Trauma/hemorrhagic shock mesenteric lymph upregulates adhesion molecule expression and IL-6 production in human umbilical vein endothelial cells

Trauma/hemorrhagic shock (T/HS) is associated with significant lung injury, which is mainly due to an inflammatory process, resulting from the local activation and subsequent interaction of endothelial cells and leukocytes. Adhesion molecules expressed by both cell types play a crucial role in the process of neutrophil-mediated endothelial cell injury. We have previously shown that mesenteric lymph duct ligation prevents T/HS-induced lung leukocyte infiltration and endothelial injury, suggesting that inflammatory factors originating from the gut and carried in the lymph are responsible for the lung injury observed following T/HS. Based on these observations, we hypothesized that inflammatory substances in T/HS lymph trigger lung injury by a mechanism involving the upregulation of adhesion molecules. To test this hypothesis, we examined whether T/HS mesenteric lymph induces the expression of E-selectin, P-selectin, and intracellular adhesion molecule-1 (ICAM-1) in human umbilical vein endothelial cells (HUVECs). Furthermore, because the cytokine IL-6 is an important component of the endothelial inflammatory process, we investigated how T/HS lymph affects the production of IL-6 by HUVECs. Mesenteric lymph from T/HS rats increased both E- and P-selectin, as well as ICAM-1 expression on HUVECS, as compared to trauma/sham shock (T/SS) lymph or medium only groups. However, T/HS lymph failed to induce the shedding of E-selectin. In HUVECs treated with T/HS lymph, IL-6 concentrations were higher than HUVECs treated with T/SS lymph. These findings suggest that mesenteric lymph produced after hemorrhagic shock potentiates lung injury by the upregulation of endothelial cell adhesion molecule expression and IL-6 production.     

Hemorrhagic shock induces endothelial cell apoptosis, which is mediated by factors contained in mesenteric lymph

OBJECTIVE: Trauma-hemorrhagic shock is one of the leading causes of acute respiratory distress syndrome. This syndrome is associated with disruption of the alveolar barrier consisting of both epithelial and endothelial cells, which leads to a major increase in epithelial and microvascular permeability in the lungs. Although alveolar epithelial cell apoptosis has been documented as a contributing factor to this increase in permeability, it is unclear whether endothelial cell apoptosis occurs following trauma-hemorrhagic shock and, if so, the source of factors leading to this process. DESIGN: Prospective animal study with concurrent control. SETTING: Small-animal laboratory. SUBJECTS: Adult male Sprague-Dawley rats. INTERVENTIONS: Trauma-hemorrhagic shock in rats was induced by laparotomy followed by blood withdrawal to achieve a mean arterial blood pressure of 30 mm Hg for 90 mins. At the end of the shock period, the rats were resuscitated, and 3 hrs later lungs were taken for histologic analysis. In other experiments, mesenteric lymph was collected from trauma-hemorrhagic shock and trauma-sham shock rats, and the biological activity of these lymph samples was tested for their ability to kill cultured endothelial cells or endothelial cells of isolated femoral veins. MEASUREMENTS AND MAIN RESULTS: Trauma-hemorrhagic shock triggered endothelial cell apoptosis in the lung as assessed using the Tunnel assay as well as by light and electron microscopic analysis. Since our previous studies have documented that mesenteric lymph is a major contributor to lung injury following shock, we also tested the hypothesis that factors in the mesenteric lymph were responsible for the endothelial cell apoptosis-inducing effect of shock. Preventing the mesenteric lymph from reaching the lung by mesenteric lymph duct ligation decreased endothelial cell apoptosis. Mesenteric lymph obtained from rats subjected to trauma-hemorrhagic shock elicited apoptosis in cultured endothelial cells and when placed into isolated femoral vein as well as increased endothelial cell monolayer permeability. CONCLUSIONS: Trauma-hemorrhagic shock induces endothelial as well as epithelial cell apoptosis in the lung via factors contained in the mesenteric lymph, thereby contributing to the pathophysiology of the acute respiratory distress syndrome.     

