OBJECTIVETo observe the protection of carbon monoxide (CO) inhalation on lipopolysaccharide (LPS)-induced rat multiple organ injury.

METHODSSprague-Dawley rats with multiple organ injury induced by 5 mg/kg LPS intravenous injection were exposed to room air or 2. 5 x 10(-4) (V/V) CO for 3 hours. The lung and intestine tissues of rats were harvested to measure the expression of heme oxygenase-1 (HO-1) with reverse transcription-polymerase chain reaction, the levels of pulmonary tumor necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6), and intestinal platelet activator factor (PAF), intercellular adhesion molecule-1 (ICAM-1) with enzyme-linked immunosorbent assay, the content of maleic dialdehyde (MDA) and the activity of myeloperoxidase (MPO) with chemical method, the cell apoptosis rate with flow cytometry, and the pathological changes with light microscope.

RESULTSCO inhalation obviously up-regulated the expression of HO-1 in lung (5.43 +/- 0.92) and intestine (6.29 +/- 1.56) in LPS + CO group compared with (3.08 +/- 0.82) and (3.97 +/- 1.16) in LPS group (both P < 0.05). The levels of TNF-alpha, IL-6 in lung and PAF, ICAM-1 in intestine of LPS + CO group were 0.91 +/- 0.25, 0.64 +/- 0.05, 1.19 +/- 0.52, and 1.83 +/- 0.35 pg/mg, respectively, significantly lower than the corresponding values in LPS group (1.48 +/- 0.23, 1.16 +/- 0.26, 1.84 +/- 0.73, and 3.48 +/- 0.36 pg/mg, all P < 0.05). The levels of MDA, MPO, and cell apoptosis rate in lung and intestine of LPS + CO group were 1.02 +/- 0.23 nmol/mg, 1.74 +/- 0.17 nmol/mg, 7.18 +/- 1.62 U/mg, 6.30 +/- 0.97 U/mg, 1.60% +/- 0.34%, and 30. 56% +/- 6.33%, respectively, significantly lower than the corresponding values in LPS group (1.27 +/- 0.33 nmol/mg, 2.75 +/- 0.39 nmol/mg, 8.16 +/- 1.49 U/mg, 7.72 +/- 1.07 U/mg, 3.18% +/- 0.51%, and 41.52% +/- 3.36%, all P < 0.05). In addition, injury of lung and intestine induced by LPS was attenuated at presence of CO inhalation.

CONCLUSIONCO inhalation protects rat lung and intestine from LPS-induced injury via anti-oxidantion, anti-inflammation, anti-apoptosis, and up-regulation of HO-1 expression.

Animals ; Base Sequence ; Carbon Monoxide ; administration & dosage ; DNA Primers ; Inhalation Exposure ; Lipopolysaccharides ; toxicity ; Male ; Multiple Organ Failure ; chemically induced ; Rats ; Rats, Sprague-Dawley

Carbon monoxide (CO), a metabolite of heme catalysis by heme oxygenase (HO), has been proposed to have anti-oxidative, anti-inflammatory and anti-apoptotic functions. Lipopolysaccharide (LPS)-induced lung injury (LI) is characterized by oxidative stress, inflammatory reaction and excessive pulmonary cell apoptosis. So we supposed that CO might have protection against LI. LI in rats was induced by intravenous injection of LPS (5 mg/kg). To observe the effect of CO inhalation, LI rats were exposed to 2.5 x 10(-4) (V/V) CO for 3 h. CO-induced changes of lung oxidative stress parameters, inflammatory cytokines, cell apoptosis, HO-1 expression and histology were examined. Results revealed that expressions of the tumor necrosis factor-alpha (TNF-alpha) and interlukin-6 (IL-6), activities of maleic dialdehyde (MDA) and myeloperoxidase (MPO), and cell apoptosis in LPS injection + CO inhalation group were (0.91+/-0.25) pg/mg protein, (0.64+/-0.05) pg/mg protein, (1.02+/-0.23) nmol/mg protein, (7.18+/-1.62) U/mg protein and (1.60+/-0.34)%, respectively, significantly lower than the corresponding values in LI group [(1.48+/-0.23) pg/mg protein, (1.16+/-0.26) pg/mg protein, (1.27+/-0.33) nmol/mg protein, (8.16+/-1.49) U/mg protein and (3.18+/-0.51) %, P<0.05]. Moreover, CO inhalation obviously increased the expressions of HO-1 and interlukin-10 (IL-10) and activity of superoxide dismutase (SOD) [(5.43+/-0.92), (0.26+/-0.07) pg/mg protein and (60.09+/-10.21) U/mg protein in LPS injection + CO inhalation group vs (3.08+/-0.82), (0.15+/-0.03) pg/mg protein and (50.98+/-6.88) U/mg protein in LI group, P<0.05]. LI was attenuated by CO inhalation. Our study demonstrates that inhalation of low concentration of CO protects lung against LPS-induced injury via anti-oxidant, anti-inflammation, anti-apoptosis and up-regulation of HO-1 expression.
Administration, Inhalation ; Animals ; Apoptosis ; drug effects ; Carbon Monoxide ; administration & dosage ; Carboxyhemoglobin ; analysis ; Cytokines ; biosynthesis ; Heme Oxygenase-1 ; genetics ; Lipopolysaccharides ; toxicity ; Lung ; drug effects ; metabolism ; pathology ; Male ; Oxidative Stress ; drug effects ; RNA, Messenger ; analysis ; Rats ; Rats, Sprague-Dawley

