Estrogen protects the liver and intestines against sepsis-induced injury in rats

BACKGROUND AND AIM: Sepsis is commonly associated with enhanced generation of reactive oxygen metabolites, leading to multiple organ dysfunctions. The aim of this study was to examine the putative protective role of estradiol against sepsis-induced oxidative organ damage. MATERIALS AND METHODS: Sepsis was induced by cecal ligation and puncture method in Wistar albino rats. Sham-operated (control) and sepsis groups received saline or estradiol propionate (10 mg/kg) intraperitoneally immediately after the operation and at 12 h. Twenty-four hours after the surgery, rats were decapitated and malondialdehyde, glutathione levels, and myeloperoxidase activity were determined in the liver and ileum, while oxidant-induced tissue fibrosis was determined by collagen contents. Tissues were also examined microscopically. Serum aspartate aminotransferase, alanine aminotransferase levels, and lactate dehydrogenase were measured for the evaluation of liver functions and tissue damage, respectively. Tumor necrosis factor-alpha was also assayed in serum samples. RESULTS: In the saline-treated sepsis group, glutathione levels were decreased significantly, while the malondialdehyde levels, myeloperoxidase activity, and collagen content were increased in the tissues (P < 0.01 to P < 0.001), suggesting oxidative organ damage, which was also verified histologically. In the estradiol-treated sepsis group, all of these oxidant responses were reversed significantly (P < 0.05 to P < 0.01). Liver function tests and tumor necrosis factor-alpha levels, which were increased significantly (P < 0.001) following sepsis, were decreased (P < 0.05 to P < 0.001) with estradiol treatment. CONCLUSION: The results demonstrate the role of oxidative mechanisms in sepsis-induced tissue damage, and estradiol, by its antioxidant properties, ameliorates oxidative organ injury, implicating that treatment with estrogens might be applicable in clinical situations to ameliorate multiple organ damage induced by sepsis.     

Resveratrol reduces renal and lung injury caused by sepsis in rats

Resveratrol (3,5,4'-trans-trihydroxystilbene), a natural phytoalexin, has various pharmacological effects, including anti-inflammatory properties via inhibition of oxidation, leukocyte priming, and expression of inflammatory mediators. The present study was aimed to investigate the possible beneficial activities of resveratrol on lung and kidney damage in a rat model of sepsis. MATERIALS AND METHODS: Sepsis was induced to Sprague-Dawley rats of both sexes (200-250 g) by cecal ligation and perforation. The rats were treated with resveratrol (30 mg/kg; i.p.) or saline after induction of sepsis and at 16 h. Twenty-four hours after the sepsis-induction, all rats were decapitated. Blood was collected for the measurement of tumor necrosis factor-alpha level and lactate dehydrogenase activity. Lung and kidney samples were taken for histological assessment and for the measurement of malondialdehyde, glutathione level, myeloperoxidase activity, and collagen content. RESULTS: Sepsis caused a significant increase in malondialdehyde levels, myeloperoxidase activity, and collagen content of the lung and kidney tissues with a concomitant reduction in glutathione levels. Microscopic examination revealed severe destruction of regular morphology in both lung and kidney tissues. Serum tumor necrosis factor-alpha and lactate dehydrogenase levels also were higher in rats with sepsis compared to those of the sham group. Resveratrol treatment reversed these biochemical parameters and preserved tissue morphology as evidenced by histological evaluation. CONCLUSIONS: Resveratrol, a phenolic compound, reduces sepsis-induced remote organ injury, at least in part, through its ability to balance oxidant-antioxidant status, to inhibit neutrophil infiltration and to regulate the release of inflammatory mediators.     

Silymarin, the antioxidant component of Silybum marianum, protects against burn-induced oxidative skin injury

