Edaravone attenuates paraquat-induced lung injury by inhibiting oxidative stress in human type II alveolar epithelial cells

Investigating the impact of inhaled paraquat: A comprehensive evaluation protocol

This paper provides a complete protocol for studying the effects of inhaled paraquat (PQ), a toxic herbicide that has negative effects systemically and on the lungs. The protocol aims to evaluate the effects of aerosolized PQ exposure on lung and systemic injury in an animal model, which will provide significant information for therapeutic interventions for PQ-induced pulmonary and systemic damage. The protocol involves the following key components: 1. Study groups: By including control, non-treated aerosolized PQ-exposed, and treated PQ-exposed animals with various agent groups in the experiment, lung and systemic injury in each group could be evaluated, and different measured parameters could be compared among groups. 2. PQ exposure: Animals in the PQ-exposed groups are subjected to PQ aerosol inhalation, simulating occupational or accidental exposure in farmers working with this herbicide. 3. Assessment measures: To determine the degree of lung and systemic injury and its physiological effects, several assessments, such as biochemical markers, histopathological analysis, and functional tests, are used. The protocol offers reliable and accurate results by using standardized methods and data collection. The effect of PQ exposure on lung and systemic injury could be evaluated by statistical analysis of the collected data, which also makes it easier to identify possible protective agents or interventions. This comprehensive evaluation protocol provides an essential basis for studying the mechanisms behind PQ-induced lung and systemic injury and assessing the effectiveness of preventative or therapeutic strategies in minimizing its adverse effects.

Astragaloside IV attenuates hypoxia/reoxygenation injury-induced apoptosis of type II alveolar epithelial cells through miR-21-5p

We aimed to explore the role of miR-21-5p in the inhibitory effects of astragaloside IV (As-IV) on hypoxia/reoxygenation injury-induced apoptosis of type II alveolar epithelial cells. Rat type II alveolar epithelial cells RLE-6TN were cultured in vitro and randomly divided into control (C), hypoxia/reoxygenation injury (H/R), As-IV and miR-21-5p-siRNA + As-IV groups (n = 6). H/R model was established by 24 h of hypoxia and 4 h of reoxygenation. As-IV group was given 1 nmol/L As-IV and incubated for 1 h before modeling. MiR-21-5p-siRNA + As-IV group was transfected with 50 nmol/L miR-21-5p-siRNA. After 48 h, they were incubated with 1 nmol/L As-IV for 1 h before modeling. Cell viability was detected by cell counting kit-8 assay, and apoptosis rate was detected by flow cytometry. The expression levels of TLR4 and NF-κB were measured by immunofluorescence assay. The targeting relationship between miR-21-5p and TLR4 was determined by luciferase assay. Compared with H/R group, the cell viability, miR-21-5p, bax and cleaved caspase-3 expressions of As-IV group increased, apoptosis rate and Bcl-2 expression decreased, and TLR4 and NF-κB expressions were down-regulated (P < 0.05). Compared with As-IV group, the cell viability, miR-21-5p, bax and cleaved caspase-3 expressions of miR-21-5p-siRNA + As-IV group decreased, apoptosis rate and Bcl-2 expression increased, and the expressions of TLR4 and NF-κB were up-regulated (P < 0.05). As-IV up-regulates miR-21-5p expression, inhibits the TLR4/NF-κB signaling pathway and suppresses the apoptosis of type II alveolar epithelial cells during hypoxia/reoxygenation injury.

Quantitative analysis of the global proteome in lung from mice with blast injury

AIM OF THE STUDY

The mechanism by which primary shock wave causes lung injury is unclear. The aim of this study is to find the changes of protein that can be helpful in understanding blast-induced lung injury.

MATERIAL AND METHODS

A quantitative analysis of their global proteome was conducted in lung from mice with blast injury using LC-MS/MS. Protein annotation, unsupervised hierarchical clustering, functional classification, functional enrichment and cluster, and protein-protein interaction analyses were performed. Furthermore, western blotting was used to validate the changed protein levels.

RESULTS

A total of 6498 proteins were identified, of which 5520 proteins were quantified. The fold-change cutoff was set at 1.2; 132 proteins were upregulated, and 104 proteins were downregulated. The bioinformatics analysis indicated that the differentially expressed proteins were involved in the cholesterol metabolism, asthma, nonalcoholic fatty liver disease. Remarkably, the processes related to the change of oxidative phosphorylation including the NADH dehydrogenase, Cytochrome C reductase, Cytochrome C oxidase and F-type ATPase were significantly upregulated, which were further verified by western blotting.

