GSH In Lung Tissue Research Articles

Voluntary wheel-running improved pulmonary fibrosis by reducing epithelial mesenchymal transformation

AimsPulmonary fibrosis seriously affects the health and life quality of patients. Exercise has been shown to have anti-inflammatory and antioxidant effects, but its effect on pulmonary fibrosis is unclear. In this study, the effect and mechanism of exercise on pulmonary fibrosis induced by paraquat were detected. Main methodsThree data sets were retrieved from GEO data. The biological significance of DEGs generation was determined by GO, KEGG, GSEA, and PPI. Thirty male BALB/C mice were randomly divided into control group, model group and exercise group. H&E staining, Masson staining, Immunohistochemistry and Western blot were used to explore the results. The levels of SOD, CAT, MDA, and GSH in lung tissue were analyzed with detection kits. The levels of inflammatory factors in serum and BALF were measured by ELISA. Key findingsCompared with the control group, the infiltration of inflammatory cells and fibrotic lesions were increased in the model group. Compared with the model group, voluntary wheel-running reducing the EMT of alveolar epithelial cells, the activation of the Wnt/β-catenin signaling pathway and the level of oxidative distress. Moreover, compared to model group, the serum IL-4, IL-10 and IFN-γ were increased, while the serum CXCL1 were decreased, while the levels of CXCL1, IL-6, IL-10, TNF-α and IFN-γ in the bronchoalveolar lavage fluid were decreased in exercise group. SignificanceVoluntary wheel-running reduced inflammatory infiltration and upregulated the expression of antioxidative distress proteins, further to improve the degree of EMT, and ultimately alleviated paraquat induced pulmonary fibrosis.

Combining Oxidative Stress Markers and Expression of Surfactant Protein A in Lungs in the Diagnosis of Seawater Drowning.

The diagnosis of seawater drowning (SWD) remains one of the most complex and contentious. It is one of the leading causes of unintentional death around the world. In most cases, the forensic pathologist must reach an accurate diagnosis from the autopsy findings and a series of complementary tests such as histopathological, biological, and chemical studies. Despite the lung being the most affected organ in death by submersion, there are few studies on this type of death's impact on this organ. The aim was to investigate human lung cadavers of forensic cases due to different causes of death, the concentration of the oxidative stress markers malondialdehyde (MDA) and γ-glutamyl-l-cysteinyl glycine (GSH), and the relationship with the expression of surfactant protein A (SP-A) to try to discriminate SWD from other types of causes of death. A total of 93 forensic autopsy cases were analyzed. Deaths were classified into three major groups based on the scene, cause of death, and autopsy findings (external foam, frothy fluid in airways, overlapping medial edges of the lungs): (a) drowning in seawater (n = 35), (b) other asphyxia (n = 33), such as hangings (n = 23), suffocations (n = 6), and strangulation (n = 4), and (c) other causes (n = 25), such as multiple suffocations. Oxidative stress markers (MDA and GSH) and the immunohistochemical expression of SP-A were determined in both lungs. MDA levels were statistically higher in both lungs in cases of SWD than in other causes of death (p = 0.023). Similarly, significantly higher levels of GSH were observed in SWD compared to the rest of the deaths (p = 0.002), which was more significant in the right lung. Higher immunohistochemical expression of SP-A was obtained in the cases of SWD than in the other causes of death, with higher levels in both lungs. The correlation analysis between the levels of oxidative stress (MDA and GSH) in the lung tissue and the expression level of SP-A showed positive and significant results in SWD, both in the alveolar membrane and the alveolar space. Determining the levels of MDA and GSH in lung tissue and the expression level of SP-A can be of great importance in diagnosing SWD and the circumstances of death. A better understanding of the physiology of submersion is essential for its possible repercussions in adopting measures in the approach to patients who have survived a submersion process. It is also necessary for forensic pathology to correctly interpret the events that lead to submersion.

Vinpocetine's immunomodulating, anti-oxidant, anti-inflammatory, ant-ifibrotic, and PDE inhibiting potencies ameliorate bleomycin-induced pulmonary fibrosis.

Pulmonary fibrosis (PF) is a global health problem with a high economic burden. Intratracheal administration of bleomycin is the best model that resembles the pathogenesis of PF in humans. Recently, vinpocetine proved to have neuroprotective, cardioprotective, hepatoprotective, anti-aging, and antifibrotic effects through its anti-oxidant, immunomodulating, and anti-inflammatory activities. The present study investigated the antifibrotic potentiality of vinpocetine in a rat model of PF induced by intratracheal bleomycin administration. PF induced by a single intratracheal instillation of 5 mg/kg bleomycin in nine-week-old Wister rats. Oral vinpocetine was used at doses of 5, 10, or 20 mg/kg to treat PF for 21 days immediately after the bleomycin instillation. Vinpocetine dose-dependently ameliorates PF induced by bleomycin administration since vinpocetine effectively restored the normal body weight gain rates, pulmonary architecture, and collagen fiber distribution and suppressed the elevated BALF cell count, lymphocytes and neutrophils percentage, BALF, IL-6, TNF-α, and TGF-β1 levels and LDH activity, lung tissue MDA level, PDE activity, hydroxyproline content, immunohistochemical expression of α-SMA and CD68 positive macrophage, and fibrosis score. Meanwhile, it efficiently augmented the reduced BALF macrophage percentage, IL-10 level, lung tissue GSH level, CAT, and SOD activities. Vinpocetine may propose a new promising agent to manage PF.

