Diabetes and hyperlipidemia induce dysfunction of VSMCs: contribution of the metabolic inflammation/miRNA pathway.

Vascular endothelial cell injury is considered to be the major factor inducing vascular complications in metabolic diseases and plays an important role in other organ damage. With diabetic and hyperlipidemic rats and cultured VSMCs, the present study was aimed at investigating whether the early damage of VSMCs during metabolic diseases plays a critical role in vascular dysfunction and the underlying mechanisms and would be a promising treatment target. With diabetic and hyperlipidemic rats and cultured VSMCs, the changes and relationships of vascular relaxation and contractile function to the vital organ damage and the underlying mechanisms were investigated; meanwhile, the protective and preventive effects of lowering blood lipid and glucose and inhibition of diabetes and hyperlipidemia-induced vascular hyperreactivity were observed. Diabetic and hyperlipidemic rats presented hyperreactivity in vascular contractile response in the early stages. Hyperglycemia and hyperlipidemia directly affected the contractile function of VSMCs. Early application of fasudil, a specific antagonist of Rho kinase, significantly alleviated diabetes and hyperlipidemia-induced organ damage by inhibiting vascular hyperreactivity. Diabetes and hyperlipidemia-induced inflammatory response could upregulate the expression of connexins and Rho kinase by selective downregulation of the expression of miR-10a, miR-139b, miR-206, and miR-222. These findings suggest that hyperglucose and lipid may directly impair VSMCs and induce vascular hyperreactivity in the early stages. Metabolic inflammation-induced changes in the miRNA-connexin/Rho kinase regulatory pathway are the main mechanism for vascular hyperreactivity and organ damage. Measures inhibiting vascular hyperreactivity are promising for the prevention of organ damage induced by metabolic diseases.

Identification of ideal resuscitation pressure with concurrent traumatic brain injury in a rat model of hemorrhagic shock.

BACKGROUND: Traumatic brain injury (TBI) is often associated with uncontrolled hemorrhagic shock (UHS), which contributes significantly to the mortality of severe trauma. Studies have demonstrated that permissive hypotension resuscitation improves the survival for uncontrolled hemorrhage. What the ideal target mean arterial pressure (MAP) is for TBI with UHS remains unclear. METHODS: With the rat model of TBI in combination with UHS, we investigated the effects of a series of target resuscitation pressures (MAP from 50-90 mm Hg) on animal survival, brain perfusion, and organ function before hemorrhage controlled. RESULTS: Rats in 50-, 60-, and 70-mm Hg target MAP groups had less blood loss and less fluid requirement, a better vital organ including mitochondrial function and better cerebral blood flow, and animal survival (8, 6, and 7 of 10, respectively) than 80- and 90-mm Hg groups. The 70-mm Hg group had a better cerebral blood flow and cerebral mitochondrial function than in 50- and 60-mm Hg groups. In contrast, 80- and 90-mm Hg groups resulted in an excessive hemodilution, a decreased blood flow, an increased brain water content, and more severe cerebral edema. CONCLUSIONS: A 50-mm Hg target MAP is not suitable for the resuscitation of TBI combined with UHS. A 70 mm Hg of MAP is the ideal target resuscitation pressure for this trauma, which can keep sufficient perfusion to the brain and keep good organ function including cerebral mitochondrial function.

δ opioid receptor antagonist, ICI 174,864, is suitable for the early treatment of uncontrolled hemorrhagic shock in rats.

BACKGROUND: Fluid resuscitation is the essential step for early treatment of traumatic hemorrhagic shock. However, its implementation is greatly limited before hospital or during evacuation. The authors investigated whether δ opioid receptor antagonist ICI 174,864 was suitable for the early treatment of traumatic hemorrhagic shock. METHODS: With uncontrolled hemorrhagic-shock rats, the antishock effects of six dosages of ICI 174,864 (0.1, 0.3, 0.5, 1, 3, and 5 mg/kg) infused with or without a small volume of lactated Ringer's solution (LR) before bleeding controlled or bleeding cessation at different times were observed. RESULTS: ICI 174,864 (0.1-3 mg/kg) with or without 1/4 volume of LR infusion showed dose-dependent increase in the mean arterial blood pressure, and significantly prolonged the survival time and 8-h survival rate, as compared with ICI 174,864 plus 1/2 volume of LR infusion. The best effect was shown with 3 mg/kg of ICI 174,864. Bleeding cessation at 1, 2, or 3 h during infusion of ICI 174,864 (3 mg/kg) plus 1/4 volume of LR improved subsequent treatment (70% 24-h survival rate vs. 50 and 10% 24-h survival rate in hypotensive resuscitation and LR group, respectively). There was significant improvement in hemodynamic parameters, oxygen delivery, and tissue perfusion of hemorrhagic-shock rats with 3 mg/kg of ICI 174,864 plus 1/4 volume of LR infusion. CONCLUSION: δ Opioid receptor antagonist ICI 174,864 alone or with small volume of fluid infusion has good beneficial effect on uncontrolled hemorrhagic shock. Its early application can "buy" time for subsequent treatment of traumatic shock.

