Exploring the potential benefit of natural product extracts in paraquat toxicity

Protective effect of Bougainvillea glabra Choisy bract in toxicity induced by Paraquat in Drosophila melanogaster

Paraquat (PQ) is a herbicide widely used in agriculture to control weeds. The damage caused to health through intoxication requires studies to combating its damage to health. Bougainvillea glabra Choisy is a plant native to South America and its bracts contain a variety of compounds, including betalains and phenolic compounds, which have been underexplored about their potential applications and benefits for biological studies to neutralize toxicity. In this study, we evaluated the antioxidant and protective potential of the B. glabra bracts (BBGCE) hydroalcoholic extract against Paraquat-induced toxicity in Drosophila melanogaster. BBGCE demonstrated high antioxidant capacity in vitro through the assays of ferric-reducing antioxidant power (FRAP), radical 2,2-diphenyl-1-picrylhydrazyl (DPPH), free radical ABTS and quantification of phenolic compounds, confirmed through identifying the main compounds. Wild males of D. melanogaster were exposed to Paraquat (1.75 mM) and B. glabra Choisy (1, 10, 50 and 100 μg/mL) in agar medium for 4 days. Flies exposed to Paraquat showed a reduction in survival rate and a significant decrease in climbing capacity and balance test when compared to the control group. Exposure of the flies to Paraquat caused a reduction in acetylcholinesterase activity, an increase in lipid peroxidation and production of reactive species, and a change in the activity of the antioxidant enzymes. Co-exposure with BBGCE was able to block toxicity induced by PQ exposure. Our results demonstrate that bract extract has a protective effect against PQ on the head and body of flies, attenuating behavioral deficit, exerting antioxidant effects and blocking oxidative damage in D. melanogaster.

Prognosis prediction of procalcitonin within 24 h for acute diquat poisoning

BACKGROUND

To explore the predictive value of procalcitonin (PCT) within 24 h after poisoning for prognosis of acute diquat poisoning.

METHODS

This retrospective study included acute diquat poisoning patients in the Nanyang City Hospital between May 2017 and July 2021.

RESULTS

Among the 45 patients included, 27 survived. The maximum PCT value within 24 h after poisoning was significantly higher in the non-survival patients [9.65 (2.63, 22.77) vs. 0.15 (0.10, 0.50) µg/mL, P < 0.001] compared to the survival patients. The area under the ROC curve (AUC) indicated that the maximum PCT value within 24 h had a good predictive value (AUC = 0.905, 95% CI: 0.808-1.000) compared to ingested quantity (AUC = 0.879, 95% CI: 0.776-0.981), serum creatinine (AUC = 0.776, 95% CI: 0.640-0.912), or APACHE II score (AUC = 0.778, 95% CI: 0.631-0.925). The predictive value of maximum PCT value within 24 h was comparable with blood lactate (AUC = 0.904, 95%CI: 0.807-1.000).

CONCLUSIONS

The maximum PCT value within 24 h after poisoning might be a good predictor for the prognosis of patients with acute diquat poisoning.

Molecular mechanism of paraquat-induced ferroptosis leading to pulmonary fibrosis mediated by Keap1/Nrf2 signaling pathway

Paraquat (PQ) is a widely used and highly toxic pesticide that is often actively ingested and causes pulmonary fibrosis in patients. Ferroptosis is a regulated form of non-apoptotic cell death associated with iron-dependent lipid peroxidation. Previous studies have shown that ferroptosis is involved in the occurrence and development of acute lung injury (ALI). In this study, a model rat with inflammatory response, oxidative stress, lipid peroxidation, and pulmonary fibrosis was successfully established by PQ administration. The occurrence of ferroptosis in PQ model rats was confirmed by TUNEL staining, iron ion detection, and Ferroptosis related biomarkers detection. Western blotting (WB) and real-time PCR (RT-PCR) showed that the expression of Keap1 was significantly up-regulated and the expression of Nrf2 was significantly down-regulated in the lung tissue of PQ rats. Further transcriptomics and proteomics confirmed: (1) Enrichment of molecular processes related to iron ion binding; (2) Keap1 may promote Nrf2 ubiquitination and lead to Nrf2 degradation; (3) There is functional enrichment in ferroptosis related pathways. Our results suggest that PQ can regulate Keap1/Nrf2 signaling pathway, leading to increased lipid peroxidation and abnormal iron uptake, thereby inducing iron death and exacerbating the progression of pulmonary fibrosis. Our study provides new insights into PQ-induced pulmonary fibrosis.