Ginsenoside Rg3 Alleviates Rotenone-induced Lung Injury in Mice by Its Anti-oxidative Properties

Objectives: Acute lung injury is commonly found in patients with insecticide poisoning and the pathogenesis is related to oxidative stress. Ginsenoside Rg3, one of the main constituents of Panax ginseng C.A. Meyer, shows an anti-oxidative activity. The aim of this study was to evaluate whether ginsenoside Rg3 can alleviate lung injury induced by rotenone in mice.
 Methods: C57BL/6J male mice were divided into five groups (n=11). The mice in ginsenoside Rg3 groups were treated with ginsenoside Rg3 at dose of 5, 10 or 20 mg/kg. Except for the control group, mice were challenged intragastrically with rotenone at dose of 30 mg/kg, once a day for 6 weeks. Subsequently, the lung tissues of mice were collected. The effect of ginsenoside Rg3 on rotenone-induced lung injury was observed by hematoxylin and eosin staining. The oxidative stress in lung tissues were also examined.
 Results: Rotenone induced substantial hemorrhage, alveolar wall thickness and neutrophils infiltration. These structural damages were attenuated significantly by ginsenoside Rg3 treatment. The lung injury induced by rotenone was associated with oxidative stress in lung tissues of mice. Compared with the control group, rotenone exposure resulted in the increase of malondialdehyde (MDA), the decreases of the activities of superoxide dismutase (SOD), glutathione peroxidase (GHS-Px), and the glutathione (GSH) content. Nevertheless, ginsenoside Rg3 treatment not only reduced MDA production but also increased the activities of SOD, GSH-Px, and the content of GSH in lung tissue of mice.
 Conclusion: Taken together, this study demonstrated that ginsenoside Rg3 has potential to ameliorate rotenone-induced lung injury and the mechanism of action of ginsenoside Rg3 is mediated by its anti-oxidative properties.
 

Oxidative and pro-inflammatory lung injury induced by desflurane inhalation in rats and the protective effect of rutin.

Desflurane is a mainstay of general inhaled anesthetics with a methyl ethyl ether structure and is widely used in clinical practice. It has been reported to induce inflammation and lipid peroxidation in rat pulmonary parenchyma, to increase alveolar macrophages, and to cause peribronchial infiltration and edema. Rutin, a flavonoid vitamin P1, is known to have biological properties including acting as an antioxidant, an anti-inflammatory, and an inhibitor of bronchoalveolar polymorphonuclear leukocyte (PNL) infiltration. The aim of this study is to examine the effects of rutin on desflurane-induced pulmonary injury using biochemical and histopathological methods. The rats were divided into 3 groups (n = 6 each): healthy control (HC), rutin+desflurane-treated (DRT) and desflurane-only (DSF). Briefly, 50 mg/kg of rutin was given orally to the DRT group and an equal volume of normal saline was given to the DSF and HC groups. After 1 h, anesthesia was induced and maintained in the DRT and DSF groups for 2 h. After the rats had been sacrificed, the lungs were removed. Malondialdehyde (MDA), total glutathione (GSH), tumor necrosis factor alpha (TNF-α), and nuclear factor kappa B (NF-κB) levels were measured in the excised lung tissue. The removed tissues were also fixed in 10% formalin, and the obtained sections were stained with hematoxylin and eosin (H&E) and evaluated under light microscopy. The biochemical and histopathological results of the DRT group were compared with those obtained from the DSF and HC groups. Desflurane increased MDA, TNF-α and NF-κB, and decreased GSH in lung tissue. The PNL infiltration, alveolar macrophages, hemorrhage, alveolar damage, and edema were observed in the lung tissue of the DSF group. Rutin was histopathologically shown to protect lung tissue from oxidative stress by preventing an increase in oxidant parameters and a decrease in antioxidants. The results suggest that rutin may be useful in the treatment of desflurane-associated lung injury.

Pharmacokinetics of 99mTc-HMPAO in isolated perfused rat lungs.

