD-8 (1 mg/kg, i.v.) or SB216763 (0.6 mg/kg, i.v.) 5 min before resuscitation abolished the renal dysfunction and liver injury caused by hemorrhagic shock. In addition, TDZD-8, but not SB216763, attenuated the increase caused by hemorrhage and resuscitation in plasma levels of the proinflammatory cytokine interleukin 6 and also of the anti-inflammatory cytokine interleukin 10. Neither of the GSK-3beta inhibitors however affected the delayed fall in blood pressure caused by hemorrhagic shock. Thus, we propose that inhibition of GSK-3beta may represent a novel therapeutic approach in the therapy of hemorrhagic shock.     

失血性休克再灌注大鼠血液NO、NOS的改变和丹参的作用

目的探讨失血性休克再灌注大鼠血液中一氧化氮(NO)、一氧化氮合酶(NOS)含量的变化及丹参对其的影响。方法健康SD大鼠30只,随机平分成正常对照组(NC组)、失血性休克再灌注组(HS-R组)和丹参治疗组(SM组)。分别测定三组血清NO、NOS含量。结果与NC组相比较,HS-R组血清NO、NOS含量明显增高(P<0.01)。SM组的血清NO、NOS含量明显低于HS-R组(P<0.01)。结论失血性休克再灌注时NOS大量激活,使NO产生增多,NO介导了失血性休克再灌注损伤,大量释放的NO参与休克再灌注损伤的脂质过氧化反应;丹参通过减少NO的生成,抗脂质过氧化反应而发挥其保护作用。     

Neuron-specific-enolase is increased in plasma after hemorrhagic shock and after bilateral femur fracture without traumatic brain injury in the rat

Neuron-specific enolase (NSE) is an acknowledged marker of traumatic brain injury. Several markers originally considered reliable in the setting of traumatic brain injury have been challenged after having been studied more extensively. The aim of our experimental study was to determine whether NSE is a reliable marker of traumatic brain injury early after trauma. Hemorrhagic shock was achieved by bleeding anesthetized rats to a mean arterial pressure (MAP) of 30-35 mmHg through a femoral catheter until incipient decompensation. MAP was maintained at 30-35 mmHg until 40% of shed blood had been administered as Ringer's solution and was then increased and maintained at 40-45 mmHg for 40 min by further administration of Ringer's solution, mimicking the phase of inadequate preclinical resuscitation. Blood samples were drawn at the end of the 40-min period of inadequate resuscitation. Femur fracture was achieved in anesthetized rats by bilateral application of forceps. Blood samples were drawn 30 and 60 min after fracture. Hemorrhagic shock caused NSE increase versus laboratory controls at the end of inadequate resuscitation (P < 0.01). Bilateral femur fracture caused NSE increase versus laboratory controls 30 min after fracture, which was significant 60 min after fracture (P < 0.01). During femur fracture, MAP remained at a level that is not associated with shock in rats. Our findings show for the first time that NSE increases after hemorrhagic shock as well as after femur fracture without hemorrhagic shock in rats. From a clinical point of view, these findings indicate that NSE cannot be considered a reliable marker of traumatic brain injury early after trauma in cases associated with hemorrhagic shock and/or femur fracture.     

Lazaroid U-83836E Improves Tolerance to Hemorrhagic Shock and Limb Ischemia and Reperfusion in Rats and Increases Cardiac Heat Shock Protein 72

