Long-term exposures to ethion and endotoxin cause lung inflammation and induce genotoxicity in mice

Assessment of the gold nanoparticles biosynthesized using Casuarina equisetifolia bark extract against the ethion induced Hepato- and neurotoxicity in rats

Ethion (Etn) is classified as an organophosphate pesticide (OP) that causes toxicity even at low concentrations and targets the liver, brain, kidney, and blood. Gold nanoparticles (Au-NPs) were biosynthesized from the whole methanolic extract of Casuarina equisetifolia bark, and their efficacy against Etn-induced hepato- and neurotoxicity in rats was assessed. In addition to determining conventional biochemical measurements, the target tissues (liver and brain) were examined for oxidative stress, inflammatory, and fibrotic markers. The protein and isoenzyme patterns were also assayed using an electrophoretic technique. Additionally, apoptotic gene expression was measured. The target tissues were also subjected to histopathological analysis. In all groups treated with C. equisetifolia bark gold nano-extract, it was observed that the levels of the hematological measurements that were impacted by the oral injection of Etn had recovered to normal. Regarding the biochemical measurements, the group that received nano-extract pretreatment showed greater improvement than the therapeutic group. The levels of inflammatory indicators significantly decreased (p ≤ 0.05), while the antioxidant system markers increased in both liver and brain tissues in the group that received the nano-extract beforehand. In both target tissues, especially in the pre-treated group, the nano-extract reduced the severity of the Etn-caused lesions. During electrophoretic assays, the nano-extract in the pre-treated group prevented the qualitative alterations indicated by the lowest similarity index (SI%) values of the Etn-injected group compared to the normal group. The molecular assay showed that the nano-extract reduced the expression of apoptotic genes that were markedly elevated in the Etn-injected rats, but it was unable to return their values to normalcy. The study concluded that in the group that received nano-extract pretreatment, the biochemical, histopathological, physiological, and molecular abnormalities caused by Etn were reduced by the C. equisetifolia bark gold nano-extract.

In Vivo Exposure of Deltamethrin Dysregulates the NFAT Signalling Pathway and Induces Lung Damage

Deltamethrin is an insecticide used to control harmful agricultural insects that otherwise damage crops and to control vector-borne diseases. Long-term exposure to deltamethrin results in the inflammation of the lungs. The present study elucidates the molecular mechanism underlying the deltamethrin-induced lung damage. The lung samples were extracted from the Swiss albino mice following the treatment of low (2.5 mg/kg) and high (5 mg/kg) doses of deltamethrin. The mRNA expression of TCR, IL-4, and IL-13 showed upregulation, while the expression of NFAT and FOS was downregulated following a low dose of deltamethrin. Moreover, the expression of TCR was downregulated with the exposure of a high dose of deltamethrin. Furthermore, the immunohistochemistry data confirmed the pattern of protein expression for TCR, FOS, IL-4, and IL-13 following a low dose of deltamethrin exposure. However, no change was seen in the TCR, NFAT, FOS, JUN, IL-4, and IL-13 immunopositive cells of the high-dose treatment group. Also, ELISA results showed increased expression of IL-13 in the BAL fluid of animals exposed to low doses of deltamethrin. Overall, the present study showed that deltamethrin exposure induces lung damage and immune dysregulation via dysregulating the NFAT signalling pathway.

Immunomodulatory approaches in managing lung inflammation in COVID-19: A double-edge sword

INTRODUCTION

The novel coronavirus infectious disease 2019 (COVID-19) which is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has emerged as a gigantic problem. The lung is the major target organ of SARS-CoV-2 and some of its variants like Delta and Omicron variant adapted in such a way that these variants can significantly damage this vital organ of the body. These variants raised a few eyebrows as the outbreaks have been seen in the vaccinated population. Patients develop severe respiratory illnesses which eventually prove fatal unless treated early.

MAIN BODY

Studies have shown that SARS-CoV-2 causes the release of pro-inflammatory cytokines such as interleukin (IL)-6, IL-1β and tumor necrosis factor (TNF)-α which are mediators of lung inflammation, lung damage, fever, and fibrosis. Additionally, various chemokines have been found to play an important role in the disease progression. A plethora of pro-inflammatory cytokines "cytokine storm" has been observed in severe cases of SARS-CoV-2 infection leading to acute respiratory distress syndrome (ARDS) and pneumonia that may prove fatal. To counteract cytokine storm-inducing lung inflammation, several promising immunomodulatory approaches are being investigated in numerous clinical trials. However, the benefits of using these strategies should outweigh the risks involved as the use of certain immunosuppressive approaches might lead the host susceptible to secondary bacterial infections.

