Edaravone, a novel antidote against lung injury and pulmonary fibrosis induced by paraquat?

Sorafenib and edaravone protect against renal fibrosis induced by unilateral ureteral obstruction via inhibition of oxidative stress, inflammation, and RIPK-3/MLKL pathway

Renal fibrosis is the common endpoint of nearly all chronic and progressive nephropathies. Cell death and sterile inflammation are the main characteristics of renal fibrosis, which can lead to end-stage renal failure. The inflammatory reaction triggered by tissue damage is strongly related to necroptosis, a type of caspase-independent, regulated cell death. Using an animal model of unilateral ureteral obstruction (UUO), the anti-fibrotic effects of sorafenib (SOF), a multi-kinase inhibitor, and edaravone (EDV), a potent antioxidant and free radical scavenger, were examined in rats with obstructive nephropathy. Experimentally, animals were divided randomly into five groups: sham; UUO; UUO + SOF (5 mg/kg/day, P.O.); UUO + EDV (20 mg/kg/day, P.O.); and UUO + SOF + EDV groups. The kidney function biomarkers, oxidant/antioxidant status, renal mRNA expressions of TNF-α, collagen-1α, protein expressions of RIPK-1, RIPK-3, MLKL, caspase-8, HYP, MPO, and TNF-α were all significantly modulated by UUO. Administration of either SOF or EDV significantly attenuated cellular and molecular changes induced by UUO. Also, histopathological changes were improved. Moreover, SOF in combination with EDV, significantly improved UUO-induced renal fibrosis compared with each drug alone. Collectively, administration of either SOF or EDV or both of them significantly attenuated the rats with obstructive nephropathy, possibly by blocking the RIPK-3/MLKL necroptotic pathway and suppressing renal oxidative stress and inflammation.

Nebulized pH-Responsive Nanospray Combined with Pentoxifylline and Edaravone to Lungs for Efficient Treatments of Acute Respiratory Distress Syndrome

The COVID-19 pandemic has become an unprecedented global medical emergency, resulting in more than 5 million deaths. Acute respiratory distress syndrome (ARDS) caused by COVID-19, characterized by the release of a large number of pro-inflammatory cytokines and the production of excessive toxic ROS, is the most common serious complication leading to death. To develop new strategies for treating ARDS caused by COVID-19, a mouse model of ARDS was established by using lipopolysaccharide (LPS). Subsequently, we have constructed a novel nanospray with anti-inflammatory and antioxidant capacity by loading pentoxifylline (PTX) and edaravone (Eda) on zeolite imidazolate frameworks-8 (ZIF-8). This nanospray was endowed with synergetic therapy, which could kill two birds with one stone: (1) the loaded PTX played a powerful anti-inflammatory role by inhibiting the activation of inflammatory cells and the synthesis of pro-inflammatory cytokines; (2) Eda served as a free radical scavenger in ARDS. Furthermore, compared with the traditional intravenous administration, nanosprays can be administered directly and inhaled efficiently and reduce the risk of systemic adverse reactions greatly. This nanospray could not only coload two drugs efficiently but also realize acid-responsive release on local lung tissue. Importantly, ZIF8-EP nanospray showed an excellent therapeutic effect on ARDS in vitro and in vivo, which provided a new direction for the treatment of ARDS.

Ferulic acid grafted into β-cyclodextrin nanosponges ameliorates Paraquat-induced human MRC-5 fibroblast injury

Paraquat (PQ) is a commercially important and effective herbicide in the world. Nevertheless, it has higher toxicity causing acute organ damage and different complications, mainly in the lungs and kidneys. Ferulic acid (FA), 4-hydroxy-3-methoxycinnamic acid imposes multiple pharmacological impacts. No protective effect of FA on PQ poisoning-caused human embryonic lung fibroblast damage has not been reported. Despite their many beneficial effects, FA is characterized by poor water solubility, low bioavailability, and phytochemical instability. To solve the problem, β-cyclodextrin nanosponge (β-CD NSs) was utilized to increase the solubility of FA so that it was grafted into β-CD NSs to establish β-CD@FA NSs. The purpose of this work was to examine for the first time the protective effect of β-CD@FA NS on MRC-5 human lung cells damages induced by PQ poisoning. MTS assay was performed to investigate the viability of MRC-5 cells at different concentrations of FA/β-CD@FA NSs when cells were co-cultured with 0.2 μg/mL PQ. The flow cytometry study was carried out to determine apoptosis. Malondialdehyde (MDA), superoxide dismutase (SOD), and catalase (CAT) levels were detected using appropriate biochemistry kits. Compared with the PQ group, the cell activity, CAT, and SOD levels were significantly increased in the FA and chiefly in β-CD@FA NSs intervention groups, whereas apoptosis and MDA levels were markedly decreased. The inflammatory factors tumor necrosis factor-alpha (TNF-α), interleukin 6 (IL-6), and interleukin 22 (IL-22) were detected. The results demonstrate that β-CD@FA NSs can inhibit PQ-induced cell damage by enhancing antioxidant stress capacity and regulation of inflammatory responses.