Objectives: Aminosteroids of the lazaroid type protect organs from ischemia–reperfusion damage. The authors hypothesized that lazaroid U‐83836E may be beneficial in a shock model with hemorrhage combined with limb ischemia. Furthermore, the authors hypothesized that lazaroids induce expression of heat shock proteins (HSPs) of the 72‐kDa family. Methods: Rats were divided into two groups (lazaroid and control groups, n= 8 each) and pretreated with the lazaroid U‐83836E (5 mg/kg) or with vehicle intraperitoneally at 12 and 24 hours before experiments. At the time of the experiment, rats were anesthetized, and the femoral artery of each rat was cannulated. After 20 minutes of stabilization, blood was shed from each rat to bring its mean arterial pressure to 24–28 mmHg for 2 hours. Bilateral tourniquets were tightened proximally on the rat thighs during those 2 hours and then released. Shed blood plus equal amounts of Ringer acetate then were infused to restore normal blood pressure, followed by a continuous infusion of Ringer acetate, the rate of which was regulated to maintain blood pressure, until 30 minutes after start of resuscitation. Fluid resuscitation was stopped, and rats were observed for another 3.5 hours. At the end of the observation period, the rats' hearts were collected for immunoblot analysis of HSP72. Additional hearts were collected from similarly pretreated rats not undergoing the episode of hemorrhagic shock and fluid resuscitation. Results: Pretreatment with U‐83836E improved mean arterial blood pressure after hemorrhagic shock and fluid resuscitation (p = 0.02), combined with improvements in acid–base balance (improved base excess and standard bicarbonate; p = 0.02 and p = 0.01, respectively). Western blot of cardiac protein extracts demonstrated that lazaroid pretreatment increased expression of HSP72. Conclusions: Pretreatment with the lazaroid U‐83836E improved outcome markers in this hemorrhagic shock model. The observed protection may be caused by increased expression of HSP72.     

Membrane-permeable radical scavenger, tempol, reduces multiple organ injury in a rodent model of gram-positive shock

OBJECTIVE: An enhanced formation of reactive oxygen species contributes to the multiple organ dysfunction syndrome (MODS) caused by endotoxin. We have recently discovered that two cell wall components, namely lipoteichoic acid (LTA) and peptidoglycan (PepG) of the gram-positive bacterium, Staphylococcus aureus, synergize to cause shock and MODS in the rat. Here, we investigate the effects of a membrane-permeable radical scavenger (tempol) on the circulatory failure and MODS (kidney, liver, lung) caused by coadministration of LTA (3 mg/kg i.v.) and PepG (10 mg/kg i.v.) in the anesthetized rat. DESIGN: Prospective, randomized study. SETTING: University-based research laboratory. SUBJECTS: Thirty-four anesthetized, male Wistar rats. INTERVENTIONS: After surgical preparation, anesthetized rats were observed for 6 hrs. Control rats were given vehicle (control plus saline, 2 mL/kg bolus injection, followed by an infusion of 1.5 mL/kg i.v., n = 6) or tempol (control plus tempol, 100 mg/kg i.v. bolus injection, followed by an infusion of 30 mg/kg i.v., n = 6). Gram-positive septic shock was induced by coadministration of LTA (3 mg/kg i.v.) and PepG (10 mg/kg i.v.) (LTA/PepG plus saline, n = 12). Another group of rats was pretreated with tempol before shock was induced (LTA/PepG plus tempol, 100 mg/kg i.v. bolus injection, 15 mins before LTA/PepG administration, followed by an infusion of 30 mg/kg i.v., n = 10). MEASUREMENTS AND MAIN RESULTS: Within 6 hrs, administration of LTA/PepG resulted in hypotension, acute renal dysfunction, hepatocellular injury, pancreatic injury, and increased plasma concentrations of nitrite/nitrate. Pretreatment of rats with tempol augmented the hypotension but attenuated the renal dysfunction and the hepatocellular injury/dysfunction caused by LTA/PepG. Tempol did not affect the increase in nitrite/nitrate caused by LTA/PepG. CONCLUSIONS: These results imply that an enhanced formation of reactive oxygen species (including superoxide anions) contributes to the kidney and liver injury and dysfunction caused by LTA/PepG in the anesthetized rat.     

Hypertonic saline and pentoxifylline prevent lung injury and bacterial translocation after hemorrhagic shock