Surface molecularly imprinted-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for highly selective and sensitive direct analysis of paraquat in complicated samples

Herein, a novel surface molecularly imprinted-based matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (SMI-MALDI-TOF MS) method for direct target paraquat (PQ) analysis in complicated samples is reported. Notably, a captured analyte-imprinted material can be directly detected via MALDI-TOF MS by using imprinted material as nanomatrix. Using this strategy, the molecular specific affinity performance of surface molecularly imprinted polymers (SMIPs) and the high-sensitivity detection capability of MALDI-TOF MS was integrated. The introduction of SMI endowed the nanomatrix with the capacity for rebinding the target analyte and ensuring specificity, prevented the interfering organic matrix, and enhanced the analyzing sensitivity. By using paraquat (PQ) as a template, dopamine as a monomer, and covalent organic frameworks with a carboxyl group (C-COFs) as a substrate, polydopamine (PDA) was decorated on C-COFs via a simple self-assembly procedure to generate an analyte-based surface molecularly imprinted polymer (C-COF@PDA-SMIP), which served the dual function of SMIP capturing the target analytes and high-efficiency ionization. Thus, a reliable MALDI-TOF MS detection PQ with high selectivity and sensitivity as well as an interference-free background was achieved. The synthesis and enrichment conditions of C-COF@PDA-SMIPs were optimized, and its structure and property were characterized. Under optimal experimental conditions, the proposed method achieved highly selective and ultrasensitive detection of PQ from 5 to 500 pg mL^-1, and the limit of detection was as low as 0.8 pg mL^-1, which is at least three orders of magnitude lower than that achieved without enrichment. In addition, the specificity of the proposed method was superior to that of C-COFs and nonimprinted polymers. Moreover, this method exhibited reproducibility, stability, and high salt tolerance. Lastly, the practical applicability of the method was successfully verified by analyzing complicated samples, such as grass and orange.

LC-MS/MS methods for the determination of 30 quaternary ammonium compounds including benzalkonium and paraquat in human serum and urine

Benzalkyldimethylammonium (or benzalkonium; BACs), alkyltrimethylammonium (ATMACs), and dialkyldimethylammonium compounds (DDACs) have been widely used for over six decades as disinfectants, especially during the COVID-19 pandemic. Here we describe methods for the determination of 7 BACs, 6 ATMACs, 6 DDACs, 8 BAC metabolites, and the structurally similar quaternary ammonium compound (QAC) herbicides diquat, paraquat, and difenzoquat in human serum and urine using liquid chromatography-tandem mass spectrometry (LC-MS/MS). The methods were optimized using isotopically labelled internal standards and solid-phase extraction with weak cation-exchange cartridges. We separated diquat and paraquat chromatographically using a mixed-mode LC column, and BACs, ATMACs, DDACs, difenzoquat, and BAC metabolites using reversed-phase (C8 and C18) LC columns. Method limits of detection (MLODs) and quantification (MLOQs) were 0.002-0.42 and 0.006-1.40 ng/mL, respectively. Recoveries of all analytes fortified at 1, 5, and 20 ng/mL concentrations in serum and urine matrices were 61-129%, with standard deviations of 0-20%. Repeated analysis of similarly fortified serum and urine samples yielded intra-day and inter-day variations of 0.22-17.4% and 0.35-17.3%, respectively. Matrix effects for analytes spiked into serum and urine matrices ranged from -27% to 15.4%. Analysis of real urine and serum samples revealed the presence of several QACs in human serum. Although no parent BACs were found in urine, we detected, for the first time, several ω-hydroxy and ω-carboxylic acid metabolites of BACs at average concentrations in the range of 0.05-0.35 ng/mL. The developed method is suitable for application in large-scale biomonitoring of human exposure to QACs and their metabolites in human serum and urine.

Toxic effects of pesticides on cellular and humoral immunity: an overview

People are exposed to pesticides through food, drinking water, and the environment. These compounds are associated with several disorders, such as inflammatory diseases, rheumatoid arthritis, cancer, and a condition related to metabolic syndrome. The immunotoxicants or immunotoxic compounds can cause a wide variety of effects on immune function, altering humoral immunity and cell-mediated immunity, resulting in adverse effects to the body. Here, immune system disorders are highlighted because they are closely linked to multiple organs, including the nervous, endocrine, reproductive, cardiovascular, and respiratory systems, leading to transient or permanent changes. Therefore, this study reviewed the mechanisms involved in the immunotoxicity of fungicides, herbicides, and insecticides in cells, animals, and humans in the past 11 years. According to the studies analyzed, the pesticides interfere with innate and adaptive immune functions, but the effects observed mainly on cellular and humoral immunity were highlighted. These compounds affected specific immune cells, causing apoptosis, changes in factor nuclear kappa B (NF-κB) expression, pro-inflammatory factors interleukin 6 (IL-6), interleukin 8 (IL-8), interferon-gamma (IFN-γ), chemokines (CXCL-c1c), and anti-inflammatory factor, such as interleukin 10 (IL-10). To verify the threats of these compounds, new evaluations with immunotoxicological biomarkers are necessary. HighlightsPesticides interfere with the innate and adaptive immune response.Cells, animals and human studies demonstrate the immunotoxicity of pesticides in the cellular and humoral immune response.Fungicides, herbicides, and insecticides alter the immune system by various mechanisms, such as pro-inflammatory and anti-inflammatory factors.

