Post-treatment with N-acetylcysteine ameliorates endotoxin shock-induced organ damage in conscious rats

N-acetylcysteine (NAC) is an antioxidant and cytoprotective agent with scavenging action against reactive oxygen species and inhibitory effects on pro-inflammatory cytokines. In a previous study, we found that pretreatment with NAC attenuated organ dysfunction and damage, reduced the production of free radicals, tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) following endotoxemia elicited by administration of lipopolysaccharide (LPS). In the present study, we tested the effects of post-treatment with NAC on the sepsis-induced change. Post-treatment imitates clinical therapeutic regimen with administration of drug after endotoxemia. Endotoxin shock was induced by intravenous injection of Klebsiella pneumoniae LPS (10 mg/kg) in conscious rats. Mean arterial pressure (MAP) and heart rate (HR) were continuously monitored for 48 h after LPS administration. NAC was given 20 min after LPS. Measurements of biochemical substances were taken to reflect organ functions. Biochemical factors included blood urea nitrogen (BUN), creatinine (Cre), lactate dehydrogenase (LDH), creatine phosphokinase (CPK), aspartate transferase (GOT), alanine transferase (GPT), TNF-alpha, interleukin-6 (IL-6), and interleukin-10 (IL-10). LPS significantly increased blood BUN, Cre, LDH, CPK, GOT, GPT, TNF-alpha, IL-6, IL-10 levels and HR, and decreased MAP. Post-treatment with NAC diminished the decrease in MAP, increased the HR, and decreased the markers of organ injury (BUN, Cre, LDH, CPK, GOT, GPT) and inflammatory biomarkers (TNF-alpha, IL-6, IL-10) after LPS. We conclude that post-treatment with NAC suppresses the release of plasma TNF-alpha, IL-6, and IL-10 in endotoxin shock, and decreases the markers of organ injury. These beneficial effects protect against LPS-induced kidney, heart and liver damage in conscious rats. The beneficial effects may suggest a potential chemopreventive effect of this compound after sepsis.     

Low-dose erythropoietin aggravates endotoxin-induced organ damage in conscious rats

Endotoxin shock can induce the production of several inflammatory mediators such as TNF-α, IL-6, and IL-1β, leading to multiple organ dysfunction and death. Erythropoietin (EPO) has been found to interact with its receptor (EPO-R), expressed in a wide variety of non-hematopoietic tissues, to induce a range of pleiotropic cytoprotective actions. We investigated the effects of low doses of EPO (300 U/kg, intravenous administration) on the physiopathology and cytokine levels in endotoxin shock in conscious rats. Endotoxin shock was induced by intravenous injection of Escherichia coli lipopolysaccharide (20 mg/kg) in conscious rats. Mean arterial pressure (MAP) and heart rate (HR) were continuously monitored for 48 h after LPS administration. Levels of biochemical and cytokine parameters, including glutamic oxaloacetic transaminase (GOT), glutamic pyruvic transaminase (GPT), blood urea nitrogen (BUN), creatinine (Cre), lactic dehydrogenase (LDH), and creatine phosphokinase (CPK) were measured at 0, 1, 3, 6, 9, 12, 18, 24, and 48 h after sepsis. Serum TNF-α, IL-6, and IL-1β level was measured at 1 h after sepsis. Endotoxin shock significantly increased blood GOT, GPT, BUN, Cre, LDH, CPK, TNF-α, IL-6, IL-1β levels, and HR, while it decreased MAP. EPO further increased the markers of organ injury (GOT, GPT, BUN, Cre, LDH, and CPK), inflammatory biomarkers (TNF-α, IL-6, and IL-1β) and did not affect MAP and HR after LPS. EPO disserved endotoxin shock-induced liver, kidney, lung, and small intestine damage in conscious rats. In conclusion, pre-treatment with low doses of EPO increased the release of TNF-α, IL-6, and IL-1β, along with aggravating endotoxin shock-induced markers of organ injury in conscious rats.     

