Relationship of oxidative stress with male infertility in sulfur mustard-exposed injuries

Association of hormone profile with various respiratory disorders in sulfur mustard-chemical veterans

BACKGROUNDS

Chronic respiratory complications such as asthma, bronchiolitis obliterans, and chronic bronchitis are prevalent among individuals exposed to sulfur mustard (SM). This study investigates the hormonal changes associated with SM-induced respiratory disorders.

METHODS

A cross-sectional analysis was conducted involving 276 male participants exposed to SM during the Iraq-Iran war and 64 healthy controls. Serum levels of various hormones were measured.

RESULTS

Testosterone, dehydroepiandrosterone sulfate (DHEA-S), luteinizing hormone (LH), DHEA-S/cortisol ratio, and DHEA-S/prolactin ratio were decreased in the SM-exposed group compared to the control group while prolactin level and prolactin/cortisol ratio were increased (P < 0.05). The prolactin was increased in bronchiolitis obliterans, chronic bronchitis, and asthma compared to the control group while DHEA-S and DHEA-S/prolactin ratio were decreased in those disorders (P < 0.05). The testosterone was only decreased in asthma, and DHEA-S/cortisol ratio was only decreased in bronchiolitis obliterans and chronic bronchitis compared to control and other disorders (P < 0.05). The principle component analysis showed that the DHEA-S/cortisol and testosterone/cortisol ratios had the most contributing to interpatient variation in total SM-exposed patients in the principle component 1 (PC1). In patients with asthma and bronchiolitis obliterans, prolactin/cortisol and testosterone/cortisol ratios had the most contributing in PC1 while in patients with chronic bronchitis, the DHEA-S/cortisol and testosterone/cortisol ratios had the most contributing.

CONCLUSION

Hormones including testosterone, prolactin, and DHEA-S or their ratios (DHEA-S/cortisol and DHEA-S/prolactin ratios) had the most alterations as delayed effects of sulfur mustard. Also, DHEA-S/cortisol, DHEA-S/prolactin, testosterone/cortisol, and prolactin/cortisol had the most contributing in changes of hormone profile for SM-induced pulmonary disorders. These data may suggest the best parameters for evaluating of hormone profile of SM-exposed people.

Effect of moxa smoke on sperm parameters and oxidative stress in rats with asthenozoospermia

Asthenozoospermia is a leading cause of male infertility, characterized by reduced sperm motility. In this study, we determined sperm motility and the activities of antioxidant enzymes and oxidation products in the testis of rats with ornidazole (ORN)-induced asthenozoospermia and further examined and compared the differential effects of moxa smoke (MS) and cigarette smoke (CS) on sperm motility and oxidative stress (OS) of asthenozoospermic rats. The smoke intervention was initiated 11 days after intragastric administration of ORN, followed by the examination of testis index, sperm parameters, OS-related gene levels, and testicular histopathology. Sperm motility and antioxidant enzyme activities, as well as oxidation products significantly decreased in ORN-induced rats compared with MS-treated rats (p < .05-.001). MS treatment restored the reduced sperm motility and activities of glutathione peroxidase, superoxide dismutase, and catalase, but increased the malondialdehyde and nitric oxide synthetase levels in ORN-induced rats (p < .05-.001). Also, the histopathological changes in the testis of ORN-induced rats were improved by MS treatment. The study highlighted that MS was an effective factor in moxibustion therapy, which notably improved the sperm motility of asthenozoospermic rats by inhibiting OS in the reproductive system.

Urinary Profile of Alkylated DNA Adducts and DNA Oxidative Damage in Sulfur Mustard-Exposed Rats Revealed by Mass Spectrometry Quantification

