Rat Model Of Peritonitis Research Articles

Anti-inflammatory and antimicrobial effect of lectin from Lonchocarpus sericeus seeds in an experimental rat model of infectious peritonitis

We have investigated the anti-inflammatory and antimicrobial effect of the lectin from Lonchocarpus sericeus seeds (LSL) in a model of infectious peritonitis in adult Wistar rats. Animals were treated with saline or LSL (10 mg kg(-1), i.v) immediately and 6 h after the induction of peritonitis via cecal ligation and single puncture. Twelve hours after surgery, animals were killed and the infectious process was monitored by total and differential count of cells from blood and peritoneal washing liquid, adenosine deaminase activity, antibiogram and the number of viable bacteria of the peritoneal cavity. LSL treatment decreased the inflammatory response evoked by the induction of peritonitis, as seen by the inhibition of neutrophil migration into peritoneal cavities, leucocytosis and reduction of adenosine deaminase activity in the peritoneal fluid. All these effects were reversed by the lectin association to N-acetyl-glucosamine. LSL in-vitro did not show any antimicrobial action, but promoted a marked decrease of the viable bacterial population in peritoneal cavities. In conclusion, LSL inhibited the inflammatory response and the bacterial colonization of infectious peritonitis in rats.

Hydroxyethyl starch 130/0.4 augments healing of colonic anastomosis in a rat model of peritonitis

Background This study was designed to investigate the role of hydroxyethyl starch (HES) 130/0.4 on the wound healing process in left colonic anastomoses in the presence of intra-abdominal sepsis. Methods The left colonic anastomosis was performed in 40 rats that were divided into 4 groups: (1) group SHAM, laparatomy plus cecal mobilization (n = 10); (2) group SHAM + HES, HES130/.4–treated controls (n = 10); and (3) group CLP, cecal ligation and puncture (n = 10); (4) group CLP + HES, CLP plus HES130/.4 (n = 10). HES130/.4 was administrated before the construction of colonic anastomosis, 15 mL/kg/24 hours and daily for 4 postoperative days. Anastomotic bursting pressures (ABPs) were measured in vivo on day 5. Tissue samples were obtained for analyses of hydroxyproline (HP) contents, myeloperoxidase (MPO) activity, malondialdehyde (MDA), reduced glutathione (GSH) levels, and nuclear factor-κB (NF-κB) activation. The plasma levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6, d-dimer, and protein C (PC) were also measured. Anastomotic granulation tissues were fixed for transmission electron microscopic (TEM) analyses. Results Intra-abdominal sepsis led to significant decreases in colonic anastomotic bursting pressures, perianastomotic tissue HP contents, GSH levels, and plasma levels of PC, along with increases in perianastomotic tissue MPO activity, MDA levels, NF-κB activation, and plasma levels of TNF-α, IL-6, and d-dimer. However, HES130/.4 treatment significantly inhibited all these responses. TEM analyses revealed that there was a trend toward a higher density of fibroblast distribution and a higher rate of fibroblast activation in the SHAM- and HES 130/0.4-treated animals, compared with the CLP group. Conclusions This study showed that moderate doses (15 mL/kg) of HES 130/0.4 administration significantly prevented this intraperitoneal sepsis-induced impaired anastomotic healing of the left colon. This beneficial effect of HES 130/0.4 can be mainly attributed to its anti-inflammatory and antioxidant properties and beneficial effects of modulating endothelial-associated coagulopathy.

