Polymicrobial Sepsis In Rats Research Articles

Time-serial expression of toll-like receptor 4 signaling during polymicrobial sepsis in rats.

Sepsis caused by aggressive infection is a severe clinical problem with an increasing incidence worldwide. Toll-like receptors and their common adapter myeloid differentiation factor 88 (MyD88) can activate immune responses by recognizing a foreign microbe’s product. This study aimed to identify the different time expression of TLR four signaling pathway in an experimental rodent model of polymicrobial sepsis. A randomized animal study was investigated in rats with septic peritonitis induced by cecal ligation and puncture (CLP). The expressions of MyD88-dependent pathway biomarkers, including MyD88, nuclear factor-κB (NF-κB), and serum tumor necrosis factor-α (TNF-α), were analyzed and compared to the sham controls at the different time points after CLP surgery. CLP-induced sepsis increased liver MyD88 mRNA expression and protein expression compared to the control groups at 2 h after surgery. The MyD88 mRNA and protein expressions in rats with CLP-induced sepsis marked increased at 4 and 6 h, and their NF-κB activities and serum TNF-α levels also increased at 4 h after CLP surgery (both p < .05). The different serial expression of MyD88-ependent pathway during sepsis may be used as biomarkers during sepsis. These results may provide further helpful information for using pro-inflammatory biomarkers of innate immunity such as MyD88 and TNF-α in clinical sepsis or related abdominal surgical emergency in the future.

Fecal Microbiota Transplantation and Hydrocortisone Ameliorate Intestinal Barrier Dysfunction and Improve Survival in a Rat Model of Cecal Ligation and Puncture-Induced Sepsis.

Sepsis is a life-threatening syndrome which can progress to multiple organ dysfunction with high mortality. Intestinal barrier failure exerts a central role in the pathophysiological sequence of events that lead from sepsis to multiple organ dysfunction. The present study investigated the role of hydrocortisone (HC) administration and fecal microbiota transplantation (FMT) in several parameters of the gut barrier integrity, immune activation, and survival, in a model of polymicrobial sepsis in rats. Forty adults male Wistar rats were randomly divided into four groups: sham (group I), cecal ligation and puncture (CLP) (group II), CLP + HC (2.8 mg/kg, intraperitoneally single dose at 6 h) (group III), and CLP + FMT at 6 h (group IV). At 24 h post-CLP, ileal tissues were harvested for histological and immunohistochemical analyses while endotoxin, IL-6, and IL-10 levels in systemic circulation were determined. In a second experiment the same groups were observed for 7 days for mortality, with daily administration of hydrocortisone (group III) and FMT (group IV) in surviving rats. HC administration and FMT significantly reduced mortality of septic rats by 50%. These interventions totally reversed intestinal mucosal atrophy by increasing villous density and mucosal thickness (μm, mean ± SD: Group I: 620 ± 35, Group II: 411 ± 52, Group III: 622 ± 19, Group IV: 617 ± 44). HC and FMT reduced the apoptotic body count in intestinal crypts whereas these increased the mitotic/apoptotic index. Activated caspase-3 expression in intestinal crypts was significantly reduced by HC or FMT (activated caspase-3 (+) enterocytes/10 crypts, mean ± SD: Group I: 1.6 ± 0.5, Group II: 5.8 ± 2.4, Group III: 3.6 ± 0.9, Group IV: 2.3 ± 0.6). Both treatments increased Paneth cell count and decreased intraepithelial CD3(+) T lymphocytes and inflammatory infiltration of lamina propria to control levels. In the sham group almost the total of intestinal epithelial cells expressed occludin (92 ± 8%) and claudin-1 (98 ± 4%) and CLP reduced this expression to 34 ± 12% for occludin and 35 ± 7% for claudin-1. Administration of HC significantly increased occludin (51 ± 17%) and claudin-1 (77 ± 9%) expression. FMT exerted also a significant restoring effect in tight junction by increasing occludin (56 ± 15%) and claudin-1 (84 ± 7%) expression. The beneficial effects of these treatments on gut barrier function led to significant reduction of systemic endotoxemia (EU/mL, mean ± SD: Group I: 0.93 ± 0.36, Group II: 2.14 ± 1.74, Group III: 1.48 ± 0.53, Group IV: 1.61 ± 0.58), while FMT additionally decreased IL-6 and IL-10 levels. Fecal microbiota transplantation and stress dose hydrocortisone administration in septic rats induce a multifactorial improvement of the gut mechanical and immunological barriers, preventing endotoxemia and leading to improved survival.