Ideal resuscitation pressure for uncontrolled hemorrhagic shock in different ages and sexes of rats.

INTRODUCTION: Our previous studies demonstrated that 50-60 mmHg mean arterial blood pressure was the ideal target hypotension for uncontrolled hemorrhagic shock during the active hemorrhage in sexually mature rats. The ideal target resuscitation pressure for immature and older rats has not been determined. METHODS: To elucidate this issue, using uncontrolled hemorrhagic-shock rats of different ages and sexes (6 weeks, 14 weeks and 1.5 years representing pre-adult, adult and older rats, respectively), the resuscitation effects of different target pressures (40, 50, 60, 70 and 80 mmHg) on uncontrolled hemorrhagic shock during active hemorrhage and the age and sex differences were observed. RESULTS: Different target resuscitation pressures had different resuscitation outcomes for the same age and sex of rats. The optimal target resuscitation pressures for 6-week-old, 14-week-old and 1.5-year-old rats were 40 to 50 mmHg, 50 to 60 mmHg and 70 mmHg respectively. Ideal target resuscitation pressures were significantly superior to other resuscitation pressures in improving the hemodynamics, blood perfusion, organ function and animal survival of uncontrolled hemorrhagic-shock rats (P < 0.01). For same target resuscitation pressures, the beneficial effect on hemorrhagic shock had a significant age difference (P < 0.01) but no sex difference (P > 0.05). Different resuscitation pressures had no effect on coagulation function. CONCLUSION: Hemorrhagic-shock rats at different ages have different target resuscitation pressures during active hemorrhage. The ideal target resuscitation hypotension for 6-week-old, 14-week-old and 1.5-year-old rats was 40 to 50 mmHg, 50 to 60 mmHg and 70 mmHg, respectively. Their resuscitation effects have significant age difference but had no sex difference.

Synergetic Effect of 4-Phenylbutyric Acid in Combination with Cyclosporine A on Cardiovascular Function in Sepsis Rats via Inhibition of Endoplasmic Reticulum Stress and Mitochondrial Permeability Transition Pore Opening.

Background: Sepsis/septic shock is a common complication in the intensive care unit, and the opening of the mitochondrial permeability transition pore (mPTP), as well as the endoplasmic reticulum stress (ERS), play important roles in this situation. Whether the combination of anti-ERS and anti-mPTP by 4-phenylbutyric acid (PBA) and Cyclosporine A (CsA) could benefit sepsis is unclear. Methods: The cecal ligation and puncture-induced septic shock models were replicated in rats, and lipopolysaccharide (LPS)-challenged primary vascular smooth muscle cells and H9C2 cardiomyocytes in vitro models were also used. The therapeutic effects of CsA, PBA, and combined administration on oxygen delivery, cardiac and vascular function, vital organ injury, and the underlying mechanisms were observed. Results: Septic shock significantly induced cardiovascular dysfunction, hypoperfusion, and organ injury and resulted in high mortality in rats. Conventional treatment including fluid resuscitation, vasoactive agents, and antibiotics slightly restored tissue perfusion and organ function in septic rats. Supplementation of CsA or PBA improved the tissue perfusion, organ function, and survival of septic shock rats. The combined application of PBA and CsA could significantly enhance the beneficial effects, compared with using PBA or CsA alone. Further study showed that PBA enhanced CsA-induced cardiovascular protection, which contributed to better therapeutic effects. Conclusion: Anti-ERS and anti-mPTP-opening by the combination of PBA and CsA was beneficial to septic shock. PBA enforced the CsA-associated cardiovascular protection and contributed to the synergetic effect.

A Novel Cross-Linked Hemoglobin-Based Oxygen Carrier, YQ23, Extended the Golden Hour for Uncontrolled Hemorrhagic Shock in Rats and Miniature Pigs.