Effect of Methylguanidine in a Model of Septic Shock Induced by LPS

Septic shock, a severe form of sepsis, is characterized by cardiovascular collapse following microbial invasion of the body. The progressive hypotension, hyporeactivity to vasopressor agents and vascular leak leads to circulatory failure with multiple organ dysfunction and death. Many inflammatory mediators (e.g. TNF-α, IL-1 and IL-6) are involved in the pathogenesis of shock and, among them, nitric oxide (NO). The overproduction of NO during septic shock has been demonstrated to contribute to circulatory failure, myocardial dysfunction, organ injury and multiple organ failure. We have previously demonstrated with in vitro and in vivo studies that methylguanidine (MG), a guanidine compound deriving from protein catabolism, significantly inhibits iNOS activity, TNF-α release and carrageenan-induced acute inflammation in rats. The aim of the present study was to evaluate the possible anti-inflammatory activity of MG in a model of septic shock induced by lipopolysaccharide (LPS) in mice. MG was administered intraperitoneally (i.p.) at the dose of 30 mg/kg 1 h before and at 1 and 6 h after LPS-induced shock. LPS injection (10 mg/kg in 0.9% NaCl; 0.1 ml/mouse; i.p.) in mouse developed a shock syndrome with enhanced NO release and liver, kidney and pancreatic damage 18 h later. NO_x levels, evaluated as nitrite/nitrate serum levels, was significantly reduced in MG-treated rats (78.6%, [Formula: See Text]). Immunohistochemistry revealed, in the lung tissue of LPS-treated group, a positive staining for nitrotyrosine and poly(adenosine diphosphate [ADP] ribose) synthase, both of which were reduced in MG-treated mice. Furthermore, enzymatic evaluation revealed a significant reduction in liver, renal and pancreatic tissue damage and MG treatment also improved significantly the survival rate. This study provides evidence that MG attenuates the degree of inflammation and tissue damage associated with endotoxic shock in mice. The mechanisms of the anti-inflammatory effect of MG is, at least in part, dependent on the inhibition of NO formation.     

Effect of methylguanidine in a model of septic shock induced by LPS

Septic shock, a severe form of sepsis, is characterized by cardiovascular collapse following microbial invasion of the body. The progressive hypotension, hyporeactivity to vasopressor agents and vascular leak leads to circulatory failure with multiple organ dysfunction and death. Many inflammatory mediators (e.g. TNF-alpha, IL-1 and IL-6) are involved in the pathogenesis of shock and, among them, nitric oxide (NO). The overproduction of NO during septic shock has been demonstrated to contribute to circulatory failure, myocardial dysfunction, organ injury and multiple organ failure. We have previously demonstrated with in vitro and in vivo studies that methylguanidine (MG), a guanidine compound deriving from protein catabolism, significantly inhibits iNOS activity, TNF-alpha release and carrageenan-induced acute inflammation in rats. The aim of the present study was to evaluate the possible anti-inflammatory activity of MG in a model of septic shock induced by lipopolysaccharide (LPS) in mice. MG was administered intraperitoneally (i.p.) at the dose of 30 mg/kg 1 h before and at 1 and 6 h after LPS-induced shock. LPS injection (10 mg/kg in 0.9% NaCl; 0.1 ml/mouse; i.p.) in mouse developed a shock syndrome with enhanced NO release and liver, kidney and pancreatic damage 18 h later. NOx levels, evaluated as nitrite/nitrate serum levels, was significantly reduced in MG-treated rats (78.6%, p < 0.0001; n = 10). Immunohistochemistry revealed, in the lung tissue of LPS-treated group, a positive staining for nitrotyrosine and poly(adenosine diphosphate [ADP] ribose) synthase, both of which were reduced in MG-treated mice. Furthermore, enzymatic evaluation revealed a significant reduction in liver, renal and pancreatic tissue damage and MG treatment also improved significantly the survival rate. This study provides evidence that MG attenuates the degree of inflammation and tissue damage associated with endotoxic shock in mice. The mechanisms of the anti-inflammatory effect of MG is, at least in part, dependent on the inhibition of NO formation.     

