metallothionein and Reperfusion-Injury

Superoxide formation in pulmonary tissue is modulated by cytokines, PO2, shear force, and disease states, and can be stimulated by drugs. Superoxide has diverse actions on pulmonary cells, including smooth muscle contraction, interaction with redox enzymes, cell proliferation, and gene transcription. In the lungs, there is an impressive array of specific defence mechanisms that destroy superoxide, especially superoxide dismutase (SOD) and metallothionein. Superoxide formation is increased in hyperoxia (e.g., oxygen therapy); however, superoxide-forming enzymes also can be up-regulated in hypoxia. Superoxide has been implicated in acute respiratory distress syndrome, lung ischaemia-reperfusion injury, and lung transplantation. Novel approaches to therapy have been explored, including SOD gene therapy and SOD targeting to the lung. In the future, new drugs interacting with superoxide may provide significant advances in the treatment of lung diseases.

Topics: Animals; Cell Division; Cell Membrane Permeability; Genetic Therapy; Humans; Hyperoxia; Hypoxia; Lung Diseases; Metallothionein; Pulmonary Artery; Reperfusion Injury; Superoxide Dismutase; Superoxides; Transcription, Genetic

The purpose of this research was to evaluate the protective effects of apocynin on renal ischemia/reperfusion (I/R) injury (RI/RI) in rats. Rats preconditioned with apocynin were subjected to renal I/R. Zinc levels in serum and renal tissues, blood urea nitrogen (BUN), and serum creatinine (Scr) were detected. We further measured the activity of superoxide dismutase (SOD); the content of malondialdehyde (MDA), IL-4, IL-6, IL-10, and TNF-α; and the expression of metallothionein (MT) in the renal tissues. Results indicated that the levels of MDA, IL-4, IL-6, IL-10, TNF-α, and MT in the kidney tissue and serum BUN and Scr levels in RI/RI group were significantly higher than those in sham-operated group, while the levels of serum Zn and kidney Zn and SOD were reduced in RI/RI group. Apocynin treatment further decreased the levels of MDA, IL-6, TNF-α, and serum BUN and Scr, whereas it significantly increased the levels of Zn, SOD, IL-4, IL-10, and MT in the kidney tissue and serum Zn. These findings suggest that apocynin might play a protective role against RI/RI in rats through regulating zinc level and MT expression involving in oxidative stress.

Topics: Acetophenones; Animals; Cytokines; Kidney; Kidney Diseases; Male; Metallothionein; Rats; Rats, Sprague-Dawley; Reperfusion Injury; Superoxide Dismutase; Zinc

After transient cerebral ischemia and reperfusion (I/R), damaging mechanisms, such as excitotoxicity and oxidative stress, lead to irreversible neurological deficits. The induction of metallothionein-II (MT-II) protein is an endogenous mechanism after I/R. Our aim was to evaluate the neuroprotective effect of MT-II after I/R in rats. Male Wistar rats were transiently occluded at the middle cerebral artery for 2 h, followed by reperfusion. Rats received either MT (10 μg per rat i.p.) or vehicle after ischemia. Lipid peroxidation (LP) was measured 22 h after reperfusion in frontal cortex and hippocampus; also, neurological deficit was evaluated after ischemia, using the Longa scoring scale. Infarction area was analyzed 72 hours after ischemia. Results showed increased LP in frontal cortex (30.7%) and hippocampus (26.4%), as compared to control group; this effect was fully reversed by MT treatment. Likewise, we also observed a diminished neurological deficit assessed by the Longa scale in those animals treated with MT compared to control group values. The MT-treated group showed a significant (P < 0.05) reduction of 39.9% in the infarction area, only at the level of hippocampus, as compared to control group. Results suggest that MT-II may be a novel neuroprotective treatment to prevent ischemia injury.

Topics: Animals; Frontal Lobe; Hippocampus; Ischemic Attack, Transient; Lipid Peroxidation; Male; Metallothionein; Rabbits; Rats; Rats, Wistar; Recovery of Function; Reperfusion Injury

The aim of the present study was to investigate whether metallothionein was involved in the protection of lung ischemic preconditioning (IP) against lung ischemia-reperfusion (I/R) injury. Adult male Sprague-Dawley rats were randomly divided into 3 groups based upon the intervention (n=8): control group (C), lung I/R group (I/R), lung I/R+IP group (IP). At the end of the experiment, the content of metallothionein was tested in lung tissue. Blood specimens collected from the arteria carotis were tested for the contents of malondialdehyde (MDA), the activities of superoxide dismutase (SOD) and myeloperoxidase (MPO). The pneumocyte apoptosis index (AI) was determined by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL). Ultrastructural changes of lung tissue were observed by using transmission electron microscope. The results showed that in I/R group, the content of metallothionein was decreased (P<0.05), the content of MDA and MPO activity were increased (P<0.01), and SOD activity was decreased (P<0.01), compared with those in control group. IP treatment significantly increased the content of metallothionein (P<0.01), attenuated the MDA level (P<0.05) and MPO activity (P<0.01), and improved SOD activity (P<0.01) in blood serum. The number of TUNEL-positive cells in IP group was significantly reduced compared with that in I/R group (P<0.01). There were abnormal ultrastructural changes in I/R group, which were markedly reversed in IP group. In conclusion, IP may protect lung against I/R injury by inducing the expression of metallothionein.