Background: Hypotensive resuscitation is widely applied for trauma and war injury to reduce bleeding during damage-control resuscitation, but the treatment time window is limited in order to avoid hypoxia-associated organ injury. Whether a novel hemoglobin-based oxygen carrier (HBOC), YQ23 in this study, could protect organ function, and extend the Golden Hour for treatment is unclear. Method: Uncontrolled hemorrhagic shock rats and miniature pigs were infused with 0.5, 2, and 5% YQ23 before bleeding was controlled, while Lactate Ringer's solution (LR) and fresh whole blood plus LR (WB + LR) were set as controls. During hypotensive resuscitation the mean blood pressure was maintained at 50-60 mmHg for 60 min. Hemodynamics, oxygen delivery and utilization, blood loss, fluid demand, organ function, animal survival as well as side effects were observed. Besides, in order to observe whether YQ23 could extend the Golden Hour, the hypotensive resuscitation duration was extended to 180 min and animal survival was observed. Results: Compared with LR, infusion of YQ23 in the 60 min pre-hospital hypotensive resuscitation significantly reduced blood loss and the fluid demand in both rats and pigs. Besides, YQ23 could effectively stabilize hemodynamics, and increase tissue oxygen consumption, increase the cardiac output, reduce liver and kidney injury, which helped to reduce the early death and improve animal survival. In addition, the hypotensive resuscitation duration could be extended to 180 min using YQ23. Side effects such as vasoconstriction and renal injury were not observed. The beneficial effects of 5% YQ23 are equivalent to similar volume of WB + LR. Conclusion: HBOC, such as YQ23, played vital roles in damage-control resuscitation for emergency care and benefited the uncontrolled hemorrhagic shock in the pre-hospital treatment by increasing oxygen delivery, reducing organ injury. Besides, HBOC could benefit the injured and trauma patients by extending the Golden Hour.

Mdivi-1 attenuates oxidative stress and exerts vascular protection in ischemic/hypoxic injury by a mechanism independent of Drp1 GTPase activity.

Vascular dysfunctions such as vascular hyporeactivity following ischemic/hypoxic injury are a major cause of death in injured patients. In this study, we showed that treatment with mitochondrial division inhibitor 1 (Mdivi-1), a selective inhibitor of dynamin-related protein 1 (Drp1), significantly improved vascular reactivity in ischemic rats by attenuating oxidative stress. The antioxidative effects of Mdivi-1 were relatively Drp1-independent, and possibly due to an increase in the levels of the antioxidant enzymes, SOD1 and catalase, as well as to enhanced Nrf2 expression. In addition, we found that while Mdivi-1 had little effect on Drp1 GTPase activity in vascular smooth muscle cells, it inhibited hypoxia-induced Drp1 phosphorylation at Ser-616, reducing excessive mitochondrial fission and slightly enhancing mitochondrial fusion. These effects possibly contributed to vascular protection at an early stage of ischemic/hypoxic injury. Finally, Mdivi-1 stabilized hemodynamics, increased vital organ perfusion, and improved rat survival after ischemic/hypoxic injury, proving a promising therapeutic agent for ischemic/hypoxic injury.

[Beneficial effects of hemoglobin-based oxygen carriers on early resuscitation in rats with uncontrolled hemorrhagic shock].