Nilotinib alleviates paraquat-induced hepatic and pulmonary injury in rats via the Nrf2/Nf-kB axis

BACKGROUND

Paraquat (PQ, 1,1'-dimethyl-4-4'-bipyridinium dichloride) is a highly toxic quaternary ammonium herbicide widely used in agriculture. It exerts its toxic effects mainly as a result of its redox cycle via the production of superoxide anions in organisms, leading to an imbalance in the redox state of the cell causing oxidative damage and finally cell death. The aim of this study was to estimate the beneficial protective role of nilotinib (NIL) on PQ-induced hepatic and pulmonary toxicity in rats.

METHODS

Male wistar rats were randomly divided into four groups, namely control, PQ (15 mg/kg), PQ plus NIL (5 mg/kg) and PQ plus NIL (10 mg/kg). NIL (5 and 10 mg/kg/day) was taken by oral syringe for five days followed by a single intra-peritoneal administration of PQ (15 mg/kg) on sixth day.

RESULTS

Pretreatment with NIL relieved the histological damage in liver and lung tissues and improved hepatic biochemical markers. It significantly (p < 0.05) reduced serum levels of ALT, AST, ALP, Y-GT and total bilirubin while increased that of albumin. Meanwhile, NIL significantly (p < 0.05) reduced oxidative stress markers via reduction of malondialdhyde (MDA) and elevation of glutathione (GSH) contents in liver and lung tissues. In addition, it significantly (p < 0.05) decreased the inflammation by reducing hepatic and pulmonary tumor necrosis factor alpha (TNF-α) and nuclear transcription factor kappa B (NF-KB/p65) contents. Nilotinib also down-regulated apoptosis by reducing cysteinyl aspartate-specific proteinase-3 (caspase-3). Furthermore, it upregulated the expression of nuclear factor erythroid 2-related factor 2 (Nrf2) and microtubule-associated protein 1A/1B-light chain 3 II (LC3II) in liver and lung tissues.

SIGNIFICANCE

NIL suppressed PQ-induced inflammation, oxidative stress and apoptosis in liver and lung tissues by modulating Nrf2/Nf-kB axis.

Edaravone protects against liver fibrosis progression via decreasing the IL-1β secretion of macrophages

Edaravone (EDA), a strong novel free radical scavenger, have been demonstrated to exert neurovascular protective effects clinically. Furthermore, EDA can suppress the lung injury, pulmonary fibrosis and skin fibrosis, while the precise effects and mechanisms of EDA on liver injury and fibrosis remain unclear. The effects of EDA on the Thioacetamide (TAA)-induced liver fibrosis were evaluated by sirius red staining, α-SMA immunohistochemistry. The percentages of immune cell subsets were analyzed by flow cytometry. Immunofluorescence assay was performed to identify the fibrotic properties of hepatic stellate cells (HSCs). Western blot and qPCR were used to detect the levels of liver fibrosis-related molecules and IL-1β. EDA displayed a hepatic protective role in TAA-induced chronic liver fibrosis via inhibiting monocyte/macrophages recruitment and IL-1β production of macrophages. Mechanically, EDA inhibited of NF-κB signal pathway and reactive oxygen species (ROS) production in macrophages. Moreover, EDA treatment indirectly suppressed the activation of HSCs by decreasing the IL-1β secretion of macrophages. Together, EDA protects against TAA-induced liver fibrosis via decreasing the IL-1β production of macrophages, thereby providing a feasible solution for clinical treatment of liver fibrosis.

Pectin/chitosan/tripolyphosphate encapsulation protects the rat lung from fibrosis and apoptosis induced by paraquat inhalation

BACKGROUND

Paraquat poisoning leads to lung injury and pulmonary fibrosis. The effect of paraquat encapsulation by previously described Pectin/Chitosan/Tripolyphosphate nanoparticles on its pulmonary toxicity was investigated in present study in a rat model of poison inhalation.

MATERIAL AND METHOD

The rats inhaled nebulized different formulation of paraquat (n = 5) for 30 min in various experimental groups. Lung injury and fibrosis scores, Lung tissue enzymatic activities, apoptosis markers were determined compared among groups.

RESULTS

Encapsulation of paraquat significantly rescued both lung injury and fibrosis scores. Lung MDA level was reduced by encapsulation. Paraquat poisoning led to lung tissue apoptosis as was evidenced by higher Caspase-3 and Bax/Bcl2 expressions in rats subjected to paraquat inhalation instead of normal saline or free nanoparticles. Again, nanoencapsulation reduced these apoptosis markers significantly. Alpha-SMA expression was also reduced by encapsulation. Nanoparticles per se have no or little toxicity as was evidenced by inflammatory and apoptotic markers and histological scores.

CONCLUSION

In a rat model of inhalation toxicity of paraquat, loading of this herbicide on PEC/CS/TPP nanoparticles reduced acute lung injury and fibrosis. The encapsulation also led to lower apoptosis, oxidative stress and alpha-SMA expression in the lung tissue.