Involvement of NO in the inhibitory effect of Calotropis procera latex protein fractions on leukocyte rolling, adhesion and infiltration in rat peritonitis model

Aim of the study The latex of Calotropis procera has been used in the traditional medicinal system for the treatment of leprosy, ulcers, tumors, piles and diseases of liver, spleen, abdomen and toothache. It comprises of a non-dialyzable protein fraction (LP) that exhibits anti-inflammatory properties and a dialyzable fraction (DF) exhibiting pro-inflammatory properties. The present study was carried out to evaluate the effect of LP sub-fractions on neutrophil functions and nociception in rodent models and to elucidate the mediatory role of nitric oxide (NO). Material and methods The LP was subjected to ion exchange chromatography and the effect of its three sub-fractions (LP PI, LP PII and LP PIII) thus obtained was evaluated on leukocyte functions in the rat peritonitis model and on nociception in the mouse model. Results LP sub-fractions exhibit distinct protein profile and produce a significant decrease in the carrageenan and DF induced neutrophil influx and exhibit anti-nociceptive property. The LP and its sub-fractions produced a marked reduction in the number of rolling and adherent leukocytes in the mesenteric microvasculature as revealed by intravital microscopy. The anti-inflammatory effect of LP PI, the most potent anti-inflammatory fraction of LP, was accompanied by an increase in the serum levels of NO. Further, our study shows that NO is also involved in the inhibitory effect of LP PI on neutrophil influx. Conclusions Our study shows that LP fraction of Calotropis procera comprises of three distinct sets of proteins exhibiting anti-inflammatory and anti-nociceptive properties of which LP PI was most potent in inhibiting neutrophil functions and its effects are mediated through NO production.

Tissue-type plasminogen activator prevents abscess formation but does not affect healing of bowel anastomoses and laparotomy wounds in rats with secondary peritonitis

Intra-abdominal application of recombinant tissue-type plasminogen activator (rtPA) can decrease the rate of abscess formation in a rat peritonitis model. Before using rtPA clinically, its effects on healing of bowel anastomoses and laparotomy wounds should be investigated. Peritonitis was induced in 148 male Wistar rats via intra-abdominal injection of a feces/bacteria mixture. Laparotomy, operative debridement and construction of a colo-colostomy after a limited colectomy or ileo-ileostomy after a limited ileal resection were performed after 1 hour. All animals received antibiotics (ceftriaxone plus metronidazole). In addition to untreated controls, other animals received rtPA in 1 of 3 dosing schemes, starting immediately after operation or 24 hour afterwards. Wound strength and hydroxyproline content of the wound were analyzed after 3 or 7 days. Mortality was 2% and manifestations of excessive bleeding were virtually absent. RtPA significantly decreased the rate of abscess formation. Neither bursting pressure nor breaking strength of the anastomoses was affected by any of the rtPA protocols. The same was true for wound strength in the abdominal fascia. Additionally, wound hydroxyproline content and architecture remained unchanged after rtPA administration. Intraperitoneal rtPA administration consistently and significantly decreased the rate of abscess formation, but did not affect wound healing. Clinical studies investigating its potential as an adjunct in the treatment of secondary peritonitis may be warranted.

Zymosan, but Not Lipopolysaccharide, Triggers Severe and Progressive Peritoneal Injury Accompanied by Complement Activation in a Rat Peritonitis Model

Fungal peritonitis is an important complication in peritoneal dialysis patients; either continuous or recurrent peritonitis may enhance peritoneal damage. Even when the peritoneal dialysis catheter is removed in patients with fungal peritonitis, peritoneal fibrosis can progress and evolve into encapsular peritoneal sclerosis. It is unclear why fungal infections are worse than bacterial in these respects. Zymosan is a cell wall component of yeast that strongly activates the complement system. In this study, we compared the effects of zymosan and bacterial LPS on peritoneal inflammation in a rat peritoneal injury model induced by mechanical scraping. Intraperitoneal administration of zymosan, but not LPS or vehicle, caused markedly enhanced peritonitis with massive infiltration of cells and deposition of complement activation products C3b and membrane attack complex on day 5. In rats administered zymosan and sacrificed on days 18 or 36, peritoneal inflammation persisted with accumulation of ED-1-positive cells, small deposits of C3b and membrane attack complex, exudation of fibrinogen, and capillary proliferation in subperitoneal tissues. When zymosan was administered daily for 5 days after peritoneal scrape, there was even greater peritoneal inflammation with peritoneal thickening, inflammatory cell accumulation, and complement deposition. Inhibition of systemic complement by pretreatment with cobra venom factor or local inhibition by i.p. administration of the recombinant complement regulator Crry-Ig reduced peritoneal inflammation in zymosan-treated rats. Our results show that yeast components augment inflammation in the injured peritoneum by causing complement activation within the peritoneal cavity. Local anticomplement therapy may therefore protect from peritoneal damage during fungal infection of the peritoneum.