Activation of autophagy is involved in the protective effect of 17β‐oestradiol on endotoxaemia‐induced multiple organ dysfunction in ovariectomized rats

Oestrogens have been reported to attenuate acute inflammation in sepsis. In this study, the effects of long‐term oestrogen replacement with 17β‐oestradiol (E₂) on endotoxaemia‐induced circulatory dysfunction and multiple organ dysfunction syndrome were evaluated in ovariectomized (Ovx) rats. E₂ (50 μg/kg, s.c., 3 times/week) was administered for 8 weeks, followed by the induction of endotoxaemia by intravenous infusion of lipopolysaccharides (LPS; 30 mg/kg/4 hrs). Oestrogen deficiency induced by ovariectomy for 9 weeks augmented the LPS‐induced damage, including endotoxic shock, myocardial contractile dysfunction, renal dysfunction and rhabdomyolysis. Cardiac levels of NF‐κB p65, iNOS and oxidized glutathione, free radical production in skeletal muscles, myoglobin deposition in renal tubules, and plasma levels of plasminogen activator inhibitor‐1, TNF‐α, and IL‐6 were more pronounced in the Ovx + LPS group than in the Sham + LPS group. Long‐term treatment of E₂ prevented this amplified damage in Ovx rats. Six hours after LPS initiation, activation of the autophagic process, demonstrated by increases in Atg12 and LC3B‐II/LC3B‐I ratios, and induction of haem oxygenase (HO)‐1 and heat‐shock protein (HSP) 70 protein expression in myocardium were increased significantly in the Ovx + E₂ + LPS group. These results suggest that activation of autophagy and induction of HO‐1 and HSP70 contribute to the protective effect of long‐term E₂ replacement on multiple organ dysfunction syndrome in endotoxaemia.     

The effect of a nitroxide antioxidant on ischemia-reperfusion injury in the rat in vivo hind limb model

Microsurgical procedures such as free tissue transfer or replantations of amputated digits involve an obligatory ischemic period leading to regional tissue oedema, rhabdomyolysis, systemic acidosis, hypercalcemia and multiple organ dysfunction syndrome reflecting ischemia-reperfusion (I/R) injury. Since nitroxide stable radicals act as antioxidants their potential protective effects were tested. Anaesthetized Sabra rats were subjected to regional ischemia of the hind limb for 2 h using a tourniquet. Upon reperfusion rats were injected with 4-OH-2,2,6,6-tetramethylpiperidine-1-oxyl (TPL). Systemic I/R-induced damage was assessed by sampling blood for differential count, lactate dehydrogenase (LDH) and creatine phosphokinase (CPK) serum levels. Regional injury was evaluated by analysing excised muscle samples for oedema (tissue water content) and inflammatory infiltrate (number of cell nuclei in histomorphometric analysis). I/R-induced changes of biomarkers reflecting systemic damage peaked about 8 h following the start of reperfusion and fully disappeared as the biomarkers relaxed to their pre-ischemic values after 24 h. TPL facilitated the recovery of some of these parameters and partially affected release of cellular CPK and LDH. The parameters of I/R-induced regional tissue injury did not demonstrate any recovery and were not inhibited by TPL.     

The effect of a nitroxide antioxidant on ischemia-reperfusion injury in the rat in vivo hind limb model

Microsurgical procedures such as free tissue transfer or replantations of amputated digits involve an obligatory ischemic period leading to regional tissue oedema, rhabdomyolysis, systemic acidosis, hypercalcemia and multiple organ dysfunction syndrome reflecting ischemia-reperfusion (I/R) injury. Since nitroxide stable radicals act as antioxidants their potential protective effects were tested. Anaesthetized Sabra rats were subjected to regional ischemia of the hind limb for 2 h using a tourniquet. Upon reperfusion rats were injected with 4-OH-2,2,6,6-tetramethylpiperidine-1-oxyl (TPL). Systemic I/R-induced damage was assessed by sampling blood for differential count, lactate dehydrogenase (LDH) and creatine phosphokinase (CPK) serum levels. Regional injury was evaluated by analysing excised muscle samples for oedema (tissue water content) and inflammatory infiltrate (number of cell nuclei in histomorphometric analysis). I/R-induced changes of biomarkers reflecting systemic damage peaked about 8 h following the start of reperfusion and fully disappeared as the biomarkers relaxed to their pre-ischemic values after 24 h. TPL facilitated the recovery of some of these parameters and partially affected release of cellular CPK and LDH. The parameters of I/R-induced regional tissue injury did not demonstrate any recovery and were not inhibited by TPL.     

