Lung Superoxide Dismutase Research Articles

The effect of vitamin C and cobalt supplementation on antioxidant status in healthy and diabetic rats

In the present study, liver, lung, heart and kidney superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), catalase (CAT) activities, lipid peroxidation, nitrite and vitamin C levels were investigated in diabetic rats. Diabetes induced in rats by streptozotocin (STZ) and the treated rats were received 1 g/l vitamin C with 0.5 mM CoCl2 in drinking water for eigth weeks. In all tissues, superoxide dismutase, glutathione peroxidase, catalase activities, lipid peroxidation and nitrite levels were significantly increased in diabetic rats at the end of 8th week (p < 0.05) whereas vitamin C level was decreased compared to those of controls. Cobalt with vitamin C treatment of diabetic rats resulted in partial restoration of SOD and CAT activities, thiobarbituric acid reactant substances (TBARS), vitamin C and nitrite levels at all times studied, whereas treatment did not significantly change GSH-Px activity compared to diabetics. These results suggest that cobalt with vitamin C, effectively but could not completely restore the altered endogenous defense systems in diabetic rat liver, lung, heart and kidney tissues. Key words: Cobalt, antioxidant enzymes, diabetes, lipid peroxidation, tissue.

Chinese green tea ameliorates lung injury in cigarette smoke-exposed rats

Epigallocatechin-3-gallate (EGCG), which has been shown to have potent antioxidant effect, comprises 80% of catechins in Chinese green tea. This study was to investigate whether cigarette smoke (CS) exposure would induce lung morphological changes and oxidative stress in the CS-exposed rat model, and whether Chinese green tea (Lung Chen tea with EGCG as its main active ingredient) consumption would alter oxidative stress in sera and lung leading to protection of CS-induced lung damage. Sprague-Dawley rats were randomly divided into four groups, i.e. sham air (SA), 4% CS, 2% Lung Chen tea plus SA or 4% CS. Exposure to SA or 4% CS was performed for 1h/day for 56 days in ventilated smoking chambers. Sera and lung tissues were collected 24h after last CS exposure for histology and all biochemical assays. Airspace enlargement and goblet cell hyperplasia were observed after 56-day CS exposure alone, which were abolished in the presence of green tea consumption. Serum 8-isoprostane level was significantly elevated (p<0.01) as well as lung superoxide dismutase (SOD) and catalase activities in CS-exposed rats compared to SA-exposed rats (p<0.05), which returned to the levels of SA-exposed rats after Chinese green tea consumption. These results indicate that increased levels of systemic oxidative stress after CS exposure play an important role in the induction of lung damage. Chinese green tea may have the ability to suppress CS-induced oxidative stress that leads to protection of lung injury.

Melatonin and 1400 W Ameliorate both Intestinal and Remote Organ Injury Following Mesenteric Ischemia/Reperfusion

Acute intestinal ischemia reperfusion (I/R) injury affects not only the intestines but also remote organs due to pro-inflammatory and tissue injurious factors. Thus, we aimed to investigate the roles of melatonin (a powerful antioxidant) and 1400W (a strong inhibitor of inducible nitric oxide) in a rat intestinal I/R injury model, since oxidative and nitrosative injury are believed to be the major causes. A total of 56 Wistar albino rats were used, with seven rats in each group. After I/R induction in the intestines by clamping/unclamping the superior mesenteric artery, we measured malondialdehyde, superoxide dismutase, glutathione peroxidase, nitric oxide, and 3-nitrotyrosine levels in lung, kidney, and liver tissues (to evaluate remote organ injury) as well as in the intestines. Study groups received melatonin, 1400W or both to examine the roles of these molecules in the pathogenesis of injury following I/R. Melatonin and 1400W had an ameliorating effect on both oxidative and nitrosative stress in the intestine and the lung against mesenteric I/R injury in rats. Moreover, each of these two agents had an inhibitory effect on oxidative injury and histopathological changes in the intestine and the lung. Furthermore, the combination of both agents (melatonin and 1400W) was more effective than either of the agents alone (P < 0.05). Melatonin and 1400W, either alone or in combination, were efficient in ameliorating experimental I/R injury of the intestines.

Does leflunomide attenuate the sepsis-induced acute lung injury?