Technical Aspects in Studying Peritoneal Morphology in Animal Models of Peritoneal Dialysis

Peritoneal biopsies are considered useful for gaining a better understanding of the pathophysiology of the peritoneum during experimental peritoneal dialysis (PD). Different peritoneal tissue samples (i.e., abdominal wall, liver, diaphragm, intestine, and omentum) may be used, but there can be artifacts due to peritoneal tissue processing. To investigate differences in peritoneal membranes from different parts of the peritoneum, and also 2 different fixatives, in experimental PD and a peritonitis model in rats. Peritoneal tissues from the anterior abdominal wall, liver, omentum, and intestine were taken from each of 3 groups of animals: sham, experimental PD, and peritonitis model. Tissue samples were immediately fixed with 4% formaldehyde and routinely processed for histological examination. Two parietal peritoneal tissue samples according to longitudinal and horizontal sections of anterior wall inner abdominal muscle were also taken. All samples were immediately fixed with 4% formaldehyde and B5 fixative (B5), and then routinely processed for histological examination. In all groups, histopathological findings were more commonly seen in the abdominal wall samples. There were no changes observed in peritoneal membranes other than those of anterior abdominal wall samples from both sham and PD model rats. However, there was a significant difference between anterior and posterior facets of liver in the peritonitis model. Furthermore, the antimesenteric site of intestinal peritoneum was less affected than the mesenteric site. There were no significant histopathological differences between B5 and 4% formaldehyde fixation (p > 0.05). Our results suggest that peritoneum obtained from the anterior abdominal wall is the most affected area and therefore the most suitable site to investigate peritoneal changes in the experimental rat PD model. There were no significant differences between fixation with 4% formaldehyde and B5 solution. Abdominal wall samples should be of the same direction of inner abdominal muscle, that is, horizontal sectioning should be used for measurements of the submesothelial area.

Effects of amniotic membrane on the healing of primary colonic anastomoses in the cecal ligation and puncture model of secondary peritonitis in rats

We aimed to investigate the effects of amniotic membrane on primary colonic anastomoses in a rat peritonitis model. Fifty female Sprague Dawley rats were used in the study. Bacterial peritonitis was induced in all rats by performing a cecal ligation and puncture. Ten rats served as controls for the bursting pressure measurement, while the other 40 animals were divided into two groups (the anastomosis group (P) or the amniotic membrane group (PA)), and all of them underwent colonic anastomosis. The latter group had amniotic membrane covering their anastomoses. Half of the PA and P groups were sacrificed on the third postoperative day (PA3, P3), and the other half on the seventh postoperative day (PA7, P7). The bursting pressures were significantly higher in groups PA3 and PA7 compared with P3 (p < 0.01) and P7 (p < 0.05), respectively. Inflammatory cell infiltration and adhesion scores were significantly lower in groups PA3 and PA7 compared with groups P3 (p < 0.001, p < 0.01, respectively) and P7 (p < 0.001, p < 0.05, respectively). Neoangiogenesis, fibroblast activity, collagen deposition, and hydroxyproline concentrations were significantly higher in groups with amniotic membrane than in groups without amniotic membrane (p < 0.05, for all comparisons). This study showed that the covering of colonic anastomoses with amniotic membrane significantly prevented the delaying effect of intraperitoneal sepsis and provided a safer and stronger anastomosis than suture and that this was the case for both the early and late phases of anastomotic healing in the colon.