OBJECTIVE: To investigate the early resuscitation effect of hemoglobin-based oxygen carriers (HBOC) in rats with uncontrolled hemorrhagic shock. METHODS: 170 Sprague-Dawley (SD) rats were randomly divided into five groups: lactate Ringer solution (LR) control group, whole blood control group, and 0.5%, 2.0%, 5.0% HBOC groups, with 34 rats in each group. The uncontrolled hemorrhagic shock model in SD rats was reproduced by cutting off the splenic artery branch, and induced mean arterial pressure (MAP) reducing to 40 mmHg (1 mmHg = 0.133 kPa). The corresponding solution was infused after model reproduction in each group, maintaining MAP at 50 mmHg for 1 hour, then completely ligating and hemostasis, and maintaining MAP at 70 mmHg for 1 hour and 80 mmHg for 1 hour respectively, after maintaining MAP 80 mmHg, all were supplemented with LR to 2 times blood loss volume. The survival rate and blood loss rate were observed in 16 rats in each group, hemodynamics parameters including MAP, left ventricular systolic pressure (LVSP) and the maximum rate of left ventricular pressure rise (+dp/dt max) were determined in another 10 rats, and cardiac output (CO) and tissue oxygen supply (DO2) were observed in the rest 8 rats. RESULTS: (1) When resuscitation by LR alone, the blood loss rate of animals was as high as 60% to 70%. Compared with the LR control group, whole blood recovery could significantly reduce the blood loss rate before hemostasis in uncontrolled hemorrhagic shock rats [(46.6±4.5)% vs. (62.3±4.0)%, P < 0.01]; 0.5%, 2.0%, 5.0% HBOC could significantly decrease the blood loss rate, especially in 5.0% HBOC group with significant difference as compared with that in the LR control group [(45.6±4.1)% vs. (62.3±4.0)%, P < 0.01]. (2) When LR was used alone for resuscitation, the rats died quickly and survived for a short time. Only one rat survived for 12 hours, and no rat survived for more than 24 hours. Compared with the LR control group, whole blood resuscitation could improve the survival rate of uncontrolled hemorrhagic shock rats, and the survival time was significantly prolonged (hours: 20.4±4.6 vs. 3.5±1.1, P < 0.01); 0.5%, 2.0% and 5.0% HBOC also significantly prolonged the survival time of rats. The 5.0% HBOC group had the best effect, 4 rats survived in 24 hours, and the survival time was significantly longer than that of the LR control group (hours: 18.4±4.0 vs. 3.5±1.1, P < 0.01), and it was the same as the whole blood control group. (3) Compared with pre-shock, CO, DO2 and hemodynamic parameters of uncontrolled hemorrhagic shock rats were significantly decreased, and the above parameters were gradually increased with the prolongation of rehydration time. Compared with the LR control group, whole blood resuscitation could significantly increase CO and DO2, and improve hemodynamics in rats with uncontrolled hemorrhagic shock at different time points. Three concentrations of HBOC could also increase CO, DO2 and other hemodynamic parameters of rats at 1 hour of maintaining MAP of 80 mmHg after hemostasis and 1 hour and 2 hours after resuscitation. The effect of 5.0% HBOC group was more significant than that of the LR control group with statistically significant difference [CO (×10-3, L/min): 72.84±2.84 vs. 63.11±2.38 at 1 hour of maintaining MAP of 80 mmHg, 70.25±4.55 vs. 59.88±9.31 at 1 hour after resuscitation, 71.51±2.90 vs. 53.24±6.32 at 2 hours after resuscitation; DO2 (L×min-1×m-2): 271.9±13.5 vs. 159.1±25.4 at 1 hour of maintaining MAP of 80 mmHg, 261.0±15.0 vs. 145.7±20.1 at 1 hour after resuscitation, 249.6±12.0 vs. 107.4±18.2 at 2 hours after resuscitation; MAP (mmHg): 82.1±2.1 vs. 74.0±2.8 at 1 hour of maintaining MAP of 80 mmHg, 107.5±9.3 vs. 64.0±5.7 at 1 hour after resuscitation, 104.0±9.7 vs. 73.0±4.2 at 2 hours after resuscitation; LVSP (mmHg): 128.6±7.9 vs. 103.8±0.8 at 1 hour of maintaining MAP of 80 mmHg, 129.3±15.0 vs. 99.4±0.0 at 1 hour after resuscitation, 127.5±11.3 vs. 97.4±0.0 at 2 hours after resuscitation; +dp/dt max (mmHg/s): 6 534.2±787.6 vs. 5 074.0±71.7 at 1 hour of maintaining MAP of 80 mmHg, 5 961.5±545.4 vs. 4 934.5±510.2 at 1 hour after resuscitation, 5 897.4±350.5 vs. 4 534.7±489.2 at 2 hours after resuscitation, all P < 0.05]. CONCLUSIONS: HBOC infusion prolonged the survival time, increased survival rate, and improved hemodynamics, cardiac function and tissue oxygen supply in a dose-dependent manner in the early stage of uncontrolled hemorrhagic shock. The recovery effect of 5.0% HBOC was similar to that of the whole blood.

A novel cross-linked haemoglobin-based oxygen carrier is beneficial to sepsis in rats.

Pathological hypoxia-induced organ dysfunction contributes to the high mortality of sepsis. Because of the microcirculation dysfunction following severe sepsis, it is difficult for erythrocytes to transport oxygen to hypoxic tissues. Haemoglobin-based oxygen carriers (HBOCs) are capable of delivering oxygen to hypoxic tissues. The aim of this study is to observe the potential benefits of a novel bovine-derived, non-polymerized, cell-free HBOC solution, YQ23, on sepsis in rats. Cecum ligation and puncture was performed to induce sepsis in Sprague-Dawley rats. Effects of Lactate Ringer's solution (LR), YQ23, and whole blood on oxygen delivery and consumption, mitochondrial function, organ protection and animal survival were observed. LR failed to restore oxygen delivery and the therapeutic effects were limited, whereas low dosage of YQ23 and whole blood significantly increased the tissue oxygen delivery and consumption, improved the mitochondrial function of heart, liver, kidney and intestine, prevented the vital organs injuries and improved the animal survival. The effects of 0.15 g·kg-1 YQ23 resembled that of the whole blood. In addition, YQ23 did not induce renal toxicity, severe oxidative effect and acute vasoconstriction. Thus, YQ23 is a safe and effective resuscitation fluid for sepsis.

Study on the blood-borne virus co-infection and T lymphocyte subset among intravenous drug users.