BACKGROUND: Despite recent advances, severe burn is one of the most common problems faced in the emergency room. Major thermal injury induces the activation of an inflammatory cascade resulting in local tissue damage, to contribute to the development of subsequent damage of multiple organs distant from the original burn wound. OBJECTIVE: Silymarin, the major component of milk thistle has been shown to have antioxidant properties. In the present study, we investigated the putative antioxidant effect of local or systemic silymarin treatment on burn-induced oxidative tissue injury. METHODS: Wistar albino rats were exposed to 90 degrees C bath for 10 s to induce burn. Silymarin either locally (30 mg/kg) applied on 4 cm(2) area or locally+systemically (50 mg/kg, p.o.) was administered after the burn and repeated twice daily. Rats were decapitated 48 h after injury and blood was collected for tumor necrosis factor-alpha (TNF-alpha) and lactate dehydrogenase (LDH) activity. In skin tissue samples malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity, and luminol-lucigenin chemiluminescense (CL) were measured in addition to the histological evaluation. RESULTS: Burn caused a significant increase in TNF-alpha and LDH levels. MDA levels were increased and GSH levels were decreased in the skin at 48 h after-burn. Both local and systemic silymarin treatments significantly reversed these parameters. The raised MPO activity and luminol-lucigenin CL were also significantly decreased. CONCLUSION: Results indicate that both systemic and local administration of silymarin was effective against burn-induced oxidative damage and morphological alterations in rat skin. Therefore, silymarin merits consideration as a therapeutic agent in the treatment of burns.     

Melatonin Protects Against Oxidative Organ Injury in a Rat Model of Sepsis

Purpose Based on the potent antioxidant effects of melatonin, we investigated the putative protective role of melatonin against sepsis-induced oxidative organ damage in rats.Methods Sepsis was induced by cecal ligation and puncture (CLP) in Wistar albino rats. Animals subjected to CLP and sham-operated control rats were given saline or melatonin 10mg/kg intraperitoneally 30min before and 6h after the operation. The rats were killed 16h after the operation and the biochemical changes were investigated in the liver, kidney, heart, lung, diaphragm, and brain tissues by examining malondialdehyde (MDA) and glutathione (GSH) levels, and myeloperoxidase (MPO) activity. We also examined the tissues microscopically.Results Sepsis resulted in a significant decrease in GSH levels and a significant increase in MDA levels and MPO activity (P < 0.05–P < 0.001) showing oxidative damage, which was confirmed by histological examination. Melatonin clearly reversed these oxidant responses and the microscopic damage, demonstrating its protective effects against sepsis-induced oxidative organ injury.Conclusion The increase in MDA levels and MPO activity and the concomitant decrease in GSH levels demonstrate the role of oxidative mechanisms in sepsis-induced tissue damage. Melatonin, by its free radical scavenging and antioxidant properties, ameliorated oxidative organ injury. Thus, supplementing antiseptic shock treatment with melatonin may be beneficial in the clinical setting.     

线粒体靶向抗氧化剂SS-31肽对脓毒血症小鼠急性肺损伤的影响

目的观察线粒体靶向抗氧化剂SS-31肽对小鼠脓毒血症引起急性肺损伤(ALI)的影响。方法采用盲肠结扎穿孔法(CLP)建立小鼠脓毒症模型。成年雄性C57BL/6小鼠48只,体重25~32g,随机均分为四组:假手术+溶剂组(A组)、假手术+SS-31肽组(B组)、CLP+溶剂组(C组)及CLP+SS-31肽组(D组)。于术后即刻及5hB、D组腹腔注射SS-31肽5mg/kg,A、C组腹腔注射等容剂量的生理盐水。假手术或CLP 24h后,采用HE染色法进行肺组织学评分,取肺组织检测肿瘤坏死因子-α(TNF-α)、白细胞介素-6(IL-6)、IL-10、丙二醛(MDA)、超氧化物歧化酶(SOD)、髓过氧化物酶(MPO)活性、干湿重比(W/D)、活性氧簇(ROS)、ATP水平、核转录因子κB(NF-κB)p65、诱导性一氧化氮合酶(iNOS)表达。结果 C组肺炎症渗出、水肿程度均明显重于A组(P0.05),D组肺组织充血、炎性细胞浸润、肺泡壁水肿明显轻于C组(P0.05);C组肺组织学评分、IL-6浓度、MDA、MPO、W/D、ROS水平、NF-κB p65及iNOS表达明显高于A组,ATP水平明显低于A组(P0.05);D组肺组织学评分、IL-6浓度、MDA、MPO、W/D、ROS水平、NF-κB p65及iNOS表达明显低于C组,ATP水平明显高于C组(P0.05)。A组与B组各项指标差异无统计学意义。四组肺组织TNF-α、IL-10浓度及SOD水平差异无统计学意义。结论 SS-31肽可改善小鼠脓毒血症引起的ALI,这可能是通过抑制脓毒血症的炎性反应和氧化应激实现的。     