The organ that is affected first and most severely in intraabdominal sepsis is the lung. Oxygen radicals and active neutrophils in the lung are important sources for severe pulmonary inflammation leading to acute lung injury (ALI)/acute respiratory distress syndrome. The aim of this study was to investigate the effects of leflunomide, an immunomodulatory agent, on oxidant/antioxidant status with nitric oxide (NO) level and myeloperoxidase (MPO) activity in rats with sepsis-induced ALI. Fifty male Wistar albino rats were divided into five groups: control, sham, sepsis, leflunomide (10 mg/kg, intragastrically for two doses with an 8 h interval prior to the experiment) and sepsis + leflunomide. After the animals were anesthetized with ketamine and xylazine, the abdominal cavity was opened and ligated just below the ileocaecal valve with 3-0 silk. The antimesentric surface of the cecum was perforated and the cecum was gently compressed until fecal matter was extruded to induce sepsis. None of the rats received antibiotics during the experimental procedures. The experiment was ended 24 h after cecal ligation puncture (CLP) with the cervical dislocation under anesthesia. The lung tissues were removed for analysis of biochemical parameters and light microscopic investigation. The lung superoxide dismutase (SOD), catalase and glutathione peroxidase activities were decreased in the sepsis group as compared to the group control, sham, leflunomide and sepsis + leflunomide (P < 0.05), and SOD activity were significantly higher in group sepsis + leflunomide than sham, control, leflunomide and sepsis group (P < 0.05). The lung MPO, malondialdehyde (MDA), protein carbonyl and NO levels were higher in the sepsis group when compared to group control, sham, leflunomide and sepsis + leflunomide (P < 0.05), and MPO, MDA and NO levels were higher in the sepsis + leflunomide group than in the sham, control and leflunomide group (P < 0.05). The light microscopic evaluation showed that pulmonary architecture was preserved, and infiltration of neutrophil and edema decreased in sepsis + leflunomide group. The grade of alveolar damage was significantly decreased in sepsis + leflunomide group in comparison with sepsis group (P < 0.05). Our findings suggested that leflunomide attenuated the lung injury after CLP-induced sepsis by inhibition of neutrophils accumulation and increasing endogenous antioxidant capacity.

Prevalidation of in vitro continuous flow exposure systems as alternatives to in vivo inhalation safety evaluation experimentations: Outcome from MAAPHRI-PCRD5 research program

Diesel engine emission aerosol-induced toxicity patterns were compared using both in vitro (organotypic cultures of lung tissue) and in vivo experimentations mimicking the inhalation situation with continuous aerosol flow exposure designs. Using liquid media resuspended diesel particles, we show that toxic response pattern is influenced by the presence of tensioactive agent in the medium which alter particle-borne pollutant bioavailability. Using continuous aerosol exposure in vitro, we show that with high sulfur fuel (300 ppm) in the absence of oxidation catalysis, particulate matter was the main toxic component triggering DNA damage and systemic inflammation, while a very limited oxidant stress was evidenced. In contrast, with ultra-low sulfur fuel in the presence of strong diesel oxidation catalysis, the specific role of particulate matter is no longer evidenced and the gas phase then becomes the major component triggering strong oxidant stress, increased NO 2 being the most probable trigger. In vivo, plasma tumor necrosis factor alpha (TNFalpha), lung superoxide dismutase (SOD), catalase and glutathione peroxidase (GPx) activity levels varied in agreement with in vitro observations. Diesel emission treatment with oxycat provokes a marked systemic oxidant stress. Again NO 2 proved to account for a major part of these impacts. In conclusion, similar anti-oxidant responses were observed in in vitro and in vivo experiments after diesel emission aerosol continuous flow exposures. The lung slice organotypic culture model-exposed complex aerosol appears to be a very valuable alternative to in vivo inhalation toxicology experimentations in rodents.

Superoxide dismutase protects against apoptosis and alveolar enlargement induced by ceramide