硫化氢与内毒素血症大鼠心肌损伤的关系

为探讨硫化氢（hydrogen sulfide,H2S）与内毒素血症大鼠心肌损伤的关系,采用静脉注射脂多糖（lipopolysaccharide,LPS）的方法制备内毒素血症大鼠模型,将雄性Wistar大鼠随机分为正常对照组、LPS组、LPS＋炔丙基甘氨酸（propargylglycine,PPG,H2S代谢酶抑制剂）组、LPS＋NaHS（H2S供体）组。观察给药后4h内大鼠平均动脉压（mean arterial pressure,MAP）的变化,测定血浆肿瘤坏死因子-α（tumor necrosis factor-α,TNF-α）和H2S含量,光学显微镜观察心肌组织形态学变化并测定心肌组织中TNF-α、H2S含量及乳酸脱氢酶（lactate dehydrogenase,LDH）和髓过氧化物酶（myeloperoxidase,MPO）的活性。结果如下：（1）与正常对照组相比,LPS组大鼠血压迅速下降,血浆TNF-α、H2S含量显著增高,且血浆中H2S含量与血压呈显著负相关,LPS注射后1、2、4h时相关系数分别为-0．936、-0．913和-0．908（均P〈0．05）;心肌组织TNF-α、H2S含量及LDH、MPO活性也明显升高,并出现组织损伤;（2）给予PPG能显著抑制血浆TNF-α、H2S含量的增高,并可显著减轻LPS所致的血压下降（均P〈0．05）和心肌组织损伤,降低心肌组织中TNF-α、H2S含量及LDH、MPO活性;（3）给予NaHS后,与LPS组相比,大鼠血浆TNF-α、H2S含量增高,血压明显下降（均P〈0．05）,心肌组织损伤加重,心肌组织中TNF-α、H2S含量及LDH、MPO活性增高。结果提示,内毒素血症大鼠低血压和心肌损伤的部分原因是由于H2S生成增多。     

淋浆对内毒素休克大鼠微循环障碍的干预作用

目的：探讨淋浆对内毒素休克的干预作用及其机制。方法：Wistar雄性大鼠60只,随机分为对照组、模型组和淋浆组,以颈静脉注射LPS（15 mg/kg）复制内毒素休克模型,造模15 min后,淋浆组自颈静脉注射正常淋浆（占全血量1/15）,观察对平均动脉血压（MAP）、回肠下段肠系膜微循环、细静脉壁白细胞粘附数、血浆P-选择素和细胞间粘附分子（ICAM-1）含量的影响。结果：正常淋浆可防止内毒素休克的MAP进行性下降,解除肠系膜微血管的病理性缩窄,减少白细胞在细静脉壁的粘附,改善微循环的流态,降低血浆P-选择素和ICAM-1的水平。结论：小量正常淋浆对LPS攻击导致内毒素休克的微循环障碍和低血压均有良好的干预作用,其机制与减少细胞粘附分子生成有关。     

Inducible nitric oxide synthase mediates cytokine release: the time course in conscious and septic rats

