Acute care for patients exposed to a chemical attack: protocol for an international multicentric observational study.

INTRODUCTION: The use of weapons of mass destruction against civilian populations is of serious concern to public health authorities. Chemical weapons are of particular concern. A few studies have investigated medical responses in prehospital settings in the immediate aftermath of a chemical attack, and they were limited by the paucity of clinical data. This study aims to describe the acute management of patients exposed to a chemical attack from the incident site until their transfer to a medical facility. METHODS AND ANALYSIS: This international multicentric observational study addresses the period from 1970 to 2036. An online electronic case report form was created to collect data; it will be hosted on the Biomedical Telematics Laboratory Platform of the Quebec Respiratory Health Research Network. Participating medical centres and their clinicians are being asked to provide contextual and clinical information, including the use of protective equipment and decontamination capabilities for the medical evacuation of the patient from the incident site of the chemical attack to the moment of admission at the medical facility. In brief, variables are categorised as follows: (1) chemical exposure (threat); (2) prehospital and hospital/medical facility capabilities (staffing, first aid, protection, decontamination, disaster plans and medical guidelines); (3) clinical interventions before hospital admission, including the use of protection and decontamination and (4) outcomes (survivability vs mortality rates). Judgement criteria focus on decontamination drills applied to any of the patient's conditions. ETHICS AND DISSEMINATION: The Sainte-Justine Research Centre Ethics Committee approved this multicentric study and is acting as the main evaluating centre. Study results will be disseminated through various means, including conferences, indexed publications in medical databases and social media. TRIAL REGISTRATION NUMBER: NCT05026645.

Mortality rate of people exposed to Mustard Gas during Iran-Iraq war in Sardasht, Iran: a 32 years retrospective cohort study.

BACKGROUND: Mustard gas (MG) is one of the most widely used chemical weapons in the past century. However, little information exists concerning long-term mortality from MG exposure. In this study, we investigated mortality rate among civilian people exposed to MG during Iran-Iraq war in Sardasht in Iran after 32 years.  METHODS: In this retrospective cohort study, data of people exposed to MG in Sardasht in 1987 were extracted from the Veterans and Martyr Affair Foundation of Iran up to March 20, 2019. Mortality rate, cumulative mortality and standardized mortality ratio with 95% confidence interval were calculated to explain mortality in the cohort, and then compared with general Iranian population. Cox regression analysis was used to indicate factor affecting the risk of death in the cohort.  RESULTS: Out of 1,203 exposed people at the beginning of the period, 148 people died by the end of the study, with an average age of 66.42 at the time of death. Total person-years of the people up to end of the study were 38,198.63 and mortality rate was equal to 387 per 100,000 persons-years. Total number of observed deaths was less than expected death and the all-cause standardized mortality ratio (SMR) was determined as 0.680 (95% CI: 0.574 - 0.798). Cause-specific SMR showed that observed death due to respiratory diseases was higher than expected (SMR: 1.75) (95% CI: 1.145 - 2.569). The results of univariate and multivariate cox regression analysis showed that increasing age and having severe late complications in lung were associated with increased risk of death among people in the cohort. CONCLUSION: In general, this result indicated that acute exposure to MG, even without wearing protective clothing and masks, could not increase all-cause mortality after 32 years if accompanied by special and ongoing care for those exposed.

Exposure to sulfur mustard increases the risk for mortality in patients with COVID-19 infection: A cohort study.

OBJECTIVE: This study aims to assess the prognosis of inpatients with COVID-19 infection who have a history of sulfur mustard exposure. METHODS: We started a cohort study in October 2020 and ended in May 2021 on inpatients with COVID-19 infection who had been admitted to university healthcare centers. The analytic sample included 960 inpatients having COVID-19 infection (192 with; and 768 without sulfur mustard exposure). The exposed patients were male war veterans, and the unexposed patients were male individually age-matched people. All patients had a positive RT-PCR test and a positive chest CT for COVID-19. The outcome was death within 28 days of admission, and the predictors were clinical features recorded at patients' bedsides. RESULTS: There was a significantly higher prevalence for asthma (p = 0.026) and pulmonary disease other than asthma (p < 0.001) in patients with the exposure. Sulfur mustard exposure was associated with increased risk for mortality of COVID-19 [hazard ratio (95% CI) = 1.92 (1.14,3.24), p = 0.013]. Early intubation signified a poor prognosis [hazard = 7.34 (4.65,11.58), p < 0.001]. However, individuals with higher PaO2 [hazard = 0.97 (0.95,0.98), p < 0.001], or people undergoing O2 therapy early upon admission [hazard = 0.58 (0.38,0.89), p = 0.011] showed lower risks for mortality. Individuals with asthma were at higher risk for mortality [hazard = 3.76 (1.69,8.36), p = 0.001]. CONCLUSION: Individuals with COVID-19 infection and sulfur mustard exposure should be considered high-risk patients and that, healthcare settings should be ready to provide critical care for them, including O2 therapy. They are more likely to have asthma or other pulmonary diseases.