AIM: To investigate the features of various blood-borne virus infections and co-infection in intravenous drug users (IDUs), and to examine the correlation of T lymphocyte subsets with virus co-infection. METHODS: Four hundred and six IDUs without any clinical manifestation of hepatitis and 102 healthy persons were enrolled in this study. HBV-DNA and HCV-RNA were detected by fluorescence quantitative PCR. HBsAg, HBeAg, anti-HBc, anti-HCV, HDV-Ag, anti-HGV, anti-HIV, and HCMV-IgM were assayed by enzyme-linked immunosorbent assay (ELISA) and immunochromatographic tests. The levels of Th1 and Th2 cytokines were measured by ELISA and radioactive immune assay (RIA). The T lymphocyte subpopulation was detected by using fluorescence immunoassay. The similar indices taken from the healthy persons served as controls. RESULTS: The viral infection rate among IDUs was 36.45% for HBV, 69.7% for HCV, 47.3% for HIV, 2.22% for HDV, 1.97% for HGV, and 3.45% for HCMV. The co-infection rate of blood-borne virus was detected in 255 of 406 (62.81%) IDUs. More than 80% (161/192) of subjects infected with HIV were co-infected with the other viruses, such as HBV, HCV. In contrast, among the controls, the infection rate was 17.65% for HBV and 0% for the other viruses. Our investigation showed that there was a profound decrease in the proportion of CD4/CD8 and the percentage of CD3 and CD4, but not in the percentage of CD8. The levels of PHA-induced cytokines (IFN-gamma and IL-4) and serum IL-2 were obviously decreased in IDUs. On the other hand, the level of serum IL-4 was increased. The level of IFN-gamma and the percentage of CD4 were continuously decreased when the IDUs were infected with HIV or HIV co-infection. IDUs with HIV and HBV co-infection was 15.1% (29/192). Of those 29 IDU with HIV and HBV co-infection, 51.72% (15/29) and 37.93% (11/29) were HBV-DNA-positive and HBeAg-positive, respectively. But, among IDUs without HIV infection, only 1.68% (2/119) of cases were HBV-DNA-positive. CONCLUSION: HCV, HBV and HIV infections are common in this population of IDU, leading to a high incidence of impaired Th1 cytokine levels and CD4 lymphocyte. IDUs with HIV and HBV/HCV co-infection have lower expression of Th1 cytokine with enhancement of the Th2 response. HIV may be causing HBV replication by decreasing Th1 function.

Epidemiology of hepatitis B, C, D and G viruses and cytokine levels among intravenous drug users.

To investigate the features of various hepatitis virus infection in intravenous drug users (IVDU), we conducted an epidemiological survey of hepatitis viruses including hepatitis B virus (HBV), hepatitis C virus (HCV), hepatitis D virus (HDV) and hepatitis G virus (HGV) in IVDU. The correlation of TH lymphocyte cytokine and hepatitis virus infection was examined. A study population of 406 IVDU consisted of 383 males and 23 females. HBV-DNA and HCV-RNA were detected by fluorescence quantitative polymerase chain reaction. HBsAg, HBeAg, anti-HBc, anti-HCV, HDV-Ag and anti-HGV were assayed by ELISA. The levels of cytokines of TH1 and TH2 were measured by ELISA. The similar indices taken from 102 healthy persons served as controls. The infection rate of each virus among IVDU was 36.45 % for HBV, 69.7 % for HCV, 2.22 % for HDV, and 1.97 % for HGV, respectively. The co-infection rate of HBV and HCV was detected in 113 of 406 (27.83 %). In contrast, among controls, the infection rate was 17.65 % for HBV and 0 % for the other hepatitis viruses. The levels of PHA-induced cytokines (IFN-gamma and IL-4) and the level of serum IL-2 were obviously decreased in IVDU. On the other hand, the level of serum IL-4 was increased. The IFN-gamma level was continuously decreased when the IVDU was infected with HBV/HCV. In conclusion, HBV and HCV infection were common in this population of IVDU and they had led to a high incidence of impaired TH1 cytokine levels.

[Two-dimensional gel electrophoresis of subcellular fractions of hepatoma cells].

OBJECTIVES: To seek a better profiling of proteins of hepatoma cells. METHODS: The homogenate of hepatoma cells QGY-7703 was fractionated into four parts by differential centrifugation: the nuclei, the pellet by 20,000 x g, the pellet by 100,000 x g and the cytosolic supernatant. The four fractions were submitted to two-dimensional gel electrophoresis and their electrophoretic patterns were analyzed. RESULTS: In comparison with the protein pattern of hepatoma cells not fractionated, the patterns of the four fractions display many more protein spots, and a large number of proteins present in the nuclei and cytosolic supernatant were not shown in the not-fractionated samples. CONCLUSION: Preparation of subcellular fractions before electrophoretic procedures proves to be very useful; not only can it improve the results of two-dimensional gel electrophoresis, but also can lead to research into the subcellular level.

[Changes in systemic and local vascular reactivity in hemorrhagic shock and the therapeutic effect of delta opioid receptor antagonist ICI174,864].