肠系膜淋巴管结扎对失血性休克大鼠的器官保护作用

目的 观察肠系膜淋巴管结扎对失血性休克大鼠肠、肝、肺组织细胞因子表达以及组织病理学的影响.方法 24只SD大鼠被随机均分成对照组、失血性休克组、失血性休克+肠系膜淋巴管结扎组.采用逆转录一聚合酶链反应(RT-PCR)检测各组大鼠肠、肝、肺组织肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)的mRNA表达;苏木素一伊红(HE)染色观察各组织的病理学改变.结果 失血性休克大鼠肠、肝、肺组织TNF-α mRNA和IL-6 mRNA表达均较对照组明显升高(TNF-α mRNA:肠0.54±0.07比0.37±0.05,肝1.014-0.06比0.56±0.07,肺0.94±0.07比0.62±0.06;IL-6 mRNA:肠0.89±0.12比0.50±0.09,肝1.07±0.10比0.57±0.12,肺1.09±0.09比0.67±0.06,P均<0.01);肠系膜淋巴管结扎可明显降低肠、肝、肺组织TNF-αmRNA和IL-6 mRNA表达(TNF-α mRNA:肠0.47±0.05比0.54±0.07,肝0.81±0.07比1.01±0.06,肺0.80±0.05比0.94±0.07;IL-6 mRNA:肠0.66±0.07比0.89±0.12,肝0.83±0.13比1.07±0.10,肺0.73±0.11比1.09±0.09,P<0.05或P<0.01).组织病理学观察显示,肠系膜淋巴管结扎可明显减轻失血性休克引起的肠黏膜绒毛坏死、脱落;减轻肝细胞变性、坏死;减轻肺水肿和炎性细胞浸润.结论 肠系膜淋巴管结扎可降低失血性休克大鼠肠、肝、肺组织细胞因子TNF-α、IL-6的表达及病理损伤程度,对器官功能起保护作用.     

Hematopoietic failure after hemorrhagic shock is mediated partially through mesenteric lymph

OBJECTIVE: To determine whether hemorrhagic shock-induced bone marrow failure is mediated by the gut through the production of toxic mesenteric lymph and whether shock-induced bone marrow failure could be prevented by division of the mesenteric lymphatics. DESIGN: Prospective, controlled study. SETTING: University surgical research laboratory. SUBJECTS: Male Sprague-Dawley rats. INTERVENTIONS: Rats were divided into five groups: unmanipulated controls (n = 12), hemorrhagic shock with laparotomy (n = 8), hemorrhagic shock with mesenteric lymph duct ligation (n = 10), sham shock with laparotomy (n = 6), and sham shock with mesenteric lymph duct ligation (n = 7). At either 3 or 6 hrs after resuscitation, bone marrow was obtained for determination of early (cobblestone forming cells) and late (granulocyte-macrophage colony forming unit and erythroid burst forming unit) hematopoietic progenitor cell growth. Parallel cultures were plated with plasma (1% and 2% v/v) from all groups to determine the effect of lymphatic ligation on hematopoiesis. MEASUREMENTS AND MAIN RESULTS: Bone marrow cellularity, cobblestone forming cells, granulocyte-macrophage colony forming unit, and erythroid burst forming unit growth in rats subjected to hemorrhagic with lymph duct ligation were similar to those observed in sham-treated animals and significantly greater than in rats subjected to shock and laparotomy without lymphatic duct ligation. Plasma from rats subjected to shock without lymph ligation was inhibitory to hematopoietic progenitor cell growth. In contrast, this shock-induced inhibition was not observed with plasma obtained from shocked rats that underwent mesenteric lymph ligation. CONCLUSIONS: Hemorrhagic shock suppresses bone marrow hematopoiesis as measured by a decrease in early and late progenitor cell growth. This suppression appears mediated through mesenteric lymph as the effect is abrogated by mesenteric lymph duct ligation. These data clearly demonstrate a link between the gut and bone marrow failure after hemorrhagic shock     

Mesenteric lymph duct ligation provides long term protection against hemorrhagic shock-induced lung injury