Alpha-lipoic acid attenuates acute neuroinflammation and long-term cognitive impairment after polymicrobial sepsis

Sepsis is a complication of an infection which imbalance the normal regulation of several organ systems, including the central nervous system (CNS). Evidence points towards inflammation and oxidative stress as major steps associated with brain dysfunction in sepsis. Thus, we investigated the α-lipoic acid (ALA) effect as an important antioxidant compound on brain dysfunction in rats. Wistar rats were subjected to sepsis by cecal ligation and perforation (CLP) or sham (control) and treated orally with ALA (200 mg/kg after CLP) or vehicle. Animals were divided into sham + saline, sham + ALA, CLP + saline and CLP + ALA groups. Twelve, 24 h and 10 days after surgery, the hippocampus, prefrontal cortex and cortex were obtained and assayed for levels of TNF-α and IL-1β, blood brain barrier (BBB) permeability, nitrite/nitrate concentration, myeloperoxidase (MPO) activity, thiobarbituric acid reactive species (TBARS) formation, protein carbonyls, superoxide dismutase (SOD) and catalase (CAT) activity and neurotrophins levels. Behavioral tasks were performed 10 days after surgery. ALA reduced BBB permeability and TNF-α levels in hippocampus in 24 h and IL-1β levels and MPO activity in hippocampus and prefrontal cortex in 24 h. ALA reduced nitrite/nitrate concentration and lipid peroxidation in 24 h in all structures and protein carbonylation in 12 and 24 h in hippocampus and cortex. CAT activity increased in the hippocampus and cortex in all times. ALA enhanced NGF levels in hippocampus and cortex and prevented cognitive impairment. Our data demonstrates that ALA reduces the consequences of polymicrobial sepsis in rats by decreasing inflammatory and oxidative stress parameters in the brain.

Kinin B1 Receptor Inhibition With BI113823 Reduces Inflammatory Response, Mitigates Organ Injury, and Improves Survival Among Rats With Severe Sepsis.

This study examined the therapeutic effects of an orally active nonpeptide kinin B1 receptor antagonist, BI113823, in a clinically relevant experimental model of polymicrobial sepsis in rats. Sepsis was induced by cecal ligation and puncture (CLP). Animals received treatment with either vehicle or BI113823. The experiment was terminated in the first set of animals 15 hours after CLP. Seven-day survival following CLP was determined in the second set of animals. Compared with vehicle treatment, administration of BI113823 reduced neutrophil and macrophage infiltration, reduced cytokine production, attenuated intestinal mucosal hyperpermeability, prevented hemodynamic derangement, and improved cardiac output. Furthermore, administration of BI113823 reduced inducible nitric oxide synthase expression and the injury score in the lung and attenuated nuclear factor ĸB activation and apoptosis in the liver. Treatment with BI113823 also reduced plasma levels of cardiac troponin, aspartate aminotransferase, alanine aminotransferase, urea, and lactate, as well as proteinuria. Finally, administration of BI113823 improved the 7-day survival rate following CLP in rats. Administration of BI113823 reduced systemic and tissue inflammatory responses, prevented hemodynamic derangement, attenuated multiorgan injury, and improved overall survival.

Protective effect of Ruta Chalepensis L. extract on oxidative stress and liver-kidney function induced by polymicrobial sepsis in rats

Sepsis, a systemic inflammatory disease developed after an infectious insult and remains the major cause of death in intensive care units. The aim of this study was to examine the protective effect of the ethanolic extract of Ruta chalepensis L. (ERC) against oxidative stress and liver-kidney functions in cecal and ligation puncture (CLP) rats. In vitro, the results showed that ERC rich in phenolic compounds possessed important antioxidant activity. In vivo, CLP-induced oxidative stress evidenced by the increase of the TBARS and decrease in the enzymatic antioxidants (SOD, CAT, GPX) in liver and kidney. Moreover, CLP induced liver-kidney toxicities showed by an increase in the ALT, AST, PAL, LDH, BUN and creatinine in the plasma. However, the administration of ERC to CLP-rats prevents all these disorders. Positive action of ERC was confirmed by histo-pathological examination. Therefore this study suggests that ERC could be a potential therapeutic agent for sepsis treatment.