Neurotoxicant exposures and rates of Chronic Multisymptom Illness and Kansas Gulf War Illness criteria in Gulf War deployed women veterans.

AIMS: This study analyzed deployment-related exposures and risk of Persian Gulf War Illness (GWI) in women veterans from the Veterans Affairs (VA) Cooperative Studies Program 585 Gulf War Era Cohort and Biorepository (GWECB CSP#585). MAIN METHODS: We examined the associations between GW deployment-related exposures and case definitions for GWI in deployed GW women. Multivariate regression analyses controlling for demographic outcomes were performed. KEY FINDINGS: Surveys were obtained from 202 GW deployed women veterans. Self-reported exposure to smoke from oil well fires as well as chemical and biological warfare were the only exposures significantly associated with the Center for Disease Control and Prevention (CDC) GWI criteria. Seventy-nine women were excluded from the rest of the analyses as they met Kansas GW illness exclusion criteria. Eligible women who self-reported deployment-related exposure to smoke from oil wells, pyridostigmine bromide (PB) pills, pesticide cream, pesticide treated uniforms, and insect baits were significantly more likely to meet the Kansas GWI criteria (n = 123) than those unexposed and exposures were related to Kansas symptom subdomain endorsements. SIGNIFICANCE: These results suggest that women GW veterans reporting deployment related exposures of pesticide, oil well fire and PB pills are significantly more likely to meet the Kansas GWI criteria in this national cohort of GW women suggesting its utility in future studies. In addition, based on these results it appears that women exposed to particular toxicants during the war may benefit from more targeted treatment strategies dependent upon the mechanism of exposure of their toxicant induced outcomes.

Glutathione conjugates of the mercapturic acid pathway and guanine adduct as biomarkers of exposure to CEES, a sulfur mustard analog.

Sulfur mustard (SM), a chemical warfare agent, is a strong alkylating compound that readily reacts with numerous biomolecules. The goal of the present work was to define and validate new biomarkers of exposure to SM that could be easily accessible in urine or plasma. Because investigations using SM are prohibited by the Organisation for the Prohibition of Chemical Weapons, we worked with 2-chloroethyl ethyl sulfide (CEES), a monofunctional analog of SM. We developed an ultra-high-pressure liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) approach to the conjugate of CEES to glutathione and two of its metabolites: the cysteine and the N-acetylcysteine conjugates. The N7-guanine adduct of CEES (N7Gua-CEES) was also targeted. After synthesizing the specific biomarkers, a solid-phase extraction protocol and a UHPLC-MS/MS method with isotopic dilution were optimized. We were able to quantify N7Gua-CEES in the DNA of HaCaT keratinocytes and of explants of human skin exposed to CEES. N7Gua-CEES was also detected in the culture medium of these two models, together with the glutathione and the cysteine conjugates. In contrast, the N-acetylcysteine conjugate was not detected. The method was then applied to plasma from mice cutaneously exposed to CEES. All four markers could be detected. Our present results thus validate both the analytical technique and the biological relevance of new, easily quantifiable biomarkers of exposure to CEES. Because CEES behaves very similar to SM, the results are promising for application to this toxic of interest.

Phosgene inhalation toxicity: Update on mechanisms and mechanism-based treatment strategies.