Effects of N-acetylcysteine on acute necrotizing pancreatitis in rats

The aim of this study was to investigate the influence of N-acetylcysteine (NAC) on acute necrotizing pancreatitis (ANP) induced by glycodeoxycholic acid in rats. The induction of ANP resulted in significant increase in mortality rate, pancreatic necrosis and serum activity of amylase, alanine aspartate transferase (ALT), interleukin-6 (IL-6), lactate dehydrogenase (LDH) in bronchoalveolar lavage (BAL) fluid, serum concentration of urea, tissue activity of myeloperoxidase (MPO) and malondialdehyde (MDA) in the pancreas and lung, and significant decrease of concentrations of calcium, blood pressure, urine output and pO(2). The use of NAC inhibited the changes in urine output, pO(2), tissue activity of MPO and MDA in pancreas and lungs, and the serum activity of IL-6, ALT, and serum concentrations of urea and calcium. NAC reduced the mortality and pancreatic damage. The use of NAC has a beneficial effect on the course of ANP in rats. It may be used in the treatment of acute pancreatitis.     

N-acetylcysteine Improves Early Cardiac Isograft Function in a Rat Heterotopic Transplantation Model

Reactive oxygen species play an important role in the early phase of ischemia-reperfusion injury. N-acetylcysteine (NAC), an antioxidant, has shown protective effects in ischemia-reperfusion injuries in some organ transplantations; however, its roles in cardiac transplantation have not been thoroughly evaluated. Lewis rats were divided into three groups (n = 8 in each group): sham, control, and NAC group. They were subjected to abdominal heterotopic cardiac transplantation and followed for 24 hours postoperation. For the NAC group, a bolus of NAC (150 mg/kg) was infused at 30 minutes before reperfusion, followed by 20 mg/kg/h for 1 hour; another 150 mg/kg NAC intraperitoneally administered 12 hours after reperfusion. Cardiac function and blood inflammation markers were measured at both 2 and 24 hours after reperfusion. Oxidative stress markers and neutrophil infiltration were evaluated in heart tissue at 24 hours postoperatively. Echocardiography showed that NAC significantly improved the postoperative fractional shortening of isografts (P < .01), although NAC had no effect on the heart rate. Serum lactate dehydrogenase also indicated a significant decrease in the NAC group at 24 hours posttransplantation (P = .02) Serum tumor necrosis factor-α and interleukin-1 concentrations which rapidly increased postoperatively were reduced by administration of NAC. In transplanted hearts, the increased malondialdehyde level and myeloperoxidase activity were partially reversed by NAC (both P < .01); NAC also replenished endogenous glutathione. Finally, neutrophil infiltration in isografts was reduced in the NAC group. Recipient treatment with continuous intravenous NAC protected cardiac isografts against posttransplantation ischemia-reperfusion injury, probably through its antioxidant and anti-inflammatory properties.     

Effects of Pyrrolidine Dithiocarbamate on Healing of Colonic Anastomoses in the Cecal Ligation and Puncture Model of Intraperitoneal Sepsis in Rats

Introduction Pyrrolidine dithiocarbamate (PDTC) is a low-molecular thiol antioxidant and potent inhibitor of nuclear factor-κB (NF-κB) activation. In recent animal studies, the delaying effect of intraperitoneal sepsis on healing of colonic anastomoses has been demonstrated. In this study, we aimed to investigate the effects of PDTC on healing of colonic anastomoses in the presence of intraperitoneal sepsis induced by a rodent model of cecal ligation and puncture (CLP). Methods Anastomosis of the left colon was performed on the day following CLP in 30 rats that were divided into three groups: sham-operated control (laparotomy and cecal mobilization, group I, n =10), cecal ligation and puncture (CLP) (group II, n = 10), PDTC-treated group (100 mg/kg IV before construction of the colonic anastomosis) (group III, n = 10). On postoperative day 6, all animals were sacrificed, and anastomotic bursting pressures were measured in vivo. Tissue samples were obtained for further investigation of colonic anastomotic hydroxyproline (HP) contents, perianastomotic myeloperoxidase (MPO) activity, and malondialdehyde (MDA) and glutathione (GSH) levels. Results There was a statistically significant increase in the activity of MPO and MDA levels in the CLP group (group II) along with a decrease in GSH levels, colonic anastomotic HP contents, and bursting pressure values when compared to controls (group I). However, PDTC treatment led to a statistically significant increase in the tissue HP contents, GSH levels, and colonic anastomotic bursting pressure values, along with a decrease in MPO activity and MDA levels in group III (p < 0.05). Conclusions This study showed that PDTC treatment significantly prevented the delaying effect of CLP-induced intraperitoneal sepsis on anastomotic healing in the colon. Further clinical studies are needed to clarify whether PDTC may be a useful therapeutic agent to increase the safety of the anastomosis during particular operations where sepsis-induced injury occurs.     