The molecular events leading to emphysema development include generation of oxidative stress and alveolar cell apoptosis. Oxidative stress upregulates ceramides, proapoptotic signaling sphingolipids that trigger further oxidative stress and alveolar space enlargement, as shown in an experimental model of emphysema due to VEGF blockade. As alveolar cell apoptosis and oxidative stress mutually interact to mediate alveolar destruction, we hypothesized that the oxidative stress generated by ceramide is required for its pathogenic effect on lung alveoli. To model the direct lung effects of ceramide, mice received ceramide intratracheally (Cer(12:0) or Cer(8:0); 1 mg/kg) or vehicle. Apoptosis was inhibited with a general caspase inhibitor. Ceramide augmentation shown to mimic levels found in human emphysema lungs increased oxidative stress, and decreased, independently of caspase activation, the lung superoxide dismutase activity at 48 h. In contrast to their wild-type littermates, transgenic mice overexpressing human Cu/Zn SOD were significantly protected from ceramide-induced superoxide production, apoptosis, and air space enlargement. Activation of lung acid sphingomyelinase in response to ceramide treatment was abolished in the Cu/Zn SOD transgenic mice. Since cigarette smoke-induced emphysema in mice is similarly ameliorated by the Cu/Zn SOD overexpression, we hypothesized that cigarette smoke may induce ceramides in the mouse lung. Utilizing tandem mass spectrometry, we documented increased lung ceramides in adult mice exposed to cigarette smoke for 4 wk. In conclusion, ceramide-induced superoxide accumulation in the lung may be a critical step in ceramide's proapoptotic effect in the lung. This work implicates excessive lung ceramides as amplifiers of lung injury through redox-dependent mechanisms.

A Role for the Receptor for Advanced Glycation End Products in Idiopathic Pulmonary Fibrosis

Idiopathic pulmonary fibrosis (IPF) is a severely debilitating disease associated with a dismal prognosis. There are currently no effective therapies for IPF, thus the identification of novel therapeutic targets is greatly needed. The receptor for advanced glycation end products (RAGE) is a member of the immunoglobulin superfamily of cell surface receptors whose activation has been linked to various pathologies. In healthy adult animals, RAGE is expressed at the highest levels in the lung compared to other tissues. To investigate the hypothesis that RAGE is involved in IPF pathogenesis, we have examined its expression in two mouse models of pulmonary fibrosis and in human tissue from IPF patients. In each instance we observed a depletion of membrane RAGE and its soluble (decoy) isoform, sRAGE, in fibrotic lungs. In contrast to other diseases in which RAGE signaling promotes pathology, immunohistochemical and hydroxyproline quantification studies on aged RAGE-null mice indicate that these mice spontaneously develop pulmonary fibrosis-like alterations. Furthermore, when subjected to a model of pulmonary fibrosis, RAGE-null mice developed more severe fibrosis, as measured by hydroxyproline assay and histological scoring, than wild-type controls. Combined with data from other studies on mouse models of pulmonary fibrosis and human IPF tissues indicate that loss of RAGE contributes to IPF pathogenesis.

Protective Effects of Erdosteine and Vitamins C and E Combination on Ischemia–Reperfusion-Induced Lung Oxidative Stress and Plasma Copper and Zinc Levels in a Rat Hind Limb Model

The aim of this study was to investigate the protective effects of erdosteine and vitamins C and E (VCE) on the lungs after performing hind limb ischemia-reperfusion (I/R) by assessing oxidative stress, plasma copper (Cu), and zinc (Zn) analysis. The animals were divided randomly into four groups as nine rats each as follows: control, I/R, I/R plus erdosteine, and I/R plus VCE combination. I/R period for 60 min was performed on the both hind limbs of all the rats in the groups of I/R, erdosteine with I/R, VCE with I/R allowing 120 min of reperfusion. The animals received orally erdosteine one time in a day and 3 days before I/R in the erdosteine group. In the VCE group, the animals VCE combination received one time in a day and 3 days before I/R, although placebo was given to control and I/R group animals. Lung lipid peroxidation (malondialdehyde [MDA]) level, superoxide dismutase (SOD), and catalase activities were increased, although lung glutathione (GSH) and plasma Zn levels decreased in I/R group in lung tissue compared with the control group. Serum MDA level, creatine kinase, and lactate dehydrogenase activities were increased in I/R group compared with the control. Lung MDA and plasma Zn levels and lung SOD activity were decreased by erdosteine administration, whereas lung GSH levels after I/R increased. The plasma Zn levels and lung SOD activity were decreased by VCE administration, although the plasma Cu and lung GSH levels increased after I/R. In conclusion, erdosteine has an antioxidant role on the values in the rat model, and it has more protective affect than in VCE in attenuating I/R-induced lung injury in rats.