Potentiation of paraquat toxicity by inhibition of the antioxidant defenses and protective effect of the natural antioxidant, 4-hydroxyisopthalic acid in Drosophila melanogaster

Exposure to pesticides such as paraquat (PQ) is known to induce oxidative stress-mediated damage, which is implicated in neurodegenerative diseases. The antioxidant enzymes are part of the endogenous defense mechanisms capable of protecting against oxidative damage, and down-regulation of these enzymes results in elevated oxidative stress. In this study, we have evaluated the protective action of 4-hydroxyisophthalic acid (DHA-I), a novel bioactive molecule from the roots of D. hamiltonii, against PQ toxicity and demonstrated the protective role of endogenous antioxidant enzymes under the condition of oxidative stress using Drosophila model. The activity of the major antioxidant enzymes, superoxide dismutase 1 (SOD1) and catalase, was suppressed either by RNAi-mediated post transcriptional gene silencing or chemical inhibition. With the decreased in vivo activity of either SOD1 or catalase, Drosophila exhibited hypersensitivity to PQ toxicity, demonstrating the essential role of antioxidant enzymes in the mechanism of defense against PQ-induced oxidative stress. Dietary supplementation of DHA-I increased the resistance of Drosophila depleted in either SOD1 or catalase to PQ toxicity. Enhanced survival of flies against PQ toxicity indicates the protective role of DHA-I against oxidative stress-mediated damage under the condition of compromised antioxidant defenses.

Thunbergia laurifolia aqueous leaf extract ameliorates paraquat-induced kidney injury by regulating NADPH oxidase in rats

We aim to study the antioxidant ability of Thunbergia laurifolia (TL) aqueous leaf extract against PQ-induced kidney injury. Rats were divided into four groups (n = 4 per group): control group, the rats received subcutaneous injection of 1 ml/kg body weight (BW) normal saline; PQ group, the rats received subcutaneous injection of 18 mg/kg BW paraquat dichloride; PQ + TL-low dose (LD) group, the rats received subcutaneous injection of 18 mg/kg BW paraquat dichloride and were orally gavaged with TL leaf extract (100 mg/kg BW); and PQ + TL-high dose (HD) group, the rats received subcutaneous injection of 18 mg/kg BW paraquat dichloride and were orally gavaged with TL leaf extract (200 mg/kg BW). This study analyzed blood urea nitrogen (BUN) and creatinine levels, renal malondialdehyde (MDA) levels, kidney histopathology, mRNA expressions of renal NADPH oxidase (NOX) and protein expressions of renal NOX-1 and NOX-4 using immunohistochemistry. The PQ group showed a significant increase in BUN and creatinine levels, renal MDA level, and a upregulation of the mRNA expression of renal NOX compared with the control group. It also demonstrated mild hydropic degeneration of the tubules. Immunohistochemistry displayed a significant increase in the protein expressions of renal NOX-1 and NOX-4 compared with the control group. TL aqueous leaf extract especially in the high dose group significantly reduced the BUN and creatinine levels, the renal MDA level, and downregulated the mRNA expression of renal NOX and protein expressions of renal NOX-1 and NOX-4 compared with the PQ group. Furthermore, it can improve PQ-induced kidney injury. TL aqueous leaf extract can ameliorate PQ-induced kidney injury by regulating oxidative stress through inhibiting NOX, especially NOX-1 and NOX-4 expressions.

Attenuating effect of Prosopis cineraria against paraquat-induced toxicity in prepubertal mice, Mus musculus

Several herbicides, especially paraquat, are persistent organic pollutants which cause damage to humans and animals through reactive oxygen and nitrogen species. Prosopis cineraria (L.) Druce exhibits antioxidant activity and can effectively manage tremors. Therefore, the present research assessed the preventive effect of Prosopis cineraria (L.) Druce ethanolic extract (PCDE) against paraquat-induced toxicity in prepubertal mice. The plant extract was chemically characterized by a high-performance liquid chromatography-diode array detector (HPLC-DAD). The PCDE was orally administered to prepubertal mice for continuous 21 days, 2 h before paraquat exposure (2 mg/kg for consecutive 3 days per week for 3 weeks). The changes in behavior, motor coordination, memory, muscle movement, anxiety, and neurotransmitter levels in the brain were assessed. Histopathology and estimation of oxidative stress parameters in the brain, liver, kidney, and heart tissues were also carried out. HPLC-DAD analysis showed a high amount of quercetin, kaempferol, and ellagic acid derivatives in the plant extract. The PCDE showed improved muscle coordination, muscle movement and memory, and reduced anxiety in prepubertal mice. Moreover, levels of dopamine and noradrenaline were increased in the brain. It successfully ameliorated the oxidative stress in different organs by increasing the level of glutathione and superoxide dismutase and by reducing malondialdehyde. The histopathological assessment showed the plant extract effectively mitigated paraquat-induced pathological lesions in the neurons, neuroglia, hepatocytes, and kidney tissues. It is concluded from the present study that the treatment with PCDE had prevented the paraquat-induced toxicity in the brain, liver, kidney, and heart through the reduction of oxidative stress possibly due to the presence of phenolic compounds and flavonoids.