CONCLUSION

The present review discusses promising immunomodulatory approaches to manage lung inflammation in COVID-19 cases which may serve as potential therapeutic options in the future and may prove lifesaving.

Reproductive toxicity and cross-generational effect of polyethylene microplastics in Paramisgurnus dabryanus

Pollution of microplastics (MPs) has become a global environmental issue due to the difficulty in its degradation and may cause unexpected ecological effects. Nevertheless, little is known about the potential effects of MPs on reproduction toxicity in aquatic species. In this study, adult loach (Paramisgurnus dabryanus, F0 generation) were exposed to two concentrations (1 and 10 mg/L) of polyethylene MPs (PE-MPs) for 15 or 30 days, and the toxic effects in parental loach and the offspring (F1 generation) were examined. Our results showed that PE-MPs exposure could change the indicators content of antioxidant system in the brain, liver, and gonad. PE-MPs can accumulate in the gonads, disrupt the transcription of HPG-axis related genes, alter sex hormone levels, increase cell apoptosis and gonadal pathological lesions, lead to the damage of biological characteristics of semen, and affect the reproduction in F0 generation. PE-MPs remaining in the parental gonads can be transferred to the F1 generation embryos and accumulated on the embryonic chorionic membrane, increasing mortality and malformation rates, accelerating hatching time, and decreasing hatching rate and body length. These results suggest that PE-MPs leads to a potential adverse influence on reproduction and serious impacts on population sustainability. This work provides a new perspective into the effects of MPs on reproductive damage and cross-generational effects in teleost fish, which have implications in fields of freshwater ecology and environmental toxicology.

Effect of modifiable risk factors in Parkinson's disease: A case-control study looking at common dietary factors, toxicants, and anti-inflammatory medications

OBJECTIVE

To investigate how common modifiable exposures, including dietary factors, select toxicants, and anti-inflammatory medications, may affect Parkinson's disease.

METHODS

Using surveys, a case-control study was conducted at a medical center, comparing Parkinson's disease patients (N  =  149) and healthy controls (N  =  105). Subjects reported exposure to red meats, vegetables, alcohol, tobacco, anti-inflammatory medications, and pesticides. The relationship between exposures and Parkinson's disease diagnosis was analyzed by logistic regression to generate odds ratio and 95% confidence interval.

RESULTS

Consuming red meat "sometimes" or "always" was positively associated with Parkinson's disease as compared to eating red meats "rarely" or "never"; (odds ratio  =   2.15, 95% confidence interval   =   1.06, 4.39; p  =  0.03) and (odds ratio   =   4.47, 95% confidence interval   =   1.67, 11.94; p  =  0.003), respectively. Exposure to pesticides showed a positive association with Parkinson's disease (odds ratio  =   2.84, 95% confidence interval   =   1.34, 6.00; p  =  0.007). "Always" use of aspirin was inversely associated with Parkinson's disease (odds ratio  =   0.32, 95% confidence interval   =   0.14, 0.70; p  =  0.004). "Ever" having used anti-histamines was inversely associated with Parkinson's disease (odds ratio  =   0.37, 95% confidence interval  =  0.17, 0.81; p  =  0.01).

DISCUSSION

Our study suggests that there are modifiable external factors that are associated with Parkinson's disease. The present study can thus assist clinicians, policy makers, and people living with Parkinson's disease in improving the experience and management of Parkinson's disease.

Lung inflammation from repeated exposure to LPS and glyphosate

Agricultural workplaces consist of multiple airborne contaminants and inhalation exposures induce respiratory effects in workers. Endotoxin (LPS) and glyphosate are two common airborne contaminants in agricultural environments. We have previously shown that exposure to a combination of LPS and glyphosate synergistically modulates immune reactions as compared to individual exposures. The immunopathogenesis of acute and chronic exposure to complex agricultural exposures including LPS and glyphosate is not known; therefore, we further investigated the lung cellular inflammatory differences in mice exposed to either a combination, or individual, LPS, and glyphosate for 1 day, 5 days, and 10 days. Exposure to a combination of LPS and glyphosate resulted in greater cellular inflammatory effects in lungs as compared to individual exposures to LPS or glyphosate. Repeated exposures to the combination of LPS and glyphosate resulted in robust infiltration of inflammatory cells in the perivascular, peribronchiolar, and alveolar regions, and increases of alveolar septal thicknesses and perivascular spaces in the lungs with intense intercellular adhesion molecule (ICAM) - 1 staining in the perivascular region, but minimal staining in the pulmonary artery endothelium.