Protective effects of the induction of heme oxygenase-1 on ischemia reperfusion lung injury: in vivo experiment with rats

To investigate the protective effects of the induction of heme oxygenase-1 (HO-1) on ischemia/reperfusion lung injury. Forty Sprague-Dawley rats were randomly divided into four equal groups: sham group, lung ischemia/reperfusion injury (I/R) group, undergoing ligaturing of the left lung hilum for 30 minutes followed by reperfusion for 120 minutes; hemin group, undergoing intraperitoneal injection of hemin, an inducer of HO-1, 48 hours before the ligation and reperfusion; zinc protoporphyrin (ZnPP) group, undergoing intravenous injection of ZnPP, an inhibitor of heme oxygenase, 15 min after the ischemia-reperfusion; and sham operation group, undergoing sham operation. Two hours after the I/R arterial blood samples were collected and then the left lungs of the rats were taken out. Plasma tumor necrosis factor-alpha (TNF-alpha) and lung superoxide dismutase (SOD) activity were examined. Lung wet-to-dry weight (W/D) ratio was measured. The ultrastructure of the pulmonary alveoli and its capillaries were studied by using transmissional electronmicroscopy. The lung W/D ratio of the hemin group was 5.92 +/- 0.66, significantly lower than that of the I/R group (7.55 +/- 0.66, P < 0.01), and that of the ZnPP group (7.34 +/- 0.39, P < 0.01). The SOD activity of the hemin group was 6.5 +/- 0.6 U/mg protein, significantly higher than those of the I/R group and ZnPP group (2.8 +/- 0.4 U/mg protein and 3.0 +/- 0.4 U/mg protein respectively, both P < 0.01). The plasma TNF-alpha was 180.36 +/- 12.46, significantly lower than those of the I/R and ZnPP groups (452.26 +/- 22.59 and 438.59 +/- 30.26 respectively, both P < 0.01). Transmissional electronmicroscopy showed that the microscopic structure of the sham group was normal and that the pathological changes of hemin group were milder then those of the T/R and ZnPP groups. The induction of heme oxygenase-1 can protect effectively the lesion of lung pathology in ischemia reperfusion in vivo.

Compositions and oxidative damage of condensate, particulate and semivolatile organic compounds from gasoline exhausts

The effects of extracts of condensate, particulate and semivolatile organic compounds from absolute gasoline exhausts on DNA single strand break, levels of malondialdehyde (MDA), carbonyl protein and activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx) were investigated in lungs and brains of adult Sprague-Dawley rats of both sexes. In addition, the non-conventional components of the extracts and concentrations of 13 polycyclic aromatic hydrocarbon (PAHs) in gasoline exhaust were measured by GS/MS. Extract of gasoline exhaust at different doses (5.6, 16.7 and 50.0 L/kg) were given to administered animals by intratracheal instillation once a week for 4 weeks, while blank control and solvent groups were given with physiological saline and dimethyl sulfoxide (DMSO). Our results showed that gasoline exhaust increased DNA single strand break, promoted lipid peroxidation and oxidative protein damage and decreased activities of SOD in lungs and brains. While, it decreased the activities of GPx in lungs but not in brains. The present data suggested that gasoline exhaust exposure could cause oxidative damage to lung and brain of rats. That was to say that gasoline is a toxin to brain of mammals, not only to lung.

Antioxidant effects of melatonin in rats during chronic exposure to hyperbaric oxygen

In addition to its beneficial effects, hyperbaric oxygen (HBO) exposure causes some detrimental effects via oxidative stress. Previous experimental studies showed that melatonin is a useful agent to block single session HBO-induced oxidative stress. In the present study, we investigated the antioxidant effect of exogenously administered as well as endogenously produced melatonin in lung and brain tissues of rats exposed to long term HBO. The HBO procedure was set as daily exposures to 2.5 ATA of oxygen for 1 hr and a total of 10 sessions. Twenty-eight male Sprague-Dawley rats were divided into four groups as follows: control, daytime HBO, daytime HBO plus melatonin (5 mg/kg), nighttime HBO. Tissue oxidative/antioxidant status was examined by determining the protein carbonyl content as a criteria for oxidative stress and the activities of the antioxidant enzymes, superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px). HBO exposure for 10 days caused significant increases in protein carbonyl content and SOD levels of lung and brain, but GSH-Px activities remained unaffected. The increases in protein carbonyls were blocked by exogenously administered melatonin and in part by nighttime exposure to darkness whereas the increase of SOD activity was only impeded by endogenously produced melatonin in brain tissue. Lung SOD activity was augmented by endogenous melatonin. In conclusion, melatonin blocks long-term HBO-induced cumulative oxidative stress as indicated changes in protein carbonyls. Both exogenously injected and physiologically secreted melatonin has this potential. The effects of HBO-exposure and melatonin on the activities of the antioxidative enzymes are less clear.