Glyphosate vs. Glyphosate-Based Herbicides Exposure: A Review on Their Toxicity

Glyphosate-based herbicide has been the first choice for weed management worldwide since the 1970s, mainly due to its efficacy and reported low toxicity, which contributed to its high acceptance. Many of the recent studies focus solely on the persistence of pesticides in soils, air, water or food products, or even on the degree of exposure of animals, since their potential hazards to human health have raised concerns. Given the unaware exposure of the general population to pesticides, and the absence of a significant number of studies on occupational hazards, new glyphosate-induced toxicity data obtained for both residual and acute doses should be analyzed and systematized. Additionally, recent studies also highlight the persistence and toxicity of both glyphosate metabolites and surfactants present in herbicide formulations. To renew or ban the use of glyphosate, recently published studies must be taken into account, aiming to define new levels of safety for exposure to herbicide, its metabolites, and the toxic excipients of its formulations. This review aims to provide an overview of recent publications (2010–present) on in vitro and in vivo studies aimed at verifying the animal toxicity induced by glyphosate, its metabolite aminomethylphosphonic acid (AMPA) and glyphosate-based formulations, evaluated in various experimental models. Apart from glyphosate-induced toxicity, recent data concerning the role of surfactants in the toxicity of glyphosate-based formulations are discussed.

Inhibition of Wnt10b/β-catenin signaling alleviates pulmonary fibrogenesis induced by paraquat in vivo and in vitro

Pulmonary fibrosis (PF) caused by paraquat remains a critical issue, and the molecular mechanisms are still unclear. Epithelial-mesenchymal transition (EMT) is regarded as a hallmark of PF, conferring alveolar epithelial cells partial mesenchymal characteristics, facilitating migration, expressing excessive extracellular matrix components, and participating in lung parenchyma remodeling and stiffening. Aberration of Wnt signaling has been identified in EMT and PF, and Wnt protein family consists of 19 ligands. The relationship of the specific Wnt ligands and fibrogenesis induced by PQ was not well defined. In current study, PQ-induced lung fibrosis rat model and EMT cell model were utilized to investigate the underlying molecular mechanisms both in vivo and in vitro. The results demonstrated that canonical Wnt/β-catenin signaling was highly activated and Wnt10b was the most affected. Additionally, suppression of Wnt10b by RNA interference could reverse EMT in vitro and detain the process of PF in vivo. These data establish Wnt10b as the key regulator of EMT and lung fibrogenesis, and suggest the potential of targeted interference against Wnt10b as a promising therapeutic strategy for lung fibrosis.

Systemic inflammation and oxidative stress induced by inhaled paraquat in rat improved by carvacrol, possible role of PPARγ receptors

Control rats were exposed to saline aerosol, two groups were exposed to paraquat (PQ), 27 (PQ-L) and 54 (PQ-H) mg/m3 aerosols and six groups were treated with carvacrol, 20 (C-L) and 80 (C-H) mg/kg/day, pioglitazone, 5 (Pio-L) and 10 (Pio-H) mg/kg/day, C-L+Pio-L and dexamethasone, 0.03 mg/kg/day, for 16 days after the end of exposure to PQ-H. Different variables were measured after the end of treatment period. Total and differential white blood cells counts, nitrite, malondialdehyde, interleukin (IL)-10, and interferon-gamma levels were significant increased, but thiol, superoxide dismutase, catalase, IL-17, and tumor necrosis factor alpha were decreased in the blood due to both doses of PQ (p < 0.05-p < 0.001). Most measured parameters were significantly improved in treated groups with both doses of carvacrol, pioglitazone, the combination of C-L+Pio-L and dexamethasone compared to PQ-H group (p < 0.05-p < 0.001). Treatment with C-L+Pio-L showed significantly higher effects compared to each one alone (p < 0.05-p < 0.001). Systemic oxidative stress and inflammation due to inhaled PQ were improved by carvacrol and pioglitazone. Higher effects of C-L+Pio-L than each one alone suggests carvacrol modulating PPAR-γ receptors.