Melatonin Receptors Mediate Improvements of Survival in a Model of Polymicrobial Sepsis

Melatonin has been demonstrated to improve survival after experimental sepsis via antioxidant effects. Yet, recent evidence suggests that this protective capacity may also rely on melatonin receptor activation. Therefore, the present study was designed to investigate whether selective melatonin receptor-agonist ramelteon may influence survival and immune response in a model of polymicrobial sepsis in rats, wild-type and melatonin receptor MT1/MT2 double knockout mice. Prospective, randomized, controlled study. University research laboratory. Male Sprague-Dawley rats (200-250 g) and male C3H/HeN wild-type and MT1/MT2 receptor knockout mice (20-22 g). Animals underwent cecal ligation and incision and remained anesthetized for evaluation of survival for 12 hours (rats: n = 15 per group) or 15 hours (mice: n = 10 per group). Analysis of immune response by means of enzyme-linked immunosorbent assay was performed before and 5 hours after cecal ligation and incision (rats only; n = 5 per group). After induction of sepsis, animals were treated IV with vehicle, different doses of melatonin (rats: 0.01/0.1/1.0/10 mg/kg; mice: 1.0 mg/kg), ramelteon, melatonin receptor-antagonist luzindole, ramelteon + luzindole, or melatonin + luzindole (each 1.0 mg/kg). Sham controls underwent laparotomy but not cecal ligation and incision. Compared with vehicle, administration of ramelteon or melatonin significantly improved median survival time in rats (sepsis/melatonin [0.1 mg/kg], 554 min, [1.0 mg/kg] 570 min, [10 mg/kg] 579 min; sepsis/ramelteon, 468 min; each p < 0.001 vs sepsis/vehicle, 303 min) and wild-type mice (sepsis/melatonin, 781 min; sepsis/ramelteon, 701 min; both p < 0.001 vs sepsis/vehicle, 435 min). This effect was completely antagonized by coadministration of luzindole in all groups. Melatonin, ramelteon, or luzindole had no significant effect on survival time in knockout mice. Significantly elevated concentrations of tumor necrosis factor-α, interleukin-6, and interleukin-10 were observed 5 hours after cecal ligation and incision in rats (p < 0.05 vs baseline and corresponding sham); neither ramelteon nor melatonin treatment significantly affected immune response. Melatonin receptors mediate improvements of survival after polymicrobial sepsis in rats and mice; this effect appears to be independent from major alterations of cytokine release.

A mouse is not a rat is not a man: species-specific metabolic responses to sepsis - a nail in the coffin of murine models for critical care research?

Sepsis and consequent multi-organ failure are the leading causes of mortality in critically ill patients. Numerous therapeutic strategies, which yielded promising results in preclinical studies, have failed to show any efficacy in clinical trials. Historically, most of our (patho)physiological understanding of cardiovascular regulation in health and disease has been established in larger mammals, e.g., dog, pig, and sheep. However, a very large body of the literature collected over recent decades originates from investigations in rodents. Despite their small size, which makes surgery difficult and limits repetitive blood sampling, murine models have been widely used, not because they are more faithful to adult human pathophysiology than larger mammals but because they are inexpensive, easy to handle and care for, and with availability of gene knockout and overexpression strains. Investigators have performed studies without necessarily having a good appreciation of some fundamental differences in the physiology of rodents. These have been long established by comparative physiologists, yet have never been taught in any medical school. One can query the logic of inferring information on mechanisms involved in septic shock using species capable of decreasing their high resting metabolic rate both rapidly and massively, and with the associated circulatory and respiratory responses. Mouse models of acute inflammatory disorders have recently been questioned by Seok et al. [1] who found that “genomic responses to different acute inflammatory stresses are highly similar in humans”, whereas “these responses are not reproduced in current mouse models”. In this context, Zolfaghari et al. [2] compared the metabolic responses to polymicrobial sepsis in rats and mice. Their main findings were that mice presented with a progressive drop in whole body O2 uptake and a concurrent fall in body temperature, which was only partially restored by external warming. This marked metabolic depression coincided with pronounced impairment of left heart systolic contractility. In sharp contrast, only severely ill rats showed a comparably decreased cardiac output, and the metabolic depression was only present during the late premortem period. How can we explain these findings by Zolfaghari et al. [2]? The authors have the merit of raising an issue of crucial importance for critical care research, i.e., whether or