ONO1714, a new inducible nitric oxide synthase inhibitor, attenuates sepsis-induced diaphragmatic dysfunction in hamsters

Sepsis causes impairment of diaphragmatic contractility and endurance capacity. Nitric oxide (NO) produced via inducible NO synthase (iNOS) has been implicated in the pathogenesis. Peroxynitrite, a NO-derived powerful oxidant, may be responsible for infection-induced diaphragmatic muscle failure. Therefore, we examined whether ONO1714, a new selective iNOS inhibitor, prevents sepsis-induced diaphragmatic dysfunction. Fifty male Golden-Syrian hamsters were randomly divided into five groups: hamsters that underwent sham laparotomy alone and received saline injection (Group Sham), those that underwent cecal ligation with puncture (CLP) and received saline injection (Group Sepsis), those that underwent sham laparotomy and received injection of ONO1714 0.3 mg/kg (Group Sham-ONO1714high), those that underwent CLP and received ONO1714 0.1 mg/kg (Group Sepsis-ONO1714low), and those that underwent CLP and received ONO1714 0.3 mg/kg (Group Sepsis-ONO1714high). ONO1714 or saline was intraperitoneally injected 10 min before surgery. Diaphragmatic contractility was assessed in vitro using diaphragm muscle strips excised 24 h after operation. Diaphragm fatigability was assessed by time until tension decreased to 50% of the initial value (T50%) during fatigue trials. Twitch, tetanic tensions, and T50% during fatigue trials were reduced in Group Sepsis. Pretreatment with ONO1714 dose-dependently attenuated sepsis-induced diaphragmatic contractile profiles and endurance capacity. CLP increased plasma nitrite/nitrate (NOx; stable NO metabolites), and diaphragm malondialdehyde (MDA; a product of lipid peroxidation), positive immunostaining for nitrotyrosine (peroxynitrite footprint), and iNOS activity. ONO1714 attenuated the increase. This beneficial effect of ONO1714 may be attributable, in part, to inhibition of peroxynitrite-induced lipid peroxidation in the diaphragm. IMPLICATIONS: Sepsis impairs diaphragmatic contractility and endurance capacity, which may be involved in acute respiratory failure. Pretreatment with ONO1714, a new selective inducible nitric oxide synthase inhibitor, attenuated sepsis-induced diaphragmatic dysfunction in hamsters.     

Rosiglitazone, a PPAR-gamma ligand, protects against burn-induced oxidative injury of remote organs

Severe burn induces the activation of an inflammatory cascade that contributes to the development of subsequent immunosuppression, increased susceptibility to sepsis, as well as generation of reactive oxygen radicals and lipid peroxidation, leading to multiple organ failure. In the present study, we investigated whether rosiglitazone, a peroxisome proliferator-activated receptor-gamma (PPAR-gamma) ligand is protective against burn-induced remote organ injury. Under brief ether anaesthesia, shaved dorsum of the rats were exposed to 90 degrees C (burn group) or 25 degrees C (control group) water bath for 10s. Rosiglitazone (4 mg/kg) or saline was administered intraperitoneally immediately after and at the 12th hour of the burn. Rats were decapitated 24h after injury and the tissue samples from lung, liver, and kidney were taken for the determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen contents. Serum aspartate aminotransferase (AST), alanine aminotransferase (ALT) levels, and creatinine, blood urea concentrations (BUN) were determined to assess liver and kidney function, respectively. Serum levels of tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta) and lactate dehydrogenase (LDH) were also assayed. Severe skin scald injury (30% of total body surface area) caused a significant decrease in GSH level, and significant increases in MDA level, MPO activity and collagen content of tissues. Similarly, serum ALT, AST and BUN levels, as well as LDH, IL-1 beta and TNF-alpha were elevated in the burn group as compared to the control group. Rosiglitazone treatment reversed all these biochemical indices. According to the findings of the present study, rosiglitazone possesses a anti-inflammatory effect that prevents burn-induced damage in remote organs and protects against organ damage.     