The effects of edaravone, a free-radical scavenger in lung injury induced by valproic acid demonstrated via different biochemical parameters

In this study, we aimed to evaluate whether edaravone (EDA) has a protective role against valproic acid (VPA)-induced lung damage via its antioxidative activity. Male Sprague-Dawley rats were split into four groups. Control (n = 8) rats; rats given EDA (30 mg kg^-1  day^-1 ; n = 10); rats given only (VPA, 500 mg kg^-1  day^-1 ; n = 10); rats given VPA + EDA (in the same dose and time) for 7 days. EDA and VPA were applied intraperitoneally. After 8 days, lung tissues were immediately taken from the rats. In lung homogenates, reduced glutathione, total antioxidant status levels, and superoxide dismutase, glutathione peroxidase, sodium/potassium ATPase, paraoxonase1, and carbonic anhydrase activities significantly abated, whereas catalase, glutathione reductase, glutathione-S-transferase activities insignificantly decreased in the VPA-treated group. In contrast, lipid peroxidation, reactive oxygen species, and total oxidant status levels, glycoprotein and protein carbonyl contents, nitric oxide, hydroxyproline levels, and xanthine oxidase, lactate dehydrogenase, arginase, and prolidase activities significantly increased in the VPA-given group. Administration of EDA caused the reverse effects. As a consequence, EDA prevented oxidative stress-mediated lung injury via its robust antioxidant effects.

Klotho Alleviates Lung Injury Caused by Paraquat via Suppressing ROS/P38 MAPK-Regulated Inflammatory Responses and Apoptosis

Acute lung injury (ALI) induced by paraquat (PQ) progresses rapidly with high mortality; however, there is no effective treatment, and the specific mechanism is not well understood. The antiaging protein klotho (KL) has multiple functions and exerts significant influences on various pathophysiological processes. This work evaluated the impact of KL on PQ-induced ALI and investigated its underlying mechanisms. As for in vivo research, C57BL/6 mice were treated with PQ (30 mg/kg) intraperitoneal (IP) injection to create a toxicity model of ALI (PQ group). The mice were divided into control group, KL group, PQ group, and PQ+KL group. For in vitro experiment, A549 cells were incubated with or without KL and then treated in the presence or absence of PQ for 24 h. In vivo result indicated that KL reduced the mortality, reduced IL-1β and IL-6 in the bronchoalveolar lavage fluid (BALF), attenuated ALI, and decreased apoptosis in situ. In vitro result revealed that KL significantly improved cell viability, reduced the levels of IL-1β and IL-6 in culture supernatants, suppressed cell apoptosis, inhibited caspase-3 activation, and enhanced mitochondrial membrane potential (ΔΨm) after PQ treatment. Besides, KL effectively abated reactive oxygen species (ROS) production, improved GSH content, and lowered lipid peroxidation in PQ-exposed A549 cells. Further experiments indicated that phosphorylated JNK and P38 MAPK was increased after PQ treatment; however, KL pretreatment could significantly lower the phosphorylation of P38 MAPK. Suppression of P38 MAPK improved cell viability, alleviated inflammatory response, and reduced apoptosis-related signals; however, it had no obvious effect on the production of ROS. Treatment with N-acetylcysteine (NAC), a classic ROS scavenger, could suppress ROS production and P38 MAPK activation. These findings suggested that KL could alleviate PQ-caused ALI via inhibiting ROS/P38 MAPK signaling-regulated inflammatory responses and mitochondria-dependent apoptosis.

Where ferroptosis inhibitors and paraquat detoxification mechanisms intersect, exploring possible treatment strategies

Paraquat (PQ) is a fast-acting and effective herbicide that is used throughout the world to eliminate weeds. Over the past years, PQ was considered one of the most popular poisoning substances for suicide, and PQ poisoning accounts for about one-third of suicides around the world. Poisoning with PQ may cause multiorgan failure, pulmonary fibrosis, and ultimately death. Exposure to PQ results in the accumulation of PQ in the lungs, causing severe damage and, eventually, fibrosis. Until now, no effective antidote has been found to treat poisoning with PQ. In general, the toxicity of PQ is due to the formation of high energy oxygen free radicals and the peroxidation of unsaturated lipids in the cell. Ferroptosis is the result of the loss of glutathione peroxidase 4 (GPX4) activity that transforms iron-dependent lipid hydroperoxides to lipid alcohols, which are inert in the biological environment. Impaired iron metabolism and lipid peroxidation are increasingly known as the driving agents of ferroptosis. The contribution of ferroptosis to the development of cell death during poisoning with PQ has not yet been addressed. There is growing evidence about the relationship between PQ poisoning and ferroptosis. This raises the possibility of using ferroptosis inhibitors for the treatment of PQ poisoning. In this hypothesis-driven review article, we elaborated how ferroptosis inhibitors might circumvent the toxicity induced by PQ and may be potentially useful for the treatment of PQ toxicity.