CONCLUSION

These results confirmed that the oxidative phosphorylation is critical to blast-induced lung injury. LC/MS-based profiling presented candidate target/pathways that could be explored for future therapeutic development.

Edaravone attenuates experimental asthma in mice through induction of HO-1 and the Keap1/Nrf2 pathway

Asthma is a chronic disease that threatens public health worldwide. Multiple studies have shown that oxidative stress plays an important role in the pathogenesis of asthma. Edaravone (Eda), a free radical scavenger, has been found to have a protective effect against lung injury due to its ability to eliminate reactive oxygen species. The present study aimed to investigate the effect of Eda on asthma and the mechanism underlying its actions. An experimental asthma model was induced in mice, before they were treated with different doses of Eda. Measurements of airway responsiveness to methacholine (Mch), cell counts and cytokine levels in bronchoalveolar lavage fluid (BALF) and of the oxidative products and antioxidant enzymes in lung tissue were taken in these asthma model mice and compared with control mice. Protein levels of kelch-like ECH-associated protein-1 (Keap1)/nuclear factor erythroid 2-related factor 2 (Nrf2) and hemeoxygenase-1 (HO-1) were determined in the lung tissue of normal mice and Nrf2 and HO-1-deficient mice subject to the asthma model to investigate the mechanisms underlying Eda action. The results indicated that Eda effectively reduced airway responsiveness to Mch. The total number of cells and the numbers of eosinophils, lymphocytes and neutrophils in BALF of asthma model mice were also significantly reduced by Eda treatment when compared with normal saline treatment. Eda treatment significantly alleviated perivascular edema, peribronchial inflammation and macrophage infiltration in the alveolar space and decreased the levels of inflammatory cytokines released in BALF compared with control. Eda also significantly reduced the levels of oxidative stress markers in BALF and restored the levels of antioxidative enzyme, superoxide dismutase, when compared with control. The Keap1/Nrf2 ratio was significantly decreased with Eda compared with control due to an increase in Nrf2 and a decrease in Keap1 expression. HO-1 expression was increased by Eda. The airway responsiveness of Nrf2^-/- mice or HO-1^-/- mice to Mch was significantly higher compared with normal mice treated with Eda. Taken together, the results of the present study show that Eda exerts anti-inflammatory and antioxidative effects, which suggests a potential use for Eda in reduction of asthma severity. The activated Keap1/Nrf2 pathway and HO-1 may be involved in the anti-asthmatic effect of Eda.

Retrospective study of clinical features and prognosis of edaravone in the treatment of paraquat poisoning

To observe whether edaravone can protect organs and inhibit pulmonary fibrosis in patients with paraquat poisoning and to provide a method for clinical intervention for paraquat poisoning.Forty-four cases of paraquat poisoning were collected from March 2011 to December 2017 in our hospital. Eighteen cases from March 2011 to November 2013 did not receive edaravone treatment and were considered the control group, and 26 cases from January 2014 to December 2017 were treated with edaravone and were considered the observation group. Injuries to the central nervous system, heart, liver, kidney, and digestive system were evaluated on at 24 hours, 3 days, and 7 days after hospitalization. The expression of serum inflammatory factors (interleukin [IL]-6, IL-10, tumor necrosis factor-α [TNF-α]) and oxidative stress correlation (superoxide dismutase [SOD] and malondialdehyde [MDA]) were assayed at 24 hours, 3 days, and 7 days after being hospitalized. After 7, 14, and 30 days, the changes in pathological lung characteristics in the 2 groups were assessed, and survival rates were calculated.Edaravone significantly increased the serum levels of SOD and obviously markedly reduce the serum levels of IL-6, IL-10, TNF-α, and MDA in patients poisoned with paraquat (P < .05). Edaravone significantly protected the liver (P = .021), cardiovascular (P = .031), and renal (P = .028) organs of patients from paraquat poisoning-induced injury after 7 days but had no significant protection or improvement on respiratory and digestive tract damage. Edaravone delayed the occurrence of pulmonary fibrosis and increase the survival time of patients at 7 and 14 days (P < .05). However, the 1-month follow-up found that edaravone did not reduce pulmonary fibrosis (77.8% vs 73.1%, P = .615) and did not increase the survival rate of the patients (61.1% vs 65.3%, P = .853).Edaravone is beneficial for protecting the kidneys and liver from paraquat poisoning through reducing oxidative stress and inhibiting inflammatory response. It can also inhibit the pulmonary fibrosis process and prolong the survival time of the patients. However, no significant improvements were seen in the probability of pulmonary fibrosis and the survival rate.