Influence of Hydroxyethyl Starch on Healing of Colonic Anastomosis in a Rat Model of Peritonitis

Background: This study was designed to evaluate the role of different intravascular volume replacement regimens of HES 130/0.4 on wound healing process in left colonic anastomoses in the presence of intra-abdominal sepsis induced by murine model of cecal ligation and puncture (CLP). Methods: The left colonic anastomosis was performed in 40 rats that were divided into five groups (n = 8/group): saline controls (30 ml/kg); CLP plus saline (30 ml/kg); CLP plus HES (7.5, 15, or 30 ml/kg, respectively). Saline or HES was treated before the construction of left colonic anastomosis and on a regular daily basis. Anastomotic bursting pressures were measured in vivo on day 5. Tissue samples were obtained for analyses of hydroxyproline (HP) contents, myeloperoxidase (MPO) acivity, malondialdehyde (MDA), reduced glutathione (GSH) levels, and nuclear factor-κ B (NF-κ B) activation. The plasma levels of tumor necrosis factor (TNF)-α and interleukin (IL)-6 were also measured. Results: Intra-abdominal sepsis led to significant decreases in colonic anastomotic bursting pressures, and perianastomotic tissue HP contents and GSH levels, along with increases in perianastomotic tissue MPO activity, MDA levels and NF-κ B activation and plasma levels of TNF-α and IL-6. After treated with HES, these provoked perianastomotic tissue MPO activity, MDA levels, NF-κ B activation, and plasma levels of TNF-α and IL-6 were suppressed and GSH levels were restored, especially in 15 ml/kg HES group. Without obvious influence on systemic nutritional condition, HES 15 ml/kg but not HES 7.5 ml/kg significantly increased anastomotic bursting pressures, and perianastomotic tissue HP contents. However, HES 30 ml/kg even led to adverse effects on anastomotic bursting pressures. Conclusions: This study showed that moderate doses (15 ml/kg) of HES 130/0.4 administration significantly prevented this intraperitoneal sepsis-induced impaired anastomotic healing of the left colon. It also suggested the possibility of poorer anastomotic healing receiving HES at higher doses (30 ml/kg). Clearly, HES 130/0.4 now should not be recommended to use at a high doses postoperatively in sepsis.

Administration of honey to prevent peritoneal adhesions in a rat peritonitis model

Aim We investigated the effects of intraperitoneal honey on the development of postoperative intra-abdominal adhesions and oxidative stress in a model of bacterial peritonitis. Methods Bacterial peritonitis was induced in 18 rats by cecal ligation and puncture. The rats were randomly assigned to three groups. Group 1 ( n = 6) received honey intraperitoneally, group 2 ( n = 6) received 5% dextrose intraperitoneally, and the third group received no fluid or medicine intraperitoneally one day after cecal ligation and puncture procedure. All animals were killed 14 days later so we could assess the adhesion score. Tissue antioxidant levels were measured in 1-g tissue samples taken from the abdominal wall. Results Adhesion scores of honey treated group were significantly lower according to the control group ( P < 0.05) and statistically significant. Adhesion scores of honey were lower from 5% dextrose but not statistically significant ( P > 0.05). Malondialdehyde values of honey group were significantly lower from the control group ( P < 0.05) and levels in 5% dextrose group was higher than the honey group. Catalase levels were high in control and 5% dextrose groups. Superoxide dismutase levels were higher in the control group than the honey group (statistically significant). Conclusions Intraperitoneal honey decreased the formation of postoperative intra-abdominal adhesions without compromising wound healing in this bacterial peritonitis rat model. Honey also decreased the oxidative stress during peritonitis.