OBJECTIVE: To investigate the changes in systemic and local vascular reactivity following hemorrhagic shock of different severity and the therapeutic effect of alpha opioid receptor antagonist ICI174,864. METHODS: Fifty-six Wistar rats were used in two experiments. In experiment I, 32 rats were equally divided into sham operation group, 1 hour, 2 hours and 3 hours hypotension groups. In the latter groups, rats were bled to a mean arterial blood pressure (MAP) of 40 mm Hg (1 mm Hg=0.133 kPa) and maintained at this level for 1, 2, 3 hours, respectively. The pressor response of blood pressure and the contractile response of superior mesenteric artery (SMA) to norepinephrine(NE, 3 ug/kg) were observed after shed blood was reinfused. In experiment II, 24 rats were divided into shock control, ICI174,864 0.5 mg/kg and 1.0 mg/kg groups. The response of blood pressure and SMA contractility to NE (3 microg/kg) were observed at 1, 2, and 4 hours after ICI174,864 administration. RESULTS: Following hemorrhagic shock, the systemic and local (SMA) vascular responsiveness was significantly decreased significantly and it was time dependent. Shed blood reinfusion alone did not restore the decreased vascular reactivity. ICI174,864 improved the decreased vascular reactivity in dose-dependent manner. CONCLUSION: Hemorrhagic shock can induce systemic and local vascular hyporeactivity. The decreased vascular reactivity is closely associated with the severity and duration of shock. Loss of systemic vascular reactivity parallels to that of the regional vessel. delta opioid receptor antagonist ICI174,864 has some beneficial effect in improving vascular hyporeactivity.

Effect of initial fluid resuscitation on subsequent treatment in uncontrolled hemorrhagic shock in rats.

SUMMARY: Using a modified uncontrolled hemorrhage shock model with massive splenic and vascular injury, we evaluated outcome and tissue oxidation injury with different resuscitation interventions during prehospital and hospital phases. The aim of our study was to explore the effect of initial fluid resuscitation on subsequent treatment of uncontrolled hemorrhagic shock in rats. Uncontrolled hemorrhagic shock was produced in 114 Wistar rat by sharp transection both of the splenic parenchyma at one location between the major branches of the splenic artery into the spleen and of one of the major branches of the splenic artery. Experimental design consisted of three phases: a "prehospital phase" (resuscitation with balanced saline to a mean arterial pressure (MAP) of 40, 50, 60, 80, and 100 mmHg, respectively, when MAP reached 30 mmHg), followed by a "hospital phase" (120 min, including control of hemorrhage and resuscitation with balanced saline and whole blood (2:1) or balanced saline alone to a MAP >80 mmHg), and a 240-min observation phase. Blood loss, infused volume, hematocrit, and survival rate were recorded. At the end of the experiment, survivors were sacrificed, and the lung, kidney, and distal ileum were harvested for determination of malondialdehyde (MDA) content and total antioxidative capacity (T-AOC). All rats that were resuscitated to a MAP >80 mmHg in the prehospital phase and received balanced saline alone in the hospital phase died, whereas those that had been resuscitated to a MAP of 40 or 50 mmHg during the prehospital phase and then resuscitated with balanced saline and whole blood in the hospital phase survived throughout the experiment. The animals whose MAP was kept higher than 80 mmHg had significantly higher MDA content and lower T-AOC than those whose MAP was maintained 40, 50, or 60 mmHg during the prehospital phase. In the hospital phase, resuscitation with balanced saline and whole blood not only relieved tissue damage but also improved the survival, as indicated by 44.4% survival rate in the rats that resuscitated to a MAP of 80 or 100 mmHg in the prehospital phase. These results suggested that in our uncontrolled hemorrhagic shock model, limited resuscitation in the prehospital phase had benefit for subsequent treatment in the hospital phase in terms of alleviated tissue damage and improved survivorship.

PMN apoptosis and its relationship with the lung injury after chest impact trauma.

BACKGROUND: Polymorphonuclear neutrophil (PMN), one of the most important inflammatory cells, functions throughout the initiation, progression and resolution of inflammation. This study aimed at investigating the relationship between PMN apoptosis and the lung injury after chest impact trauma. METHODS: PMNs were purified from rabbits subjected to the chest impact trauma and their apoptosis, necrosis, survival and respiratory burst were detected by flow cytometry. Meanwhile, lactate dehydrogenase and (LDH) [Ca2+]i were measured. RESULTS: The delayed apoptosis of PMNs in bronchoalveolar lavage fluid was observed from 2 hours to 12 hours after trauma, and viable cells increased. Respiratory burst of PMNs in bronchoalveolar lavage fluid was increased significantly from 2 hours with the peak at 8 hours. Meanwhile, lactate dehydrogenase in bronchoalveolar lavage fluid was higher than that in control (P < 0.05) from 4 hours to 24 hours, and intracellular free Ca2+ in PMN was increased temporarily. CONCLUSIONS: Retention of PMN in tissues and the abnormality in apoptotic pathway inevitably generate persistent activation of PMN and excessive release of toxic substances, resulting in tissue injury. The temporary increase of intracellular free Ca2+ may be responsible for the delayed apoptosis of PMN.

Protective effect of bactericidal/permeability-increasing protein in mice with E. coli sepsis.