Alkylation reagents, represented by sulfur mustard (SM), can damage DNA molecules directly as well as lead to oxidative stress, causing DNA lesions indirectly. Correspondingly, two types of biomarkers including alkylated DNA adducts and oxidative DNA adducts are commonly involved in the research of DNA damage evaluation caused by these agents. However, the correlations and differences of the occurrence, duration, severity, and traceability between alkylation and oxidation lesions on the DNA molecular level reflected by these two types of biomarkers have not been systematically studied. A simultaneous determination method for four alkylated DNA adducts, i.e., N7-(2-hydroxyethylthioethyl)2'-guanine (N7-HETEG), O6-(2-hydroxyethylthioethyl)-2'-guanine (O6-HETEG), N3-(2-hydroxyethylthioethyl)-2'-adenine (N3-HETEA), and bis(2-ethyl-N7-guanine)thioether (Bis-G), and the oxidative adduct 8-hydroxy-2'-deoxyguanosine (8-OH-dG) in urine samples by isotope-dilution high-performance liquid chromatography-tandem mass spectrometry (ID-HPLC-MS/MS) was built with a lower limit of detection of 0.02 ng/mL (except Bis-G, 0.05 ng/mL) and a recovery of 79-111%. The profile of these adducts was simultaneously monitored in urine samples after SD rats' dermal exposure to SM in three dose levels (1, 3, and 10 mg/kg). The time-effect and dose-effect experiments revealed that when exposed to SM, DNA alkylation lesions would happen earlier than those of oxidation. For the two types of biomarkers, alkylated DNA adducts showed an obvious dose-effect relationship and could be used as internal exposure dose and effect biomarkers, while 8-OH-dG did not show a correlation with exposure dose, demonstrating that it was more suitable as a biomarker for DNA oxidative lesions but not an indicator for the extent of cytotoxicity and internal exposure.

The predictive association between radiological findings and lung cancer development in patients exposed to sulfur mustard gas: 4 decades follow up of 719 victims

BACKGROUND

Respiratory diseases are the leading cause of morbidity and mortality in the survivors exposed to Sulfur Mustard (SM). The late abnormalities can be present as chronic bronchitis, tracheobronchial stenosis, asthma, bronchiectasis, airway narrowing, lung fibrosis, and lung cancers. This study aims to investigate the association between radiological findings and lung cancer development in patients exposed to sulfur mustard gas.

METHODS

We entered 719 victims exposed to SM during the Iran-Iraq war into our follow-up study in a consensus manner. They were periodically followed with Chest HRCT scans from 2001 to an interval of 2014-2019. The mean year interval between exposure and the last follow-up was 38 years. For confirming the lung cancer in those with evidence of malignancy in their imaging, fine needle aspiration/biopsy and/or surgical intervention were done.

RESULTS

Among 719 patients, 57% were free from any pathologic findings in their HRCT scan. Among the subjects who had the abnormal radiologic findings, Air Trapping (AT), Lung Fibrosis (LF), Bronchiectasis (B), and the evidence of lung cancer were found in 265 (36.9%), 207 (28.8%), 151 (21.0%), and 42 (5.8%), respectively. Adenocarcinoma (38.1%) was the most common type of cancer. The right lung was involved more than the left one regarding LF, B, and cancer (p value < 0.05). Considering the laterality, a significant correlation was found between the side of LF and B and the tumor side. Furthermore, it was shown that the lung lobes with LF were statistically correlated to tumor-involved lobes. The relative risk of AT and B existence for tumor development was 11.73 [4.87-28.26] and 10.14 [5.12-20.090], respectively. The most predictive finding was LF which caused the risk of developing tumor 17.75 [7.35-42.86] times higher in the patient with this pathology. By each increment of the number of LF and B, the risk of developing tumors increased by 51% and 76%, respectively.

CONCLUSION

In survivors exposed to Sulfur Mustard, those with bronchiectasis and lung fibrosis have a significantly higher risk of developing lung cancers, so a close follow-up of these victims is recommended. Trial registration This study was confirmed by the institutional review board and ethics committee at Shiraz University of Medical Sciences (SUMS) with the ethical code IR.SUMS.MED.REC.1399.637.

Is a Ketogenic Diet Superior to a High-Fat, High-Cholesterol Diet Regarding Testicular Function and Spermatogenesis?