Recently we have shown that ligation of the main mesenteric lymph (MLN) duct prior to an episode of hemorrhagic shock (HS) prevents shock-induced lung injury. Yet, ligation or diversion of intestinal lymph immediately prior to injury is not clinically feasible. Diversion of intestinally derived lymph after injury to protect against secondary insults is possible, but it is not known how long the protective effects of lymph ligation would last. Thus, we tested whether ligation of the MLN duct seven days prior to HS would still be protective. Male Sprague-Dawley rats were subjected to laparotomy with or without MLN duct ligation. Seven days later, half of the sham and actual MLN duct ligated animals randomly were selected to undergo HS (30 mmHG for 90 min). The other half of the animals was subjected to sham shock. Lung permeability, pulmonary myeloperoxidase (MPO) activity, and bronchoalveolar fluid (BALF) protein content were used to determine lung injury. Lymphatic division 7 days prior to HS continued to prevent shock induced lung injury as assessed by a lower Evans Blue dye concentration, BALF protein and MPO activity. In addition, there was no evidence of Patent Blue dye in the previously ligated MLN duct. Since ligation of the main mesenteric lymphatic duct continues to protect against shock-induced lung injury 1 week after duct ligation, it is feasible that lymphatic ligation performed after an injury remains protective against certain secondary insults for at least 1 week.     

Pancreatic duct ligation abrogates the trauma hemorrhage-induced gut barrier failure and the subsequent production of biologically active intestinal lymph

The studies of the mechanisms by which trauma-hemorrhagic shock leads to gut injury and dysfunction have largely ignored the nonbacterial factors contained within the lumen of the intestine. Yet, there is increasing evidence suggesting that intraluminal pancreatic proteases may be involved in this process. Thus, we tested the hypothesis that pancreatic proteases are necessary for the trauma-hemorrhagic shock-induced gut injury and the production of biologically active mesenteric lymph by determining the extent to which pancreatic duct ligation (PDL) would limit gut injury and mesenteric lymph bioactivity. To assess the effect of PDL on gut injury and dysfunction gut morphology, the mucus layer structure and the gut permeability were measured in the following four groups of male rats subjected to laparotomy (trauma) and hemorrhagic shock (pressure, 30 mmHg for 90 min): (1) rats subjected to trauma plus sham-shock (T/SS), (2) T/SS rats undergoing PDL (T/SS + PDL), (3) rats subjected to trauma and hemorrhagic shock (T/HS), and (4) rats subjected to T/HS + PDL. The ability of mesenteric lymph from these four rat groups to kill endothelial cells and activate neutrophils was tested in vitro. The PDL did not affect any of the parameters studied because there were no differences between the T/SS and the T/SS + PDL groups. However, PDL protected the gut from injury and dysfunction because PDL significantly abrogated T/HS-induced mucosal villous injury, loss of the intestinal mucus layer, and gut permeability. Likewise, PDL totally reversed the endothelial cell cytotoxic activity of T/HS lymph and reduced the ability of T/HS lymph to prime naive neutrophils for an augmented respiratory burst. Thus, it seems that intraluminal pancreatic proteases are necessary for the T/HS-induced gut injury and the production of bioactive mesenteric lymph.     

Lymph from a primate baboon trauma hemorrhagic shock model activates human neutrophils

We have reported that toxic factors in intestinal lymph are responsible for acute lung injury and bone marrow suppression and that they contribute to a systemic inflammatory state based on studies in rodent models of trauma-hemorrhagic shock. Rodent models may not completely reflect the responses of injured patients. Thus, it is important to confirm these findings in primates before applying them to injured human patients with trauma. Thus, we have recently established baboon trauma-hemorrhagic shock (T/HS) and trauma-sham shock (T/SS) models that showed that gut-derived factors carried in the lymph potentiates lung injury and causes human endothelial dysfunction and suppresses human bone marrow progenitor cell growth. Here, we further investigated the effects of these primate lymph samples on human neutrophils. We hypothesized that toxic factors in baboon lymph may prime and/or activate human polymorphonuclear leukocyte (PMN) leading to overproduction of superoxide, thereby contributing to the development of adult respiratory distress syndrome and multiple organ failure. To this effect, we have examined the priming effect of baboon T/HS and T/SS lymph on PMN respiratory burst and expression of adhesion molecule in human neutrophils. The results of these studies indicate that PMN treated with baboon T/HS lymph showed significantly induced respiratory burst responses compared with PMN treated with T/SS lymph or medium when phorbol myristate acetate PMA was applied after lymph pretreatment. Secondly, we found that the expression of CD11b adhesion molecule was increased by incubation with T/HS lymph. These results suggest that baboon lymph from T/HS models can increase respiratory burst and adhesion molecule expression in human PMN, thereby potentially contributing to PMN-mediated organ injury.     