Phosgene (carbonyl dichloride) gas is an indispensable high-production-volume chemical intermediate used worldwide in numerous industrial processes. Published evidence of human exposures due to accidents and warfare (World War I) has been reported; however, these reports often lack specificity because of the uncharacterized exposure intensities of phosgene and/or related irritants. These may include liquid or solid congeners of phosgene, including di- and triphosgene and/or the respiratory tract irritant chlorine which are often collectively reported under the umbrella of phosgene exposure without any appreciation of their differences in causing acute lung injury (ALI). Among these irritants, phosgene gas is somewhat unique because of its poor water solubility. This prevents any appreciable retention of the gas in the upper airways and related trigeminal sensations of irritation. By contrast, in the pulmonary compartment, amphiphilic surfactant might scavenge this lipophilic gas. The interaction of phosgene and the surfactant may affect basic physiological functions controlled by Starling's and Laplace's laws, which can be followed by cardiogenic pulmonary edema. The phenotypic manifestations are dependent on the concentration × exposure duration (C × t); the higher the C × t is, the less time that is required for edema to appear. It is hypothesized that this type of edema is caused by cardiovascular and colloid osmotic imbalances to initial neurogenic events but not because of the injury itself. Thus, hemodynamic etiologies appear to cause imbalances in extravasated fluids and solute accumulation in the pulmonary interstitium, which is not drained away by the lymphatic channels of the lung. The most salient associated findings are hemoconcentration and hypoproteinemia. The involved intertwined pathophysiological processes coordinating pulmonary ventilation and cardiopulmonary perfusion under such conditions are complex. Pulmonary arterial catheter measurements on phosgene-exposed dogs provided evidence of 'cor pulmonale', a form of acute right heart failure produced by a sudden increase in resistance to blood flow in the pulmonary circulation about 20 h postexposure. The objective of this review is to critically analyze evidence from experimental inhalation studies in rats and dogs, and evidence from accidental human exposures to better understand the primary and secondary events causing cardiopulmonary dysfunction and an ensuing life-threatening lung edema. Mechanism-based diagnostic and therapeutic approaches are also considered for this form of cardiogenic edema.

Identification of creatine kinase and alpha-1 antitrypsin as protein targets of alkylation by sulfur mustard.

Sulfur mustard (SM) is a toxic chemical warfare agent deployed in several conflicts within the last 100 years and still represents a threat in terroristic attacks and warfare. SM research focuses on understanding the pathophysiology of SM and identifying novel biomarkers of exposure. SM is known to alkylate nucleophilic moieties of endogenous proteins, for example, free thiol groups of cysteine residues. The two-dimensional-thiol-differences in gel electrophoresis (2D-thiol-DIGE) technique is an initial proteomics approach to detect proteins with free cysteine residues. These amino acids are selectively labeled with infrared-maleimide dyes visualized after GE. Cysteine residues derivatized by alkylating agents are no longer accessible for the maleimide-thiol coupling resulting in the loss of the fluorescent signal of the corresponding protein. To prove the applicability of 2D-thiol-DIGE, this technology was exemplarily applied to neat human serum albumin treated with SM, to lysates from human cell culture exposed to SM as well as to human plasma exposed to CEES (chloroethyl ethyl sulfide, an SM analogue). Exemplarily, the most prominent proteins modified by SM were identified by matrix-assisted laser desorption/ionization time-of-flight (tandem) mass spectrometry, MALDI-TOF MS(/MS), as creatine kinase (CK) from human cells and as alpha-1 antitrypsin (A1AT) from plasma samples. Peptides containing the residue Cys282 of CK and Cys232 of A1AT were unambiguously identified by micro liquid chromatography-electrospray ionization high-resolution tandem-mass spectrometry (µLC-ESI MS/HR MS) as being alkylated by SM bearing the specific hydroxyethylthioethyl-(HETE)-moiety. Both peptides might represent potential biomarkers of SM exposure. This is the first report introducing these endogenous proteins as targets of SM alkylation.

Neurochemical and Neurobiological Weapons.

Nerve agents and neurobiological weapons are among the most devastating and lethal of weapons. Acetylcholinesterase inhibitors act by increasing the amount of acetylcholine in the neuromuscular junction, resulting in flaccid paralysis. Tabun, VX, soman, and sarin are the major agents in this category. Exposure to nerve agents can be inhalational or through dermal contact. Neurotoxins may have peripheral and central effects on the nervous system. Atropine is an effective antidote to nerve agents. Neurobiological weapons entail using whole organisms or organism-synthesized toxins as agents. Some organisms that can be used as biological weapons include smallpox virus.

Identification of S419 on human serum albumin as a novel biomarker for sarin and cyclosarin exposure.