Nitric oxide (NO), tumor necrosis factor-alpha (TNF-alpha), and interleukin 1-beta (IL-1beta) are postulated to play a key pathophysiologic role during sepsis. In this study, we examined the time course of inducible NO synthase (iNOS) mRNA expression and the plasma TNF-alpha and IL-1beta in lipopolysaccharide (LPS)-treated conscious rats. The hemodynamic pattern in septic shock is more similar to clinical conditions without anesthesia. The data showed that a significant increase in iNOS mRNA levels was found in the spleen, lung, liver, with slight elevation in the heart and kidney at 3 h after LPS administration. However, iNOS mRNA levels were not elevated significantly in all tissues examined at 24 h. In the plasma, TNF-alpha and IL-1beta culminated within 1 h, and reduced gradually to baseline levels in a relatively short period (within 9 h). The results suggest that local NO production by activation of iNOS mRNA expression and cytokine release may contribute to LPS-induced organ dysfunction at various time points.     

Post-Natal Inhibition of NF-κB Activation Prevents Renal Damage Caused by Prenatal LPS Exposure

Prenatal exposure to an inflammatory stimulus has been shown to cause renal damage in offspring. Our present study explored the role of intra-renal NF-κB activation in the development of progressive renal fibrosis in offspring that underwent prenatal exposure to an inflammatory stimulus. Time-dated pregnant rats were treated with saline (control group) or 0.79 mg/kg lipopolysaccharide (LPS) through intra-peritoneal injection on gestational day 8, 10 and 12. At the age of 7 weeks, offspring from control or LPS group were treated with either tap water (Con+Ve or LPS+Ve group) or pyrollidine dithiocarbamate (PDTC, 120mg/L), a NF-κB inhibitor, via drinking water starting (Con+PDTC or LPS+PDTC group), respectively, till the age of 20 or 68 weeks. The gross structure of kidney was assessed by hematoxylin-eosin, periodic acid–Schiff staining and Sirius red staining. The expression levels of TNF-α, IL-6, α-smooth muscle actin (α-SMA) and renin-angiotensin system (RAS) genes were determined by real time polymerase chain reaction and/or immunohistochemical staining. Our data showed that post-natal persistent PDTC administration efficiently repressed intra-renal NF-κB activation, TNF-α and IL-6 expression. Post-natal PDTC also prevented intra-renal glycogen deposition and collagenous fiber generation as evident by the reduced expression of collagen III and interstitial α-SMA in offspring of prenatal LPS exposure. Furthermore, post-natal PDTC administration reversed the intra-renal renin-angiotensin system (RAS) over-activity in offspring of prenatal LPS exposure. In conclusion, prenatal inflammatory exposure results in offspring’s intra-renal NF-κB activation along with inflammation which cross-talked with excessive RAS activation that caused exacerbation of renal fibrosis and dysfunction in the offspring. Thus, early life prevention of NF-κB activation may be a potential preventive strategy for chronic renal inflammation and progressive renal damage.     

Effects of various antioxidants on endotoxin-induced lung injury and gene expression: mRNA expressions of MnSOD, interleukin-1beta and iNOS

Antioxidants have been shown to be effective in attenuating acute lung injury. In this study, we determine the effects of various antioxidants by different mechanisms on the lipopolysaccharide (LPS)-induced changes. LPS was administered intravenously at a dose of 10 mg/kg to anesthetized rats. LPS induced a significant decrease in blood pressure (P < 0.01) and increased exhaled nitric oxide (NO) from 3.60+/-0.18 to 35.53+/-3.23 ppb (P < 0.01) during an observation period of 4 h. Plasma nitrate concentrations also increased from 0.61+/-0.06 to 1.54+/-0.22 micromol/l (P < 0.05). LPS-induced oxygen radical release from white blood cells isolated from rat peripheral blood also increased significantly (P < 0.001). After the experiment, the lung weight was obtained and lung tissues were taken for the determination of mRNA expression of inducible nitric oxide synthase (iNOS), tumor necrosis factor alpha (TNF-alpha), interleukin-1beta (IL-1beta) and manganese superoxide dismutase (MnSOD). Histological examination of the lungs was also performed. In the control group injected with saline solution, mRNA expressions of iNOS, IL-1beta, TNF-alpha and MnSOD were absent. Four hours after LPS administration, mRNA expressions of iNOS, IL-1beta, and MnSOD were significantly enhanced, but TNF-alpha was not discernibly expressed. LPS also caused a twofold increase in lung weight. Pathological examination revealed endothelial cell damage and interstitial edema. Various antioxidants were given 1 h after LPS administration. These agents include SOD, catalase (CAT), SOD + CAT or vitamin C (ascorbic acid). These antioxidants effectively reversed the systemic hypotension, reduced the quantity of exhaled NO and plasma nitrate concentration, and prevented acute lung injury. Administration of various antioxidants also significantly attenuated LPS-induced oxygen radical release by rat white blood cells. LPS induced mRNA expressions of MnSOD and iNOS were significantly depressed by these antioxidants. However, only SOD + CAT and vitamin C inhibited the mRNA expression of IL-1beta. These results suggest that oxygen radicals are responsible for LPS-induced lung injury. Antioxidants can attenuate the lung injury by inhibiting mRNA expressions of iNOS and IL-1beta.     