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.

Determination of LCt50 of aerosolized paraquat and its pulmonary toxic implications in non-anesthetized rats

Paraquat (PQ), a highly popular agricultural herbicide, is a serious occupational hazard with lethality reported at doses as low as 35 mg/kg body weight with intoxication occurring via inhalation or dermal route. The main objective of this study was to determine the median lethal concentration (LCt₅₀) of paraquat through whole body exposure in adult male Wistar rats. Aerosolized PQ dissolved in water was delivered in a dose-dependent manner, to fully conscious rats confined in whole body plethysmograph (WBP), in a nebulized form with concentrations ranging from 40-200 mg/kg of air over a 4 h exposure period. Animals were observed up to 24-48 h post-exposure to observe any lethality. LCt₅₀ estimates (±95% confidence interval) were obtained from the sequential stage-wise experiments using probit analysis. Rat lungs were examined radiologically and histopathologically. Gas chromatography-mass spectrometry (GC-MS) analysis determined the correlation of PQ accumulation in the lungs with the actual exposed dose of PQ. The actual LCt₅₀ was found to be 218 g·min/m³ whereas 57.9 ± 2.90 µg/g of PQ accumulated in the lungs of each lifeless animal. All animals exhibited severe respiratory changes and pulmonary abnormalities. This study demonstrated that when compared with the actually exposed dose, the amount of PQ that accumulated in the lungs was very low, but enough to cause death in 50% of animal population and cause pulmonary abnormalities in each of the experimental animal. The PQ exposure carried out in WBP also facilitated the dermal absorption of aerosolized PQ, which replicated the real-life situation in workers operating with PQ.

Resveratrol and Montelukast Alleviate Paraquat-Induced Hepatic Injury in Mice: Modulation of Oxidative Stress, Inflammation, and Apoptosis

Paraquat (PQ) is one of the most used herbicide worldwide. Its cytotoxicity is attributed to reactive radical generation. Resveratrol (Res) and montelukast (MK) have anti-inflammatory and antioxidant properties. The protective effects of Res, MK, or their combination against PQ-induced acute liver injury have not been investigated before. Therefore, we explored the protective potential of Res and/or MK against PQ hepatic toxicity in a mouse model. Mice were randomly assigned to five groups: group I served as the normal control and group II received a single dose of PQ (50 mg/kg, i.p.). Groups III, IV, and V received PQ plus oral Res (5 mg/kg/day), MK (10 mg/kg/day), and Res/MK combination, respectively. Res and/or MK reduced PQ-induced liver injury, evidenced by normalization of serum total protein, ALT, and AST. Res and/or MK significantly reversed PQ-induced oxidative stress markers glutathione and malondialdehyde. Res and/or MK significantly reduced PQ-induced inflammation reflected in TNF-α levels. Furthermore, Res and/or MK reversed PQ-induced apoptosis assessed by differential expression of p53, Bax, and Bcl-2. Histopathologic examination supported the biochemical findings. Although Res and MK displayed antioxidative, anti-inflammatory, and antiapoptotic activities, their combination was not always synergistic.

Curcumin inhibits paraquat induced lung inflammation and fibrosis by extracellular matrix modifications in mouse model

OBJECTIVE

Paraquat (PQ), a potent herbicide can cause severe toxicity. We report here that fibroproliferation phase of acute lung injury (ALI) is initiated much earlier (within 48 h) after PQ intoxication than previously reported (after 2 weeks) and we aimed to study the protective effects of intranasal curcumin as new therapeutic strategy in mouse model.

METHODS

Mice (Park's strain) were divided into five experimental groups (I) control, received only saline (0.9 % NaCl) (II) PQ, mice intoxicated with PQ (50 mg/kg, i.p., single dose); (III) curcumin, treated with curcumin (5 mg/kg, i.n) an hour before PQ administration; (IV)Veh, DMSO (equal volume to curcumin) given an hour before PQ exposure; (V) DEXA, mice treated with dexamethasone (1 mg/kg, i.p) before an hour of PQ intoxication. After 48 h of the PQ exposure, all mice were sacrificed and samples were analyzed.

RESULTS

Pretreatment with intranasal curcumin (5 mg/kg) could modify the PQ-intoxication (50 mg/kg, i.p) induced structural remodeling of lung parenchyma at an early phase of acute lung injury. Significant increase in inflammatory cell count, reactive oxygen species and hydroxyproline levels were decreased after curcumin pretreatment (all p < 0.05). Histological examination and zymography results were also found consistent.

CONCLUSION

Our results show that curcumin pretreatment decreased the expression of alpha smooth muscle actin (α-SMA), matrix metalloproteinases-9 (MMP-9) and changed the expression of tissue inhibitors of metalloproteinase (TIMP-1) after PQ intoxication. Single toxic dose of PQ has initiated fibroproliferation within 48 h and intranasal curcumin may prove as new therapeutic strategy for PQ induced ALI and fibroproliferation.