Peritonitis induces rat cardiac myocytes to promote polymorphonuclear leukocyte emigration and activate endothelial cells: effect of lipopolysaccharide pretreatment

OBJECTIVE: Peritonitis induced by cecal ligation and perforation results in inflammation and dysfunction of the rat myocardium, an organ remote from the locus of infection. This peritonitis-induced pathology can be prevented by pretreating these animals with lipopolysaccharide before cecal ligation and perforation. In the present study, we assessed a) whether cardiomyocytes obtained from rats subjected to cecal ligation and perforation could induce polymorphonuclear leukocyte transendothelial migration, b) whether these cardiomyocytes could activate endothelial cells (increased proadhesive phenotype), and c) whether these responses could be attenuated by lipopolysaccharide pretreatment. DESIGN: Prospective animal study. SETTING: Experimental animal laboratory. SUBJECTS: Male Sprague Dawley rats. INTERVENTIONS: Lipopolysaccharide pretreated and nonpretreated rats were subjected to cecal ligation and perforation or to laparotomy. Myocytes were isolated 6 hrs after surgery and used for in vitro experiments. MEASUREMENTS AND MAIN RESULTS: Myocytes isolated from cecal ligation and perforation rats promoted migration of polymorphonuclear leukocytes across a rat endothelial cell monolayer, an effect prevented by platelet activating factor receptor antagonists. Myocytes isolated from these animals also increased surface level expression of intercellular adhesion molecule-1 on rat endothelial cells, an effect also prevented by platelet activating factor receptor antagonists. Myocytes isolated from rats pretreated with lipopolysaccharide and then subjected to cecal ligation and perforation did not a) promote polymorphonuclear leukocyte transendothelial migration or b) increase intercellular adhesion molecule-1 surface expression on endothelial cells. CONCLUSIONS: Our findings indicate that induction of peritonitis results in a systemic response that induces cardiac myocytes to become proinflammatory (i.e., these myocytes produce chemotactic factors and activate endothelial cells). This effect of cecal ligation and perforation is abrogated by pretreating animals with lipopolysaccharide before induction of peritonitis.     

Kinetics of P-selectin expression in regional vascular beds after resuscitation of hemorrhagic shock: a clue to the mechanism of multiple system organ failure

Leukocyte-endothelial cell interactions play an important role in mediating organ dysfunctions observed after hemorrhagic shock. P-selectin is the first endothelial cell adhesion molecule to be upregulated after an ischemic insult. The objective of this study was to define kinetics of P-selectin expression in different regional vascular beds of mice exposed to hemorrhagic shock. In-vivo P-selectin expressions were determined using dual radiolabeled monoclonal antibody technique in lungs, heart, liver, kidneys, intestinal mesentery, stomach, small bowel, and colon 0.5, 1, 2, 5, 10, and 24 h after resuscitation of 40 mmHg hemorrhagic shock. In another group, P-selectin expression was determined in same organs 5 h after resuscitation of 30 mmHg hemorrhagic shock. Hemorrhagic shock of 40 mmHg caused significant upregulation of P-selectin in lungs and liver at 30 min after resuscitation (P < 0.001). There was a second and more pronounced upregulation of P-selectin in lungs and liver at 5 h after resuscitation (P < 0.001). In heart, intestinal mesentery, stomach, small bowel, and colon, P-selectin was not upregulated until 5 h after resuscitation from 40 mmHg hemorrhagic shock (P < 0.001). While hemorrhagic shock of 40 mmHg did not cause P-selectin upregulation in kidneys, hemorrhage to 30 mmHg did elicit a significant increase at 5 h after resuscitation (P < 0.001). We conclude that P-selectin is upregulated after resuscitation of hemorrhagic shock in lungs, liver, heart, stomach, and intestines. P-selectin upregulation in kidneys only takes place after more severe hemorrhagic shock.     