Lung uptake of technetium-labeled hexamethylpropyleneamine oxime (HMPAO) increases in rat models of human acute lung injury, consistent with increases in lung tissue glutathione (GSH). Since 99mTc-HMPAO uptake is the net result of multiple cellular and vascular processes, the objective was to develop an approach to investigate the pharmacokinetics of 99mTc-HMPAO uptake in isolated perfused rat lungs. Lungs of anesthetized rats were excised and connected to a ventilation-perfusion system. 99mTc-HMPAO (56 MBq) was injected into the pulmonary arterial cannula, a time sequence of images was acquired, and lung time-activity curves were constructed. Imaging was repeated with a range of pump flows and perfusate albumin concentrations and before and after depletion of GSH with diethyl maleate (DEM). A pharmacokinetic model of 99mTc-HMPAO pulmonary disposition was developed and used for quantitative interpretation of the time-activity curves. Experimental results reveal that 99mTc-HMPAO lung uptake, defined as the steady-state value of the 99mTc-HMPAO lung time-activity curve, was inversely related to pump flow. Also, 99mTc-HMPAO lung uptake decreased by ~65% after addition of DEM to the perfusate. Increased perfusate albumin concentration also resulted in decreased 99mTc-HMPAO lung uptake. Model simulations under in vivo flow conditions indicate that lung tissue GSH is the dominant factor in 99mTc-HMPAO retention in lung tissue. The approach allows for evaluation of the dominant factors that determine imaging biomarker uptake, separation of the contributions of pulmonary versus systemic processes, and application of this knowledge to in vivo studies.NEW & NOTEWORTHY We developed an approach for studying the pharmacokinetics of technetium-labeled hexamethylpropyleneamine oxime (99mTc-HMPAO) in isolated perfused lungs. A distributed-in-space-and-time computational model was fit to data and used to investigate questions that cannot readily be addressed in vivo. Experimental and modeling results indicate that tissue GSH is the dominant factor in 99mTc-HMPAO retention in lung tissue. This modeling approach can be readily extended to investigate the lung pharmacokinetics of other biomarkers and models of lung injury and treatment thereof.

Effects of Long-Term Simulated Microgravity on Oxidant and Antioxidant Values in the Plasma and Lung Tissues of Rhesus Macaque

This study evaluated the influence of long-term simulated microgravity on oxidative stress and total antioxidant capacity in the plasma and lung tissues of rhesus macaque (-10°C head-down tilting). Fifteen healthy male rhesus macaques were randomly divided into groups 1 (control, n=5), groups 2 (head-down tilting for 6 weeks, n=5) and groups 3 (head-down tilting for 6 weeks and recover from 4 weeks, n=5). Oxidative stress was evaluated by critical SOD, GSH, H2O2 in plasma and SOD, GSH in lung tissues. HE staining was used to observe the histopathological structure changes of pulmonary tissues. CAT, SOD1, SOD2, SOD3, GPX1, GPX4, GPX7, PRDX1, HMOX1, ALOX5 and DUOX1 mRNA were measured by real-time PCR. GSH concentration was significantly decreased, whereas H2O2 level was significantly increased in group 2 compared with group 1 and group 3. Compared to group 1, histopathological examination revealed alveolar septal thickening, and alveolar and interstitial lymphocytic infiltration in group 2 and group 3 and the pathological changes in group 3 were smaller than those in group 2. Group 2 and group 3 showed significant up-regulation of SOD3 gene compared with group 1 by real-time PCR. In a long-term simulated microgravity environment, systemic antioxidant level of GSH was reduced but an oxidative stress marker of H2O2 was increased. Meanwhile, long-term simulated microgravity caused lung injury and induced the mRNA of SOD3 expression in lung tissues. But oxidant stress is not a major factor involved in the development of lung damage under simulated microgravity. Further study still clarifies the mechanism about the lung injury under microgravity.

The protective effect of rosiglitazone on the rats with high altitude pulmonary edema

Objective To investigate the protective effect of rosiglitazone on the rats with high altitude pulmonary edema. Methods Thirty-six SD rats were randomly(random number) divided into 6 groups(n=6 each): control group(Control), hypobaric hypoxia model group(HH), rosiglitazone groups(RSG)which were administered with 3 different doses[RSG-L: 5 mg/(kg·d), RSG-M: 10 mg/(kg·d), RSG-H: 20 mg/(kg·d) ], dexamethasone group[Dex, 4 mg/(kg·d)]. Rats were injected intraperitoneally with different doses of rosiglitazone (RSG), dexamethasone(Dex)or vehicle (Control and HH) for 3 days before placed in simulated altitude of 6 000 m hypobaric hypoxia animal chamber where the temperature and pressure were constant. After 72 h in the chamber, each rat was anesthetized.The water content of lung was determined with wet/dry weight ratio. Bronchoalveolar lavage fluid was measured by bradford method. The contents of GSH was measured by micro-ezymed labeled method. The contents of MDA was measured by TBA method. The enzymatic activities of SOD was measured by WST-1 method.The changes of the TNF-α, IL-6 and IL-10 in serum were determined by ELISA.Light microscope was used to observe the pathological changes of lung tissue. Results Compared with Control group, the wet/dry weight ratio of lung(5.08±0.24) and total protein content of BALF(351.06±44.55)μg/mL increased significantly (P<0.01) in HH group. There were red blood cells in the alveolar and interstitium, pink fluid exudation in the alveolar, the alveolar septum enhancement, and a large number of inflammatory cell infiltration; the SOD activity(10.65±0.94)U/mgprot and the content of GSH(1.63±0.20)μmol/gprot in lung tissue were significantly decreased (P<0.01), the contents of MDA(2.15±0.18)nmol/mgprot increased significantly (P<0.01), TNF-α(56.92±2.87)pg/mL and IL-6(217.80±48.01)pg/mL levels in serum were significantly increased (P<0.01), and IL-10(76.85±16.72)pg/mL level decreased (P<0.05). Compared with the HH group, the wet/dry ratio of lung and total protein content of BALF in different doses of rosiglitazone group significantly decreased (P<0.01), the pathological changes of the lung tissue was significantly improved, SOD activity and the content of GSH in lung tissue was significantly increased (P<0.01), the content of MDA decreased (P<0.01), The levels of TNF-α and IL-6 in serum were significantly decreased (P<0.01), while the IL-10 level was significantly increased (P<0.01). Conclusion Rosiglitazone could protect the high altitude pulmonary edema by alleviating the oxidative stress and inflammatory response. Key words: Rosiglitazone; High altitude pulmonary edema; Oxidative stress; Inflammation; Rat