Tebuconazole-induced toxicity and the protective effect of Ficus carica extract in Neotropical fruit-eating bats

Tebuconazole (TEB) is a triazole fungicide widely used in agriculture known to cause metabolic and endocrine disorders in mammals. Several plant extracts have shown to be beneficial against pesticide effects due to their hepatoprotective, antioxidant and anti-inflammatory properties. As fruit bats play a critical role in rainforest regeneration and are constantly exposed to pesticides, we aimed at evaluating TEB-induced toxicity and the possible protective effect of the Ficus carica plant extract in Neotropical fruit-eating bats (Artibeus lituratus). Bats were captured and assigned to 4 experimental groups, offered: 1) CTL (n = 6): papaya; 2) DMSO (n = 6): papaya treated with 1.25% dimethyl sulfoxide (DMSO); 3) TEB (n = 6): papaya treated with tebuconazole (commercial formulation) 0.1%; and 4) TEBFC (n = 6): papaya treated with tebuconazole 0.1% and Ficus carica extract (20%) in DMSO (1.25%). After seven days of exposure, TEB bats showed increased lipid peroxidation, increased superoxide dismutase (SOD) and catalase (CAT) activities, vascular congestion and inflammatory infiltrate in the liver, and increased serum transaminase enzyme activities. We found the same alterations in oxidative stress parameters in the breast muscles of TEB-exposed bats. In the testes, all oxidative stress markers were increased in TEB bats and corroborate findings of histopathological and increased serum testosterone levels observed following TEB exposure. The co-administration of the fungicide with the F. carica plant extract attenuated most oxidative stress markers in exposed bats' liver and testes and decreased liver damage, but failed to revert the steroid imbalance caused by the fungicide exposure.

Zataria multiflora and Pioglitazone Affect Systemic Inflammation and Oxidative Stress Induced by Inhaled Paraquat in Rats

The effects of Zataria multiflora (Z. multiflora) and pioglitazone (a PPAR-γ agonist) alone and in combination, on systemic inflammation and oxidative stress induced by inhaled paraquat (PQ) as a herbicide, which induced inflammation in rats, were examined. Rats were exposed to (1) saline (control) and (2) 54 mg/m³ PQ aerosols (8 times, every other day, each time for 30 min) without treatment or treated with (3 and 4) two doses of Z. multiflora (200 and 800 mg/kg/day), (5 and 6) two doses of pioglitazone (5 and 10 mg/kg/day), (7) low doses of Z.multiflora + pioglitazone, (Pio-5+Z-200 mg/kg/day) or (8) dexamethasone (0.03 mg/kg/day) for 16 days, after the last PQ exposure. Different variables were measured at the end of the treatment period. Exposure to PQ significantly increased total and differential white blood cells (WBC) counts, serum levels of nitrite (NO₂), malondialdehyde (MDA), interleukin- (IL) 17, and tumor necrosis factor alpha (TNF-α), but reduced thiol, superoxide dismutase (SOD), catalase (CAT), IL-10, and interferon-gamma (INF-γ) (p < 0.05 to p < 0.001). Most measured parameters were significantly improved in groups treated with either doses of the extract, pioglitazone, Pio-5+Z-200 mg/kg/day, or dexamethasone compared to the PQ group (p < 0.05 to p < 0.001). The combination of low doses of Pio-5+Z-200 mg/kg/day showed significantly higher effects compared to each one alone (p < 0.05 to p < 0.001). Systemic oxidative stress and inflammation due to inhaled PQ were improved by Z. multiflora and pioglitazone. Higher effects of Pio-5+Z-200 mg/kg/day compared to each one alone suggest modulation of PPAR-γ receptors by the plant extract, but further studies using PPAR-γ antagonists need to be done in this regard.

Esophagitis dissecans superficialis associated with acute transoral paraquat poisoning: Clinical study of 15 cases

To analyze the clinical characteristics and therapeutic effects of transoral paraquat poisoning combined with Esophagitis dissecans superficialis (EDS). A retrospective observational study was conducted on paraquat poisoning patients between January 1, 2011 and August 30, 2016 in Qilu hospital. Fifteen patients with EDS were enrolled in this study. The clinical characteristics, prognosis, and pathological features of esophageal necrosis mucosa of these patients were retrospectively analyzed and summarized. Esophageal mucosal dissection occurs mainly within 3-8 days after transoral paraquat poisoning in 15 patients. Dosage of paraquat is range from 50 to 100 ml. Most patients have physical problems with swallowing before the intramural esophageal dissection occurred. And there are other symptoms, including sore throat or dysphagia (100%), nausea and vomiting (86.7%), heartburn or upper abdominal pain (73.3%), hematemesis (60%), abdominal distension (20%) and cough frequently (6.7%). In death group, most patients demonstrate features of the multiple organ failure when the esophageal mucosal stripping happened, including lung injury, renal failure, and hepatic failure. The shape of esophageal dissection was tubular in 60%, irregular in 40%, and they vary in size. Pathological examination showed extensive injury, necrosis and hemorrhage of digestive tract epithelium, and obvious inflammatory reaction of epithelial tissue. Transoral paraquat poisoning has certain damage to the patient's esophageal mucosa, and some may be complicated with EDS, and the prognosis is poor, especially when combined with multiple organ dysfunction. Esophageal damage is mainly located in the esophageal mucosa and have different degrees. Special attention should be paid on such patients.