The effect of N-acetylcysteine on pulmonary lipid peroxidation and tissue damage

BACKGROUND: We aimed to investigate the effect of N-acetylcysteine (NAC) on pulmonary lipid peroxidation and tissue damage in experimental obstructive jaundice (OJ) stimulated by lipopolysaccharide (LPS) in this study. MATERIALS AND METHODS: We randomized 40 rats into five groups. Group A: Sham (n = 8); group B: OJ (n = 8); group C: OJ + lipopolysaccharide (LPS; n = 8); group D: OJ + NAC + LPS (n = 8); group E: OJ + LPS + NAC (n = 8). OJ was performed by common bile duct ligation and division in all groups except the sham group. At the fifth day, the rats were jaundiced. At the fifth day of OJ, LPS was injected 10 mg/kg intraperitoneally to the rats and at the tenth day, the rats were sacrificed in group C. In group D; at the fifth day of OJ, NAC was started 100 mg/kg subcutaneously and the same dose NAC injection repeated every day for 5 days. At the tenth day of OJ, LPS was injected 10 mg/kg intraperitoneally to the rats and then after 6 h they were sacrificed. In group E; 10 mg/kg LPS was administered intraperitoneally at fifth day of OJ and after then NAC was started 100 mg/kg subcutaneously and the same dose NAC injection repeated every day for 5 days and at the tenth day, the rats were sacrificed. Tissue samples were harvested through a midline incision, and lungs were resected and examined histopathologically and immunohistochemically for tissue damage scoring. The blood was taken by cardiac puncture and malondialdehyde (MDA), myeloperoxidase (MPO), and levels of total antioxidant status were detected with biochemical methods to evaluate lung tissue damage. RESULTS: Increase in lung and serum MDA and MPO levels, as well as decrease in total antioxidant status, were observed in groups B and C when compared with the sham group (P = 0.0001, for each comparison). Furthermore, the lung tissue damage was observed in the same groups by histopathological examination when compared with sham group. There was significant decrease at serum and lung MPO and MDA levels after the NAC application in groups D and E, when compared with group C (P = 0.0001, for each comparison). Antioxidant status in groups D and E were increased in the presence of NAC (P = 0.0001, for each comparison). Lung histology was prevented relatively in group D when compared with groups B and C. CONCLUSION: Results of the study indicate that NAC has protective effect on pulmonary lipid peroxidation and tissue damage before and after LPS administration.     

Oxytocin protects against sepsis-induced multiple organ damage: role of neutrophils

BACKGROUND: Sepsis, commonly associated with enhanced generation of reactive oxygen metabolites, leads to multiple organ dysfunctions. The neurohypophyseal hormone oxytocin (OT), released during social contact, was recently shown to modulate the immune and inflammatory processes. We investigated the protective role of OT against sepsis-induced pelvic inflammation. MATERIALS AND METHODS: Under anesthesia, sepsis was induced in female Sprague-Dawley rats (200-250 g) by cecal ligation and perforation method. Sham-operated rats served as controls. Either saline or OT (1 mg/kg) was given subcutaneously immediately after and at the 16th hour, and rats were decapitated at the 24th hour of sepsis induction. Colon, uterus, and liver samples were obtained for the histopathological analysis of damage and for the measurement of myeloperoxidase (MPO) activity, indicating neutrophil infiltration, malondialdehyde (MDA), indicating lipid peroxidation, and glutathione (GSH), a key antioxidant, levels. RESULTS: Colonic, uterine and liver MDA levels in the sepsis group were significantly increased (P < 0.01-P < 0.001), while colonic and uterine GSH levels were decreased (P < 0.05-P < 0.01) when compared to the control group. OT treatment reversed the MDA and GSH levels back to the control levels, while hepatic GSH levels were not altered. MPO activity in the colon and liver was increased by sepsis (P < 0.05-P < 0.001) while OT treatment abolished the elevated MPO activity. Collagen levels in the uterus and liver were increased by sepsis (P < 0.01) and OT treatment reduced the collagen levels in both tissues (P < 0.01-P < 0.05). Serum TNF-alpha levels were significantly increased by sepsis (P < 0.001) and OT treatment abolished the sepsis-induced increase in TNF-alpha levels. CONCLUSIONS: OT protects against sepsis-induced oxidative damage by acting as an antioxidant agent and its protective effect in the colon and liver appears to be dependent on its inhibitory effect on neutrophil infiltration. Our results suggest that OT may have a therapeutic value in limiting sepsis-associated multiple organ damage.     