RATIONALE: Organophosphorus nerve agents are highly toxic because they inhibit acetylcholinesterase activity, thereby causing a series of symptomatic poisoning. Upon entering the body, nerve agents bind active amino acid residues to form phosphonylated adducts. A potentially beneficial method for specific verification of exposure of nerve agents is based on albumin adducts, which have a half-life of 18 days. This appears to be more effective than the fluoride reactivation method, based on acetylcholinesterase. METHODS: After the exposure of human serum albumin to nine nerve agents, human serum albumin was denatured, reduced, alkylated and digested with trypsin according to standard mass spectrometry-based proteomics procedures. The phosphonylated peptides of human serum albumin were identified using positive ion electrospray ionization with a quadrupole orbitrap mass spectrometer. RESULTS: The peptide KVPQVSTPTLVESR showed a good mass spectrometric response to the nine nerve agents. The tendency of sarin and cyclosarin was to bind to S419 on the peptide, while the other nerve agents (tabun, soman and V-type nerve agents) were shown to bind more readily to K414 on the peptide. CONCLUSIONS: This research revealed a new site, S419, of the tryptic peptide KVPQVSTPTLVEVSR on human albumin to be a valuable biomarker for sarin/cyclosarin exposure, helping to further distinguish sarin and cyclosarin poisoning from that of other nerve agents and providing an important tool for the identification of sarin or cyclosarin in terrorist attacks.

The introduction of gas warfare and its medical response in world war one.

The introduction of gas warfare in World War One was impactful, as it both expanded the breadth of warfare and fueled the invention of techniques required to treat these new injuries. Gas injuries were responsible for 91,000 of 1.3 million deaths in World War One. Gassed soldiers had wounds which the world had never seen. They presented in large scale to medical tents and base hospitals across Europe. As gas casualties poured in, doctors and nurses had to treat these conditions in the best way they knew. Gas warfare changed how war was performed and how casualties of this attack were treated. The techniques learned from treating the multitudes of men with gas burns led to advances in the field of burn care, which have helped to improve mortality and reduce morbidity in hospitals across the world.

Debridement of Sulfur Mustard Skin Burns: A Comparison of Three Methods.

Sulfur mustard burns are characterized by delayed symptoms, slow healing, and recurrence after closure. Incomplete debridement at the level of the basement membrane is the postulated cause. Graham pioneered laser debridement of mustard burns. For field or mass-casualty use, saline wet-to-wet or antibiotic-soak debridement is more practical. In this study, we compared laser, saline, and antibiotic debridement in a porcine model of deep partial-thickness injury. Deep-dermal sulfur mustard burns were produced in 18 anesthetized Gottingen minipigs using 10-µl saturated vapor cap exposure time of 90 minutes. Debridement was started 48 hours postinjury and consisted of a single laser treatment; 5 days of 5% aqueous mafenide acetate wet-to-wet dressings; or 7 to 12 days of saline wet-to-wet dressings. Wounds were treated with daily silver sulfadiazine for 30 days and, then, assessed by histopathology, silver-ion analysis, colorimetry, and evaporimetry. All wounds healed well with no sign of infection. Antibiotic debridement showed no advantage over saline debridement. There were no significant differences between groups for colorimetry or evaporimetry. Histopathology was graded on a mustard-specific scale of 1 to 15 where higher values indicate better healing. Mean histology scores were 13.6 for laser, 13.9 for mafenide, and 14.3 for saline. Saline debridement statistically outperformed laser (P < .05) but required the longest debridement time. Laser debridement had the benefit of requiring a single treatment rather than daily dressing changes, significantly decreasing need for wound care and personnel resources. Development of a ruggedized laser for field use is a countermeasures priority.

Potent opioids and implications for national defense.

Potent opioids are increasingly responsible for morbidity and mortality in the Western world. Fentanyl and fentanyl derivatives are increasingly prevalent as adulterants or substitutes for opioid drugs of abuse in Europe and in North America. Trafficking and distribution of these chemicals evolve continuously and are poorly characterized at this time. Rescue and emergency personnel are increasingly concerned with the possibility of unintentional environmental exposures that might occur in the course of their operational duties. There is evidence that opioid agonists have been broadcast or applied directly in an offensive manner as incapacitating agents. Defending against toxicity from such agents requires a thoughtful plan for protection, decontamination, and treatment.

Acute Toxic Injuries of Rat's Visceral Tissues Induced by Different Oximes.