The study aimed to determine effects of a ketogenic diet on metabolic dysfunction, testicular antioxidant capacity, apoptosis, inflammation, and spermatogenesis in a high-fat and high-cholesterol diet-induced obese mice model. Forty-two male C57BL/6 mice were fed either a normal diet (NC group) or a high-fat and high-cholesterol (HFC) diet (HFC group) for 16 weeks, and mice from the HFC group were later randomly divided into two groups: the first were maintained on the original HFC diet, and the second were fed a medium-chain triacylglycerol (MCT)-based ketogenic diet for 8 weeks (KD group). A poor semen quality was observed in the HFC group, but this was eliminated by the ketogenic diet. Both the HFC and KD groups exhibited enhanced apoptosis protein expressions in testis tissue, including caspase 3 and cleaved PARP, and higher inflammation protein expressions, including TNF-α and NF-κB. However, the KD group exhibited a statistically-significant reduction in lipid peroxidation and an increased glutathione peroxidase level as compared with the HFC group. The HFC diet induced obesity in mice, which developed body weight gain, abnormal relative organ weights, metabolic dysfunction, and liver injury. Overall, the results showed that a ketogenic diet attenuated oxidative stress and improved the semen quality reduced by the HFC diet.

Sulfur mustard and biological ageing: A multisystem biological health score approach as an extension of the allostatic load in Sardasht chemical veterans

BACKGROUND

Mustard gas as a chemical weapon has been used in wars and its long-term side effects are substantial in the human body. This study was aimed to apply an extension of allostatic load, known as synthetic biological health score (BHS), including the wear-and-tear of four physiological systems (endocrine, inflammatory, cardiovascular and metabolic systems) and two organs (liver and kidney) to estimate biological aging caused by sulfur mustard (SM) gas poisoning.

METHODS

The plasma samples were prepared from two following groups of people; 1) 446 individuals exposed to SM gas in 1987. 2) 115 healthy members, at the same range of age and residence, as the non-exposed group. These people were chosen from the same patients' families and have not had any exposure to SM or pulmonary dysfunction. To estimate BHS, 18 blood-derived biomarkers of the mentioned systems and organs were measured and the relative contribution of many social and body parameters across the age groups was explored.

RESULTS

It was revealed, in BHS calculation, the cardiovascular system had the most effect. Also, in the SM group, BHS was significantly higher than in the control group. This feature has a positive correlation with physical parameter (BMI) and a negative correlation with social parameters (salary and educational levels).

CONCLUSION

The multisystem BHS could be useful in the evaluation of biological aging due to SM exposure. Social (education, good-paying job) and physical (BMI) parameters could influence BHS and the higher BHS indicates the progress of biological aging due to mustard gas.

Pregnancy Outcomes of Wives of Chemical and Non-Chemical Weapons Exposed Veterans in Ahvaz, Iran: A Retrospective Cohort Study

BACKGROUND

Sulphur mustard (HD) is a lipophilic caustic alkylating vesicant (blister agent) that has mutagenic and carcinogenic effects. Among the studied perturbations are long-term genitourinary (GU) and fertility effects. Approximately 50,000 Iranian soldiers and civilians were exposed to HD during the Iraq-Iran war (1980-1989). This study questioned the wives of Iraq-Iran war veterans to determine the effects of male HD-exposure on pregnancy complications, adverse pregnancy outcomes, and secondary infertility.

METHODS

A retrospective, survey-based cohort study was conducted of wives of Iranian military veterans that survived HD-associated injuries while serving in Ahvaz, Iran during the Iraq-Iran war (1980-1989), as compared to non-exposed veterans serving concomitantly. Patients were identified from a database of injured veterans maintained by the Foundation of Martyrs and Veterans Affairs (Iran) via a systematic random sampling method utilizing a random number table. Using a validated questionnaire, collected data included: demographics; type and severity of chemical injury; spouse's obstetric history (pregnancy number, duration, complications, and outcomes before and after spouse's chemical injury); and secondary infertility.

RESULTS

An increase in spontaneous abortion (P = .03), congenital anomalies (P < .0001), and secondary infertility (P = .003) were observed. These findings were greatest amongst those with HD injuries affecting >50% body surface area. No difference in stillbirth, premature birth, or low birth weight was observed.

CONCLUSION

Exposure to HD in combat may have long-lasting fertility effects on soldiers and their spouses, including spontaneous abortion, congenital anomalies, and secondary infertility. Further investigation is needed into the long-term effects of HD exposure as well as methods to better protect soldiers.