Protective effects of edaravone combined puerarin on inhalation lung injury induced by black gunpowder smog

OBJECTIVE

The present study aimed to investigate the combined effects of puerarin with edaravone on inhalation lung injury induced by black gunpowder smog.

MATERIALS AND METHODS

Male Wistar rats were divided into five groups (control group, edaravone group, puerarin group, edaravone combined with puerarin group and inhalation group). The severity of pulmonary injuries was evaluated after inducing acute lung injury. Arterial blood gas, inflammatory cytokines, biochemical, parameters, cell counting, W/D weight ratio and histopathology were analyzed. Results in lung tissues, either edaravone or puerarin treatment alone showed significant protective effects against neutrophil infiltration and tissue injury, as demonstrated by myeloperoxidase activity and histopathological analysis (all p<0.05). In addition, combined treatment with both edaravone and puerarin demonstrated additive protective effects on smog-induced lung injury, compared with single treatment.

CONCLUSIONS

Combination of edaravone and puerarin shows promise as a new treatment option for acute lung injury/acute respiratory distress syndrome patients.

The role of p38 MAPK in acute paraquat-induced lung injury in rats

CONTEXT

Paraquat (PQ; 1,1'-dimethyl-4,4'-bipyridinium dichloride) is highly toxic and accounts for a large proportion of the herbicide poisonings seen in clinic. The major cause of mortality is respiratory failure. The p38 mitogen-activated protein kinase (MAPK) signal transduction pathway coordinates various cellular stress responses that have been shown to participate in the pathogenesis of PQ-induced lung injury.

OBJECTIVE

To evaluate the effect of the specific p38 MAPK inhibitor SB203580 on PQ-induced lung injury and cytokine secretion.

METHODS

In groups of 24, rats were treated with PQ, PQ and SB203580 (SB + PQ), SB203580 alone (SB) or normal saline (control group). Six rats from each group were euthanized at 1, 3, 5 or 7 d. Pathology of lung specimens was scored through hematoxylin and eosin staining. Edema in the lung was quantified from wet-to-dry weight ratios. p38 and p-p38MAPK proteins were measured via electrochemiluminescent Western blots. tumor necrosis factor (TNF)-alpha and interleukin-1 beta (IL-1β) concentrations in lung specimens and bronchoalveolar lavage fluid (BALF) were quantified via enzyme-linked immunosorbent assay.

RESULTS

The mortality rate of the SB + PQ group (16.7%) was significantly lower than that of the PQ group (33.3%; p < 0.05). The PQ group had significantly higher pulmonary histology scores, wet-to-dry weight ratios and phosphorylated p-p38 MAPK levels, as well as higher IL-1β and TNF-alpha levels in BALF and lung tissues, that did the SB + PQ and control groups (p < 0.05, all).

CONCLUSION

The data suggest that the p38 MAPK signaling pathway has an important role in regulating the production of IL-1β and TNF-alpha in PQ-induced lung injury in rats.

Effect of ulinastatin on paraquat-induced-oxidative stress in human type II alveolar epithelial cells

BACKGROUND:

Ulinastatin (UTI) is a urinary trypsin inhibitor extracted and purified from urine of males. This study aimed to explore the effects of UTI on paraquat-induced-oxidative stress in human type II alveolar epithelial cells.

METHODS:

The human type II alveolar epithelial cells, A549 cells, were cultured in vitro. The A549 cells were treated with different concentrations of paraquat (200, 400, 600, 800, 1 000, 1 200 µmol/L) and ulinastatin(0, 2 000, 4 000, 6 000, 8 000 U/mL) for 24 hours, the cell viability was measured by cell counting kit-8 and the median lethal concentration was selected. In order to establish an in vitro model of paraquat intoxication and to determine the safe dose of ulinastatin, we calculated LD50 using cell counting kit-8 to determine the survival rate of the cells. A549 cells were divided into normal control group, paraquat group and paraquat+ulinastatin group. The levels of malondialdehyde (MDA) and myeloperoxidase (MPO) were detected by biochemistry colorimetry, while the level of reactive oxygen spies (ROS) was detected by DCFH-DA assay.

RESULTS:

The survival rate of A549 cells treated with different concentrations of paraquat decreased in a concentration-dependent manner. Whereas there was no decrease in the survival rate of cells treated with 0–4 000 U/mL ulinastatin. The levels of MDA, MPO, and ROS were significantly higher in the paraquat group than in the normal control group after 24-hour-exposure. And the survival rate of the paraquat+ulinastatin group was higher than that of the paraquat group, but lower than that of the normal control group. The levels of MDA, MPO, and ROS were lower than those of the paraquat group.

CONCLUSION:

Ulinastatin can alleviate the paraquat-induced A549 cell damage by reducing oxidative stress.

Clinical characteristics of paraquat poisoning in 22 Chinese children

OBJECTIVE

To retrospectively analyze the clinical characteristics and experience of Chinese children with paraquat poisoning.

METHODS

Twenty-two children with paraquat poisoning who presented to the hospital from October 2007 through September 2012 were enrolled into this study. The clinical indices of these cases were collected and analyzed.