Circulating intercellular adhesion molecule-1 as an early predictor of hepatic failure in patients with septic shock

OBJECTIVE: To investigate whether endotoxin, interleukin-6, and circulating adhesion molecules, measured sequentially in blood, can predict mortality and organ dysfunction in sepsis. DESIGN: Inception cohort study with follow-up for 28 days. SETTING: Surgical intensive care unit at a university hospital. PATIENTS: A total of 14 consecutive patients were enrolled in the study within the first 24 hrs after onset of septic shock. Seven healthy subjects were studied as controls. INTERVENTIONS: Patients were analyzed for mortality and development of organ dysfunction. MEASUREMENTS AND MAIN RESULTS: At the end of the 28-day follow-up period, seven of the patients were still alive (survivors) but the other seven (nonsurvivors) had died. At the time of enrollment in the study (day 0), the Acute Physiology and Chronic Health Evaluation II score was 28.4 in survivors (n = 7) and 28.7 in nonsurvivors (n = 7). In contrast, circulating intercellular adhesion molecule-1 (ICAM-1) was significantly higher in nonsurvivors than in survivors. Circulating ICAM-1 predicted mortality in patients with septic shock with a sensitivity and a specificity of 71.4% each. Endotoxin, interleukin-6, circulating L-selectin, P-selectin, E-selectin, and platelet endothelial cell adhesion molecule-1, however, did not distinguish between survivors and nonsurvivors. In addition, circulating ICAM-1 at day 0 showed a significant correlation with the highest serum bilirubin observed during the entire study period (r2 = 0.963). CONCLUSIONS: Because only circulating ICAM-1 was higher in nonsurvivors than in survivors at day 0, circulating ICAM-1 may serve as an early prognostic marker for outcome in septic shock. In addition, measurement of circulating ICAM-1 facilitates identification of those patients with the highest risk of developing liver dysfunction.     

肠系膜淋巴管结扎对失血性休克大鼠肺组织一氧化氮及其表达的影响

目的 观察结扎肠系膜淋巴管对不同时期重症失血性休克大鼠肺组织一氧化氮（NO）及其表达的影响，探讨肠淋巴途径在休克大鼠急性肺损伤（ALI）中的作用。方法 雄性Wistar大鼠78只，按随机数字表法分为假手术组（n=6）、休克组（n=42）和结扎组（n=30）。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；休克组于休克后90min、输液复苏后0h，休克组及结扎组于输液复苏后1、3、6、12和24h各时间点处死大鼠，制备肺组织匀浆，检测NO及其合酶的变化；用逆转录-聚合酶链反应（RT—PCR）测定各组大鼠肺组织诱生型一氧化氮合酶（iNOS）．mRNA表达。结果 休克组大鼠复苏后3h肺组织NO含量、NOS活性及iNOSmRNA表达开始升高，复苏后6～12h持续在较高水平，均显著高于假手术组、休克后90min及复苏后0h（P〈0．05或P〈0．01）；结扎组仅于3h和6h增高，且结扎组复苏后6、12和24h肺组织NO含量、NOS活性以及iNOSmRNA表达均显著低于休克组相同时间点（P〈0．05或P〈0．01）。结论 肠系膜淋巴管结扎可降低重症失血性休克大鼠肺组织NO生成及iNOSmRNA表达，从而减轻肺损伤。     

A fish oil emulsion used for parenteral nutrition attenuates monocyte-endothelial interactions under flow