Novel additive for sperm cryopreservation media: Holotheria parva coelomic cavity extract protects human spermatozoa against oxidative stress-A pilot study

Cryopreservation is the most effective method for preserving semen for a long period of time. However, during the freeze-thaw process, production of reactive oxygen species (ROS) leads to a steep reduction in sperm fertility indices. In this study, we tested the effects of the extract of the coelomic cavity of five Holotheria parva, a marine organism rich in antioxidants, for its ROS-scavenging activity and cryoprotective effects on oxidative stress. Using a total of 50 semen samples, our results demonstrated that doses of 250 and 500 µg/ml of H. parva coelomic cavity extract significantly increased sperm vitality as compared to the control (p < .05). The addition of 250 µg/ml of the extract exerted a significant positive effect on sperm motility. Moreover, sperm DNA damage and ROS production were significantly reduced at extract concentrations of 250 and 500 µg/ml (p < .05). To the best of our knowledge, the results of this study represent the first demonstration of the possibility of improving sperm parameters and reducing ROS production and DNA damage by supplementing sperm freezing media with H. parva coelomic extract. Our results suggested that H. parva coelomic extract could be useful for improving the fertilising ability of frozen-thawed human semen.

Soy Isoflavones Improve the Spermatogenic Defects in Diet-Induced Obesity Rats through Nrf2/HO-1 Pathway

Soy isoflavones (SIF) are biologically active compounds of non-steroidal and phenolic properties that are richly present in soybeans, which can reduce the body weight and blood lipids of obese animals. Recently, SIF have been reported to affect reproductive ability in obese male rats. However, the specific mechanism has not been well defined. The aim of the current study was to study the possible mechanisms for the effect of SIF administration on obesity induced spermatogenic defects. Obese rats model induced by high-fat diets were established and gavage treated with 0, 50,150 or 450 mg of SIF/kg body weight/day for 4 weeks. Here, our research shows that obesity resulted in spermatogenic degeneration, imbalance of reproductive hormone, testicular oxidative stress and germ cell apoptosis, whereas evidently recovery effects were observed at 150 and 450 mg/kg SIF. We also have discovered that 150 and 450 mg/kg SIF can activate Nrf2/HO-1 pathway in control of Bcl-2, BAX and cleaved caspase-3 expression with implications in antioxidant protection. Our study indicates the potential mechanism of SIF regulating spermatogenic function in obese rats, and provides a scientific experimental basis for the regulation of biological function of obese male reproductive system by SIF.

Cellular and molecular mechanisms of sulfur mustard toxicity on spermatozoa and male fertility

Sulfur mustard (SM) is a toxic compound that can target human spermatozoa. SM induces a wide variety of pathological effects in human reproductive organs, including sexual hormone disturbance, testicular atrophy, impaired spermatogenesis, poor sperm quality, defects in embryo development, childhood physical abnormalities, and severe fertility problems. However, the molecular and cellular mechanisms of SM action on male reproductive health and human sperm function are unclear. Excessive production of reactive oxygen species and the resulting oxidative stress is likely a significant mechanism of SM action, and could be associated with sperm DNA damage, membrane lipid peroxidation, reduced membrane fluidity, mitochondrial deficiency, apoptosis, and poor sperm quality. In this review, we aim to discuss the cellular and molecular mechanisms of SM action on sperm and reproductive health, the significance of OS, and the mechanisms through which SM enhances the infertility rate among SM-exposed individuals.

Effects of zinc deficiency on impaired spermatogenesis and male infertility: the role of oxidative stress, inflammation and apoptosis

Zinc (Zn) is necessary for the normal function of the male reproductive system and spermatozoa. Although influences of zinc deficiency on impaired spermatogenesis and male infertility have been widely considered, the molecular and cellular mechanisms of these abnormalities are not well understood. General abnormalities, including hypogonadism, Leydig cells damage, deficiency of sex hormone production and impaired spermatogenesis, as well as inflammation, antioxidant depletion, sperm death and male infertility can be observed during zinc deficiency. However, it is not obvious which pathways are relevant to the pathogenesis of zinc deficiency. Oxidative stress (OS) induced by reactive oxygen species is likely as the main mechanism of zinc deficiency which is associated with sperm DNA fragmentation, decrease in sperm membrane integrity, apoptosis, depletion of antioxidants, and consequently poor sperm quality and male infertility. Therefore, identification of these pathways will give valuable information regarding the mechanisms of zinc deficiency on the male reproductive system and the potential way for developing a better clinical approach. In this review, we aim to discuss the proposed cellular and molecular mechanisms of zinc deficiency on the male reproductive system, the importance of OS and mechanisms by which zinc deficiency induces OS and depletion of other antioxidants.