Protective effects of melatonin and N-acetylcysteine on hepatic injury in a rat cardiopulmonary bypass model

BACKGROUND: An increasing number of patients were undergoing cardiac surgery with cardiopulmonary bypass (CPB) and more attention had been paid to hepatic injury after CPB. This study was designed to test the hypothesis that melatonin and N-acetylcysteine (NAC) could attenuate hepatic injury induced by CPB in rats. MATERIALS AND METHODS: Male Sprague Dawley rats were randomly divided into four groups: sham, control (CPB + placebo), NAC (CPB + 250 mg/kg N-acetylcysteine), and melatonin (CPB + 20 mg/kg melatonin). Blood samples were collected at the beginning, at the end of CPB, and at 0.5, 1, 2, 3, and 24 h postoperation. Liver samples were harvested at 24 h after the operation. RESULTS: In the control group, the levels of serum liver enzymes and tumor necrosis factor-alpha, activities of inducible nitric oxide synthase, malondialdehyde, and myeloperoxidase in liver tissue were significantly increased. In addition, swollen hepatocytes, vacuolization, and congestion in sinusoids were observed. These changes were markedly reversed in both NAC and melatonin groups. Furthermore, the glutathione content and liver antioxidative enzymes activities were significantly decreased in the control group compared with the sham group. However, the levels of these antioxidants were markedly elevated after NAC or melatonin treatment compared with placebo treatment. CONCLUSIONS: Our findings showed that NAC and melatonin had acceptably beneficial effects against the CPB-induced hepatic injury.     

Propylthiouracil (PTU)-induced hypothyroidism alleviates burn-induced multiple organ injury

Oxidative stress has an important role in the development of multiorgan failure after major burn. This study was designed to determine the possible protective effect of experimental hypothyroidism in hepatic and gastrointestinal injury induced by thermal trauma. Sprague Dawley rats were administered saline or PTU (10 mgkg(-1) i.p.) for 15 days, and hypothyroidism was confirmed by depressed serum T(3) and T(4) concentrations. Under brief ether anesthesia, shaved dorsum of rats was exposed to 90 degrees C (burn group) or 25 degrees C (control group) water bath for 10s. PTU or saline treatment was repeated at the 12th hour of the burn. Rats were decapitated 24h after injury and tissue samples from liver, stomach and ileum were taken for the determination of malondialdehyde (MDA) and glutathione (GSH) levels, myeloperoxidase (MPO) activity and collagen contents. Formation of reactive oxygen species in tissue samples was monitored by using chemiluminescence (CL) technique with luminol and lucigenin probes. Tissues were also examined microscopically. Tumor necrosis factor (TNF)-alpha and lactate dehydrogenase (LDH) were assayed in serum samples. Severe skin scald injury (30% of total body surface area) caused a significant decrease in GSH level, which was accompanied with significant increases in MDA level, MPO activity, CL levels and collagen content of the studied tissues (p<0.05-0.001). Similarly, serum TNF-alpha and LDH were elevated in the burn group as compared to control group. On the other hand, PTU treatment reversed all these biochemical indices, as well as histopathological alterations induced by thermal trauma. Our results suggest that PTU-induced hypothyroidism reduces oxidative damage in the hepatic, gastric and ileal tissues probably due to hypometabolism, which is associated with decreased production of reactive oxygen metabolites and enhancement of antioxidant mechanisms.     

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 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.     