Previous reports have shown beneficial effects of pentoxifylline (PTX) and hypertonic saline (HS) in the treatment of hemorrhagic shock. We compared the effects of these solutions to those of conventional lactated Ringer's (LR) treatment on bacterial translocation (BT), lung injury and total and differential cell count in the bronchoalveolar lavage fluid (BAL) after hemorrhagic shock. Rats (280-330 g) were bled to a MAP of 35 mmHg for 1 h and then randomized into 4 groups: LR (3x shed blood); HS (7,5% NaCl, 4 mL/kg); LR+PTX (25 mg/kg) and SHAM (no shock, no treatment). Additionally, total shed blood was reinfused. At 24 h lung injury was analyzed by a pathologist blinded to the groups, and a score was calculated. BT was determined by microbiological cultures of mesenteric lymph node complex. BAL was performed on a separate set of animals that received the same treatments. Lung score was significantly higher in LR group (11.5+/-1.4) as compared to HS (6.8+/-0.9), and PTX treated animals (7.2+/-0.9). The percentage of neutrophils in the BAL of LR animals (15.8%) was also significantly higher as compared with HS (5.25%) and PTX groups (9.72%). BT was noted in 50% of rats for LR group, 30% for PTX, 10% for HS and 0% for sham group. HS and PTX reduced BT and lung injury after hemorrhage. Attenuation of lung injury could be the result of less neutrophil infiltration into the lungs of HS and PTX treated animals. LR resuscitation caused pronounced lung injury and BT.     

Dependence of liver injury after hemorrhage/resuscitation in mice on NADPH oxidase-derived superoxide

Hemorrhagic shock and resuscitation cause hepatocellular damage by mechanisms involving oxidative stress. However, the sources of free radicals mediating hepatocellular injury remain controversial. Thus, this study tested the hypothesis that NADPH oxidase plays a role in producing hepatocellular injury after hemorrhagic shock and resuscitation. Both wild-type and NADPH oxidase-deficient mice (p47(phox) knockout mice) were subjected to hemorrhagic shock (3 h at 30 mmHg). The mice were resuscitated over 30 min with the shed blood and additional lactated Ringer's solution (50% of the shed blood volume). Serum alanine aminotransferase (ALT) levels increased at 1 and 6 h postresuscitation in wild-type animals to 4735 +/- 1017 IU/L and 1450 +/- 275 IU/L (mean +/- SE), respectively, whereas in knockout mice, this ALT increase was blunted at both time points (732 +/- 241 IU/L and 328 +/- 69 IU/L, P < 0.05). Liver necrosis assessed histologically 6 h after the end of reperfusion was also attenuated in the knockout mice (3.5% +/- 0.95% of area vs. 0.9% +/- 0.26%, P < 0.05). In hemorrhaged wild-type mice, infiltrating neutrophils were twice as numerous compared with hemorrhaged NADPH oxidase-deficient animals 6 h after reperfusion. In knockout animals, hepatic 4-hydroxynonenal content, indicative of lipid peroxidation from reactive oxygen species, was blunted (6.7% +/- 0.6% vs. 26.4% +/- 2.3% of stained area, P < 0.05), as shown by immunohistochemistry. Immunohistochemical staining for 3-nitrotyrosine, indicative of reactive nitrogen species formation, was also blunted in the livers of knockout mice (11.6% +/- 2.8% vs. 37.4% +/- 3.4, P < 0.05). In conclusion, hemorrhagic shock and resuscitation cause hepatocellular damage via NADPH oxidase-mediated oxidative stress. The absence of NADPH oxidase substantially attenuates hepatocellular injury after hemorrhagic shock and resuscitation, blunts neutrophil infiltration, and decreases formation of reactive oxygen and reactive nitrogen species.     

Effects of RU486 on Glu-6-pase gene expression in hemorrhage and resuscitation

To assess the role of glucocorticoid receptor antagonists and mediators released by Kupffer cells and other resident macrophages, we have used RU486 and gadolinium chloride to prevent the induction of glucose-6-phosphatase (Glu-6-Pase) gene expression in the liver following hemorrhagic shock (HS) and lactated Ringer's (LR) solution resuscitation. HS was induced in fasted, anesthetized, and cannulated rats by rapid phlebotomy to a mean arterial pressure of 40 mmHg and maintained for 30 min by withdrawal or infusion of blood. The LR solution group underwent induction and maintenance of HS for 30 min followed by LR resuscitation. Rats were injected with gadolinium chloride (7 mg/kg) to inhibit the phagocytic function of Kupffer cells, and with glucocorticoid receptor antagonist RU486 (20 mg/kg) prior to induction of HS. Arterial blood samples were obtained and livers were freeze clamped in liquid nitrogen and stored at -70 degrees C for subsequent analysis. Northern blot analysis indicated that Glu-6-Pase mRNA abundance increased 2-fold in HS rats and a further 2-fold with resuscitation. Gadolinium chloride administration had no significant effect on Glu-6-Pase mRNA abundance in HS or in LR solution. In contrast, RU486 pre-treatment reduced Glu-6-Pase mRNA by about one half in HS rats compared with control and that in LR solution to normal. This was associated with a normalization of Glu-6-Pase activity and plasma glucose toward pre-hemorrhage levels. These results suggest that gadolinium chloride inhibition of macrophage factor release has no effect on the induction of Glu-6-Pase mRNA during HS or in LR solution resuscitation. On the other hand, the suppression of Glu-6-Pase mRNA by RU486 suggests that glucocorticoids are responsible for the induction of the mRNA in HS and during LR resuscitation. KEYWORDS-Shock, hyperglycemia, corticosterone, gadolinium chloride, diltiazem, animal model, mRNA     