Correction to: An evidence-based review of the genotoxic and reproductive effects of sulfur mustard

This is with reference to the note of the Editor-in-Chief of the Archives of Toxicology.

Sulfur mustard triggers oxidative stress through glutathione depletion and altered expression of glutathione-related enzymes in human airways

CONTEXT

Sulfur mustard (SM) is a lipophilic and reactive chemical compound that targets human airway system.

OBJECTIVE

Glutathione (GSH) depletion, oxidative stress (OS) status, and changes in expression of GSH-dependent antioxidant enzymes were considered in human mustard lungs.

MATERIALS AND METHODS

Lung biopsies and bronchoalveolar lavage (BAL) were collected from non-exposed (n = 10) individuals and SM-exposed patients (n = 12). Alterations in expression of GSH-dependent enzymes were studied using RT² Profiler™ PCR array. OS was evaluated by determining BAL fluid levels of total antioxidant capacity (TAC), malondialdehyde (MDA), and GSH.

RESULTS

Mean TAC (0.142 ± 0.027 µmol/l) and GSH (4.98 ± 1.02 nmol/l) in BAL fluids of control group was significantly higher (p < .05) than those in SM-exposed patients (TAC = 0.095 ± 0.018 µmol/l and GSH= 3.09 ± 1.02 nmol/l), while MDA level in BAL fluids of these patients (0.71 ± 0.06 nmol/l) was significantly (p = .001) higher than that in controls (0.49 ± 0.048 nmol/l). Glutathione peroxidases (GPXs), glutathione-s-transferases (GSTs), and glutathione synthetase (GSS) enzymes were overexpressed in mustard lung biopsies, while glutathione reductase (GSR) was significantly downregulated (14.95-fold).

CONCLUSIONS

GSH depletion induced by GSR downregulation may be a major mechanism of SM toxicity on human lung. Despite overexpression of GSTs and GPXs genes, GSH depletion may decline the productivity of these enzymes and total antioxidants capacity, which is associated with OS.

Altered expression of cyclooxygenase-2, 12-lipoxygenase, inducible nitric oxide synthase-2 and surfactant protein D in lungs of patients with pulmonary injury caused by sulfur mustard

CONTEXT

Sulfur mustard (SM) is a strong alkylating toxicant that targets different organs, particularly human lung tissue. Change in genes expression is one of the molecular mechanisms of SM toxicity in damaged tissue.

OBJECTIVE

The purpose of this investigation is to characterize the expression of cyclooxygenase-2 (COX-2), 12-lipoxygenase (12-LO), inducible nitric oxide synthase 2 (iNOS2), and surfactant protein D (SFTPD) in lungs of patients who exposed to SM.

METHODS

Lung biopsies were provided from SM-exposed patients (n = 6) and controls (n = 5). Total RNA were extracted from all specimens and then cDNA was synthesized for each sample. Changes in gene expression were measured using RT² Profiler ™PCR Array.

RESULTS

Pulmonary function tests revealed more obstructive and restrictive spirometric patterns among patients compared to the control group. Expression of COX-2 and 12-LO in the lung of patients was increased by 6.2555 (p = 0.004) and 6.2379-folds (p = 0.002), respectively. In contrast, expression of SF-D and iNOS genes was reduced by 8.5869-fold (p = 0.005) and 2.4466-folds (p = 0.011), respectively.

CONCLUSIONS

Mustard lungs were associated with overexpression of COX-2 and 12-LO, which are responsible for inflammation, overproduction of free radicals and oxidative stress. Downregulation of iNOS2 and SF-D are probably the reason for lung disease and dysfunction among these patients. Therefore, the expression of these genes could be an important, routine part of the management of such patients.