Attenuation of ischemia/reperfusion injury by N-acetylcysteine in a rat hind limb model

BACKGROUND: Ischemia/reperfusion is a complex set of events with severe pathologic consequences. Reperfusion initiates both the local and systemic damage in part through rapid oxygen generation. N-acetylcysteine (NAC) is a scavenger of free radical species, inhibits neutrophil accumulation, acts as a vasodilator and also improves microcirculation. In present study, we examined the protective effect of NAC in a rat hind limb ischemia/ reperfusion model. Dimethyl-sulfoxide (DMSO), a well-known antioxidant was also tested for comparison. MATERIALS AND METHODS: Ischemia was induced for 4 h by vascular clamping and followed by 1 h of reperfusion. Muscle injury was evaluated in 3 groups as a saline group (control), DMSO group, and NAC group. Plasma levels of creatine kinase, lactate dehydrogenase, thiobarbituric acid reactive substances (TBARS), and blood HCO(3), as well as muscle tissue TBARS, were measured at the end of reperfusion. Muscle tissue samples were taken for histological evaluation. RESULTS: DMSO and NAC group showed significant amelioration of plasma CPK (P < 0.05, P < 0.05), plasma TBARS (P < 0.05, P < 0.05), and muscle tissue TBARS (P < 0.05, P < 0.05) compared with the control group. Similarly, neutrophil infiltration in DMSO and NAC groups were significantly less prominent than the control group (P < 0.01, P < 0.01). CONCLUSIONS: These results show that NAC improved effectively ischemia reperfusion injury in a rat hind limb model.     

The effects of methylene blue on lung injury in septic rats

PURPOSE: We aimed to investigate the effects of methylene blue (MB) on NO production, myeloperoxidase (MPO) activity, antioxidant status and lipid peroxidation in lung injury during different stages of sepsis in rats. MATERIAL AND METHODS: Rats were randomly divided into 4 groups (n = 20): group C, sham operated; group CMB, sham operated and receiving MB (25 mg/kg, i.p.); group S, sepsis; group SMB, sepsis and receiving MB (25 mg/kg, i.p.). Sepsis was induced by cecal ligation and puncture (CLP). The MB dose was administered after CLP. Each group was subdivided into two subgroups (n = 10) which were sacrificed at 9 or 18 h after the surgical procedure. The levels of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-PX) and MPO activity, total nitrite/nitrate and malondialdehyde (MDA) in the lung tissue were measured. Lung injury was graded from 1 (injury to 25% of the field) to 4 (diffuse injury) by the pathologist. RESULTS: In group SMB, while SOD and CAT increased in both early and late sepsis periods, GSH-PX increased significantly only in the early sepsis period when compared with group S. Increase in lung MPO activity after CLP-induced sepsis was prevented by MB administration. MB significantly decreased to nitrite/nitrate and MDA levels both in early and late sepsis periods when compared with group S (p < 0.05). Group S showed a marked increase in neutrophil infiltration into the interstitial space and thickening of the alveolar septa, whereas the alveolar damage score was lower in the SMB group (p < 0.05). CONCLUSION: MB reduced the MPO activity and lipid peroxidation by both decreasing oxidative stress and NO overproduction in the lungs, which resulted in the attenuation of lung injury after CLP-induced sepsis in rats.     

Garlic extract ameliorates renal and cardiopulmonary injury in the rats with chronic renal failure

Chronic renal failure (CRF) is associated with oxidative stress that promotes production of reactive oxygen species and cytokine release. We aimed to investigate the possible protective and antioxidant effects of aqueous garlic extract (AGE) in a rat model of CRF. Male Sprague-Dawley rats were randomly assigned as either CRF group with 5/6 reduction in the renal mass or sham-operated control group. CRF group received either saline or AGE (250 mg/kg/day/1 mL) orally for 3 weeks. At the end of the 3 weeks, rats were decapitated and trunk blood was collected. Creatinine, blood urea nitrogen (BUN) and lactate dehydrogenase (LDH) activity, and TNF-α and IL-1β levels were measured in the serum samples, while malondialdehyde (MDA), glutathione (GSH) levels, and myeloperoxidase (MPO) activity were determined in the kidney, lung, and heart samples. CRF caused significant decreases in tissue GSH, which were accompanied with significant increases in MDA levels and MPO activities, while the circulating levels of the LDH activity, creatinine, BUN, TNF-α, and IL-1β were elevated. AGE treatment alleviated CRF-induced oxidative changes in the injured tissues, while CRF-induced elevations in the blood levels of the pro-inflammatory cytokines and LDH were reduced. In conclusion, CRF-induced oxidative tissue injury occurs via the activation of pro-inflammatory mediators and by neutrophil infiltration into tissues and that the protective effects of garlic on CRF-induced injury can be attributed to its ability to inhibit neutrophil infiltration and pro-inflammatory mediators. These findings suggest that garlic, as a supplementary to diet, may have a potential therapeutic use in delimitating the systemic oxidant effects of CRF on remote organs.