高渗氯化钠溶液复苏对失血性休克大鼠T淋巴细胞亚群的早期影响

目的 探讨高渗氯化钠溶液(HS)复苏对失血性休克大鼠T淋巴细胞亚群的早期影响及其意义.方法 将18只SD大鼠制作成重度失血性休克模型,随机分为假手术组(Sham组)、高渗氯化钠溶液复苏组(HS组)和等渗盐水复苏组(NS组),每组6只,采用双抗体标记流式细胞分析技术测定休克前及复苏/急救后各组大鼠的外周血CD4+、CD8+的百分率及二者比值CD4+/CD8+.结果 在失血性休克/复苏/急救后的早期阶段,HS组和NS组大鼠的外周血CD4+细胞亚群表达均显著升高(P＜0.05),HS组大鼠的外周血CD8+细胞亚群表达也有所升高,而NS组大鼠的外周血CD8+细胞亚群表达则无明显改变,从而导致NS组大鼠的外周血CD4+/CD8+比值较Sham组和HS组明显增高,差异具有统计学意义(P＜0.05).结论 在重度失血性休克大鼠模型中,与NS复苏相比较,HS复苏能明显减轻复苏后早期的免疫炎症调节功能紊乱,有助于维持T细胞的辅助-抑制免疫炎症调节网络的平衡.     

Kupffer cells and neutrophils as paracrine regulators of the heme oxygenase-1 gene in hepatocytes after hemorrhagic shock

Heme oxygenase (HO) plays a pivotal role for the maintenance of liver blood flow and hepatocellular integrity after hemorrhagic shock. We investigated the role of Kupffer cells and neutrophils as paracrine modulators of hepatocellular HO-1 gene expression in a rat model of hemorrhage and resuscitation. Male Sprague-Dawley rats (n = 6-10/group) were anesthetized (pentobarbital, 50 mg/kg intraperitonal) and subjected to hemorrhagic shock (mean arterial blood pressure: 35 mmHg for 60 min) or a sham protocol. Based on the time course of HO-1 gene expression, the effect of various antioxidants, Kupffer cell blockade [gadolinium chloride (GdCl3); 10 mg/kg; 24 h prior to hemorrhage or dichloromethylene diphosphonate (Cl2MDP); 1 mg/kg; 2 days prior to hemorrhage], or neutrophil depletion (vinblastine, 0.5 mg/kg, 5 days prior to hemorrhage) on induction of the HO-1 gene was assessed at 5 h of resuscitation, i.e., the time point of maximal induction. Kupffer cell blockade and antioxidants abolished HO-1 mRNA and protein induction after hemorrhage, while neutrophil depletion failed to affect hepatocellular HO-1 gene expression. In addition, Kupffer cell blockade aggravated hepatocellular injury. N-formyl-methionine-leucyl-phenylalanin (fMLP) induced a substantial influx of neutrophils into the liver but failed to induce hepatocellular HO-1 mRNA expression. These data suggest that Kupffer cells but not neutrophils induce an adaptive hepatocellular stress response after hemorrhage and resuscitation. Oxygen-free radicals released by Kupffer cells may serve as paracrine regulators of a hepatocellular stress gene which is necessary to maintain liver blood flow and integrity under stress conditions.