RESULTS

All the children were poisoned due to oral ingestion of paraquat. Different degrees of damage were found in multiple systems in their bodies. All of them were administered pulse therapy using methylprednisolone (20 mg/kg/d × 3d) and Gamma globulin (total 2 g/kg divided into 3 d to 5 d) in the early stage. Prednisone was then given orally for 4 wk to 8 wk. The total mortality rate of the patients was 63.6 % (14 of 22 patients died). Statistical differences (P < 0.05) were found between the surviving and dead patients, with regard to age, plasma paraquat levels, the highest levels of alanine aminotransferase, aspartate aminotransferase, γ-glutamyl transferase, total bilirubin, direct bilirubin, indirect bilirubin, blood urea nitrogen, creatinine and pH value, the lowest levels of PaO2, PaCO2 and SaO2. Plasma paraquat level was positively related to pH value, but was negatively related to PaO2, PaCO2 and SaO2 levels. None of the patients died from hepatic and renal complications. Pulmonary fibrosis was the most severe complication and the primary cause of death.

CONCLUSIONS

Paraquat poisoning is difficult to cure. In this study, pulmonary fibrosis was the primary cause of death. Treatment by administering large doses of glucocorticoids and Gamma globulin proved to be effective in the early stage. However, the treatment may not reverse the development of pulmonary fibrosis. The long-term prognosis of paraquat poisoning was not optimistic. The plasma paraquat level could be a significant factor in predicting the prognosis.

FTY720 attenuates paraquat-induced lung injury in mice

Paraquat (PQ) poisoning, with the lung as a primary target organ, is a devastating disease which irreversibly progresses to diffuse alveolitis followed by extensive lung fibrosis. In the present study, we aimed to investigate the effect of FTY720, an immune modulator, on PQ-induced lung injury in mice. C57BL/6 mice were randomized into four groups: 1) PQ group (n=12): mice was instilled with PQ (30 mg/kg, ip); 2) PQ+FTY720 group (n=12): animals received FTY720 (0.1mg/kg, ip) solution 2h after PQ exposure and twice a week for 4 consecutive weeks; 3) FTY720 group (n=5): FTY720 (0.1mg/kg, ip) was administrated twice a week for 4 consecutive weeks; and 4) Control group (n=10): same volumes of saline were injected. Mice were sacrificed on either day 3 or day 28 for histopathological, biochemical and immunohistochemical analyses of lung damage indicators. We found that FTY720 treatment attenuated PQ-induced acute lung injury and lung fibrosis as evaluated by histopathological changes and Ashcroft score. On day 3, FTY720 administration reduced PQ-induced increases in lung wet weight/body weight (LW/BW), total protein and cytokine levels including interleukin-1β (IL-1β), interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) in bronchoalceolar lavage fluid (BALF). On day 28, the expressions of alpha-smooth muscle actin (α-SMA), transforming growth factor-beta (TGF-β) and vascular endothelial growth factor (VEGF) detected by immunohistochemistry, as well as the mRNA levels of α-SMA, Type-I Collagen and Type-III Collagen examined by Real-time PCR were down-regulated after FTY720 treatment. These results indicate that FTY720 could attenuate PQ-induced lung injury, but further investigation is necessary.

Effect of methylsulfonylmethane on paraquat-induced acute lung and liver injury in mice

Methylsulfonylmethane (MSM) is a natural organosulfur compound that exhibits antioxidative and anti-inflammatory effects. This study was carried out to investigate the effect of MSM on paraquat (PQ)-induced acute lung and liver injury in mice. A single dose of PQ (50 mg/kg, i.p.) induced acute lung and liver toxicity. Mice were treated with MSM (500 mg/kg/day, i.p.) for 5 days. At the end of the experiment, animals were euthanized, and lung and liver tissues were collected for histological and biochemical analysis. Tissue samples were used to determine malondialdehyde (MDA), myeloperoxidase (MPO), catalase (CAT), superoxide dismutase (SOD), glutathione (GSH), and tumor necrosis factor-α (TNF-α) levels. Blood samples were used to measure plasma alanine transaminase (ALT), γ-glutamyl transferase (GGT), and alkaline phosphatase (ALP). Histological examination indicated that MSM decreased lung and liver damage caused by PQ. Biochemical results showed that MSM treatment significantly reduced tissue levels of MDA, MPO, and TNF-α, while increased the levels of SOD, CAT, and GSH compared with PQ group. MSM treatment also significantly reduced plasma levels of ALT, GGT, and ALP. These findings suggest that MSM as a natural product attenuates PQ-induced pulmonary and hepatic oxidative injury.