Zymosan, but not LPS, triggers severe and progressive peritoneal injury accompanied by complement activation in a rat peritonitis model initiated by mechanical scraping

Zymosan, but not LPS, triggers severe and progressive peritoneal injury accompanied by complement activation in a rat peritonitis model initiated by mechanical scraping

Inhibition of the Kupffer Cell and Neutralization of IL-10 Increase the Expression of Chemokines in the Lung in a Rat Peritonitis Model

Elimination of Kupffer cells (KCs) exacerbated acute lung injury and mortality by inhibiting serum interleukin (IL)-10 levels in a rat peritonitis model. Since infiltrating inflammatory cells play a pivotal role in organ injury, the specific purpose of this study was to determine whether elimination of the KC and systemic IL-10 affect the expression of inflammatory mediators and the number of infiltrating inflammatory cells in the lung in the peritonitis model. Rats were given saline or gadolinium chloride (GdCl(3)), a KC toxicant, 24 h before cecal ligation and puncture (CLP). Tissue and serum samples were harvested after CLP, and the expression of inflammatory mediators was investigated. In another set of experiments, anti-rat IL-10 antibodies (anti-IL-10 Abs) were injected immediately after CLP to investigate the effects of immunoneutralization of endogenous IL-10. Serum levels of proinflammatory cytokines and chemokines were significantly greater in the GdCl(3) group than the control group after CLP. Furthermore, expression inflammatory mediators, as well as the number of infiltrating inflammatory cells in the lung were significantly greater in the GdCl(3) group than the control group. Alternatively, serum levels of inflammatory cytokines and chemokines, and the number of infiltrating inflammatory cells into the lung also increased significantly in rats treated with anti-IL-10 Abs compared with IgG after CLP. Thus, depletion of KCs and neutralization of IL-10 increased the expression of chemokines and the number of infiltrating inflammatory cells in the lung, leading to exacerbated acute lung injury in sepsis.

Pulmonary Phagocyte Depression Induced by an Acid or Alkaline Solution in a Rat Model of Peritonitis

Peritonitis is a surgical problem with a high mortality rate attributable to various complications, including respiratory infection. This complication is more common under certain conditions reflective of the origin of peritonitis, suggesting that the composition of the peritoneal fluid exerts an influence on the intensity of the macrophage and peritoneal response. To establish a correlation among macrophage function, absorption of bacteria from the peritoneal cavity, and the pH of the peritoneal fluid, we carried out this study. Thirty female Wistar rats were divided into three equal groups, all of which received infusions of 0.9% saline by parietal puncture. In group A (control), the saline pH was 7.0; in group B, it was 2.5; and in group C, it was 8.5. After 40 min, 0.25 mL of a suspension containing 10(11) colony-forming units of (99m)Tc-labeled Escherichia coli was infused by the same route. After another 40 min, samples of vena caval blood, spleen, liver, and lung were removed; the radioactivity was counted; bacterial absorption was determined; and the proportional radioactivity/g of tissue was calculated. The values were compared among the groups by the Student t-test, with the level of significance set at p < 0.05. There was significantly greater bacterial absorption in group B than in group C (p = 0.004) but no differences in the numbers of bacteria in the liver and spleen. Bacteria were significantly more numerous in the peripheral blood in group B than in groups A and C (p = 0.04 for both). Pulmonary phagocytosis was significantly reduced in group B compared with group A (p = 0.008) and group C (p = 0.005). Peritonitis associated with acidic conditions in the peritoneal cavity is correlated with a reduction in pulmonary phagocytosis and an increase in the numbers of nonphagocytized bacteria in the peripheral blood, possibly representing a direct or indirect cause of the higher incidence of pneumonia and sepsis in these individuals.

Development of a lethal model of peritonitis for assessment of laparoscopic and laparotomic treatments in rats

Development of a lethal model of peritonitis to assess the results of treating that peritonitis using videolaparoscopy and laparotomy. We developed a model of peritonitis in rats using cecal ligation (CLP) against a 2-mm diameter rigid mold and puncture. Two experiments were performed: determination of seven-day lethality; and analysis of white cell counts, blood cultures and cytokines (Interleukin-1 beta, Tumor Necrosis Factor-alpha and IL-6). The animals were divided into four groups: I--Sham surgery; II--CLP; III--CLP + Videolaparoscopy; and IV--CLP + Laparotomy . Seven-day lethality was 0% in group I, 80% in the group II (p<0.05), 60% in group III , and 20 % in group IV. There was a significant reduction in leukocyte counts and higher levels of serum IL-1 beta, TNF-alpha and IL-6 in the group II compared to controls. The percentages of positive blood cultures were higher after videolaparoscopic compared to laparotomic treatment. The experimental model provoked a lethal form of peritonitis and that videolaparoscopic treatment had more bacteraemia than laparotomy.