Dobutamine Pretreatment Improves Survival, Liver Function, and Hepatic Microcirculation After Polymicrobial Sepsis in Rat

Dobutamine is recommended for the treatment of sepsis-related circulatory failure in international guidelines. Furthermore, dobutamine has been demonstrated to improve liver function and hepatic perfusion after experimental hemorrhagic shock. Yet, it is unknown whether dobutamine may also induce hepatoprotective effects in sepsis. This study was designed to investigate the effect of dobutamine on survival, hepatic function, and microcirculation after polymicrobial sepsis in rat. Under general anesthesia, male Sprague-Dawley rats (n = 25/group) underwent pretreatment with dobutamine (10 μg/kg per minute) in the presence or absence of β1-receptor antagonist esmolol (500 μg/kg per minute), esmolol alone, or vehicle for 6 h, before induction of sepsis (cecal ligation and incision [CLI]). Sham-operated animals were treated likewise but underwent no CLI. Five hours after CLI, either liver function was assessed by plasma disappearance rate of indocyanine green (n = 5/group), or intravital microscopy was performed (n = 5/group) for evaluation of hepatic perfusion index and hepatic integrity (as propidium iodide-stained cells per field). Alternatively, survival time after induction of CLI was monitored under general anesthesia (n = 15/group). Compared with controls, dobutamine pretreatment significantly improved plasma disappearance rate of indocyanine green (13.8% ± 4.1% vs. 20.6% ± 4.6%; P = 0.029), hepatic perfusion index (275.0 ± 126.1 vs. 703.5 ± 177.4 pL/s per mm; P < 0.001), hepatocellular injury (22.2 ± 6.7 vs. 6.4 ± 3.1 cells per field; P < 0.001), and survival time (326 ± 20 vs. 603 ± 41 min; P < 0.001). Coadministration of esmolol abolished the protective effect of dobutamine completely. Our results indicate that pretreatment with dobutamine may improve survival, liver function, and hepatic microcirculation after polymicrobial sepsis in rat via β1-adrenoceptor activation. Dobutamine could therefore play a relevant role for hepatoprotection under septic conditions.

Effect of IL-1 receptor antagonist on the cerebrospinal fluid nitric oxide concentrations during experimental polymicrobial sepsis in rats

Effect of IL-1 receptor antagonist on the cerebrospinal fluid nitric oxide concentrations during experimental polymicrobial sepsis in rats

Dobutamine pretreatment improves hepatic microcirculation after polymicrobial sepsis in rat

Dobutamine pretreatment improves hepatic microcirculation after polymicrobial sepsis in rat

Melatonin receptors mediate improvements of survival after polymicrobial sepsis in rat

Melatonin receptors mediate improvements of survival after polymicrobial sepsis in rat

Effects of propofol on pro-inflammatory cytokines and nuclear factor kappaB during polymicrobial sepsis in rats

Nuclear factor kappa B (NF-kappaB) plays a central role in regulating the transcription of several genes associated with sepsis/septic shock. Therefore, the author investigated the effects of propofol on the plasma tumor necrosis factor alpha and interleukin 6 (TNF-alpha and IL-6) levels and NF-kappaB activation during polymicrobial sepsis in rats. Male Sprague-Dawlay rats were subjected to cecal ligation and puncture (CLP, a model of polymicrobial sepsis) or sham operation. The animals were randomly assigned into four equal groups (n = 10): sham CLP group, CLP group, PPF (propofol) I group and PPF II group. Thirty minutes before CLP, propofol (5 and 10 mg kg(-1) h(-1), respectively) was infused continuously through the left femoral vein cannula in PPF I group or PPF II group, CLP group and sham CLP group receiving 0.9% saline only at the rates of 5 ml kg(-1) h(-1). The right femoral artery was cannulated to monitor mean arterial pressure (MAP) and heart rates (HR). CLP produced progressive hypotension and a first increase followed by a decrease in HR. The plasma TNF-alpha and IL-6 levels and the hepatic NF-kappaB activation significantly increased after CLP alone. Compared with CLP group, propofol treatment reversed hypotension, slightly steadied heartbeats, and decreased the plasma TNF-alpha and IL-6 levels, and significantly suppressed NF-kappaB activation. Propofol has inhibited the hepatic NF-kappaB activation and the pro-inflammatory cytokine response during polymicrobial sepsis in rats.