Certain AChE reactivators, asoxime, obidoxime, K027, K048, and K075, when taken in overdoses and sometimes even when introduced within therapeutic ranges, may injure the different organs. As a continuation of previously published data, in this study, Wistar rats have sacrificed 24 hrs and 7 days after single im application of 0.1LD50, 0.5LD50 and 1.0LD50 of each reactivator, and examinated tissue samples were obtained for pathohistological and semiquantitative analysis. A severity of tissue alteration, expressed as different tissue damage scores were evaluated. Morphological structure of examinated tissues treated with of 0.1LD50 of all reactivators was comparable with the control group of rats. Moderate injuries were seen in visceral tissues treated with 0.5LD50 of asoxime, obidoxime and K027. Acute damages were enlarged after treatment with 0.5LD50 and 1.0LD50 of all reactivators during the next 7 days. The most prominent changes were seen in rats treated with 1.0LD50 of K048 and K075 (P < 0.001 vs. control and asoxime-treated group). All reactivators given by a single, high, unitary dose regimen, have an adverse effect not only on the main visceral tissue, but on the whole rat as well, but the exact mechanism of cellular injury remains to be confirmed in further investigation.

Expression of miR-15b-5p, miR-21-5p, and SMAD7 in Lung Tissue of Sulfur Mustard-exposed Individuals with Long-term Pulmonary Complications.

Sulfur mustard (SM)-exposed individuals develop late pulmonary complications, which are associated with chronic inflammation and fibrotic changes in the lung tissue. MicroRNAs are known to act as important regulators of inflammatory responses, including inflammation and fibrosis-related cytokine signaling. In this study, we investigated the expression miR-15b-5p and miR-21-5p, two regulators of TGF-ß signaling, as well as their target molecule, SMAD7, in lung tissues from SM-exposed and control individuals. Total RNA was extracted from formalin-fixed paraffin-embedded (FFPE) lung tissue biopsies obtained during surgery from SM-exposed (n=20) or control (n=20) cases. Quality of the extracted RNA was evaluated by an Agilent Bioanalyzer and RNA was quantified using a NanoDrop. MiR-21-5p, miR-15b-5p and SMAD7 expression levels were measured by real-time RT-PCR. miR-21-5p expression levels were significantly decreased (2.7 fold) in the lung tissues from SM-exposed individuals compared with tissues obtained from the control group (p=0.02). There were no significant differences in miR-15b-5p expression levels between the two groups (p=0.94). Interestingly, SMAD7 expression levels were significantly higher (5.8 fold) in SM-exposed individuals' lung tissues compared with the control group (p=0.045). Our data indicate that exposure to sulfur mustard affects the expression of miR-21-5p as well as its target, SMAD7, in lung tissues many years after exposure. Considering the role of SMAD7 in the regulation of TGF-ß signaling, these changes might point to a potential mechanism by which SM-exposure regulates inflammatory/fibrotic alterations in lung tissue.

Is the Inflammasome Pathway Active in the Peripheral Blood of Sulfur Mustard-exposed Patients?

The mustard lung is a late consequence of exposure to sulfur mustard (SM) in veterans who had participated in the Iraq-Iran war. Three mechanisms are contributed in the pathogenesis of mustard lung including oxidative stress, protease-antiprotease imbalance, and dysregulated immune response. In the context of the immune response, the role of the inflammasome complex and their inflammatory cytokines are important. This study aims to investigate the inflammasome pathway and their inflammatory cytokine (i.e IL-1 and IL-18) in the peripheral blood of mustard lung patients as well as chronic obstructive pulmonary disease (COPD) patients. This research was conducted as a cross-sectional analytical study on 15 SM patients and was compared with 15 COPD patients and 15 healthy controls. The real-time polymerase chain reaction was used to assess gene expression levels of inflammasome components (NLRP1, NLRP3, NLRC4, and ASC), inflammatory cytokines (IL-1ß, IL-18, and IL-1ßR), and IL-37 as an anti-inflammatory cytokine. Finally, the data were analyzed by SPSS version 21 software. The gene expression level of molecules involved in inflammasome pathway showed a slight increase in the peripheral blood of SM and COPD patients compared to the control group. However, this difference was not statistically significant. Only IL-37 and NLRP1 had a significant increase in mustard lung and COPD patients; compared to healthy controls (p<0.05). Due to the normal expression of genes involved in the inflammasome pathway, it can be stated that the inflammasome pathway is not active in the blood of mustard lung patients.