Impairment of apoptosis pathway via Apaf1 downregulation during chlorpyrifos and/or cypermethrin induced lung damage

Chlorpyrifos is an organophosphate and the cypermethrin is type 2 pyrethroid insecticide that are used for indoor and outdoor pest control. The present study aimed to investigate differential transcriptional profiling to identify the candidate gene associated with lung injury following exposure to chlorpyrifos and/or cypermethrin in a mouse model system. Swiss male albino mice (n = 24) were divided into three treatment groups (n = 6 each) that were given chlorpyrifos (2.76 mg kg^-1 body weight), cypermethrin (2 mg kg^-1 body weight) and the combination of both pesticides orally dissolved in corn oil and one control group (n = 6) that received corn oil for 90 days. The pulmonary expression of the Apaf1 was observed using RT2 Profiler PCR Array. The results showed that chronic exposure to chlorpyrifos, cypermethrin and their combination downregulated (67, 63 and 66 genes) and upregulated (4, 2 and 2 genes), respectively. The pulmonary expression of Apaf1 that plays important role in apoptosis was found to be downregulated. The immunohistochemistry depicted reduced expression of Apaf1 in both airway epithelium and alveolar septa following exposure to chlorpyrifos and/or cypermethrin. In conclusion, results demonstrated that exposure to chlorpyrifos, cypermethrin and their combination cause lung damage by the dysregulation of Apaf1 gene expression.

Elevated pulmonary levels of Axin2 in mice exposed to herbicide 2,4-D with or without endotoxin

2,4-Dichlorophenoxyacetic acid (2,4-D), a member of the phenoxy family of herbicides is commonly used in agriculture for controlling broadleaf weeds but its uncontrolled and incoherent use has been linked to incidences of lung toxicity. The present study aimed to understand the molecular mechanisms behind the 2,4-D alone or in combination with endotoxin (lipopolysaccharide [LPS]) induced pulmonary toxicity. Blood and lung samples were collected from Swiss albino mice (n = 48) following chronic exposure to high (37 mg/kg; 1/10th of LD₅₀ ) and low (18.5 mg/kg; 1/20th of LD₅₀ ) doses of 2,4-D alone or in combination with endotoxin (80 µg/animal). Transcriptome analysis revealed Wnt Canonical signaling as one of the top dysregulated pathways in mice lung following exposure to 2,4-D with and without endotoxin (LPS) co-exposure. Global view of differentially expressed genes showed increased messenger RNA expression of Axin2 by 0.26, 2.58, 3.14, 2.59, and 2.97 folds following exposure to LPS, high dose alone or in combination with LPS and low dose alone or in combination with LPS, respectively. The microarray data were validated using quantitative polymerase chain reaction and immunohistochemistry. Furthermore, the plasma concentration of Axin2 was elevated in the high dose group as revealed by Sandwich ELISA. The data taken together suggest a role of Axin2 to activate the Canonical Wnt signaling pathway in 2,4-D and or endotoxin-induced lung damage in mice.

Effects of Chlorpyrifos on Serine Hydrolase Activities, Lipid Mediators, and Immune Responses in Lungs of Neonatal and Adult Mice

Chlorpyrifos (CPF) is an organophosphate (OP) pesticide that causes acute toxicity by inhibiting acetylcholinesterase (AChE) in the nervous system. However, endocannabinoid (eCB) metabolizing enzymes in brain of neonatal rats are more sensitive than AChE to inhibition by CPF, leading to increased levels of eCBs. Because eCBs are immunomodulatory molecules, we investigated the association between eCB metabolism, lipid mediators, and immune function in adult and neonatal mice exposed to CPF. We focused on lung effects because epidemiologic studies have linked pesticide exposures to respiratory diseases. CPF was hypothesized to disrupt lung eCB metabolism and alter lung immune responses to lipopolysaccharide (LPS), and these effects would be more pronounced in neonatal mice due to an immature immune system. We first assessed the biochemical effects of CPF in adult mice (≥8 weeks old) and neonatal mice after administering CPF (2.5 mg/kg, oral) or vehicle for 7 days. Tissues were harvested 4 h after the last CPF treatment and lung microsomes from both age groups demonstrated CPF-dependent inhibition of carboxylesterases (Ces), a family of xenobiotic and lipid metabolizing enzymes, whereas AChE activity was inhibited in adult lungs only. Activity-based protein profiling (ABPP)-mass spectrometry of lung microsomes identified 31 and 32 individual serine hydrolases in neonatal lung and adult lung, respectively. Of these, Ces1c/Ces1d/Ces1b isoforms were partially inactivated by CPF in neonatal lung, whereas Ces1c/Ces1b and Ces1c/BChE were partially inactivated in adult female and male lungs, respectively, suggesting age- and sex-related differences in their sensitivity to CPF. Monoacylglycerol lipase (MAGL) and fatty acid amide hydrolase (FAAH) activities in lung were unaffected by CPF. When LPS (1.25 mg/kg, i.p.) was administered following the 7-day CPF dosing period, little to no differences in lung immune responses (cytokines and immunophenotyping) were noted between the CPF and vehicle groups. However, a CPF-dependent increase in the amounts of dendritic cells and certain lipid mediators in female lung following LPS challenge was observed. Experiments in neonatal and adult Ces1d^-/- mice yielded similar results as wild type mice (WT) following CPF treatment, except that CPF augmented LPS-induced Tnfa mRNA in adult Ces1d^-/- mouse lungs. This effect was associated with decreased expression of Ces1c mRNA in Ces1d^-/- mice versus WT mice in the setting of LPS exposure. We conclude that CPF exposure inactivates several Ces isoforms in mouse lung and, during an inflammatory response, increases certain lipid mediators in a female-dependent manner. However, it did not cause widespread altered lung immune effects in response to an LPS challenge.