The effects of carbon monoxide releasing molecules on paraquat-induced pulmonary interstitial inflammation and fibrosis

Paraquat, an herbicide used extensively worldwide, can cause severe toxicity in humans and animals, leading to irreversible, lethal lung fibrosis. The potential of CO-releasing molecules (CORMs), substances that release CO (Carbon monoxide) within animal tissues, for treating paraquat-induced ROS generation and inflammation is investigated here. Our results show that the fast CO releaser CORM-3 (4-20 μM) acts as a potential scavenger of free radicals and decreases fibrosis progression by inhibiting paraquat-induced overexpression of connective tissue growth factor and angiotensin II in MRC-5 cells. The slow CO releaser CORM-A1 (5 mg/kg) clearly decreased expression of the lung profibrogenic cytokines COX-2, TNF-α, and α-SMA and serum hydroxyproline, resulting in a lower mortality rate in paraquat-treated mice. Mice treated with higher-dose CORM-A1 (10 mg/kg) had relatively intact lung lobes and fewer fibrotic patches by gross observation, with less collagen deposition, mesangial matrix accumulation, and pulmonary fibrosis resulting from the mitigation of TGF-β overexpression. In conclusion, our data demonstrate for the first time that CORM-A1 alleviated the development of the fibrotic process and improved survival rate in mice exposed to PQ, would be an attractive therapeutic approach to attenuate the progression of pulmonary fibrosis following PQ exposure.

Prognostic value of liver and kidney function parameters and their correlation with the ratio of urine-to-plasma paraquat in patients with paraquat poisoning

Acute paraquat poisoning resulting from multiple organ failure usually has a high mortality rate. Liver and kidney, as the key oranges of paraquat detoxification and elimination, their injuries may suppress toxin excretion and enhance the toxicity of paraquat in other organs and worsen the prognosis. Therefore, we intended to explore the prognostic value of liver and kidney function parameters, and further evaluate their correlation with a more stable index urine-to-plasma paraquat (urine paraquat concentrations/plasma paraquat concentrations) instead of considering paraquat concentrations in plasma or urine alone. The study included 33 patients with acute paraquat poisoning admitted to four centres in China from January 2018 to December 2019. Seventeen patients (10 male/7 female) survived, whereas 16 patients (7 male/9 female, 48.48%) died from paraquat poisoning. Alanine aminotransferase (ALT) and the blood urea nitrogen (BUN) represent liver and kidney function parameters, respectively. The ratio of urine-to-plasma paraquat is negatively correlated with ALT (r = -0.94, P = 0 .02) and BUN (r = -0.82, P = 0.03). For receiver operating characteristic curve (ROC) analysis, ALT, BUN and urine-to-plasma paraquat have an AUC over 0.80. The study shows that the functional indexes of liver and kidney, as well as the ratio of urine-to-plasma paraquat, could be considered for evaluating the extent of organ injury and excretion rate of paraquat.

Antioxidant Peptides from Sepia esculenta Hydrolyzate Attenuate Oxidative Stress and Fat Accumulation in Caenorhabditis elegans

The hydrolysate of golden cuttlefish (Sepia esculenta) was prepared by using papain, and then, it was further separated by ultrafiltration, gel filtration chromatography, and reverse-phase high-performance liquid chromatography (RP-HPLC). The peptide components of the active fraction were identified by liquid chromatography-tandem mass spectrometry (LC-MS/MS), and then two novel peptides, SeP2 (DVEDLEAGLAK, 1159.27 Da) and SeP5 (EITSLAPSTM, 1049.22 Da), were obtained and displayed significant alleviation effects on oxidative stress in Caenorhabditis elegans. Studies indicated that S. esculenta antioxidant peptides (SePs) increase superoxide dismutase (SOD) activity but reduce reactive oxygen species (ROS) and malondialdehyde (MDA) levelsin oxidation-damaged nematodes. Using transgenic CF1553 nematodes, the sod-3p::GFP expression in the worms treated with SePs was significantly higher than that of the control nematodes. Real-time PCR also demonstrated that the expression of stress-related genes such as sod-3 is up-regulated by SePs. Furthermore, studies showed that SePs could obviously decrease fat accumulation as well as reduce the elevated ROS and MDA levels in high-fat nematodes. Taken together, these results indicated that SePs are capable of the activation of antioxidant defense and the inhibition of free radicals and lipid peroxidation, play important roles in attenuating oxidative stress and fat accumulation in C. elegans, and might have the potential to be used in nutraceutical and functional foods.