Topics: Animals; Ischemic Preconditioning; Lung; Male; Metallothionein; Random Allocation; Rats; Rats, Sprague-Dawley; Reperfusion Injury

Acute systemic hypoxia induces delayed cardioprotection against ischaemia-reperfusion injury in the heart. As cobalt chloride (CoCl₂) is known to elicit hypoxia-like responses, it was hypothesized that this chemical would mimic the preconditioning effect and facilitate acclimatization to hypobaric hypoxia in rat heart.. Male Sprague-Dawley rats treated with distilled water or cobalt chloride (12.5 mg Co/kg for 7 days) were exposed to simulated altitude at 7622 m for different time periods (1, 2, 3 and 5 days).. Hypoxic preconditioning with cobalt appreciably attenuated hypobaric hypoxia-induced oxidative damage as observed by a decrease in free radical (reactive oxygen species) generation, oxidation of lipids and proteins. Interestingly, the observed effect was due to increased expression of the antioxidant proteins hemeoxygenase and metallothionein, as no significant change was observed in antioxidant enzyme activity. Hypoxic preconditioning with cobalt increased hypoxia-inducible factor 1α (HIF-1α) expression as well as HIF-1 DNA binding activity, which further resulted in increased expression of HIF-1 regulated genes such as erythropoietin, vascular endothelial growth factor and glucose transporter. A significant decrease was observed in lactate dehydrogenase activity and lactate levels in the heart of preconditioned animals compared with non-preconditioned animals exposed to hypoxia.. The results showed that hypoxic preconditioning with cobalt induces acclimatization by up-regulation of hemeoxygenase 1 and metallothionein 1 via HIF-1 stabilization.

Topics: Acclimatization; Animals; Cardiotonic Agents; Cobalt; DNA-Binding Proteins; Erythropoietin; Heart; Heme Oxygenase-1; Hypoxia; Hypoxia-Inducible Factor 1, alpha Subunit; Male; Metallothionein; Myocardium; Oxidative Stress; Rats; Rats, Sprague-Dawley; Reactive Oxygen Species; Reperfusion Injury; Up-Regulation; Vascular Endothelial Growth Factor A

Topics: Animals; Brain Ischemia; Male; Metallothionein; Metallothionein 3; Nerve Tissue Proteins; Neurons; Rats; Rats, Wistar; Reperfusion Injury; RNA, Messenger

To investigate the effect of liposome-carried metallothionein (lipo-MT) on secondary ischemia-reperfusion injury in the rat island flap.. An abdominal island flap was created in the Wistar rat. The animals were divided into four groups: the sham group, the secondary ischemia-reperfusion group, the group treated with blank liposome and the group treated with lipo-MT. The malondialdehyde (MDA) content, the myeloperoxidase (MPO) activity was assayed immediately, at 30 minutes and 7 days after the secondary venous ischemia-reperfusion. The level of endothelin (ET) and lactic dehydrogenase (LDH) of the rat plasma was measured at 30 minutes after secondary venous ischemia-reperfusion. The content of MT of the flap was assayed by Cd-hemoglobin saturation method at 7 days after the operation.. The treatment of lipo-MT significantly decreased the content of MDA, MPO of the flap, decreased the activity of ET, LDH of the rat palsma, increased the content of MT of the flap and improved the flap viability.. Lipo-MT can improve flap survival by reducing ischemia-reperfusion injury.

Topics: Animals; Endothelins; Graft Survival; Ischemia; Lactate Dehydrogenases; Liposomes; Malondialdehyde; Metallothionein; Peroxidase; Rats; Rats, Wistar; Reperfusion Injury; Surgical Flaps; Time Factors

To study the possibility of metallothionein (MT) participating in the process of ischemia/reperfusion protection.. The model of pig latissimus dorsi island flap and cultured myocytes were used in this study. The island flap was preconditioned with ischemia and the cultured myocytes were treated with anoxia. MT was detected in the flap and the cultured myocytes instantly and at 12 and 24 hours after the treatment. The protection effect of precondition on flap ischemia/reperfusion damage was observed by recording flap necrosis and the serum LDH level. The protection effect of precondition on myocyte anoxia/reoxygenation damage was observed by recording the cell survival rate and MDA content. The change in the protection effect was also observed after the MT was inhibited by PD098059.. The content of MT in cultured myocytes increased obviously 12 hours after precondition. Similar result was observed in flap tissue 24 hours later. Compared with the non-conditioned flap, the necrosis areas of the preconditioned flaps were smaller, the serum LDH was lower. The survival rate of preconditioned cultured myocytes was higher compared with non-conditioned cells (P < 0.05). The content of MDA and the quantity of discharged LDH were less (P < 0.05). When MT was inhibited by PD098059, the delaying protection of precondition disappeared. The observed quotas at that time were the same with those of simple I/R or A/R groups (P > 0.05).. 24 hours after precondition, the flap and the cultured myocytes are protected from re-damage of I/R or A/R. MT is involved in this process.