Endotoxemia in newborn rats attenuates acute pancreatitis at adult age.

Bacterial endotoxin (lipopolysaccharide, LPS), at high concentration is responsible for sepsis, and neonatal mortality, however low concentration of LPS protected the pancreas against acute damage. The aim of this study was to investigate the effect of exposition of suckling rats to LPS on the course of acute pancreatitis at adult age. Suckling rat (30-40g) received intraperitoneal (i.p.) injection of saline (control) or LPS from Escherichia coli or Salmonella typhi (5, 10 or 15 mg/kg-day) during 5 consecutive days. Two months later these rats have been subjected to i.p. cearulein infusion (25 microg/kg) to produce caerulein-induced pancreatitis (CIP). The following parameters were tested: pancreatic weight and morphology, plasma amylase and lipase activities, interleukin 1beta (IL-1 beta), interleukin 6 (IL-6), and interleukin 10 (IL-10) plasma concentrations. Pancreatic concentration of superoxide dismutase (SOD) and lipid peroxidation products; malondialdehyde (MDA) and 4-hydroxynonenal (4-HNE) have been also measured. Caerulein infusion produced CIP in all animals tested, that was confirmed by histological examination. In the rats, which have been subjected in the neonatal period of life to LPS at doses 10 or 15 mg/kg-day x 5 days, all manifestations of CIP have been reduced. In these animals acute inflammatory infiltration of pancreatic tissue and pancreatic cell vacuolization have been significantly diminished. Also pancreatic weight, plasma lipase and alpha-amylase activities, as well as plasma concentrations of IL-1beta and IL-6 have been markedly decreased, whereas plasma anti-inflammatory IL-10 concentration was significantly increased in these animals as compared to the control rats, subjected in the infancy to saline injection instead of LPS. Caerulein-induced fall in pancreatic SOD concentration was reversed and accompanied by significant reduction of MDA + 4 HNE in the pancreatic tissue. The effects of LPS derived from E. coli or S. typhi were similar. Pretreatment of suckling rats with LPS at dose of 10 mg/kg-day x 5 days resulted in the most prominent attenuation of acute pancreatitis at adult age, whereas LPS at dose of 5 mg/kg-day x 5 days given to the neonatal rats failed to affect significantly acute pancreatitis induced in these animals 2 months later. We conclude that: 1/ Prolonged exposition of suckling rats to bacterial endotoxin attenuated acute pancreatitis induced in these animals at adult age. 2/ This effect could be related to the increased concentration of antioxidative enzyme SO in the pancreatic tissue and to the modulation of cytokines production in these animals.     