Effects of Long-Term Simulated Microgravity on Oxidant and Antioxidant Values in the Plasma and Lung Tissues of Rhesus Macaque

This study evaluated the influence of long-term simulated microgravity on oxidative stress and total antioxidant capacity in the plasma and lung tissues of rhesus macaque (-10℃ head-down tilting). Fifteen healthy male rhesus macaques were randomly divided into groups 1 (control, n=5), groups 2 (head-down tilting for 6 weeks, n=5) and groups 3 (head-down tilting for 6 weeks and recover from 4 weeks, n=5). Oxidative stress was evaluated by critical SOD, GSH, H₂O₂ in plasma and SOD, GSH in lung tissues. HE staining was used to observe the histopathological structure changes of pulmonary tissues. CAT, SOD1, SOD2, SOD3, GPX1, GPX4, GPX7, PRDX1, HMOX1, ALOX5 and DUOX1 mRNA were measured by real-time PCR. GSH concentration was significantly decreased, whereas H2O2 level was significantly increased in group 2 compared with group 1 and group 3. Compared to group 1, histopathological examination revealed alveolar septal thickening, and alveolar and interstitial lymphocytic infiltration in group 2 and group 3 and the pathological changes in group 3 were smaller than those in group 2. Group 2 and group 3 showed significant up-regulation of SOD3 gene compared with group 1 by real-time PCR. In a long-term simulated microgravity environment, systemic antioxidant level of GSH was reduced but an oxidative stress marker of H₂O₂ was increased. Meanwhile, long-term simulated microgravity caused lung injury and induced the mRNA of SOD3 expression in lung tissues. But oxidant stress is not a major factor involved in the development of lung damage under simulated microgravity. Further study still clarifies the mechanism about the lung injury under microgravity.

Vitamin E effect in a rat model of toluene diisocyanate-induced asthma.

Background and aimThe aim of the study was to evaluate vitamin E effect upon oxidative stress associated with toluene −2, 4-diisocyanate (TDI)-induced asthma in rats.MethodsThe five study groups were: control, vehicle, TDI, vehicle+E, TDI+E. TDI animals were sensitized by nasal administration of TDI 10% (5μl/nostril) between days 1–7 and 15–21. Between days 22–28 groups TDI+E and vehicle+E rats received vitamin E (50 mg/kg, i. v.), and control, vehicle and TDI groups received saline solution. On day 29 the rats were challenged by intranasal application of 5% TDI (5 μl/nostril). On day 30 blood, BALF and lung biopsy were harvested. Oxidative stress tests were malondialdehyde (MDA), protein carbonyls (PC), total thiols (tSH), 1,1-diphenyl-2-picryl hydrazyl (DPPH) and reduced glutathione (GSH).ResultsTDI sensitization increased oxidative stress systemically, but also locally in the respiratory airways and lung tissue. There was an increase of MDA and PC formation associated with a deficiency of the antioxidant defense reflected by DPPH decreases. There were no differences between systemic and local lung concentrations of oxidized molecules.After vitamin E treatment oxidative stress was reduced mostly due to serum, BALF and lung tissue GSH and DPPH increase.ConclusionThe study showed that in rat TDI-induced asthma there was oxidative stress caused by increased ROS production and antioxidants deficiency, and vitamin E reduced ROS production and improved antioxidant defense.

Toxic effects of the Fe2O3 nanoparticles on the liver and lung tissue.