THE PROTECTIVE EFFECT OF THE CHOLINERGIC ANTI-INFLAMMATORY PATHWAY AGAINST SEPTIC SHOCK IN RATS

To investigate the effects of the cholinergic anti-inflammatory pathway on hemodynamics, blood biochemistry, the plasma TNF-alpha level, and the nuclear factor-kappaB (NF-kappaB) activation during septic shock, male Sprague-Dawley rats were subjected to cecal ligation and puncture (CLP, a model of polymicrobial sepsis) or sham operation. Forty-eight rats were randomly assigned into six equal groups: sham CLP group; CLP group; VGX group was subjected to bilateral cervical vagotomy after CLP; STM group was subjected to bilateral cervical vagotomy after CLP plus the left vagus nerve trunk electrical stimulation; THA group was administered tetrahydroaminoacridine after CLP and bilateral cervical vagotomy; and alpha-BGT group was administered alpha-bungarotoxin before electrical stimulation of the vagus nerve. The right carotid artery was cannulated to monitor MAP. The plasma TNF-alpha level was measured using enzyme-linked immunosorbent assays. The hepatic NF-kappaB activation was determined by Western blotting. Cecal ligation and puncture produced progressive hypotension. Serum aspartate transaminase and alanine transaminase levels significantly increased after CLP challenge. The plasma TNF-alpha level and the hepatic NF-kappaB activation significantly increased after CLP alone or with bilateral cervical vagotomy compared with sham-operated group. Application of constant voltage pulses to the caudal vagus trunk significantly prevented the development of CLP-induced hypotension, alleviated the hepatic damage, and reduced the plasma TNF-alpha production, but electrical stimulation had no effect on the hepatic NF-kappaB activation. Tetrahydroaminoacridine administration after bilateral cervical vagotomy reversed hypotension and attenuated the plasma TNF-alpha response; in addition, it had no effect on the hepatic NF-kappaB activation. alpha-Bungarotoxin pretreatment significantly reversed the inhibitory effect of vagal electrical stimulation, but it had no effect on the hepatic NF-kappaB activation. Our results showed that the cholinergic anti-inflammatory pathway might produce a potential protective effect on polymicrobial sepsis in rats.

Plasma Thrombin Activatable Fibrinolysis Inhibitor and Tissue Factor Pathway Inhibitor Changes Following Sepsis

Sepsis-induced systemic inflammation results in coagulation abnormalities that may be different in gram-positive and gram-negative infections. We used ciprofloxacin to induce a predominantly gram-positive Enterococcus faecalis polymicrobial sepsis in rats. Ciprofloxacin-untreated rats exhibited a predominantly gram-negative polymicrobial sepsis. Rats were subjected to 30% body surface area burn (B), cecal ligation puncture (CLP) with a 22-gauge needle, and B + CLP. Ciprofloxacin-treated B + CLP rats showed a significant decrease in plasma thrombin activatable fibrinolysis inhibitor (TAFI) levels compared with sham rats. However, plasma tissue factor pathway inhibitor (TFPI) levels decreased significantly in B, CLP, and B + CLP groups compared with sham rats. The ciprofloxacin-untreated group showed a significant decrease in plasma TAFI levels in CLP and B + CLP and plasma TFPI levels decreased in all 3 groups compared with sham rats. Histological changes in the liver and kidney included vascular congestion and parenchyma bleed following B + CLP in ciprofloxacin-untreated rats. These results suggest that plasma TAFI and TFPI levels differ depending on the type of bacteria involved in the septic process.