Exposures to 2,4-Dichlorophenoxyacetic acid with or without endotoxin upregulate small cell lung cancer pathway

Background

Pesticide residues in food and environment along with airborne contaminants such as endotoxins pose health risk. Although herbicide 2,4-Dichlorophenoxyacetic acid (2,4-D) has been associated with increased risk of lung cancers such as small cell lung cancer (SCLC) among agricultural workers, there are no data on the SCLC signaling pathway upon 2,4-D exposure without LPS or in combination with endotoxin.

Methods

We exposed Swiss albino mice (N = 48) orally to high (9.58 mg kg^− 1) and low (5.12 mg kg^− 1) dosages of 2,4-D dissolved in corn oil for 90 days followed by E. coli lipopolysaccharide (LPS) or normal saline solution (80 μl/animal). Lung samples and broncho-alveolar fluid (BALF) were subjected to Total histological score (THS) and total leucocyte count (TLC) and differential leucocytes count (DLC) analyses, respectively. We used microarray and bioinformatics tools for transcriptomic analyses and differentially expressed genes were analyzed to predict the top canonical pathways followed by validation of selected genes by qRT-PCR and immunohistochemistry.

Results

Total histological score (THS) along with BALF analyses showed lung inflammation following long term dietary exposure to high or low doses of 2,4-D individually or in combination with LPS. Microarray analysis revealed exposure to high dose of 2,4-D without or with LPS upregulated 2178 and 2142 and downregulated 1965 and 1719 genes, respectively (p < 0.05; minimum cut off 1.5 log fold change). The low dose without or with LPS upregulated 2133 and 2054 and downregulated 1838 and 1625 genes, respectively. Bioinformatics analysis showed SCLC as topmost dysregulated pathway along with differential expression of Itgb1, NF-κB1, p53, Cdk6 and Apaf1. Immunohistological and quantitative real time PCR (qRT-PCR) analyses also supported the transcriptomic data.

Conclusions

Taken together, the data show exposures to high and low dose of 2,4-D with/without LPS induced lung inflammation and altered pulmonary transcriptome profile with the involvement of the SCLC pathway. The data from the study provide the insights of the potential damage on lungs caused by 2,4-D and help to better understand the mechanism of this complex relation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12995-021-00304-4.

Co-administration of lipopolysaccharide and D-galactosamine induces genotoxicity in mouse liver

The acute liver injury (ALI) and hepatic fibrosis caused by the co-treatment of lipopolysaccharide (LPS)/D-galactosamine (D-GalN) have been extensively studied. However, whether LPS/D-GalN are genotoxic has been left unknown. In this study, male mice were divided into eight groups with eight animals in each group. For acute challenge of LPS/D-GalN, the mice in each group received a combination of LPS/D-GalN via intraperitoneal injection at the dose of 25 μg/kg/250 mg/kg, 25 μg/kg/500 mg/kg, or 50 μg/kg/500 mg/kg body weight. An additional group for chronic administration of test compounds was conducted by i.p. injection of LPS/D-GalN (10 μg/kg/100 mg/kg) every other day for 8 weeks. Saline solution (0.9%) and cyclophosphamide (CTX) (50 mg/kg body weight) given by i.p. injection was used as the negative and positive control, respectively. The results of single cell gel electrophoresis (SCGE) assay indicated that acute exposure of the mice to LPS/D-GalN caused severe DNA damage in hepatic cells, but not in the brain, sperm or bone marrow cells, which evidenced the genotoxicity of LPS/D-GalN administrated in combination. Interestingly, the chronic administration of LPS/D-GalN triggered significant genotoxic effects not only in hepatic but also in brain cells, with negative results in sperm and bone marrow cells. Histopathological examination in the liver and brain tissues revealed changes consistent with the SCGE results. The present study indicates genotoxic potential of LPS/D-GalN co-administered in mice, which may serve as an in vivo experimental model for relevant genotoxic study.