Iron oxide nanoparticles are magnetic nanoparticles which have widespread application in MRI and heat therapy of cancer as contrast elements. They are also used effectively for drug and gene delivery because of effective penetrating to the cells and tissues. However, these features cause Fe2O3 nanoparticles have toxic effects that are not completely understood yet. In this study, effects of iron oxide nanoparticles on lung tissue in adult male Wistar rats were studied. We used pulmonary inhalation method for nanoparticle administration and used ether as a helper. Our results showed administered nanoparticles penetrated to the circulation and rapidly reached to liver and created serious inflammation in lung and liver tissues. This study used two different nanoparticle doses (20 and 40 mg/kg) and two exposing numbers (7 and 14 times). Results showed significant enhancement of free radicals and reduction of the GSH in lung tissue. Histological studies showed nanoparticle treatment of rats caused pulmonary emphysema, interstitial hyperemia and inflammation in lungs. By increasing the administrated dose lung tissue showed all of the mentioned symptoms with increased intensity. Nanoparticle exposition causes presence of neutrophils, lymphocytes and eosinophils in the lung tissue that confirmed there is a serious pathologic condition. Hepatic cells injuries cause penetration of the hepatic enzymes in to the blood serum (Tab. 2, Fig. 4, Ref. 32). Text in PDF www.elis.sk.

Usnic acid protects LPS-induced acute lung injury in mice through attenuating inflammatory responses and oxidative stress.

Usnic acid is a dibenzofuran derivative found in several lichen species, which has been shown to possess several activities, including antiviral, antibiotic, antitumoral, antipyretic, analgesic, antioxidative and anti-inflammatory activities. However, there were few reports on the effects of usnic acid on LPS-induced acute lung injury (ALI). The aim of our study was to explore the effect and possible mechanism of usnic acid on LPS-induced lung injury. In the present study, we found that pretreatment with usnic acid significantly improved survival rate, pulmonary edema. In the meantime, protein content and the number of inflammatory cells in bronchoalveolar lavage fluid (BALF) significantly decreased, and the levels of MPO, MDA, and H2O2 in lung tissue were markedly suppressed after treatment with usnic acid. Meanwhile, the activities of SOD and GSH in lung tissue significantly increased after treatment with usnic acid. Additionally, to evaluate the anti-inflammatory activity of usnic acid, the expression of pro-inflammatory cytokines including tumor necrosis factor alpha (TNF-α), interleukin-6 (IL-6) and anti-inflammatory cytokine IL-10, and chemokines interleukin-8 (IL-8) and macrophage inflammatory protein-2 (MIP-2) in BALF were studied. The results in the present study indicated that usnic acid attenuated the expression of TNF-α, IL-6, IL-8 and MIP-2. Meanwhile, the improved level of IL-10 in BALF was observed. In conclusion, these data showed that the protective effect of usnic acid on LPS-induced ALI in mice might relate to the suppression of excessive inflammatory responses and oxidative stress in lung tissue. Thus, it was suggested that usnic acid might be a potential therapeutic agent for ALI.

Depleted energy charge and increased pulmonary endothelial permeability induced by mitochondrial complex I inhibition are mitigated by coenzyme Q1 in the isolated perfused rat lung

Mitochondrial dysfunction is associated with various forms of lung injury and disease that also involve alterations in pulmonary endothelial permeability, but the relationship, if any, between the two is not well understood. This question was addressed by perfusing isolated intact rat lung with a buffered physiological saline solution in the absence or presence of the mitochondrial complex I inhibitor rotenone (20μM). Compared to control, rotenone depressed whole lung tissue ATP from 5.66±0.46 (SEM) to 2.34±0.15µmol·g−1 dry lung, with concomitant increases in the ADP:ATP and AMP:ATP ratios. Rotenone also increased lung perfusate lactate (from 12.36±1.64 to 38.62±3.14µmol·15min−1 perfusion·g−1 dry lung) and the lactate:pyruvate ratio, but had no detectable impact on lung tissue GSH:GSSG redox status. The amphipathic quinone coenzyme Q1 (CoQ1; 50μM) mitigated the impact of rotenone on the adenine nucleotide balance, wherein mitigation was blocked by NAD(P)H-quinone oxidoreductase 1 or mitochondrial complex III inhibitors. In separate studies, rotenone increased the pulmonary vascular endothelial filtration coefficient (Kf) from 0.043±0.010 to 0.156±0.037ml·min−1·cm H2O−1·g−1 dry lung, and CoQ1 protected against the effect of rotenone on Kf. A second complex I inhibitor, piericidin A, qualitatively reproduced the impact of rotenone on Kf and the lactate:pyruvate ratio. Taken together, the observations imply that pulmonary endothelial barrier integrity depends on mitochondrial bioenergetics as reflected in lung tissue ATP levels and that compensatory activation of whole lung glycolysis cannot protect against pulmonary endothelial hyperpermeability in response to mitochondrial blockade. The study further suggests that low-molecular-weight amphipathic quinones may have therapeutic utility in protecting lung barrier function in mitochondrial insufficiency.