New insights into antioxidant strategies against paraquat toxicity

Paraquat (PQ, 1,1'-dimethyl-4-4'-bipyridinium dichloride) is a highly toxic quaternary ammonium herbicide widely used in agriculture, it exerts its toxic effects mainly because of its redox cycle through the production of superoxide anions in organisms, leading to an imbalance in the redox state of the cell causing oxidative damage and finally cell death. The contribution of mitochondrial dysfunction including increased production of reactive oxygen species besides the reduction in oxygen consumption as well as in the activity of some respiratory complexes has emerged as a key component in the mechanisms through which PQ induces cell death. Although several aspects of PQ-mitochondria interaction remain to be clarified, recent advances have been conducted with reproducible results. Currently, there is no treatment for PQ poisoning; however, several studies taking into account oxidative stress as the main mechanism of PQ-induced toxicity suggest an antioxidant therapy as a viable alternative. In fact, it has been shown that the antioxidants naringin, sylimarin, edaravone, Bathysa cuspidata extracts, alpha-lipoic acid, pirfenidone, lysine acetylsalicylate, selenium, quercetin, C-phycocyanin, bacosides, and vitamin C may be useful in the treatment against PQ toxicity. The main mechanisms involved in the protective effect of these antioxidants include the reduction of oxidative stress and inflammation and the induction of antioxidant defenses. Interestingly, recent findings suggest that the induction of nuclear factor erythroid like-2 (Nrf2), a major regulator of the antioxidant response, by some of the above-mentioned antioxidants, has been involved in the protective effect against PQ-induced toxicity.

The dose of cyclophosphamide for treating paraquat-induced rat lung injury

BACKGROUND/AIMS

Cyclophosphamide (CP) is a promising treatment for severe cases of paraquat (PQ) poisoning. We investigated the effective dose of CP for mitigating PQ-induced lung injury.

METHODS

Adult male Sprague-Dawley rats were allocated into five groups: control, PQ (35 mg/kg, intraperitoneal injection), and PQ + CP (1.5, 15, or 30 mg/kg). The dimensions of lung lesions were determined using X-ray microtomography (micro-CT), and histological changes and cytokine levels were recorded.

RESULTS

The micro-CT results showed that 15 mg/kg CP was more effective than 1.5 mg/kg CP for treating PQ-induced lung injury. At a dose of 1.5 mg/kg, CP alleviated the histological evidence of inflammation and altered superoxide dismutase activity. Using 15 mg/kg CP reduced the elevated catalase activity and serum transforming growth factor (TGF)-β1 level.

CONCLUSIONS

A CP dose of > 15 mg/kg is effective for reducing the severity of PQ-induced lung injury as determined by histological and micro-CT tissue examination, possibly by modulating antioxidant enzyme and TGF-β1 levels.

Size changes in honey bee larvae oenocytes induced by exposure to Paraquat at very low concentrations

The effects of the herbicide Paraquat were investigated in honey bee larvae with attention focused on oenocytes. Honey bee larvae were exposed to Paraquat at different concentrations in the food: 0, 0.001, 0.01, 0.1 and 1 µg/kg. In controls, between 24 h and 48 h, oenocytes grew from 630.1 to 1643.8 µm(2) while nuclei changed in size from 124.9 to 245.6 µm(2). At 24 h, Paraquat induced a slight decrease in the size of oenocytes and nuclei. N-acetylcysteine (NAC), an antioxidant substance, slightly lowered the effects of Paraquat. At 48 h, Paraquat elicited a strong concentration-dependent decrease in the size of oenocytes, even at the lowest concentration. NAC reversed the effect of Paraquat at a concentration of ≥0.01 µg/kg. This reversion suggested different modes of action of Paraquat, with an oxidant action prevalent at concentrations ≥0.01 µg/kg. This study is the first which reports an effect of a pesticide at the very low concentration of 1 ng/kg, a concentration below the detection limits of the most efficient analytic methods. It shows that chemicals, including pesticides, are likely to have a potential impact at such exposure levels. We also suggest that Paraquat could be used as a suitable tool for investigating the functions of oenocytes.

Role of NADPH oxidase/ROS in pro-inflammatory mediators-induced airway and pulmonary diseases

Reactive oxygen species (ROS) are products of normal cellular metabolism and are known to act as second messengers. Under physiological conditions, ROS participate in maintenance of cellular 'redox homeostasis' in order to protect cells against oxidative stress. In addition, regulation of redox state is important for cell activation, viability, proliferation, and organ function. However, overproduction of ROS, most frequently due to excessive stimulation of either reduced nicotinamide adenine dinucleotide phosphate (NADPH) by pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) or the mitochondrial electron transport chain and xanthine oxidase, results in oxidative stress. Oxidative stress is a deleterious process that leads to airway and lung damage and consequently to several respiratory inflammatory diseases/injuries, including acute respiratory distress syndrome (ARDS), asthma, cystic fibrosis (CF), and chronic obstructive pulmonary disease (COPD). Many of the known inflammatory target proteins, such as matrix metalloproteinase-9 (MMP-9), intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), cyclooxygenase-2 (COX-2), and cytosolic phospholipase A(2) (cPLA(2)), are associated with NADPH oxidase activation and ROS overproduction in response to pro-inflammatory mediators. Thus, oxidative stress regulates both key inflammatory signal transduction pathways and target proteins involved in airway and lung inflammation. In this review, we discuss mechanisms of NADPH oxidase/ROS in the expression of inflammatory target proteins involved in airway and lung diseases. Knowledge of the mechanisms of ROS regulation could lead to the pharmacological manipulation of antioxidants in airway and lung inflammation and injury.