Effects of a membrane-permeable radical scavenger, Tempol, on healing of colonic anastomoses in the cecal ligation and puncture model of polymicrobial sepsis in rats

Background Tempol (Sigma-Aldrich, Steinheim, Germany) is a stable piperidine nitroxide of low molecular weight that permeates biologic membranes and scavenges superoxide anions in vitro. In recent animal studies, the delaying effect of intraperitoneal sepsis on the healing of colonic anastomoses has been shown. In this study we aimed to investigate the effects of Tempol on the healing of colonic anastomoses in the presence of polymicrobial sepsis. Methods Anastomosis of the left colon was performed on the day after cecal ligation and puncture (CLP) in 30 rats that were divided into 3 groups: sham-operated control (laparotomy and cecal mobilization, group I, n = 10), CLP (group II, n = 10), Tempol-treated group (30 mg/kg intravenously before the construction of colonic anastomosis, group III, n = 10). On postoperative day 6, all animals were killed and anastomotic bursting pressures were measured in vivo. Tissue samples were obtained for further investigation of anastomotic hydroxyproline (HP) contents, perianastomotic myeloperoxidase (MPO) activity, malondialdehyde (MDA), and glutathione (GSH) levels. Results There was a statistically significant increase in MPO activity and MDA levels in the CLP group (group II), along with a decrease in GSH levels, anastomotic HP contents, and bursting pressure values when compared with controls (group I). However, Tempol treatment led to a statistically significant increase in anastomotic bursting pressure values, tissue HP contents, and GSH levels, along with a decrease in MPO activity and MDA levels in group III ( P < .05). Conclusions This study showed that Tempol treatment significantly prevented the delaying effect of CLP-induced polymicrobial sepsis on anastomotic healing in the left colon. Further clinical studies are needed to clarify whether Tempol may be a useful therapeutic agent to increase the safety of the anastomosis during particular surgeries in which sepsis-induced organ injury occurs.

Influence of hydroxyethyl starch 130/0.4 in pulmonary neutrophil recruitment and acute lung injury during polymicrobial sepsis in rats

Acute lung injury (ALI) is a progressive syndrome associated with significant mortality in sepsis patients. Neutrophils are key cells in the inflammatory response that characterizes ALI. This study was designed to explore the effects of hydroxyethyl starch (HES) 130/0.4 (a novel plasma substitute) on pulmonary neutrophil recruitment and associated ALI in a rat sepsis model induced by cecal ligation and puncture (CLP). Animals were randomly assigned to six groups [saline control; CLP and saline; CLP and HES (7.5, 15 and 30 ml/kg); and HES control], subjected to CLP and infused with or without HES 130/0.4 4 h after CLP. Six hours later, the pulmonary capillary permeability (PCP), myeloperoxidase (MPO) activity, lung histological changes, tumor necrosis factor-alpha, interleukin-1beta and cytokine-induced neutrophil chemoattractant levels, P-selectin mRNA expression and nuclear factor-kappa B (NF-kappaB) activation were measured. Resuscitation with HES 130/0.4 significantly attenuated the CLP-induced increase in PCP, MPO activity, cytokine/chemokine levels, mRNA expression of P-selectin and NF-kappaB activation, all of which are involved in the recruitment of neutrophils. Groups receiving the higher doses of HES 130/0.4 (15 and 30 ml/kg) were more adequately resuscitated. HES 130/0.4 can inhibit CLP-induced neutrophil recruitment and subsequent ALI by attenuating cytokines/chemokines, adhesion molecule-mediated inflammation and NF-kappaB activation.