CFTR is the primary known apical glutathione transporter involved in cigarette smoke-induced adaptive responses in the lung

One of the most abundant antioxidants in the lung is glutathione (GSH), a low-molecular-weight thiol, which functions to attenuate both oxidative stress and inflammation. GSH is concentrated in the epithelial lining fluid (ELF) of the lung and can be elevated in response to the increased oxidant burden from cigarette smoke (CS). However, the transporter(s) responsible for the increase in ELF GSH with cigarette smoke is not known. Three candidate apical GSH transporters in the lung are CFTR, BCRP, and MRP2, but their potential roles in ELF GSH transport in response to CS have not been investigated. In vitro, the inhibition of CFTR, BCRP, or MRP2 resulted in decreased GSH efflux in response to cigarette smoke extract. In vivo, mice deficient in CFTR, BCRP, or MRP2 were exposed to either air or acute CS. CFTR-deficient mice had reduced basal and CS-induced GSH in the ELF, whereas BCRP or MRP2 deficiency had no effect on ELF GSH basal or CS-exposed levels. Furthermore, BCRP or MRP2 deficiency had little effect on lung tissue GSH. These data indicate that CFTR is predominantly involved in maintaining basal ELF GSH and increasing ELF GSH in response to CS.

Intravenous Administration of Hyperoxygenated Solution Attenuates Pulmonary Edema Formation in Phosgene-Induced Acute Lung Injury in Rabbits

The aim of this study was to investigate the post-treatment effect of intravenous hyperoxygenated solution (HOS) on pulmonary parameters in rabbits whole-body-exposed to the toxic gas phosgene. Twenty-four New Zealand rabbits were divided into four groups randomly: rabbits were exposed whole-body to either filtered room air or 539 ppm phosgene for 5 minutes followed by room air washout for 5 minutes. Phosgene-exposed group (exposed to phosgene without treatment, PH group); Control group (exposed to air, Control group); Lactate Ringer's solution (LRS)-treated group (intravenous infusion of LRS by 30 ml·kg-1 after phosgene exposure, LRS group); Hyperoxygenated solution (HOS)-treated group (intravenous infusion of HOS after phosgene exposure by 30 mL·kg-1, HOS group). Arterial blood was collected for blood gas analysis at 1, 3, 8, and 12 hours after phosgene or air exposure. Rabbits were put to death 12 hours after exposure. Lung edema was assessed gravimetrically by measuring tissue wet/dry weight ratio (W/D) and lung coefficient (LC). Bronchoalveolar lavage (BAL) was performed and fluid was analyzed for total maloaldehyde (MDA), glutathione peroxidase (GSH-Px), and protein concentration. Lungs were perfused with saline to remove blood, snap-frozen in liquid nitrogen (N2), analyzed for tissue reduced glutathione (GSH) and oxidized glutathione (GSSG). Parts of lung tissues were reserved for histopathology examination. In the PH, LRS, and HOS groups, phosgene inhalation caused serious lung edema, W/D and LC, lung tissue GSSG, BALF MDA, and protein content increased significantly. Meanwhile, PaO2, lung tissue GSH, and BALF GSH-Px decreased markedly. However, after HOS treatment in the HOS group, PaO2 was clearly higher than that in the PH group and LRS group at 3, 8, 12 hours (P < 0.01). W/D and LC, lung tissue GSSG, BALF MDA, and protein content in the HOS group were apparently lower than that in the PH group and LRS group (P < 0.01). In the HOS group, lung tissue GSH and BALF GSH-Px increased compared with both PH and LRS group, respectively. There was no difference on lung tissue GSH among the PH, LRS, and HOS groups (P > 0.05). Intravenous HOS infusion after phosgene exposure can clearly lessen phosgene-induced lung edema formation, lipid peroxidatic reaction, and ameliorate hypoxemia associated with phosgenismus; it is a safe, simple, and effective measure to protect animals from phosgene-induced lung injury.