A comprehensive analysis of corneal mRNA levels during sulfur mustard induced ocular late pathology in the rabbit model using RNA sequencing.

Exposure to sulfur mustard (SM) may result in severe ocular injuries. While some of the eyes show a clinical resolution of the injury (defined as clinically non-impaired), part of the eyes develop irreversible late ocular pathologies (defined as clinically impaired) that may lead to corneal blindness. Understanding the pathological mechanisms underlying the development of the late pathology may lead to improved treatment options. Therefore, this study aimed to investigate the mRNA expression profiles of corneas from clinically impaired, clinically non-impaired and naïve eyes. Rabbit eyes were exposed to SM vapor and a clinical follow-up was carried out up to 4 weeks using a slit lamp microscope. At this time point, corneal tissues from clinically impaired, clinically non-impaired and naïve eyes were processed for RNA sequencing (RNA-seq) and differential expression analyses. The differential expression profiles were further subjected to pathway enrichment analysis using Ingenuity Pathway Analysis (IPA). Real-time PCR was used for RNA-seq validation. The late pathology developed in 54%-80% of the eyes following ocular exposure to SM, clinically manifested by inflammation, corneal opacity and neovascularization. RNA-seq results showed significant differences in mRNA levels of hundreds of genes between clinically impaired, clinically non-impaired and naïve corneas. Pathway enrichment analysis showed common pathways that were activated in all of the exposed eyes, such as Th1 and Th2 activation pathway, in addition to pathways that were activated only in the clinically impaired eyes compared to the clinically non-impaired eyes, such as IL-6 and ERK5 signaling. Corneal mRNA expression profiles for the clinically impaired, clinically non-impaired and naïve eyes generated a comprehensive database that revealed new factors and pathways, which for the first time were shown to be involved in SM-induced late pathology. Our data may contribute to the research on both the pathological mechanisms that are involved in the development of the late pathology and the protective pathways that are activated in the clinically non-impaired eyes and may point out towards novel therapeutic strategies for this severe ocular injury.

Relevance of Erk1/2-PI3K/Akt signaling pathway in CEES-induced oxidative stress regulates inflammation and apoptosis in keratinocytes.

2-Chloroethyl ethyl sulfide (CEES) is a well-known chemical warfare agent that induces cellular stress in exposed individuals. However, molecular mechanisms of CEES-induced oxidative stress-mediated metabolic deregulation are not clearly elucidated. Here we investigated CEES-induced free radical production act as key functional mediators of metabolic stress via Erk1/2 mitogen-activated protein kinases (MAPKs) and phosphatidylinositol-3-kinase (PI3K/Akt) signaling cascades in keratinocytes. We observed that CEES exposure disrupts the cellular antioxidant defense capacities leading to increase in free oxygen and nitrogen radical accumulation in keratinocytes. These unusual cellular abnormalities initiate cellular stress via Erk1/2-PI3K/Akt signaling pathways. Biochemical tools were used to analyze the changes in metabolites including sulfur amino acids (SAAs), namely, L-glutathione (GSH) and L-cysteine (Cys), in the presence of selective inhibitors of reactive oxygen/nitrogen species (ROS/RNS), Erk1/2, or PI3K/Akt after CEES exposure. Importantly, these metabolite changes were accompanied by a decrease in the glycolytic flux, consistent with the observed decrease in 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase (PFK-2) concentration and these CEES-induced phenomena were attenuated by pretreatment of Erk1/2 or PI3-K/Akt inhibitors. On the other hand, CEES exposure disrupts the protein carbonylation (PC) and lipid peroxidation (LPO) in keratinocytes leading to inflammation, crash of the cell-cell communication, cell cycle deregulation, and apoptosis via Erk1/2-PI3K/Akt pathways. However, pretreatment of Erk1/2 or PI3K/Akt inhibitors attenuated the CEES action. Collectively, these results illustrated that accumulated free radicals act as key functional mediators for inflammation, and apoptosis via Erk1/2-PI3K/Akt regulatory signaling cascades induced by CEES exposure. Treatment of pharmacological Erk1/2-PI3K/Akt inhibitors attenuated the CEES-induced keratinocyte injury that may provide the basis for the development of therapeutic strategy to work against CEES exposure.