Monocyte adhesion contributes to perfusion abnormalities, tissue damage, and activation of the coagulation system seen during trauma, shock, or overwhelming inflammation. This study was performed to determine whether an intravenous fish oil emulsion used for parenteral nutrition attenuates monocyte-endothelial interactions under flow and reduces procoagulant activity, measured as tissue factor (TF) expression on adherent monocytes in vitro. Endothelial cell monolayers were incubated with either an intravenous fish oil emulsion or a conventional omega-6 lipid emulsion at 0.05 to 1 mg/ml for 24 h. Six hours following activation with TNFalpha (25 ng/ml), expression of endothelial cell adhesion molecules was measured by flow cytometry. Adhesion of isolated monocytes to pretreated endothelium was examined in a parallel plate flow chamber at a shear stress of 1.5 dynes/cm2. Following perfusion, the cells were cocultured for an additional 4 h and TF expression on monocytes was determined by flow cytometry. In contrast to omega-6 lipids, fish oil down-regulated E-selectin, intercellular adhesion molecule-1, and vascular cell adhesion molecule-1 in a dose-dependent manner. P-selectin, however, remained unchanged. In addition, firm adhesion was reduced to 54%, whereas rolling interactions remained unchanged. Fish oil exhibited no effect on the TF expression on cocultured monocytes. We conclude that intravenous fish oil emulsions reduce both endothelial cell adhesion molecule expression and monocyte adhesion. However, under postcapillary flow conditions, rolling interactions via P-selectin remain unaltered. The functional importance of this effect is illustrated by the corresponding upregulation of TF in response to residual monocyte-endothelial interactions.     

Trauma-hemorrhage-induced neutrophil priming is prevented by mesenteric lymph duct ligation

Our objective in this study was to test the hypothesis that priming of neutrophils (PMN) in vivo by trauma-hemorrhagic shock (T/HS) is mediated by factors carried in intestinal lymph that prime PMNs by enhancing their responses to inflammatory mediators. Previous studies have shown that T/HS-induced lung injury is mediated by factors contained in mesenteric lymph and that ligation of the main mesenteric lymph duct (LDL) can prevent T/HS-induced lung injury. Since T/HS-induced lung injury is associated with PMN infiltration, one mechanism underlying this protective effect may be the prevention of PMN priming and activation. Therefore, we assessed the ability of T/HS to prime PMN responses to inflammatory agonists, and the ability of mesenteric lymph duct division to protect against such T/HS-induced PMN priming in an all-rat system. PMN were collected from male rats 6 h after laparotomy (trauma) plus hemorrhagic shock (30 mmHg for 90 min; T/HS) or trauma plus sham shock (T/SS). Uninstrumented rats were used as controls (UC). In a second set of experiments, rats were subjected to T/HS with or without mesenteric lymph duct division. PMN were then stimulated with chemokine (GRO, MIP-2) and lipid (PAF) chemoattractants, and cell calcium flux was used to quantify responses to those agonists. T/SS primed PMN responses to GRO, MIP-2. and PAF in comparison to UC rats, but the addition of shock (T/HS) amplified PMN priming in a significant manner, especially in response to GRO. Mesenteric lymph duct division prior to T/HS diminished PMN priming to the levels seen in T/SS. This reversal of priming was significant for GRO and GRO/MIP-2 given sequentially, with the other agonist regimens showing similar trends. The results support the concept that trauma and hemorrhagic shock play important additive roles in inflammatory PMN priming. Entry of gut-derived inflammatory products into the circulation via mesenteric lymph seems to play a dominant role in mediating the conversion of physiologic shock insults into immunoinflammatory PMN priming. Shock-induced gut lymph priming enhances PMN responses to many important chemoattractants, most notably the chemokines, and mesenteric lymph duct division effectively reverses such priming to priming levels seen in trauma without shock.     

The role of lymph factors in lung injury, bone marrow suppression, and endothelial cell dysfunction in a primate model of trauma-hemorrhagic shock