Therapeutic Treatments of Phosgene-Induced Lung Injury

A series of studies was performed to address treatment against the former chemical warfare edemagenic gas phosgene. Both in situ and in vivo models were used to assess the efficacy of postexposure treatment of phosgene-induced lung injury using clinically existing drugs. The degree of efficacy was judged by examining treatment effects on pulmonary edema formation (PEF) as measured by wet/dry weight (WW/DW) ratios, real-time (in situ) lung weight gain (LWG), survival rates (SR), odds ratios, and glutathione (GSH) redox states. Drugs included N-acetylcysteine (NAC), ibuprofen (IBU), aminophylline (AMIN), and isoproterenol (ISO). Using the in situ isolated perfused rabbit lung model (IPRLM), intratracheal (IT) NAC (40 mg/kg bolus) delivered 45–60 min after phosgene exposure (650 mg/m3) for10 min lowered pulmonary artery pressure, LWG, leukotrienes (LT) C4/D4/E4, lipid peroxidation, and oxidized GSH. We concluded that NAC protected against phosgene-induced lung injury by acting as an antioxidant by maintaining protective levels of GSH, reducing both lipid peroxidation and production of arachidonic acid metabolites. Also in IPRLM, administration of AMIN (30 mg/kg) 80–90 min after phosgene exposure significantly reduced lipid peroxidation and perfusate LTC4/D4/E4, reduced LWG, and prevented phosgene-induced decreases in lung tissue cAMP. These data suggest that protective mechanisms observed with AMIN involve decreased LTC4/D4/E4 mediated pulmonary capillary permeability and attenuated lipid peroxidation. Direct antipermeability effects of AMIN-induced upregulation of cAMP on cellular contraction may also be important in protection against phosgene-induced lung injury. Posttreatment with ISO in the IPRLM by either combined intravascular (iv; infused into pulmonary artery at 24 μg/min infused) + IT (24 μ g bolus) or IT route alone 50–60 min after phosgene exposure significantly lowered pulmonary artery pressure, tracheal pressure, and LWG. ISO treatment significantly enhanced GSH products or maintained protective levels when compared with results from phosgene-exposed only rabbits. These data suggest that protective mechanisms for ISO involve reduction in vascular pressure, decreased LTC4/D4/E4-mediated pulmonary capillary permeability, and favorably maintained lung tissue GSH redox states. For in vivo male mouse (CD-1, 25–30 g) studies IBU was administered ip within 20 min after a lethal dose of phosgene (32 mg/m3 for 20 min) at 0 (saline), 3, 9, or 15 mg/mouse. Five hours later, a second IBU injection was given but at half the original doses (0, 1.5, 4.5, and 7.5 mg/mouse); therefore, these treatment groups are now referred to as the 0/0, 3/1.5, 9/4.5, and 15/7.5 mg IBU/mouse groups. SRs and odds ratios were calculated for each dose at 12 and 24 h. The 12-h survival was 63% for 9/4.5 mg IBU and 82% for the 15/7.5 mg IBU groups, compared with 25% for saline-treated phosgene-exposed mice. At 24 h, those survival rates were reduced to 19%, 19%, and 6%, respectively. In the 15/7.5 mg IBU group, lung WW/DW ratios were significantly lower than in saline-treated mice at 12 h. Lipid peroxidation was lower only for the 9/4.5 mg IBU dose; however, nonprotein sulfhydryls (a measure of GSH) were greater across all IBU doses. The odds ratio was 5 for the 9/4.5 IBU group at 12 h and 13 for the 15/7.5 mg IBU group, compared with 3.5 for both groups at 24 h. IBU posttreatment increased the survival of mice at 12 h by reducing PEF, lipid peroxidation, and GSH depletion. In conclusion, effective treatment of phosgene-induced lung injury involves early postexposure intervention that could reduce free radical species responsible for lipid peroxidation, correct the imbalance in the GSH redox state, and prevent the release of biological mediators such as leukotrienes, which are accountable for increased permeability.

Effect of dietary treatment with n‐propyl gallate or vitamin E on the survival of mice exposed to phosgene

Phosgene, widely used in industrial processes, can cause life-threatening pulmonary edema and acute lung injury. One mechanism of protection against phosgene-induced lung injury may involve the use of antioxidants. The present study focused on dietary supplementation in mice using n-propyl gallate (nPG)--a gallate acid ester compound used in food preservation--and vitamin E. Five groups of male mice were studied: group 1, control-fed with Purina rodent chow 5002; group 2, fed 0.75% nPG (w/w) in 5002; group 3, fed 1.5% nPG (w/w) in 5002; group 4 fed 1% (w/w) vitamin E in 5002; and group 5, fed 2% (w/w) vitamin E also in 5002. Mice were fed for 23 days. On day 23 mice were exposed to 32 mg m-3 (8 ppm) phosgene for 20 min (640 mg. min m-3) in a whole-body exposure chamber. Survival rates were determined at 12 and 24 h. In mice that died within 12 h, the lungs were removed and lung wet weights, dry weights, wet/dry weight ratios, lipid peroxidation (thiobarbituric acid reactive substances, TBARS) and glutathione (GSH) were assessed. Vitamin E had no positive effect on any outcome measured. There was no significant difference between 1.5% nPG and any parameter measured or survival rate compared with 5002 + phosgene. However, dietary treatment with 0.75% nPG significantly increased survival rate (P </= 0.002) and lowered TBARS (P </= 0.05) compared with 5002 + phosgene at 12 h after exposure. Mice fed 0.75% nPG had a lower wet/dry wt ratio compared with those fed 1.5% nPG and a significantly increased lung tissue GSH 36%, compared with the 5002 + phosgene group. In conclusion, dietary treatment with a low level of the antioxidant nPG protected mice by decreasing lipid peroxidation and increasing lung tissue GSH. The higher level of nPG and both levels of vitamin E diets were ineffective, suggesting that a ceiling threshold level of antioxidants in lung tissue is required for survival against phosgene-induced lung injury. Published in 2001 by John Wiley & Sons, Ltd.