[Paraquat poisoning. Case report and overview]

Paraquat poisoning in Germany is rare. Because plasma levels do not necessarily match the ingested amount of paraquat, repeated measurement of plasma levels is imperative. There is a large potential in the prehospital phase to improve prognosis: further resorption must be terminated by rigorous charcoal administration and early tracheal intubation if necessary. Because paraquat can be resorbed by dermal contact, steps to ensure sufficient protection of emergency medical personnel must be taken.As soon as further resorption has been prevented sufficiently, forced diuresis, renal replacement therapy, and hemoperfusion can be of help, but still remain controversial. To reduce pulmonary fibrosis, inspiratory oxygen concentrations must be adjusted to the minimal amount needed to ensure satisfactory tissue oxygenation. Data supporting the advantageous use of cyclophosphamide combined with methylprednisolone for the treatment of pulmonary fibrosis were recently published. Since the toxic mechanism implies a mismatch of oxidants and anti-oxidants, co-administration of ascorbic acid and N-acetylcysteine are simple treatments with few side effects.

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

BACKGROUND

Edaravone (3-methyl-1-penyl-2-pyrazolin-5-one) is a potent free-radical scavenger and has the antioxidant ability to inhibit lipid peroxidation. The study aimed to examine the effect of edaravone on protecting the acute injury of human type II alveolar epithelial cells (A549 cells) induced by paraquat (PQ) and the change of production of reactive oxygen species (ROS), malondialdehyde (MDA), superoxide dismutase (SOD).

METHODS

A549 cells were cultured and divided into PQ group (group P), edaravone-treated group (group E) and normal control group (group C). The cells in group P were exposed to paraquat (600 μmol/L), and the cells in group E were treated with edaravone (100 μmol/L) additionally, and no drug intervention was given to the cells in group C. Real-time monitoring by LSCM was used to detect the cell response and the intracellular dynamic change of ROS level in A549 cells after administration of PQ and edaravone. And the levels of SOD and MDA were detected respectively by biochemistry colorimetry. Data were expressed as mean ± standard error of the mean. Statistical analysis was carried out with the soft SPSS 16.0.

RESULTS

The concentration of intracellular ROS significantly increased when PQ was given to A549 cells. But after administration of edaravone, the concentration of intracellular ROS was decreased. Compared to the PQ group, the levels of SOD in the edaravone group were significantly increased while the levels of MDA were markedly decreased.

CONCLUSIONS

Paraquat can increase the oxidative stress, and induce the lipid peroxidation of A549 cells. Edaravone has the effect to scavenge reactive oxygen species, and to protect against the PQ-induced lung toxicity.

Pharmacological antioxidant strategies as therapeutic interventions for COPD

Cigarette/tobacco smoke/biomass fuel-induced oxidative and aldehyde/carbonyl stress are intimately associated with the progression and exacerbation of chronic obstructive pulmonary disease (COPD). Therefore, targeting systemic and local oxidative stress with antioxidants/redox modulating agents, or boosting the endogenous levels of antioxidants are likely to have beneficial effects in the treatment/management of COPD. Various antioxidant agents, such as thiol molecules (glutathione and mucolytic drugs, such as N-acetyl-L-cysteine and N-acystelyn, erdosteine, fudosteine, ergothioneine, and carbocysteine), have been reported to modulate various cellular and biochemical aspects of COPD. These antioxidants have been found to scavenge and detoxify free radicals and oxidants, regulate of glutathione biosynthesis, control nuclear factor-kappaB (NF-kappaB) activation, and hence inhibiting inflammatory gene expression. Synthetic molecules, such as specific spin traps like α-phenyl-N-tert-butyl nitrone, a catalytic antioxidant (ECSOD mimetic), porphyrins (AEOL 10150 and AEOL 10113), and a superoxide dismutase mimetic M40419, iNOS and myeloperoxidase inhibitors, lipid peroxidation inhibitors/blockers edaravone, and lazaroids/tirilazad have also been shown to have beneficial effects by inhibiting cigarette smoke-induced inflammatory responses and other carbonyl/oxidative stress-induced cellular alterations. A variety of oxidants, free radicals, and carbonyls/aldehydes are implicated in the pathogenesis of COPD, it is therefore, possible that therapeutic administration or supplementation of multiple antioxidants and/or boosting the endogenous levels of antioxidants will be beneficial in the treatment of COPD. This review discusses various novel pharmacological approaches adopted to enhance lung antioxidant levels, and various emerging beneficial and/or prophylactic effects of antioxidant therapeutics in halting or intervening the progression of COPD. This article is part of a Special Issue entitled: Antioxidants and Antioxidant Treatment in Disease.