Topics: Animals; Cell Hypoxia; Cell Survival; Cells, Cultured; Enzyme Inhibitors; Flavonoids; Ischemic Preconditioning; L-Lactate Dehydrogenase; Malondialdehyde; Metallothionein; Muscles; Necrosis; Reperfusion Injury; Surgical Flaps; Swine; Time Factors

Zinc may have an antioxidant effect mediated by induction of metallothionein. Based on the assumption that metallothionein can scavenge oxygen free radicals, we examined whether zinc administration prior to renal ischemia would improve renal dysfunction caused by ischemia-reperfusion injury in rats. Wistar rats weighing 265 g were treated with an intraperitoneal injection of 20 mg/kg zinc 24 h prior to the renal ischemia-reperfusion procedure, which was achieved by a 30-min clamping of the bilateral renal vessels and subsequent 90-min reperfusion. Thirty-minute renal clearance tests were performed before and after renal ischemia in zinc- (n = 11) and saline-treated (n = 8) rats. Thiobarbituric acid reactive substance, conjugated diene, and metallothionein levels in the renal tissues were also determined. Sham-operated rats (n = 5 in each treatment) served as control for the ischemia-reperfusion rats. Ischemia-reperfusion resulted in significantly lower glomerular filtration rate values and marked increases in tissue concentrations of thiobarbituric acid reactive substance and conjugated diene compared with sham-operation. Zinc administration improved the reduced glomerular filtration rate values seen after the ischemia-reperfusion procedure, but not to the extent of pre-ischemic levels. Zinc pretreatment significantly reduced the increased levels of thiobarbituric acid reactive substance and conjugated diene during ischemia-reperfusion and increased metallothionein levels compared with saline injection. These findings suggest that zinc has an antioxidant effect mediated through the induction of metallothionein, but appears only to have a minor protective effect on renal function induced by renal ischemia-reperfusion injury.

Topics: Acute Kidney Injury; Animals; Antioxidants; Disease Models, Animal; Glomerular Filtration Rate; Kidney; Lipid Peroxidation; Male; Metallothionein; Rats; Rats, Wistar; Reactive Oxygen Species; Renal Circulation; Reperfusion Injury; Thiobarbiturates; Treatment Outcome; Zinc

The aim of this study was to determine the lung levels of metallothionein (MT), a free radical scavenger, because oxygen-derivated free radicals (ODFRs) have been involved both in reperfusion injury of transplanted lungs and in cardiac or renal allograft destruction. First, MT localization was evaluated in 14 normal human lung biopsy specimens. Then, in lung transplant recipients, MT content in BAL fluid (BALF) and its transcription rate in alveolar macrophages (AMs) were determined. The BALFs of 69 patients were separated into six groups: lung transplant recipients in clinically stable condition (CSR), those with acute rejection (AR), asymptomatic cytomegalovirus infection (ACMV), cytomegalovirus pneumonitis (CMVP), bronchiolitis obliterans syndrome (BOS), and patients without transplants who served as control subjects (NTCs). In normal lungs, 83% of AMs were positively stained. MT staining was also observed in pleural endothelial cells and basal cells from bronchial epithelium. In lung transplant recipients, MT levels in BALF were significantly higher in patients with CSR, AR, ACMV, and CMVP compared with NTCs, while during BOS, MT had a significantly lower level compared with other lung transplant groups. However, no difference among groups was found concerning MT-II messenger RNA expression in AMs, showing that, as in normal lung, AMs are not the only cells that produce MT. These data report for the first time to our knowledge MT cell distribution in human lung with specific emphasis on its enhanced levels after lung transplantation, even in the absence of complication. Possible correlation among MT levels, ODFRs, cytokine levels, and corticosteroid treatment during complications of lung transplantation are discussed.

Topics: Acute Disease; Adrenal Cortex Hormones; Adult; Aged; Bronchiolitis Obliterans; Bronchoalveolar Lavage Fluid; Coloring Agents; Cytomegalovirus Infections; Endothelium, Vascular; Epithelium; Female; Free Radical Scavengers; Free Radicals; Gene Expression Regulation; Graft Rejection; Graft Survival; Humans; Interleukin-6; Lung; Lung Transplantation; Macrophages, Alveolar; Male; Metallothionein; Middle Aged; Pleura; Pneumonia, Viral; Reactive Oxygen Species; Reperfusion Injury; RNA, Messenger; Transcription, Genetic; Tumor Necrosis Factor-alpha