Carvacrol and Zataria multiflora influenced the PPARγ agonist effects on systemic inflammation and oxidative stress induced by inhaled paraquat in rat

OBJECTIVES

The effects of PPAR-γ agonist alone and in combination with carvacrol and Zataria multiflora on inhaled paraquat (PQ) induced-systemic inflammation and oxidative stress were examined.

MATERIALS AND METHODS

Control group exposed to normal saline aerosol, one group exposed to 54 mg/m3 PQ aerosol and four groups exposed to PQ aerosol and treated with 5 mg/kg/day pioglitazone, pioglitazone + 200 mg/kg/day Z. multiflora extract, pioglitazone + 20 mg/kg/day carvacrol, and 0.03 mg /kg/day dexamethasone for 16 days after the end of exposure to PQ were studied. Exposure to normal saline or PQ was performed every other days for 30 min (8 times). Different variables were measured after the end of treatment period.

RESULTS

PQ exposure significantly increased serum levels of NO2, MDA and IL-6 but dexreased CAT and IFN-γ levels and IFN-γ/IL-6 ratio compared to control group (P<0.01 to P<0.001). Treatment with pioglitazone only improved serum level of MDA (P<0.01). Treatment with combination of pioglitazone and carvacrol as well as treatment with dexamethasone improved all measured variables compared to PQ exposed group (P<0.05 to P<0.001). The effects of pioglitazone + Z. multiflura and pioglitazone + carvacrol on almost all measured variables were significantly higher than pioglitazone alone (P<0.05 to P<0.001).

CONCLUSION

The effects of combination therapy of pioglitazone with Z. multiflora or carvacrol on inhaled paraquat (PQ) induced-oxidative stress and systemic inflammation were higher than the effects of pioglitazone alone. These results suggested that the effects of the extract and carvacrol may mediated through PPAR-γ receptors.

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.

Toxicology of paraquat and pharmacology of the protective effect of 5-hydroxy-1-methylhydantoin on lung injury caused by paraquat based on metabolomics

Paraquat (PQ) is a non-selective herbicide and is exceedingly toxic to humans. The mechanism of PQ toxicity is very complex and has not been clearly defined. There is no specific antidote for PQ poisoning. 5-hydroxy-1-methylhydantoin (HMH) is an intrinsic antioxidant and can protect against renal damage caused by PQ. The mechanism of PQ toxicology and the possible effects of HMH on PQ-induced lung injury were determined in this study. It was found that PQ decreased superoxide dismutase (SOD) activity and elevated the level of malondialdehyde (MDA), while HMH elevated SOD activity and decreased the level of MDA. Based on metabolomics, the citrate cycle, glutathione metabolism, taurine and hypotaurine metabolism, regulation of lipolysis in adipocytes, inflammatory mediator regulation of TRP channels, purine and pyrimidine metabolism, aldosterone synthesis and secretion, and phenylalanine metabolism were changed in the PQ group. Compared with the PQ group, the levels of N-acetyl-l-aspartic acid, L-glutamic acid, L-aspartic acid, mesaconic acid, adenosine 5′ monophosphate, methylmalonic acid, cytidine, phosphonoacetic acid, hypotaurine, glutathione (reduced) and cysteinylglycine increased, while the levels of corticosterone, xanthine, citric acid, prostaglandin G2, 4-pyridoxic acid and succinyl proline decreased in the HMH group. These metabolites revealed that HMH can alleviate inflammation caused by PQ and elevate the activity of intrinsic antioxidants. In conclusion, our results revealed PQ toxicology and the pharmacology underlying the protective effect of HMH on lung injury due to PQ. Toxicity caused by PQ results in lipid peroxidation and an increase in reactive oxygen species (ROS), nitric oxide (NO), damage to the biliary system, gastrointestinal system and nervous system, in addition to lungs, kidneys, and the liver. HMH is a good antioxidant and protects against lung injury caused by PQ. In summary, HMH efficiently reduced PQ-induced lung injury in mice.

8-Formylophiopogonanone B Antagonizes Paraquat-Induced Hepatotoxicity by Suppressing Oxidative Stress

Flavonoids are some of the most important natural products with a variety of physiological activities. 8-Formylophiopogonanone B (8-FOB) is a naturally existing homoisoflavonoid in Ophiopogon japonicus. Paraquat (PQ) has been widely used as a potent herbicide and has high toxicity in humans. The goal of the present study was to investigate whether 8-FOB could protect against PQ-induced hepatotoxicity in vitro and in vivo. We first tested the protective effects of 8-FOB on PQ-induced cytotoxicity in L02 cells by determining cell viability, intracellular oxidative stress levels, mitochondrial function, and apoptosis in vitro. To verify the protective effects of 8-FOB, we pretreated mice with 8-FOB and assessed liver function, hepatic oxidative stress, and histopathological changes after PQ administration. Our results revealed that 8-FOB could antagonize PQ-induced hepatotoxicity in vitro and in vivo. The antagonistic effects could be attributed to suppressing oxidative stress, preserving mitochondrial function, and inhibiting apoptosis. The present study is the first to document that 8-FOB, a homoisoflavonoid compound, is an effective antioxidant for antagonizing PQ-induced hepatotoxicity.