Tinospora cordifolia induces enzymes of carcinogen/drug metabolism and antioxidant system, and inhibits lipid peroxidation in mice

The present study is an effort to identify a potent chemopreventive agent against various diseases (including cancer) in which oxidative stress plays an important causative role. Here, we investigated the effect of a hydroalcoholic (80% ethanol: 20% distilled water) extract of aerial roots of Tinospora cordifolia (50 and 100mg/kg body wt./day for 2 weeks) on carcinogen/drug metabolizing phase-I and phase-II enzymes, antioxidant enzymes, glutathione (GSH) content, lactate dehydrogenase and lipid peroxidation in liver of 8-week-old Swiss albino mice. The modulatory effect of the extract was also examined on extrahepatic organs, i.e., lung, kidney and forestomach, for the activities of GSH S-transferase (GST), DT-diaphorase (DTD), superoxide dismutase (SOD) and catalase. Significant increases in the levels of acid-soluble sulfhydryl (-SH) and cytochrome P(450) contents, and enzyme activities of cytochrome P(450) reductase, cytochrome b(5) reductase, GST, DTD, SOD, catalase, GSH peroxidase (GPX) and GSH reductase (GR) were observed in the liver. Both treated groups showed decreased malondialdehyde (MDA) formation. In lung SOD, catalase and GST; in kidney SOD and catalase; and in forestomach SOD, DTD and GST showed significant increase at both dose levels of treatment. BHA (0.75%, w/w in diet), a pure antioxidant compound, was used as a positive control. This group showed increase in hepatic levels of GSH content, cytochrome b(5), DTD, GST, GR and catalase, whereas MDA formation was inhibited significantly. In the BHA-treated group, the lung and kidney showed increased levels of catalase, DTD and GST, whereas SOD was significantly increased in the kidney and forestomach; the latter also showed an increase in the activities of DTD and GST. The enhanced GSH level and enzyme activities involved in xenobiotic metabolism and maintaining antioxidant status of cells are suggestive of a chemopreventive efficacy of T. cordifolia against chemotoxicity, including carcinogenicity, which warrants further investigation of active principle (s) present in the extract responsible for the observed effects employing various carcinogenesis models.

Effect of Wen-Pi-Tang extract on lung damage by influenza virus infection

The effect of Wen-Pi-Tang extract on influenza virus infection in mice was investigated. The administration of Wen-Pi-Tang extract at a dose of 100mg/kg body wt. for 8 consecutive days to influenza virus-infected mice reversed the lack of body wt. gain and prevented the increase in lung weight caused by the infection in comparison with uninfected mice, while allopurinol, a xanthine oxidase (XOD) inhibitor, did not show these effects. The serum levels of uric acid and allantoin in influenza virus-infected mice were reduced by Wen-Pi-Tang extract administration. Moreover, Wen-Pi-Tang extract reduced the uric acid level more as the dose increased, although it exerted lower activity than allopurinol. The XOD activity of the lungs was elevated by influenza virus infection, but Wen-Pi-Tang extract administration inhibited this activity, indicating prevention of lung damage by oxygen free radicals generated by XOD. After the administration of Wen-Pi-Tang extract to influenza virus-infected mice, the lung superoxide dismutase activity was not significantly different from that of uninfected mice, whereas lung catalase activity was lower in the former than the latter, but slightly higher than that of influenza virus-infected mice, suggesting that Wen-Pi-Tang extract may prevent the generation of highly toxic hydroxyl radicals in the lung. In addition, the administration of both Wen-Pi-Tang extract and allopurinol reduced the degree of lung consolidation caused by influenza virus infection. In particular, Wen-Pi-Tang extract reduced the consolidation score in a dose-dependent manner and more markedly than allopurinol did. This study suggests that Wen-Pi-Tang extract could improve pathological conditions of the lungs induced by influenza virus infection.

The effect of one year swimming exercise on oxidant stress and antioxidant capacity in aged rats.