Oxidative responses and defense mechanism of hyperpigmented P. aeruginosa as characterized by proteomics and metabolomics

Pseudomonas aeruginosa is known to produce multiple types of pigment which are involved in its pathogenicity and survival in certain environments. Herein, we reported the identification of P. aeruginosa dark-brown hyperpigmented (HP) strains which have been isolated from clinical samples. In order to study the role of these dark-brown containing secretions, alterations of metabolic processes and cellular responses under microenvironment of this bacterial pathogen, two-dimensional gel electrophoresis (2-DE) in conjunction with peptide mass fingerprinting (PMF) were performed. Protein spots showing the most significant differences and high spot optical density values were selected for further characterization. Fold difference of protein expression levels among those spots were calculated. Three major groups of proteins including anti-oxidant enzyme such as catalase, alkyl hydroperoxide reductase and also iron-superoxide dismutase (Fe-SOD), transmembrane proteins as well as proteins involved in energy metabolism such as ATP synthase and pyruvate/2-oxoglutarate dehydrogenase were significantly decreased in P. aeruginosa HP. Whereas, malate syntase and isocitrate lyase, the key enzyme in glyoxylate cycle as well as alcohol dehydrogenase were significantly increased in P. aeruginosa HP, as compared to the reference strain ATCC 27853. Moreover, the HP exerted SOD-like activity with its IC₅₀ equal to 0.26 mg/ml as measured by NBT assay. Corresponding to secretomic metabolome identification, elevated amounts of anti-oxidant compounds are detected in P. aeruginosa HP than those observed in ATCC 27853. Our findings indicated successful use of proteomics and metabolomics for understanding cell responses and defense mechanisms of P. aeruginosa dark-brown hyperpigmented strains upon surviving in its microenvironment.

Chloroquine attenuates paraquat-induced lung injury in mice by altering inflammation, oxidative stress and fibrosis

Paraquat is one of the most extensively used herbicides and has high toxicity for humans and animals. However, there is no effective treatment for paraquat poisoning. The aim of the present study was to evaluate the effects of chloroquine on paraquat-induced lung injury in mice. Mice received a single intraperitoneal injection of paraquat and a daily intraperitoneal injection of the indicated dosages of chloroquine or dexamethasone. The histological changes, inflammation and oxidative stress in the lungs were examined at day 3, and the degree of pulmonary fibrosis was examined at day 28. H&E staining showed that chloroquine markedly attenuated lung injury induced by paraquat. In addition, the inflammatory responses induced by paraquat were inhibited after treatment with chloroquine, as indicated by the decreased number of leukocytes, the reduced levels of TNF-α, IL-1β and IL-6 in the bronchoalveolar lavage fluid, the reduced NO content, and downregulation of iNOS expression in lung tissues. No different effect was found between high-dose chloroquine and dexamethasone. Additionally, the treatment with chloroquine increased the activity of SOD and decreased the level of MDA in the lung tissues. The expressions of the anti-oxidative proteins, Nrf2, HO-1 and NQO1, were also upregulated by chloroquine treatment. The high-dose chloroquine was more effective than dexamethasone in its anti-oxidation ability. Finally, the results of Masson's staining illustrated that chloroquine markedly attenuated fibrosis in the paraquat-exposed lungs. Immunohistochemistry staining showed that the expressions of the pro-fibrotic proteins TGF-β and α-SMA were downregulated after treatment with chloroquine. In conclusion, chloroquine effectively attenuated paraquat-induced lung injury in mice.

Edaravone protects rats and human pulmonary alveolar epithelial cells against hyperoxia injury: heme oxygenase-1 and PI3K/Akt pathway may be involved

PURPOSE/AIM

Hyperoxic acute lung injury (HALI) is a clinical syndrome as a result of prolonged supplement of high concentrations of oxygen. As yet, no specific treatment is available for HALI. The present study aims to investigate the effects of edaravone on hyperoxia-induced oxidative injury and the underlying mechanism.