OBJECTIVE: To investigate the effect of bactericidal/permeability-increasing protein(BPI) on the outcome of sepsis in mice and its possible mechanism. METHODS: Sepsis was induced by injection of 2x10(6) colony-formed unit E. coli J5 via the tail vein. BPI of 5 mg/kg or equal volume of normal saline(NS) were injected intravenously at the same time. Endotoxin and TNFalpha levels in serum were assayed using a chromogenic limulus amebocyte lysate test and ELISA respectively. RESULTS: Seventy-two hour survival rate of septic mice was significantly higher in the BPI group (15/18) than in the NS group(8/18, P<0.01). Serum endotoxin levels in the BPI group (1.3+/-0.3 and 0.7+/-0.4 &mgr;g/L) were significantly lower than those in the NS group (3.9+/-0.8 and 2.5+/-0.9 &mgr; g/L, P<0.01) 0.5 and 1 hour following injection of bacteria respectively. The peak levels of serum tumor necrosis factor-alpha(TNFalpha)in the BPI group (1.9+/-0.6 &mgr;g/L) were also markedly lower than those in the NS group (3.8+/-0.8 &mgr;g/L, P<0.01) 1.5 hours following bacterial injection. But there was no significant difference in blood bacterial count between the BPI and NS groups 0.5, 1.5 and 3.0 hours after injection of bacteria. CONCLUSIONS: BPI has a marked protective effect on E. coli sepsis, which might be related to its action against bacterial endotoxin and its inhibition of TNFalpha production in sepsis.

[Mechanism of better result of limited resuscitation in a model of uncontrolled hemorrhagic shock].

OBJECTIVE: To investigate the mechanism of better result of limited resuscitation in a model of uncontrolled hemorrhagic shock. METHODS: Uncontrolled hemorrhagic shock was produced in 54 rats by a standardized massive splenic injury with transection of the middle branch of splenic artery (MSIA). The rats were randomly assigned to six groups (n=6) by maintenance of the level of mean arterial pressure (MAP): sham-operated group (SS), 40 (RS40), 50 (RS50), 60 (RS60), 80 (RS80) and 100 mm Hg (RS100, 1 mm Hg=0.133 kPa). When the MAP reached 40 mm Hg, resuscitation was begun. Ringer's solution was continued as needed to maintain the following desired endpoints for 45 minutes (T45 point): MAP of 40, 50, 60, 80 and 100 mm Hg. After the bleeding was controlled, resuscitation was continued with Ringer's solution and whole blood (2:1) to raise the MAP to 100 mm Hg for 120 minutes (T165 point), followed by a 240 minutes observation period (T405 point). All animals were observed for 240 minutes or till death. The blood samples were withdrawn from artery for hematocrit (Hct), blood lactate (BL), base excess(BE) at T0, T45, T165, T405 points. At the end of the experiment, a small amount of hepatic tissue was collected for measuring tissue blood perfusion, total antioxidative capacity (T-AOC), Na(+)-K(+)-ATPase, and malondialdehyde (MDA). RESULTS: At T45, T405 points, Hct in SS, RS50 and RS60 were significantly higher than in RS80 and RS100(P<0.05). At T405 point, BL and BE levels in RS80 and RS100 were significantly higher than that of the other groups (P<0.05). The contents of MDA in SS, RS40, and RS50 were significantly lower than in RS80 and RS100(P<0.05). T-AOC level, Na(+)-K(+)-ATPase were significantly lower in RS80 and RS100 than that in the other groups. Blood perfusion was significantly lower in RS80 and RS100 than that in SS, RS40, and RS50. CONCLUSION: In the setting of uncontrolled hemorrhagic shock, limited resuscitation could balance well the needs of organ perfusion and decrease lactate level. It might also exert a protective effect against ischemia/reperfusion injury to liver tissue.

[Beneficial effect of thyrotropin-releasing hormone in combination with HSD on hemorrhagic shock with pulmonary edema at high altitude in the rat].

OBJECTIVE: To study the effects of thyrotropin-releasing hormone (TRH) in combination with hypertonic saline/dextran (7.5% NaCl + 6% Dextran 40, HSD ) on hemorrhagic shock with pulmonary edema in the rats which were recently brought to high altitude. METHODS: Forty-nine SD rats, transported to Lasa, Tibet, which was 3,760 meters above the sea level, were anesthetized one week later with sodium pentobarbital (30 mg/kg, intraperitoneal). Hemorrhagic shock with pulmonary edema was induced by hemorrhage (50 mm Hg maintained for 1 hour,1 mm Hg=0.133 kPa) plus intravenous injection of oleic acid (50 microl/kg). They were equally divided into seven groups (n=7): normal control, hemorrhagic shock, hemorrhagic shock with pulmonary edema (HSPE), HSPE plus TRH (5 mg/kg), HSPE plus HSD (4 ml/kg), and HEPE plus TRH and HSD in combination. Hemodynamic parameters including mean arterial blood pressure(MAP), left intraventricular systolic pressure (LVSP) and the maximal change rate of intraventricular pressure rise or decline (+/- dp/dt max) were observed at 15, 30, 60 and 120 minutes, blood gases were analyzed at 30 and 120 minutes, and the water content of lung and brain was determined at 120 minutes after drug administration. RESULTS: TRH or HSD used alone or in combination significantly increased MAP, LVSP and +/- dp/dt max (P<0.05 or P<0.01 ), ameliorated acid-base imbalance, and decreased the water content of lung and brain. The effect of the two in combination was superior to either drug used alone. CONCLUSION: TRH in combination with HSD can be used in the treatment of hemorrhagic shock with pulmonary edema at high altitude.