OBJECTIVETo study the protective effect of carbon monoxide (CO) inhalation on the serious limb ischemia/reperfusion (I/R) injury, and which effects caused to shock in rats.

METHODS36 SD rats were randomly divided into I/R, I/R + CO (RC), sham operation (S) groups. I/R injury models were made by the occlusion of the femoral artery for 8 h and the reperfusion for 12 h, 10 d. Before reperfusion of 2 h, RC group started to breathe medical air containing CO (the volume fraction of CO: 0.075%) continuously, until after reperfusion for 4 h, a total of inhalation 6 h. S, I/R groups exposed to air, breathe freely. Caudal artery pressures (CAP), ten days survival rate, serum lactate dehydrogenase (LDH) and creatine kinase (CK) activity, limb wet - to - dry weight ratio (W/D) and the pathologic changes of limb were observed.

RESULTSOnce the reperfusion started, the CAP decreased rapidly in I/R group, and the mean reduced to(5.3259 +/- 0.3832) kPa when reperfusion for 8 h. Compared to I/R group, the CAP decreased slower and smaller in RC group, moreover, its mean reduced to (8.3300 +/- 0.4224) kPa when reperfusion for 8 h. The 10 d survival rate in I/R group was that 8 rats died all between reperfusion for 13 - 20 h. Only 1 rat died in RC group and the other 7 rats were still alive when reperfusion for 10 d. Compared to I/R group, the pathological features of the ischemic limb were significant ly improved, and the figures of W/D, serum LDH and CK value were remarkable lower in RC group (P < 0.05).

CONCLUSIONInhaling exogenous low-dose CO has a reverse regulation in the blood pressure decline caused by serious limb I/R injury in rats. And at the same time, it can effectively prevent the occurrence of shock, reduce physical damage, significantly increase the survival rate of animals.

Administration, Inhalation ; Animals ; Carbon Monoxide ; administration & dosage ; pharmacology ; Creatine Kinase ; blood ; Extremities ; blood supply ; L-Lactate Dehydrogenase ; blood ; Male ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; physiopathology ; prevention & control ; Shock ; etiology ; prevention & control

Gaseous molecules continue to hold new promise in molecular medicine as experimental and clinical therapeutics. The low molecular weight gas carbon monoxide (CO), and similar gaseous molecules (e.g., H2S, nitric oxide) have been implicated as potential inhalation therapies in inflammatory diseases. At high concentration, CO represents a toxic inhalation hazard, and is a common component of air pollution. CO is also produced endogenously as a product of heme degradation catalyzed by heme oxygenase enzymes. CO binds avidly to hemoglobin, causing hypoxemia and decreased oxygen delivery to tissues at high concentrations. At physiological concentrations, CO may have endogenous roles as a signal transduction molecule in the regulation of neural and vascular function and cellular homeostasis. CO has been demonstrated to act as an effective anti-inflammatory agent in preclinical animal models of inflammation, acute lung injury, sepsis, ischemia/reperfusion injury, and organ transplantation. Additional experimental indications for this gas include pulmonary fibrosis, pulmonary hypertension, metabolic diseases, and preeclampsia. The development of chemical CO releasing compounds constitutes a novel pharmaceutical approach to CO delivery with demonstrated effectiveness in sepsis models. Current and pending clinical evaluation will determine the usefulness of this gas as a therapeutic in human disease.
Administration, Inhalation ; Animals ; Anti-Inflammatory Agents/administration & dosage/adverse effects/metabolism/*therapeutic use ; Carbon Monoxide/administration & dosage/adverse effects/metabolism/*therapeutic use ; Dose-Response Relationship, Drug ; Environmental Pollutants/adverse effects ; Gases ; Heme/metabolism ; Heme Oxygenase (Decyclizing)/metabolism ; Humans ; Inhalation Exposure/adverse effects ; Risk Assessment ; Signal Transduction