Contribution of Gene Expression to Metabolic Fluxes in Hypermetabolic Livers Induced Through Burn Injury and Polymicrobial Sepsis in Rats

Contribution of Gene Expression to Metabolic Fluxes in Hypermetabolic Livers Induced Through Burn Injury and Polymicrobial Sepsis in Rats

Effects of ketamine on proinflammatory cytokines and nuclear factor kappaB in polymicrobial sepsis rats

To explore the effects of ketamine on hemo-dynamics, plasma proinflammatory cytokine (TNF-alpha and IL-6) levels and nuclear factor kappa B (NF-kappaB) activation during polymicrobial sepsis. Male Sprague-Dawley rats were subjected to cecal ligation and puncture (CLP) or sham operation. The rats were randomly assigned into four equal groups: sham CLP group, CLP group, ketamine (KT) I group and KT II group. Thirty minutes before CLP, ketamine (5 mg/kg per hour and 10 mg/kg per hour, respectively) was infused continuously through the left femoral vein cannula in KT I group or KT II group. Sham CLP group and CLP group received 0.9% saline only (5 mL/kg per hour). The right femoral artery was cannulated to monitor mean arterial pressure (MAP) and heart rates (HR),and draw blood samples. The proinflammatory cytokine (TNF-alpha and IL-6) levels of plasma were measured using enzyme-linked immunosorbent assays (ELISA). The hepatic NF-kappaB activation was determined by Western blot and HPIAS 2000 image analysis system. Twenty hours after CLP, the rats were killed by right femoral artery phlebotomization. CLP produced progressive hypotension, and a first increase followed by a decrease in HR. The hypotension was prevented, and the HR was slightly steady in ketamine treated rats. TNF-alpha levels of plasma reached a peak value at 2 h after CLP. Ketamine (KT I group or KT II group) caused a significant decrease compared with CLP group at 2, 5 and 9 h time points after CLP (14.3 +/- 1.9 vs 4.3 +/- 0.9, 9.7 +/- 1.4 vs 4.3 +/- 0.9; 9.3 +/- 1.5 vs 4.3 +/- 0.9, 8.7 +/- 1.4 vs 4.3 +/- 0.9; 6.0 +/- 1.5 vs 5.0 +/- 1.7, 5.3 +/- 0.8 vs 5.0 +/- 1.7; P < 0.01, respectively). The IL-6 levels of plasma firstly ascended and then descended in CLP group, and reached a peak value at 9 h after CLP. Ketamine (KT I group or KT II group) caused a significant decrease compared with CLP group at 5, 9 or 20 h after CLP (135.0 +/- 52.6 vs 60.0 +/- 16.3, 112.5 +/- 52.6 vs 60.0 +/- 16.3; 410.0 +/- 68.7 vs 62.5 +/- 12.5, 250.0 +/- 28.0 vs 62.5 +/- 12.5; 320.0 +/- 25.9 vs 52.5 +/- 10.1, 215.0 +/- 44.6 vs 52.5 +/- 10.1; P < 0.05, respectively). The IL-6 levels of plasma in KT II group were lower than those of KT I group at 9 h after CLP (250.0 +/- 28.0 vs 410.0 +/- 68.7; P < 0.05). In addition, CLP increased hepatic NF-kappaB expression compared with sham CLP. Ketamine suppressed NF-kappaB activation in a dose-dependent manner at 4 h after CLP (237.7 +/- 3.5 vs 246.9 +/- 3.1; P < 0.05). Ketamine stabilizes the hemodynamics, attenuates the proinflammatory cytokine responses, and inhibits hepatic NF-kappaB activation. These findings suggest that ketamine has protective effects against polymicrobial sepsis in rats.

Repetitive Pneumoperitoneum with Ozonized Oxygen as a Preventive in Lethal Polymicrobial Sepsis in Rats

The aim of this study was to test whether repetitive pretreatments of rats with ozonized oxygen at relatively low gas volumes into the abdomen (20 ml per rat per day) have any beneficial or detrimental effects on the course of a polymicrobial-induced lethal peritonitis. Peritonitis was induced in a surgical or a nonsurgical model by usage of fecal material from the cecum. As the biological read out we used the mortality analysis. To include possible mechanisms by which ozone might influence the septic outcome, we characterized the gene expression of the pro-inflammatory cytokines IL-1β, IL-2, and TNF-α mRNA in lymphoid organs. In both models, we found a significant beneficial influence of a dose-dependent O₂/O₃pneumoperitoneum on the survival rate when compared to control animals or to room air. The ozone-enhanced survival seems to be independent from altered cytokine expression because there were no differences noticed in the levels of bacterial-induced gene expression of IL-1β and TNF-α in septic animals pretreated with ozonized oxygen when compared to control animals.