Pro- and anti-inflammatory activities of the latex from Calotropis procera (Ait.) R.Br. are triggered by compounds fractionated by dialysis

Previous studies have described pro- and anti-inflammatory activities displayed by the latex from Calotropis procera. This report aims to clarify these observations and shows that such activities can be segregated from the whole latex. The latex was divided into water-soluble fractions devoid of poly-isoprene by centrifugation and dialysis and both the activities were assayed by the peritonitis model in rats. The drugs dexamethasone, thalidomide, meclizine, indomethacin and celecoxib were used to modulate the inflammatory stimuli. Inflammation in rats was observed 2 h after intraperitoneal administration of the stimulus (DL fraction) in a dose dependent manner. This activity was inhibited by previous intravenous injection of dexamethasone, thalidomide and meclizine. Indomethacin and celecoxib did not reverse inflammation. These results suggest the involvement of histamine release and TNF-alpha mediated inflammation while prostaglandins seem not to be required. The anti-inflammatory fraction (NDL) inhibited inflammation triggered by proinflammatory fraction (DL) suggesting that NDL ought to follow a similar pathway of action to that of the anti-inflammatory drugs that were able to inhibit inflammation triggered by DL. Pro- and anti-inflammatory activities of the latex are displayed by compounds suitable to be fractionated on the basis of their molecular size.

Auto-Cross-Linked Hyaluronic Acid Gel Does Not Reduce Intra-Abdominal Adhesions or Abscess Formation in a Rat Model of Peritonitis

Prevention of adhesion and abscess formation would decrease mortality and morbidity after peritonitis. In this study the effect of a new anti-adhesive, auto-cross-linked hyaluronic acid polysaccharide (ACP) gel, on adhesion and abscess formation was studied in a rat peritonitis model. In experiment 1, bacterial peritonitis was induced in 24 Wistar rats, using a cecal ligation and puncture model. Animals were randomized to receive 4 mL ACP gel (4%) or 4 mL phosphate buffered saline (PBS). After 2 weeks animals were killed and adhesions and abscesses were scored. In experiment 2, 72 rats underwent the same procedure but were randomized to receive 2 mL ACP gel, 4 mL ACP gel, or 4 mL PBS. After 1 and 3 weeks, respectively, half of the animals in each group were killed and adhesions and abscesses were scored. The median total adhesion score was 12 (range, 3-20) in the ACP group and was 9 (range, 6-12) in the PBS group (not significant) in experiment 1. 91% of rats in the ACP group developed abscesses, versus 90% in the control group. There were no significant differences in abscess size or number of abscesses. In experiment 2, total adhesion scores in the 2 mL ACP group, 4 mL ACP group, and PBS group were 4 (range, 2-20), 6 (range, 1-11), and 6 (range, 1-18), respectively, (not significant) after 1 week and 3.5 (range, 1-8), 5 (range, 2-15), and 4 (range, 0-9), respectively, (not significant) after 3 weeks. All rats in the 2 mL ACP group and the PBS group and 83% of the 4 mL ACP group had developed abscesses after 1 week. After 3 weeks these percentages were 80, 75, and 73, respectively. There were no significant differences in size or number of abscesses between groups both after 1 and 3 weeks. ACP does not reduce adhesion and abscess formation in a rat peritonitis model.