The regional cerebral blood flow of four patients with delayed carbon monoxide sequelae and four age matched controls was measured, using a xenon inhalation CT scan (GE 9800). Variable patterns of decreased cerebral blood perfusion according to the clinical state of the patient were noted among the patients. Follow up studies, 2 months later, indicated that there was a correlation between the fluctuation of symptoms and the changes in regional cerebral blood flow. It is suggested that the impairment of cerebral perfusion may play a critical role in delayed carbon monoxide sequelae.
Administration, Inhalation ; Aged ; Brain/*blood supply ; Brain Ischemia/chemically induced/physiopathology/*radiography ; Carbon Monoxide Poisoning/*complications ; Case Report ; Female ; Human ; Male ; Middle Age ; Regional Blood Flow/drug effects ; Support, Non-U.S. Gov't ; Time Factors ; Tomography, X-Ray Computed ; Xenon/administration and dosage/diagnostic use

BACKGROUNDSuccessful lung transplantation has been limited by the scarcity of donors. Brain death (BD) donors are major source of lung transplantation. Whereas BD process induces acute lung injury and aggravates lung ischemia reperfusion injury. Carbon monoxide (CO) inhalation at 50-500 parts per million (ppm) can ameliorate lung injury in several models. We examined in rats whether CO inhalation in BD donor would show favorable effects on lung grafts.

METHODSRats were randomly divided into 4 groups. In sham group, donor rats received insertion of a balloon catheter into the cranial cavity, but the balloon was not inflated. In BD-only group, donor rats were ventilated with 40% oxygen after BD confirmation. In BD+CO250 and BD+CO500 groups, donor rats inhaled, after BD confirmation, 250 ppm or 500 ppm CO for 120 minutes prior to lung procurement, and orthotopic lung transplantation was performed. The rats were sacrificed 120 minutes after the lung transplantation by exsanguination, and their blood and lung graft samples were obtained. A total of 8 rats fulfilling the criteria were included in each group.

RESULTSThe inhalation decreased the severity of lung injury in grafts from BD donors checked by histological examination. CO pretreatment reversed the aggravation of PaO2/FiO2 in recipients from BD donors. The CO inhalation down-regulated pro-inflammatory cytokines (TNF-alpha, IL-6) along with the increase of anti-inflammatory cytokine (IL-10) in recipient serum, and inhibited the activity of myeloperoxidase in grafts tissue. The inhalation significantly decreased cell apoptosis in lung grafts, inhibiting mRNA and protein expression of intercellular adhesion molecule-1 (ICAM-1) and caspase-3 in lung grafts. Further, the inhalation activated phosphorylation of p38 expression and inhibited phosphorylation of anti-extracellular signal-regulated kinase (ERK) expression in lung grafts. The effects of CO at 500 ppm were greater than those at 250 ppm.

CONCLUSIONSCO exerts potent protective effects on lung grafts from BD donor, exhibiting anti-inflammatory and anti-apoptosis functions by modulating the mitogen-activated protein kinase (MAPK) signal transduction.

Administration, Inhalation ; Animals ; Apoptosis ; Brain Death ; Carbon Monoxide ; administration & dosage ; Extracellular Signal-Regulated MAP Kinases ; antagonists & inhibitors ; Inflammation ; prevention & control ; Intercellular Adhesion Molecule-1 ; analysis ; genetics ; Lung Transplantation ; methods ; Male ; Phosphorylation ; RNA, Messenger ; analysis ; Rats ; Rats, Wistar ; Tissue Donors ; p38 Mitogen-Activated Protein Kinases ; metabolism

BACKGROUNDTreatment with inhaled carbon monoxide (CO) has been shown to ameliorate intestinal injury in experimental animals induced by lipopolysaccharide (LPS) or ischemia-reperfusion. We hypothesized that CO intraperitoneal administration (i.p.) might provide similar protection to inhaled gas. This study aimed to investigate the effects of continuous 2 L/min of 250 ppm CO i.p. on rat intestine injury induced by LPS and to try to develop a more practical means of delivering the gas.