BHA DIET ENHANCES THE SURVIVAL OF MICE EXPOSED TO PHOSGENE: The Effect of BHA on Glutathione Levels in the Lung

Phosgene-induced pulmonary edema formation has been under investigation for many years. One mechanism of protection may involve the use of antioxidants. Previously, it has been shown that butylated hydroxyanisole (BHA) treatment can enhance glutathione (GSH) levels. The present study focused on dietary supplementation in mice using BHA, a phenolic compound used in food preservation. Three groups of male CD1 mice were studied: group 1, control animals fed with Purina rodent chow 5002; group 2, fed 0.75% BHA (w/w) in 5002; and group 3, fed 1.5% BHA (w/w) in 5002. Mice were fed for 22 days. On day 23 mice were exposed to 32 mg/m3 phosgene for 20 min in a whole-body exposure chamber. Survival rate (SR) and odds ratio (OR) were determined at 12 and 24 h. In mice that died within 12 h, the lungs were removed immediately and lung wet weights (WW), dry weights (DW), lung wet weight/body weight ratio (LWW/BW), and lung tissue total glutathione (GSH) were assessed. For 12-h data, 6 mice from the 1.5% BHA group were sacrificed for lung tissue measurements. The SR for 0.75% BHA was 80% at 12 h and 55% at 24 h, compared with 36% and 23%, respectively, for controls. For 1.5% BHA, the 12- and 24-h SR were 100% and 92%, respectively. Odds ratios of 6.9 for 0.75% BHA and 46.6 for 1.5% BHA at 12 h and 4.0 and 42 for 0.75% and 1.5% BHA, respectively, at 24 h were significantly (2) higher than control diet phosgene-exposed mice. Dietary pretreatment with 0.75% and 1.5% BHA significantly enhanced lung tissue GSH, 1.8-fold (p </-.01) and 5.8-fold (p </- .01), respectively, compared with phosgene-exposed control diet. Both BHA-supplemented diets significantly reduced WW. Only 1.5% BHA reduced DW, a measure of lung hyperaggregation. and LWW/BW compared with control diet. In air-exposed controls, BHA induced a dose-responsive decrease in WW, DW, LWW/BW ratio, and GSH. In conclusion, dietary pretreatment with BHA at the two dose levels reduced lung edema and lethality by enhancing lung tissue GSH in mice exposed to phosgene.

Glutathione supplements protect preterm rabbits from oxidative lung injury.

The main objective of this study was to determine if glutathione (GSH) supplementation attenuated hyperoxic lung injury. Preterm (29 days) rabbits were delivered and exposed for 24 h to 1) room air, 2) room air and GSH, 3) 95% oxygen and GSH. GSH supplements (1 mM) were delivered in the nutritional support of 10% dextrose and saline through a peritoneal catheter. Animals assigned to oxygen had decreased lung volumes at 35 cmH2O, decreased lung compliance, increased edema, decreased cell viability, and decreased lung tissue and lavage-reduced/oxidized GSH levels, compared with control animals. Despite exposure to hyperoxia, animals supplemented with GSH were not different from room air controls with respect to lung mechanics, edema, cell viability, or tissue and lavage GSH. These studies suggest that GSH supplementation maintains normal lavage and lung tissue GSH levels in preterm animals exposed to hyperoxia and attenuates the changes in lung mechanics associated with oxygen-induced lung injury.

Response of rodents to inhaled diluted diesel exhaust: Biochemical and cytological changes in bronchoalveolar lavage fluid and in lung tissue

The effect of long-term (24 months) inhalation of diesel exhaust on the bronchoalveolar region of the respiratory tract of rodents was assessed by serial (every 6 months) analysis of bronchoalveolar lavage fluid (BALF) and of lung tissue from F344/Crl rats and CD-1 mice (both sexes) exposed to diesel exhaust diluted to contain 0, 0.35, 3.5, or 7.0 mg soot/m 3. The purpose of the study was twofold. One was to assess the potential health effects of inhaling diluted exhaust from light-duty diesel engines. The second was to determine the usefulness of BALF analysis in detecting the early stages in the development of nononcogenic lung disease and differentiating them from the normal repair processes. No biochemical or cytological changes in BALF or in lung tissue were noted in either species exposed to the lowest, and most environmentally relevant, concentration of diesel exhaust. In the two higher levels of exposure, a chronic inflammatory response was measured in both species by dose-dependent increases in inflammatory cells, cytoplasmic and lysosomal enzymes, and protein in BALF. Histologically, after 1 year of exposure, the rats had developed focal areas of fibrosis associated with the deposits of soot, while the mice, despite a higher lung burden of soot than the rats, had only a fine fibrillar thickening of an occasional alveolar septa in the high-level exposure group. Higher increases in BALF β-glucuronidase activity and in hydroxyproline content accompanied the greater degree of fibrosis in the rat. BALF levels of glutathione (GSH) and glutathione reductase activity increased in a dose-dependent fashion and were higher in mice than in rats. Lung tissue GSH was depleted in a dose-dependent fashion in rats but was slightly increased in mice. This depletion may have played a role in the greater fibrogenic response observed in rats. Other tissue changes in enzymatic activity were small compared to changes observed in BALF. The exposure did not increase the cytochrome P-450 content of the lung in either species. The results suggest that, for the noncarcinogenic health effects reported in this paper, there is a threshold of exposure below which adverse effects were not observed. This threshold was well above environmentally relevant levels of diesel exhaust but may be in the range of some occupational exposures. The analysis of BALF proved a useful adjunct to the chronic toxicity study to quantitate the inflammatory changes accompanying the development of pulmonary disease.