Studies in rodent models of trauma-hemorrhagic shock (T/HS) have shown that factors contained in the intestinal lymph are responsible for acute lung injury and bone marrow suppression, and that they contribute to a systemic inflammatory state. Because results observed in rodent T/HS models may not fully reflect the response of injured patients, it is necessary to determine if these results can be replicated in primates before the institution of invasive studies in humans. Thus, the three goals of this study were to determine if diversion of thoracic duct lymph reduced T/HS-induced lung injury; to compare the biologic activity of thoracic duct lymph from baboons subjected to T/HS or trauma sham-shock (T/SS); and to compare the biologic activity and composition of plasma from baboons subjected to T/SS, T/HS, and T/HS with thoracic duct lymph drainage. Three groups of baboons were studied: T/SS plus lymph diversion via a thoracic duct catheter, T/HS, and T/HS plus lymph diversion (T/HS-LD). The trauma component consisted of a neck dissection with resection of the proximal clavicle plus a laparotomy. HS was to a mean arterial pressure of 40 mmHg and was maintained at 40 mmHg until the base excess reached -5 mEq or the total shock period reached 3 h. Volume resuscitation was carried out by reinfusing the shed blood plus crystalloids. Before, during, and after the T/HS or T/SS period, blood and lymph samples were obtained for analysis, and lung samples were harvested for measurement of lung wet-to-dry ratio at 5 h after the end of the shock period. Diversion of thoracic duct lymph prevented T/HS-induced lung injury as reflected in lung wet-to-dry weight ratios (T/SS = 4.6 +/- 0.5; T/HS+LD = 4.8 +/- 0.7; T/HS = 5.4 +/- 0.6; P < 0.05). Lymph from the T/HS group collected during the early postshock period was cytotoxic for human endothelial cells (HUVECs; 16% vs. 100% survival in T/SS lymph) and increased HUVEC monolayer permeability almost 2-fold (P < 0.01). T/HS lymph and plasma also suppressed red blood cell (erythroid burst-forming unit) and white blood cell (granulocyte-monocyte colony-forming unit) progenitor cell growth of human bone marrow to approximately 50% of control, whereas T/SS lymph and plasma were not suppressive (P < 0.05). Plasma cytokine levels were increased to a similar degree in the two T/HS groups. Thus, in a primate model of T/HS, gut-derived factors carried in the lymph potentiates lung injury and endothelial dysfunction, and suppresses bone marrow progenitor cell growth.     

肠淋巴途径在失血性休克大鼠肠源性细菌/内毒素移位发病学中的作用

目的观察失血性休克大鼠肠系膜淋巴液及门静脉血毒性物质的变化，同时观察结扎肠系膜淋巴管对重症失血性休克大鼠器官内毒素（ET）及肠系膜淋巴结和脾脏组织细菌培养的影响，探讨肠淋巴途径在休克大鼠肠源性细菌／内毒素移位（BET）发病学中的作用。方法雄性Wistar大鼠24只被随机分为休克组及对照组。复制重症失血性休克大鼠模型后，分别留取休克淋巴液、休克门静脉血、正常淋巴液、正常门静脉血，检测其中的ET、肿瘤坏死因子-α（TNF～α）、白细胞介素-6（IL-6）水平。另取30只大鼠被随机分为假手术组、休克组、结扎组。休克组与结扎组复制重症失血性休克大鼠模型。结扎组于休克复苏后行肠系膜淋巴管结扎术，分别于休克输液复苏3h和6h后，制备肺、肝、心、肾组织匀浆，检测其中ET含量；制备肠系膜淋巴结和脾组织匀浆，进行细菌培养。结果休克淋巴液中ET、TNF—α、IL-6的含量均显著高手休克血浆、正常血浆和正常淋巴液（P均〈0．01）；失血性休克大鼠输液复苏后3h和6h肺、肝、心、肾组织中ET含量均显著高于假手术组与结扎组（P〈0．05或P〈0．01）；休克组大鼠复苏后3h和6h肠系膜淋巴结及脾组织中均可见细菌生长，而结扎组大鼠相应组织中则无细菌生长。结论肠淋巴途径在失血性休克致大鼠肠道屏障功能下降、引起肠源性BET的发病学中具有首要作用。     