The effect of exercise on oxidant stress and on alterations in antioxidant defense in elderly has been investigated extensively. However, the impact of regularly performed long-term physical activity starting from adulthood and prolonged up to the old age is not yet clear. We have investigated the changes in the activities of antioxidant enzymes - superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) - and lipid peroxidation in various tissues of rats which had performed (old-trained) or had not performed (old-control) regular swimming exercise for one year. These animals were compared with young-sedentary rats. Increased lipid peroxidation was observed with ageing in all tissues (heart, liver, kidney, striated muscle) and swimming had no additional effect on this elevation of lipid peroxidation. Heart and striated muscle SOD activites, and striated muscle CAT activity increased as a consequence of ageing, whereas kidney and liver CAT activities, as well as GPx activities in kidney, liver, lung and heart were significantly decreased compared to young controls. Lung and heart SOD, liver CAT activities as well as GPx activities in liver, lung and heart were increased significantly in rats which performed exercise during ageing, compared to the old-control group. These findings suggest that lifelong exercise can improve the antioxidant defense in many tissues without constituting any additional oxidant stress.

Exposure to Low Doses of Endosulfan and Chlorpyrifos Modifies Endogenous Antioxidants in Tissues of Rats

Two experiments were conducted in male SD rats (225–250 g) to determine changes in the activities of endogenous antioxidants superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPX) and concentrations of glutathione (GSH) in tissues after exposure to low doses of endosulfan and chlorpyrifos using a whole body exposure technique. In both experiments, 6 rats/group were exposed 3 hr/day, 5 days/week for 30 days to: 0 (control), 5, 10, 20, 40 and 60% of LD50 of either pesticide in 50% ethanol; actual concentrations were: endosulfan = 0, 0.5, 1.0, 2.0, 4.0, 6.0 mg/250 g body weight; chlorpyrifos = 0, 1.9, 3.8, 7.6, 15.2, and 22.8 mg/250 g body weight. Endosulfan decreased erythrocyte SOD by 21% in all groups and chlorpyrifos increased SOD by 18% in groups 40 and 60. Liver SOD was 12%–20% lower after endosulfan exposure; lung SOD was altered: endosulfan decreased activity by 21% and 51% and chlorpyrifos by 58 and 75% in the 40 and 60 groups, respectively (P ≤ 0.05). Both pesticides increased plasma GPX activity at lower levels and reduced it by 26% and 19% in groups 40 and 60, respectively (P ≤ 0.05). Liver GPX increased in the 60 group and lung GPX declined between 20% and 38% after endosulfan exposure. GSH in the liver and lung: endosulfan reduced GSH by about 30% at lower levels and increased by 41% or 70% at higher levels; chlorpyrifos decreased GSH by 28–40% in 20 and 60 groups, respectively (P ≤ 0.05). Exposure to low, increasing levels of endosulfan and chlorpyrifos can differentially modify endogenous antioxidants SOD, GPX and GSH, which may lead to the development of oxidative stress in some tissues.

Acute Lung Injury Does Not Impair Adenoviral-Mediated Gene Transfer to the Alveolar Epithelium

Studies1,2,3,4,5 have shown that overexpression of genes such as superoxide dismutase, catalase, Na,K-adenosine triphosphatase, and interleukin-10 in the distal lung can protect from acute injury. All of these prior studies transduced the lungs prior to the onset of injury. In order for gene transfer to be clinically useful for acute lung injury (ALI), it will be necessary to transduce the alveolar epithelium after the onset of injury. However, the pathobiology of ALI includes alveoli filled with fluid, fibrin, inflammatory cells, and cytokines, all of which can impair alveolar gene transfer.

Antioxidant Defense System in Cobalt Treated Diabetic Rat Lung

ABSTRACTTo study the effect of cobalt intake on catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) activities and the levels of lipid peroxidation by measuring thiobarbituric acid reactive substance (TBARS), streptozotocin (STZ)-induced diabetic rats were treated with cobalt chloride (CoC12)(0.5 mM in the drinking water) for up to 44 days. Diabetes was associated with a significant increase in the activity of CAT, SOD, GSH-Px and TBARS in lung. Cobalt therapy effectively normalized the increased activities of CAT, SOD and TBARS levels but could not restore GSH-Px in the lung. The ensemble of results suggests that, the cobalt dose which was used in this study can be considered as the regulation of oxidative and antioxidative systems.