Study of ethion and lipopolysaccharide interaction on lung in a mouse model

Ethion is an organophosphate used commonly in India despite being banned in many other countries. The present study was designed to study the interaction of ethion and lipopolysaccharide (LPS) together on lung after single low dose ethion exposure. Mice (n = 20) were alienated into control and treatment groups (n = 10 each). The treatment group was orally fed ethion (8 mg/kg/animal/day) dissolved in corn oil. The animals (n = 5 each) from both the groups were challenged with 80 μg Escherichia coli lipopolysaccharide (LPS) intranasally and the remaining animals (n = 5 each) were administered normal saline solution after 24 h. Ethion along with LPS induced lung inflammation as indicated by increased neutrophils and total leukocyte count (TLC) in broncheoalveolar lavage fluid. Ethion induced histomorphological alterations in lung as shown by increased pulmonary inflammation score in histopathology. Real time PCR analysis showed that ethion followed by LPS resulted significant (p < 0.05) increase in pulmonary Toll-like receptor (TLR)-4 (48.53 fold), interleukin (IL)-1β (7.05 fold) and tumor necrosis factor (TNF)-α (5.74 fold) mRNA expression. LPS co-exposure suggested synergistic effect on TLR4 and TNF-α mRNA expression. Ethion alone or in combination with LPS resulted genotoxicity in blood cells as detected by comet assay. The data suggested single dietary ethion exposure alone or in conjunction with LPS causes lung inflammation and genotoxicity in blood cells.

Pulmonary expression of MYCN mRNA following exposure to 2,4-D with or without endotoxin challenge

The present study aimed to observe the expression of MYCN in lungs of mice following chronic exposure of 2,4-D with or without lipopolysaccharide (LPS). 2,4-D was administered orally dissolved in corn oil at high and low dose (1/10th and 1/20th of LD50) for 90 days. After 90 days of exposure, animals from each group were challenged with LPS/normal saline solution at 80 μg/animal. The lung tissues were processed for microarray and real time studies. LPS resulted decrease (–0.173 fold) in m-RNA expression level of MYCN as compared to control, while High dose of 2,4-D alone and in combination with LPS resulted 0.949-fold change and 1.656-fold change increase in expression of MYCN m-RNA, respectively, as compared to control. Similarly, Low dose of 2,4-D alone or in combination with LPS also altered MYCN expression. The microarray data when validated by Real Time PCR was found to be in concordance with the Real Time PCR data. The data taken together suggest that, high and low exposure of 2,4-D alone or in combination with LPS alters expression of MYCN at m-RNA level.

Multiple exposures to poultry barn air and lipopolysaccharide synergistically increase the pulmonary expression of TLR-4 and IL-1β

Objective

Poultry farm workers are exposed to barn air and suffer from various respiratory disorders. Due to frequent prevalence of endotoxin in the farm settings workers can get co‐exposed to barn air and endotoxin. The study was aimed to explore the pulmonary damage following long‐term multiple exposures to poultry barn air with or without endotoxin.

Methods

We studied the pulmonary expression of Toll‐like receptor 4 (TLR4) and Interleukin‐1β (IL‐1β) by exposing Swiss albino mice to poultry barn air for 6 days (Monday‐Saturday) in a week for 5 and 10 weeks. At the end of exposure, animals were challenged with lipopolysaccharide (LPS) or normal saline solution @80 μg/mouse intranasally. Histopathology, bronchoalveolar lavage (BAL) fluid and blood analysis were used to characterize lung damage. mRNA and protein expression of TLR4 and IL‐1β were evaluated using quantitative polymerase chain reaction (qPCR) and immunohistochemistry, respectively.

Results

Histopathology along with TLC and DLC of blood and BAL fluid revealed lung damage following multiple exposures and damage was severe in combination with LPS. Exposures altered mRNA and protein expression of TLR‐4 and IL‐1β and the expression was more marked following 30 days of exposure. Further LPS co‐challenge showed a synergistic effect on the expression of TLR4 and IL‐1β.

Conclusions

The data suggest that long‐term exposures with or without LPS caused lung damage and altered the pulmonary expression of TLR4 and IL‐1β.