动脉压力感受性反射受损后血浆和心脏、肾脏组织AngⅡ含量的变化

既往的研究表明,动脉压力感受性反射（ABR）功能下降在高血压靶器官损伤中起独立作用。为进一步研究ABR功能下降致器官损伤的可能机制,实验采用去窦弓神经（SAD）大鼠作为ABR受损的动物模型,分别测定清醒、自由活动状态下SAD及对照的假手术组大鼠24h动脉血压、心率、血压波动性（BPV）及心率波动性（HRV）。并采用放免法测定血浆、心脏和肾脏组织的血管紧张素Ⅱ（AngⅡ）含量。结果发现,SAD术后1周大鼠的24h平均收缩压（SBP）、舒张压（DBP）均显著高于对照组及术后18周的慢性期SAD大鼠。SAD术后18周,24h平均SBP、DBP及HR与假手术对照组均无显著差异;24h收缩压波动性（SBPV）和舒张压波动性（DBPV）均显著高于对照组大鼠。SAD大鼠术后1周的血浆、心脏和肾脏组织的AngⅡ含量及术后18周的血浆AngⅡ水平与对照组之间相比无显著差异。而在术后慢性期（18周）,SAD大鼠的心肌及肾组织AngⅡ含量显著高于假手术对照组大鼠。在术后18周时,接受慢性应激刺激的SAD大鼠,其血浆、心肌及肾组织中AngⅡ水平显著高于同处应激状态下的假手术对照组大鼠及未接受应激刺激的SAD大鼠。这些结果表明,SAD术后急性期血压增高,但在慢性期平均血压并无增高,仅BPV增高;慢性期心、肾组织内AngⅡ的分泌增加。在慢性期接受应激可致AngⅡ过度分泌,上述结果提示,BPV增高和心、肾组织AngⅡ含量升高与SAD大鼠发生心脏、肾脏等器官损害有关。     

Lactic and hydrochloric acids induce different patterns of inflammatory response in LPS-stimulated RAW 264.7 cells

Metabolic acidosis frequently complicates sepsis and septic shock and may be deleterious to cellular function. Different types of metabolic acidosis (e.g., hyperchloremic and lactic acidosis) have been associated with different effects on the immune response, but direct comparative studies are lacking. Murine macrophage-like RAW 264.7 cells were cultured in complete medium with lactic acid or HCl to adjust the pH between 6.5 and 7.4 and then stimulated with LPS (Escherichia coli 0111:B4; 10 ng/ml). Nitric oxide (NO), IL-6, and IL-10 levels were measured in the supernatants. RNA was extracted from the cell pellets, and RT-PCR was performed to amplify corresponding mediators. Gel shift assay was also performed to assess NF-kappa B DNA binding. Inc easing concentrations of acid caused increasing acidification of the media. Trypan blue exclusion and lactate dehydrogenase release demonstrated that acidification did not reduce cell viability. HCl significantly increased LPS-induced NO release and NF-kappa B DNA binding at pH 7.0 but not at pH 6.5. IL-6 and IL-10 expression (RNA and protein) were reduced with HCl-induced acidification, but IL-10 was reduced much more than IL-6 at low pH. By contrast, lactic acid significantly decreased LPS-induced NO, IL-6, and IL-10 expression in a dose-dependent manner. Lactic acid also inhibited LPS-induced NF-kappa B DNA binding. Two common forms of metabolic acidosis (hyperchloremic and lactic acidosis) are associated with dramatically different patterns of immune response in LPS-stimulated RAW 264.7 cells. HCl is essentially proinflammatory as assessed by NO release, IL-6-to-IL-10 ratios, and NF-kappa B DNA binding. By contrast, lactic acidosis is anti-inflammatory.     

Carbohydrate metabolism in temporal and persistent hypoglycemic chickens induced by insulin infusion