Altered expression of extracellular superoxide dismutase in mouse lung after bleomycin treatment

The antioxidant enzyme extracellular superoxide dismutase (EC-SOD) is highly expressed in the extracellular matrix of lung tissue and is believed to protect the lung from oxidative damage that results in diseases such as pulmonary fibrosis. This study tests the hypothesis that proteolytic removal of the heparin-binding domain of EC-SOD results in clearance of the enzyme from the extracellular matrix of pulmonary tissues and leads to a loss of antioxidant protection. Using a polyclonal antibody to mouse EC-SOD, the immunodistribution of EC-SOD in normal and bleomycin-injured lungs was examined. EC-SOD labeling was strong in the matrix of vessels, airways, and alveolar surfaces and septa in control lungs. At 2 d post-treatment, a slight increase in EC-SOD staining was evident. In contrast, lungs examined 4 or 7 d post-treatment, showed an apparent loss of EC-SOD from the matrix and surface of alveolar septa. Notably, at 7 d post-treatment, the truncated form of EC-SOD was found in the bronchoalveolar lavage fluid of bleomycin-treated mice, suggesting that EC-SOD is being removed from the extracellular matrix through proteolysis. However, loss of EC-SOD through proteolysis did not correlate with a decrease in overall pulmonary EC-SOD activity. The negligible effect on EC-SOD activity may reflect the large influx of intensely staining inflammatory cells at day 7. These results indicate that injuries leading to pulmonary fibrosis have a significant effect on EC-SOD distribution due to proteolytic removal of the heparin-binding domain and may be important in enhancing pulmonary injuries by altering the oxidant/antioxidant balance in alveolar interstitial spaces.

Effects of carbon dioxide pneumoperitoneum on free radical formation in lung and liver tissues.

The purpose of this study was to investigate the possible effects of carbon dioxide (CO2) pneumoperitoneum on free radical formation and lipid peroxidation in the lung and liver tissues of rats. For this study, 50 male Sprague-Dawley rats were divided into five equal groups: control (group 1); sham operation (group 2); 5, 10, or 15 mmHg (group 3, 4, or 5) pneumoperitoneum with CO2 groups. At the end of the procedures, the rats were killed, and perfusion was performed via vena jugularis with cold Ringer's lactate. After the perfusion procedure, the lung and liver were harvested, and the supernatant fractions of the lungs and livers were assayed for superoxide dismutase (SOD), catalase (CAT), and malondialdehyde (MDA). Both the lung and liver CAT activities were elevated consistently and significantly in the order of the study groups, as compared with the previous groups (p < 0.01 for all comparisons). The lung and liver SOD levels were elevated in groups 4 and 5, as compared with the other groups (p < 0.05). The lung MDA was significantly higher in groups 3 and 4, but not in group 5. Significant elevation in liver MDA was noted only in the 5-mmHg pnemoperitoneum group (p < 0.05). These results indicate that CO2 pneumoperitoneum applied with 5, 10, or 15 mmHg pressure increases the formation of free oxygen radicals, which is counterbalanced by increased SOD and CAT activities of the lung and liver tissues. This effect of CO2 pneumoperitoneum on free radicals and lipid peroxidation appears to be pressure dependent in rats. The mechanism underlying this pressure dependency is still under investigation.

Overexpression of manganese superoxide dismutase (MnSOD) in whole lung or alveolar type II cells of MnSOD transgenic mice does not provide intrinsic lung irradiation protection.

Intratracheal (IT) injection of the transgene for human manganese superoxide dismutase in plasmid/liposome (SOD2-PL) complex prior to irradiation protects C57BL/6J mice from whole lung irradiation-induced organizing alveolitis/fibrosis. Transgene mRNA was detected in alveolar type II (AT-II) and tracheobronchial tree cells explanted to culture 48 hours after gene therapy. To determine whether constitutive overexpression of murine MnSOD (Sod2) in whole lung or surfactant promoter-restricted AT-II cells (SP1)-SOD2 mice would provide intrinsic radioresistance, transgenic mice of two strains were compared with age-matched controls. Other groups of surfactant promoter-restricted (SP1)-SOD2 transgenic mice or control FeVB/NHsd mice received IT SOD2-PL gene therapy prior to irradiation. There was no significant intrinsic lung protection in either strain of MnSOD transgenic mice. The SP1-SOD2 transgenic mice were protected from lung damage by IT injection of the human SOD2-PL complex 24 hours prior to irradiation. Thus, overexpression of either human SOD2 or murine Sod2 in the lungs of transgenic mice does not provide intrinsic lung irradiation protection. The overexpression of SOD2 in the SP1-SOD2 mice may have made the mice more sensitive to irradiation.