METHODSA total of 72 male Sprague-Dawley rats were randomly assigned to 4 groups: control group, CO i.p. group, LPS group and LPS+CO i.p. group. One hour after intravenously received 5 mg/kg LPS, the rats in LPS group and LPS+CO i.p. group were exposed to room air and 2 L/min of 250 ppm CO i.p., respectively, and the rats of control group and CO i.p. group intravenously received an equal volume of 0.9% NaCl and 1 hour later, were exposed to room air and 2 L/min of 250 ppm CO i.p., respectively. One, 3 and 6 hour of each group after treated with room air or CO i.p., the animals (n = 6 for each time point) were sacrificed and intestinal tissues were collected for determinating the levels of platelet activator factor (PAF) and intercellular adhesion molecule-1 (ICAM-1) with enzyme-lined immunosorbent assays. The maleic dialdehyde (MDA) content and the myeloperoxidase (MPO) activity were determined with a chemical method. The phosphorylated p38 mitogen activated protein kinase (MAPK) expression was assayed with Western blotting and the cell apoptotic rate with flow cytometery. The arterial oxygenation was measured by blood gas analysis, and the pathology determined by light microscope.

RESULTSAfter treatment with 2 L/min of 250 ppm CO i.p., the increase of PAF, ICAM-1, MDA, MPO, and cell apoptotic rate induced by LPS was markedly reduced (P < 0.05 or 0.01), and accompanied by ameliorating intestine injury. Western blotting showed that these effects of CO i.p. were mediated by p38 MAPK pathway. There were no significant differences in all observed parameters between control group and CO i.p. group.

CONCLUSIONThe injury to the intestine via anti-oxidant, anti-inflammation and anti-apoptosis, which may involve the p38 MAPK pathway, was induced by 2 L/min of 250 ppm CO i.p. exerting potent protection against LPS.

Aldehydes ; metabolism ; Animals ; Blotting, Western ; Carbon Monoxide ; administration & dosage ; pharmacology ; therapeutic use ; Flow Cytometry ; Intercellular Adhesion Molecule-1 ; metabolism ; Intestines ; drug effects ; metabolism ; pathology ; Lipopolysaccharides ; toxicity ; Male ; Microscopy ; Peroxidase ; metabolism ; Platelet Activating Factor ; metabolism ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; chemically induced ; drug therapy ; p38 Mitogen-Activated Protein Kinases ; metabolism

OBJECTIVETo study the protective effect of carbon monoxide(CO) inhalation in the limb ischemia/reperfusion (I/R) injury of rats.

METHODSForty-four Sprague-Dawley rats were randomly divided into three groups: S, I/R and RC groups. I/R injury model was made by the occlusion of the femoral artery for four hours and the reperfusion for forty-eight hours. RC group was exposed to medical air mixed CO (the volume fraction of CO: 0.05%) during limb reperfusion in rats. The other two groups were exposed to the routine air. Gross morphology of the ischemic limb, wet-to-dry weight ratio (W/D), and skeletal muscle histopathology were observed. The apoptosis index and expression levels of Bax and Bcl-2 in the muscle were assessed with Flow Cytometry. The activities of serum lactate dehydrogenase (LDH) and creatine kinase (CK) were tested by Automatic Biochemical Analyzer.

RESULTSCompared to I/R group, W/D, serum LDH and CK activities, the apoptosis index and Bax expression level in the muscle were all significantly decreased, the Bcl-2 expression level was significantly increased, gross morphology of the ischemic limb and muscle histopathology were obviously improved in RC group.

CONCLUSIONInhaling exogenous CO can attenuate limb I/R injury.

Administration, Inhalation ; Animals ; Carbon Monoxide ; pharmacology ; Creatine Kinase ; metabolism ; Extremities ; blood supply ; Femoral Artery ; Ischemia ; physiopathology ; L-Lactate Dehydrogenase ; metabolism ; Male ; Proto-Oncogene Proteins c-bcl-2 ; metabolism ; Rats ; Rats, Sprague-Dawley ; Reperfusion Injury ; prevention & control ; bcl-2-Associated X Protein ; metabolism