肠系膜淋巴管结扎对失血性休克大鼠肺损伤的影响

目的观察结扎肠系膜淋巴管对不同时期重症失血性休克大鼠肺组织自由基、炎症介质的影响，探讨肠淋巴途径在休克大鼠急性肺损伤（ALI）中的作用。方法78只雄性Wistar大鼠被随机分为假手术组、休克组和结扎组。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90min、液体复苏后0、1、3、6、12和24h各处死6只大鼠，制备肺组织匀浆，检测丙二醛（MDA）、超氧化物歧化酶（SOD）、肿瘤坏死因子-α（TNF—α）、白细胞介素-6（IL-6）以及髓过氧化物酶（MPO）活性。结果休克组大鼠输液复苏后各时间点肺组织匀浆MDA、TNF—α、IL-6以及MPO活性均有不同程度的升高，3～12h持续在较高水平，均显著高于假手术组，肺组织匀浆SOD活性显著低于假手术组（P〈0．05或P〈0．01）；结扎组输液复苏后3，6、12和24h肺组织匀浆MDA、TNF-α、IL-6以及MPO活性均显著低于休克组，SOD活性高于休克组（P〈0．05或P〈0．01）。结论肠系膜淋巴管结扎可干预重症失血性休克大鼠ALI，其机制与减少肺中性粒细胞扣押，降低TNF—α、IL-6、自由基释放与SOD消耗等因素有关。     

肠淋巴途径在大鼠休克致肝脏炎症反应中的作用

目的 观察结扎肠系膜淋巴管对重症失血性休克不同时期大鼠肝脏炎症介质、自由基的变化,探讨阻断肠淋巴途径对休克大鼠肝脏炎症反应的影响.方法 78只雄性Wistar大鼠被随机分为假手术组(n=6)、休克组(n=42)和结扎组(n=30).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90 min、输液复苏后0、1、3、6、12和24 h各处死6只大鼠,制备肝组织匀浆,检测肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、一氧化氮(NO)、一氧化氮合酶(NOS)、丙二醛(MDA)、超氧化物歧化酶(SOD)以及髓过氧化物酶(MPO)水平;采用逆转录-聚合酶链反应(RT-PCR)测定肝组织诱生型一氧化氮合酶(iNOS)mRNA表达.结果 休克组大鼠输液复苏后不同时间点肝组织TNF-α、IL-6、NO、NOS、MDA、MPO以及iNOS mRNA均有不同程度的升高,6～12 h持续在较高水平,均显著高于假手术组,肝组织SOD活性显著低于假手术组(P＜0.05或P＜0.01);结扎组输液复苏后3、6、12和24 h肝组织TNF-α、IL-6、NO、NOS、MDA、MPO以及iNOS mRNA均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(P＜0.05或P＜0.01).结论 肠系膜淋巴管结扎可减少肝脏中性粒细胞扣押,降低TNF-α、IL-6释放,抑制iNOS mRNA表达及NO生成,减少自由基损伤与SOD消耗,从而减轻肝脏的炎症反应.     

Natural history of long-term lung injury in mouse experimental pancreatitis

OBJECTIVE: In patients suffering from acute pancreatitis, the pathogenesis of pancreatitis-associated lung injury is not completely understood. Several rodent models of pancreatitis-associated lung injury suggested that activated neutrophils and the release of proinflammatory mediators after the activation of inflammatory cells within the pancreas might play an important role in translating the pancreatic inflammation to the lungs. In this study, we examined the natural history of pancreatitis-associated lung injury during an entire week. SUBJECTS: Mice were administered 12 hourly intraperitoneal injections of a supramaximal dose of cerulein. MEASUREMENTS AND MAIN RESULTS: The severity of pancreatitis was time-dependent, with a maximal injury by 12-24 hrs after the start of cerulein administration. Pancreatitis was associated with a significant lung injury characterized by a rise in lung microvascular permeability, sequestration of neutrophils within the lungs, and a marked thickening of alveolar membranes. Within the lungs, the peak of macrophage inflammatory peptide-2, which attracts inflammatory cells within the injured area, preceded the peaks of both tumor necrosis factor-alpha and intercellular adhesion molecule-1. Moreover, histologic injury peaked by 12 hrs, with a full recovery at day 7. Serum macrophage inflammatory peptide-2 concentrations were significantly correlated with the occurrence of pulmonary leakage. Lung macrophage inflammatory peptide-2 concentrations peaked 12 hrs before pancreatic concentrations. CONCLUSIONS: Mediators released by the pancreas into the blood during acute pancreatitis induce within the lungs the chronological expression of macrophage inflammatory peptide-2, tumor necrosis factor-alpha, and intercellular adhesion molecule-1.