Intraperitoneal Tenoxicam to Prevent Abdominal Adhesion Formation in a Rat Peritonitis Model

We investigated the effects of intraperitoneal tenoxicam on the development of postoperative intra-abdominal adhesions and oxidative stress in a model of bacterial peritonitis. Bacterial peritonitis was induced in 24 rats by cecal ligation and puncture. The rats were randomly assigned to one of three groups. Group 1 (n = 8) received 2 ml saline intraperitoneally, group 2 (n = 8) received 2 ml (0.5 mg/kg) tenoxicam (Oksamen) intraperitoneally, and group 3 (n = 8) was a control, which did not receive any injection. All animals were killed 14 days later so we could assess the adhesion score and measure anastomotic bursting pressures. Tissue antioxidant levels were measured in 1-g tissue samples taken from the abdominal wall. The adhesion score was significantly lower in the tenoxicam group than in the saline and control groups. The anastomotic bursting pressures were higher in the saline and tenoxicam groups than in the control group. The catalase (CAT) levels were higher in the saline and tenoxicam groups than in the control group. The malondialdehyde (MDH) levels were higher in the saline group than in the tenoxicam and control groups. Intraperitoneal tenoxicam inhibited the formation of postoperative intra-abdominal adhesions without compromising wound healing in this bacterial peritonitis rat model. Tenoxicam also decreased the oxidative stress during peritonitis.

Effect of Melatonin on Healing of Colonic Anastomosis in a Rat Model of Peritonitis

Background: The aim of this study is to determine the effect of melatonin on intestinal anastomosis in the presence of peritonitis. Material and Methods: 32 Wistar albino rats were randomized into four groups (n = 8): A (sham), B (control), C (melatonin 5 mg/kg), and D (melatonin 10 mg/kg). In group A, only cecal dissection was carried out. In the other groups, cecal ligation and puncture (CLP) followed cecal dissection in order to induce bacterial peritonitis. 24 h after the previous operation, cecal resection and iliocolic anastomosis were performed in the rats of all groups. In group C (5 mg/kg) and group D (10 mg/kg), melatonin was injected for 5 consecutive days starting after CLP. At the 48th hour of the CLP procedure, blood was drawn via the tail vein for tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) analysis, and on the 4th day of the experiment relaparotomy was carried out for bursting pressure (BP) measurements. The intestinal tissue containing the anastomotic line was then snap-frozen in liquid nitrogen and stored at –80°C for determination of tissue levels of malondialdehyde (MDA) and glutathione (GSH). Results: The tissue MDA level, blood TNF-α and IL-6 levels of group B were significantly higher than in the other groups, whereas the BP results and GSH levels of group B were found to be significantly lower than in the other groups. The results of groups C and D are statistically different from those of group B. When we compared the results of groups C and D, we found significantly higher results in terms of BP and GSH levels in group D and also significantly lower results in terms of MDA, blood TNF-α and IL-6 levels in group D. Conclusion: The findings of this experiment suggest that melatonin has a dose-independent positive effect on wound healing of colonic anastomosis.

Higher neutrophil infiltration mediated by osteopontin is a likely contributing factor to the increased susceptibility of females to alcoholic liver disease

Alcoholic liver disease (ALD) is a major public health problem in the United States and women are known to be more susceptible to ALD. However, the precise mechanism for increased susceptibility of females to ALD is not completely understood. The present study is based on the hypothesis that induction of osteopontin (OPN), a matricellular protein, is the likely contributing factor for higher neutrophil recruitment in females during alcoholic steatohepatitis (ASH). ASH was induced in male and female Sprague-Dawley rats by feeding them a Lieber-DeCarli diet containing ethanol (EtOH) for 6 weeks, followed by a single injection of lipopolysaccharide (LPS, 10 mg/kg, ip). Liver injury, measured by plasma transaminase elevations and confirmed by haematoxylin and eosin-stained liver sections, revealed approximately 25-fold higher liver injury in the female ASH model compared with the males. Although steatosis, necrosis, and neutrophil infiltration were evident in both male and female rats, hepatic neutrophilic necrotic foci were noted as early as 2 h after LPS injection in the EtOH-treated female rats. Hepatic neutrophil infiltration correlated with higher expression of cleaved (cOPN) and uncleaved OPN in the EtOH + LPS-treated female rats compared with the males. OPN secretion was localized predominantly in the biliary epithelium and females had significantly higher OPN mRNA than their male counterparts in the ASH model. The ability of OPN to attract neutrophils was further confirmed in vivo, in a peritonitis rat model, and by neutralizing OPN (nOPN) antibody experiments. Hepatic neutrophil infiltration was largely inhibited ( approximately 50%) by nOPN antibody. Flow cytometry experiments revealed OPN-mediated up-regulation of the CD11b neutrophil adhesion molecule. In conclusion, these data suggest that higher hepatic expression of OPN is the likely reason for higher and early hepatic neutrophil infiltration making females more susceptible to ALD during ASH.