MATERIALS AND METHODS

We treated rats and human pulmonary alveolar epithelial cells with hyperoxia and different concentration of edaravone, then examined the effects of edaravone on cell viability, cell injury and two oxidative products. The roles of heme oxygenase-1 (HO-1) and PI3K/Akt pathway were explored using Western blot and corresponding inhibitors.

RESULTS

The results showed that edaravone reduced lung biochemical alterations induced by hyperoxia and mortality of rats, dose-dependently alleviated cell mortality, cell injury, and peroxidation of cellular lipid and DNA oxidative damage. It upregulated cellular HO-1 expression and activity, which was reversed by PI3K/Akt pathway inhibition. The administration of zinc protoporphyrin-IX, a HO-1 inhibitor, and LY249002, a PI3K/Akt pathway inhibitor, abolished the protective effects of edaravone in cells.

CONCLUSIONS

This study indicates that edaravone protects rats and human pulmonary alveolar epithelial cells against hyperoxia-induced injury and the antioxidant effect may be related to upregulation of HO-1, which is regulated by PI3K/Akt pathway.

Paraquat Induces Apoptosis through a Mitochondria-Dependent Pathway in RAW264.7 Cells

Paraquat dichloride (N,N-dimethyl-4-4′-bipiridinium, PQ) is an extremely toxic chemical that is widely used in herbicides. PQ generates reactive oxygen species (ROS) and causes multiple organ failure. In particular, PQ has been reported to be an immunotoxic agrochemical compound. PQ was shown to decrease the number of macrophages in rats and suppress monocyte phagocytic activity in mice. However, the effect of PQ on macrophage cell viability remains unclear. In this study, we evaluated the cytotoxic effect of PQ on the mouse macrophage cell line, RAW264.7 and its possible mechanism of action. RAW264.7 cells were treated with PQ (0, 75, and 150 μM), and cellular apoptosis, mitochondrial membrane potential (MMP), and intracellular ROS levels were determined. Morphological changes to the cell nucleus and cellular apoptosis were also evaluated by DAPI and Annexin V staining, respectively. In this study, PQ induced apoptotic cell death by dose-dependently decreasing MMP. Additionally, PQ increased the cleaved form of caspase-3, an apoptotic marker. In conclusion, PQ induces apoptosis in RAW264.7 cells through a ROS-mediated mitochondrial pathway. Thus, our study improves our knowledge of PQ-induced toxicity, and may give us a greater understanding of how PQ affects the immune system.

Effect of SP-A/B in lipoic acid on acute paraquat poisoning

BACKGROUND

This study was undertaken to observe the concentration of SP-A/B and the pulmonary surfactant in the lung tissue of rats with acute lung injury/acute respiratory distress syndrome caused by paraquat poisoning after the treatment of metabolic antioxidant-lipoic acid and whether its influence was related to TNF-α.

METHODS

Sixty-six male Sprage-Dawley rats were randomly divided into three groups: normal control group (NS group), 6 rats; paraquat poisoning group (PQ group), 30 rats; and paraquat+lipoic acid treatment group (LA group), 30 rats. The rats in the PQ and LA groups were subdivided into 3-, 6-, 12-, 24-, 48-hour subgroups, with 6 rats in each group. After the rats were sacrificed, lung tissue from the same part was taken from the rats. After HE staining, histological changes were observed in the tissue under a light microscope. Lung tissue was also taken to test the levels of superoxide dismutase (SOD) and malondialdehyde (MDA). Whole blood (0.8 mL) without anticoagulant was drawn from the tail vein of rats for the determination of the TNF-α level. The total RNA of the lung tissue was collected, and the Rt-PCR method was used to measure the levels of SP-A and SP-B mRNA.

RESULTS

HE staining showed that histopathological changes were milder in the LA group than in the PQ group. There were significant differences in MDA and SOD levels between different intervals both in intergroups and intragroups except the 3-hour subgroup (P<0.01). Likewise, the significant differences in the levels of TNF-α were also present between the three groups and between different intervals (P<0.01). The significant differences in SP-A mRNA and SP-B mRNA amplification ratio were seen between the three groups at the same intervals (P<0.01), but the differences between different intervals in the PQ group were statistically significant (P<0.05). The differences between different intervals in the LA group were statistically significant (P<0.01).

CONCLUSION

Lipoic acid in acute paraquat poisoning could diminish lung tissue damage by regulating directly tumor necrosis factor and indirectly the content of pulmonary surfactant so as to reduce pulmonary edema, improve lung compliance, and finally protect lung tissues.