Ghrelin ameliorates A549 cell apoptosis caused by paraquat via p38-MAPK regulated mitochondrial apoptotic pathway

Paraquat has relatively strong detrimental effects on humans and animals and can cause acute lung injury with high mortality. Ghrelin is a brain-gut peptide which plays important roles in regulating various physiological processes. This study investigated whether ghrelin could inhibit paraquat-induced lung injuries and attempted to elucidate the possible molecular mechanisms. A549 cells were preincubated with different concentrations of ghrelin and then treated with 200 μM of PQ for 24 h. Then cell survival, apoptosis, cellular oxidative stress and lipid peroxidation of A549 cells were detected after different treatments. Subsequently, we analyzed the mitochondrial membrane potential (ΔΨm) and measured caspase-3 activation in A549 cells. In addition, we investigated the activation of the MAPKs pathway and the function of p38-MAPK within mitochondrial apoptosis. Our study indicated that ghrelin administration improved cell viability and reduced apoptosis of PQ-treated A549 cells dose-dependently. Ghrelin treatment reduced the elevation of ROS and MDA, while improved GSH content in A549 cells after paraquat exposure. Moreover, we found that ghrelin dose-dependently increased ΔΨm and decreased caspase-3 activity. The phosphorylated p38 MAPK and JNK levels elevated following PQ exposure, while the phosphorylation of p38 MAPK decreased following ghrelin pretreatment. p38 MAPK siRNA or SB203580 pretreatment ameliorated PQ-caused cell injury and apoptosis related signals, however, the intracellular ROS production was not affected. N-Acetylcysteine (NAC), a classic antioxidant pretreatment decreased the phosphorylated p38 MAPK level and intracellular ROS production, alleviated cell injury, and inhibited apoptosis. The results showed that p38-MAPK pathway plays an important role in PQ-caused alveolar epithelial cell insult, and ghrelin might attenuate PQ-induced cell injury by inhibiting ROS-induced p38-MAPK modulated mitochondrial apoptotic pathway.

Ameliorative role of aspirin in paraquat-induced lung toxicity via mitochondrial mechanisms

Paraquat (PQ) has accounted for numerous suicide attempts in developing countries. Aspirin (ASA) as an adjuvant treatment in PQ poisoning has an ameliorative role. And, it's uncoupling of mitochondrial oxidative phosphorylation role has been well established. The current study aimed at examining the aspirin mechanism on lung mitochondria of rats exposed to PQ. Male rats were randomly allocated in five groups: Control group, PQ group (50 mg/kg; orally, only on the first day), and PQ + ASA (100, 200, and 400 mg/kg; i.p.) groups for 3 weeks. Mitochondrial indices and respiratory chain-complex activities were determined. PQ induced lung interstitial fibrosis; however, ASA (400 mg/kg) led to decrease in this abnormal alteration. In comparison with PQ group, complex II and IV activity, and adenosine triphosphate content in ASA groups had significantly increased; however, reactive oxygen species production, mitochondrial membrane permeabilization, and mitochondrial swelling were significantly reduced. In conclusion, aspirin can alleviate lung injury induced by PQ poisoning by improving mitochondrial dynamics.

Possible involvement of transcriptional activation of nuclear factor erythroid 2-related factor 2 (Nrf2) in the protective effect of caffeic acid on paraquat-induced oxidative damage in Drosophila melanogaster

Paraquat (PQ) is a widely used herbicide with no antidote which is implicated in the pathogenesis of the Parkinson's disease. The present study then investigated the potential of caffeic acid (CA), a known antioxidant, cardioprotective and neuroprotective molecule to counteract oxidative stress mediated by PQ. In addition, molecular docking was performed to understand the mechanism underlying the inhibitory effect of CA against PQ poisoning. The fruit fly, Drosophila melanogaster, was exposed to PQ (0.44 mg/g of diet) in the absence or presence of CA (0.25, 0.5, 1 and 2 mg/g of died) for 7 days. Data showed that PQ-fed flies had higher incidence of mortality which was associated with mitochondrial dysfunction, increased free Fe(II) content and lipid peroxidation when compared to the control. Co-exposure with CA reduced mortality and markedly attenuated biochemical changes induced by PQ. The mechanism investigated using molecular docking revealed a strong interaction (-6.2 Kcal/mol) of CA with D. melanogaster transcriptional activation of nuclear factor erythroid 2-related factor 2 (Nrf2). This was characterized by the binding of CA to keap-1 domain of Nrf2. Taking together these results indicate the protective effect of CA against PQ-induced oxidative damage in D. melanogaster was likely through its coordination which hinders Nrf2-keap-1 binding leading to an increase of the antioxidant defense system.