The Kupffer cell protects against acute lung injury in a rat peritonitis model: role of IL-10

The possibility that Kupffer cells (KCs) play key beneficial and deleterious roles in multiple organ injury in sepsis has been discussed. The role of KCs in lung injury in a rat peritonitis model was investigated. Specifically, the involvement of interleukin (IL)-10, which has anti-inflammatory effects, was examined. Rats were given saline or gadolinium chloride (GdCl3), a KC toxicant, 24 h before cecal ligation and puncture (CLP). Survival was assessed for 7 days after CLP. The liver, lung, and serum were harvested, and the expression of cytokines was assessed. Macrophages were isolated from each organ after CLP, and the mRNA expression of inflammatory mediators was assessed. GdCl3 treatment increased lung injury and mortality. Plasma endotoxin levels were significantly greater, whereas serum IL-10 levels were lower in the GdCl3 than in the control group after CLP. IL-10 levels were significantly greater in the aorta than the hepatic vein. The mRNA expression of IL-10 was less in KCs from the GdCl3 than the control group. In the liver, the expression of IL-10 increased rapidly and continuously, up to 9 h in the control group, but values were significantly lower in the GdCl3 group. Rabbit anti-rat IL-10 antibodies were injected just after CLP to investigate the effects of immunoneutralization of endogenously produced IL-10. In the antibody-treated group, lung injury and mortality increased compared with animals treated with rabbit immunoglobulin G. Taken together, these results indicate that KCs play a protective role in lung injury in sepsis by production of IL-10.

Effect of Intraperitoneal Application of an Endotoxin Inhibitor on Survival Time in a Laparoscopic Model of Peritonitis in Rats

Gram-negative sepsis due to fecal peritonitis is a hazardous disease with a high percentage having a lethal course. The inflammatory effects are induced by endotoxin release. We performed this study to evaluate the potential of direct intraperitoneal application of an endotoxin inhibitor in a laparoscopic peritonitis model in rats. The human feces specimen was prepared, and a standard fecal specimen (0.5 ml/kg b.w.) was applied via minilaparotomy. The rats were randomized to two studies. First, rats were randomized to three groups to define the survival time: (1) rats without further manipulation; (2) rats with laparoscopic lavage using NaCl; (3) rats with laparoscopic lavage using endotoxin inhibitor. Second, rats underwent the same procedure used in the first part of the study and an additional group with only NaCl lavage without peritonitis was randomized. To evaluate the immunologic or biochemical effects, animals were killed at a standard time of 20 hours until the postmortem examination was established. Interleukins 6 and 10 (IL-6, IL-10), malondialdehyde, and protein carbonyl group levels in plasma and particularly in peritoneal fluid were assayed. The first part of the experiment showed significantly increased survival after endotoxin inhibitor lavage. In the second part, administration of endotoxin inhibitor intraperitoneally caused a significant reduction of IL-6 in the peritoneal fluid, in contrast to that in the other groups. Laparoscopic application of endotoxin inhibitor intraperitoneally thus produced a beneficial effect on survival and reduction of IL-6 in peritoneal fluid. Hence, it is possible to influence the inflammation cascade by causing intraperitoneal endotoxin inhibition.