[Effect of different volumes of fluid resuscitation on hemorrhagic shock with pulmonary edema at high altitude in the unacclimated rat].

OBJECTIVE: To study the effects of different volumes of fluid resuscitation on hemorrhagic shock with pulmonary edema at high altitude in the unacclimated rat. METHODS: One hundred and twenty-six SD rats transported to Lasa, Tibet, 3 760 meters above the sea level, were anesthetized one week later with sodium pentobarbital (30 mg/kg, intraperitoneal). Hemorrhagic shock with pulmonary edema model was induced by hemorrhage (50 mm Hg for 1 hour, 1 mmHg=0.133 kPa) plus intravenous injection of oleic acid (50 microl/kg). Experiments were then conducted in two parts. Sixty-three rats in part I were equally divided into nine groups (n=7): normal control, hemorrhagic shock control, hemorrhagic shock with pulmonary edema (HSPE) without fluid infusion, HSPE plus infusing lactated Ringer's solution (LR) with 0.5-, 1-, 1.5-, 2- or 3- fold volume shed blood, and 1 volume of LR plus mannitol (10 ml/kg). Hemodynamic parameters including mean arterial blood pressure (MAP), left intraventricular systolic pressure (LVSP) and the maximal change rate of intraventricular pressure rise or decline (+/- dp/dt max) were observed at 15, 30, 60 and 120 minutes after infusion, blood gases were measured at 30 and 120 minutes after infusion and the water content of lung and brain was determined at 120 minutes after infusion. In part II, additional 63 rats were used to observe the effect of different volumes of fluid resuscitation on survival time of HSPE rats. RESULTS: 0.5 volume of LR infusion significantly improved MAP, LVSP and +/- dp/dt max, prolonged the survival time of HSPE animals (all P<0.01), while it did not increase the water content of lung and brain and had no marked influence on blood gases. One volume of LR infusion slightly improved hemodynamic parameters, prolonged the survival time and increased the water content of lung. More than 1 volume of LR infusion including 1.5-, 2- and 3- fold volume LR deteriorated the hemodynamic parameters and decreased the survival time of shocked animal, meanwhile they apparently increased the water content of lung. One volume of LR plus mannitol (10 ml/kg) infusion did not improve the hemodynamic parameters and blood gases; also it did not decrease the water content of lung. CONCLUSION: The tolerance to fluid infusion for the unacclimated animal subjected to hemorrhagic shock with pulmonary edema at high altitude is significantly decreased. 0.5-1 volume of LR infusion appears to be beneficial effect on resuscitation at high altitude, while over 1 volume of LR infusion would aggravate pulmonary edema and exacerbate fluid resuscitation effect.

Small doses of arginine vasopressin in combination with norepinephrine "buy" time for definitive treatment for uncontrolled hemorrhagic shock in rats.

Implementation of fluid resuscitation and blood transfusion are greatly limited in prehospital or evacuation settings after severe trauma or war wounds. With uncontrolled hemorrhagic shock rats, we investigated if arginine vasopressin (AVP) in combination with norepinephrine (NE) is independent (or slightly dependent) of fluid resuscitation and can "buy" time for the subsequently definitive treatment of traumatic hemorrhagic shock in the present study. The results showed that AVP (0.4 U/kg) alone or with NE (3 µg/kg) with one-eighth and one-fourth volumes of total blood volume of lactated Ringer's infusion significantly increased and maintained the mean arterial pressure. Among all groups, 0.4 U/kg of AVP + NE (3 µg/kg) with one-eighth volume of lactated Ringer's infusion had the best effect: it significantly increased and maintained hemodynamics and prolonged the survival time. This early treatment strategy significantly improved the effects of subsequently definitive treatments (after bleeding controlled): it increased the subsequent survival, improved the hemodynamic parameters, improved the cardiac function, and increased the tissue blood flow and oxygen delivery. These results suggested that early application of small doses of AVP (0.4 U/kg) + NE before bleeding control can "buy" time for the definitive treatment of uncontrolled hemorrhagic shock, which may be an effective measure for the early treatment of traumatic hemorrhagic shock.