In order to elucidate the regulatory mechanism of blood glucose concentrations specific to chickens, carbohydrate metabolism in the liver, muscle and kidney and metabolite concentrations in the blood were investigated in chickens with acute and persistent hypoglycemia. Acute and persistent hypoglycemia were experimentally induced by a single injection of insulin (8 U/kg BW) or by continuous infusion of insulin (22.5 U/kg BW/day) for 4 days. Non-esterified fatty acid (NEFA) concentration in plasma and D-3-hydroxybutyrate (3HB) concentrations in liver and muscle increased in the acute hypoglycemia. Plasma NEFA concentration and 3HB concentration in the blood and liver were not changed at day 3 of persistent hypoglycemia, while 3HB concentration in the muscle was decreased. Phosphofructokinase (PFK) activity in the liver tended to increase but PFK and pyruvate kinase (PK) activities were unchanged in acute hypoglycemia. In persistent hypoglycemia, increase of hepatic PFK activity at day 1 in which it was reversed at day 3, and a small increase of muscle PK activity were observed, while PK and phosphoenolpyruvate carboxykinase (PEPCK) activities in the liver and kidney were not significantly changed. These results show that in the persistent hypoglycemic chickens, hepatic glycolysis transiently increases, which is followed by a small decrease, while glycolysis in muscles and gluconeogenesis in the liver and kidney are not significantly changed.     

1H NMR-Based Metabolite Profiling of Plasma in a Rat Model of Chronic Kidney Disease

Chronic kidney disease (CKD) is characterized by the gradual loss of the kidney function to excrete wastes and fluids from the blood. ¹H NMR-based metabolomics was exploited to investigate the altered metabolic pattern in rats with CKD induced by surgical reduction of the renal mass (i.e., 5/6 nephrectomy (5/6 Nx)), particularly for identifying specific metabolic biomarkers associated with early of CKD. Plasma metabolite profiling was performed in CKD rats (at 4- or 8-weeks after 5/6 Nx) compared to sham-operated rats. Principle components analysis (PCA), partial least squares-discriminant analysis (PLS-DA) and orthogonal partial least squares-discriminant analysis (OPLS-DA) score plots showed a significant separation between the groups. The resulting metabolic profiles demonstrated significantly increased plasma levels of organic anions, including citrate, β-hydroxybutyrate, lactate, acetate, acetoacetate, and formate in CKD. Moreover, levels of alanine, glutamine, and glutamate were significantly higher. These changes were likely to be associated with complicated metabolic acidosis in CKD for counteracting systemic metabolic acidosis or increased protein catabolism from muscle. In contrast, levels of VLDL/LDL (CH₂)_n and N-acetylglycoproteins were decreased. Taken together, the observed changes of plasma metabolite profiles in CKD rats provide insights into the disturbed metabolism in early phase of CKD, in particular for the altered metabolism of acid-base and/or amino acids.     

Vascular changes in cyclosporine A-induced hypertension and nephrotoxicity in spontaneously hypertensive rats on high-sodium diet.

Functional and morphological changes of blood vessels in cyclosporine A (CsA)-induced hypertension and nephrotoxicity were studied in spontaneously hypertensive rats (SHR). The role of the L-arginine-nitric oxide (NO) pathway and the importance of oxidative stress in CsA toxicity were also assessed. SHR (7-8 week old) on a high-sodium diet were treated with CsA (5 mg kg(-1) d(-1) s.c.) for 6 weeks. A proportion of the rats were treated concomitantly with the NO precursor L-arginine (1.7 g kg(-1)d(-1) p.o.). CsA elevated blood pressure and caused renal dysfunction and morphological nephrotoxicity. CsA also impaired mesenteric and renal arterial function and caused structural damage to intrarenal and extrarenal small arteries and arterioles. Medial atrophy of the mesenteric resistance vessels and decreased viability of smooth muscle cells of the thoracic aorta were observed. Renal and arterial damage was associated with the presence of inflammatory cells. CsA did not affect markers of the L-arginine-NO pathway (urinary cyclic GMP excretion or endothelial or inducible NO synthase expression in kidney, aorta or heart) or oxidative stress (urinary excretion of 8-isoprostaglandin F2alpha, plasma urate concentration or total radical trapping capacity). Concomitant L-arginine treatment did not affect CsA-induced changes in blood pressure or histological findings but tended to alleviate the arterial dysfunction. The renal and cardiovascular toxicity of CsA was associated with arterial dysfunction and morphological changes in small arteries and arterioles in SHR on a high-sodium diet. The findings did not support the role of oxidative stress or a defect in the L-arginine-NO pathway.