Regulatory Functions of MicroRNAs in Male Reproductive Health: A New Approach to Understanding Male Infertility

MicroRNAs (miRNAs) are a novel class of small noncoding RNAs (ncRNAs) that play critical roles in regulation of gene expression, especially at posttranscriptional level. Over the past decade, the degree to which miRNAs are involved in male infertility has become clear. They are expressed in a cell- or phase-specific manner during spermatogenesis and play crucial role in male reproductive health. Therefore, dysregulation of miRNAs in testicular cells can be considered as a molecular basis for reproductive failure and male infertility. The abnormal expression pattern of miRNAs can be transmitted to the offspring via assisted reproductive techniques (ART) and results in the birth of children with a higher risk of infertility, congenital abnormalities, and morbidity. This review expounds on the miRNAs reported to play essential roles in somatic cells development, germ cells differentiation, steroidogenesis, normal spermatogenesis, sperm maturation, and male infertility, as well as emphasizes their importance as minimally invasive biomarkers of male infertility.

An insight into the possible mechanisms of antispermatogenic action of Dalbergia sissoo in male mice

This study investigated the possible mechanisms of antispermatogenic action of Dalbergia sissoo in Parkes male mice. Mice were orally administered aqueous leaf extract of Dalbergia sissoo (50 and 100 mg kg^-1 body weight day^-1 for 35 days) and various testicular indices such 3β- and 17β-hydroxysteroid dehydrogenase (HSD) activities, Western blot analyses of StAR, cytochrome P450scc and caspase-3, germ cell apoptosis by TUNEL, and lipid peroxidation and antioxidant enzymes activities were assessed. A significant increase in lipid peroxidation level and a marked decrease in activities of superoxide dismutase, catalase, 3β- and 17β-HSD were noted in the testis of Dalbergia-treated mice compared to controls. The treatment also had adverse effect on expression levels of StAR and cytochrome P450scc in the testis. There was an increase in the number of TUNEL-positive germ cells and in expression level of caspase-3 in testes of Dalbergia-treated mice, especially in those treated with 100 mg dose compared to controls. By 56 days of withdrawal therapy, the alterations induced in the above parameters recovered to control levels. Our results thus suggest that Dalbergia treatment interferes with steroidogenesis and produces oxidative stress in the testis, which may induce germ cell apoptosis leading to suppression of spermatogenesis.

Sulfur mustard causes oxidants/antioxidants imbalance through the overexpression of free radical producing-related genes in human mustard lungs

The aim of this study is to analyze oxidative stress (OS) and changes in expression of reactive oxygen species (ROS) producing-related genes in mustard lungs. Human lung biopsies provided from controls (n=5) and sulfur mustard (SM)-exposed patients (n=6). Changes in expression of dual oxidases (DUOXs), aldehyde oxidase 1 (AOX1), thyroid peroxidase (TPO), myeloperoxidase (MPO) and eosinophil Peroxidase (EPO) were measured using RT(2) Profiler(™) PCR Array. OS was evaluated by determining bronchoalveolar lavage fluids (BALF) levels of total antioxidant capacity (TAC) and malondialdehyde (MDA). Higher TAC value was observed in BALF of controls compared with patients (0.138±0.02683μmol/l vs 0.0942±0.01793μmol/l), whereas a significant increase in MDA concentration was found in patients (0.486±0.04615 nmol/l vs 0.6467±0.05922 nmol/l). All ROS producing-related genes were overexpressed in the order AOX1>MPO>DUOX2>DUOX1>TPO>EPO. Upregulation of these genes may be a reason for overproduction of ROS, oxidants/antioxidants imbalance, OS and respiratory failures in mustard lungs.

Gene expression profile of oxidative stress and antioxidant defense in lung tissue of patients exposed to sulfur mustard

Sulfur mustard (SM) is a potent alkylating agent that targets several organs, especially lung tissue. Although pathological effects of SM on mustard lung have been widely considered, molecular and cellular mechanisms for these pathologies are poorly understood. We investigated changes in expression of genes related to oxidative stress (OS) and antioxidant defense caused by SM in lung tissue of patients. We performed gene expression profiling of OS and antioxidant defense in lung tissue samples from healthy controls (n=5) and SM-exposed patients (n=6). Changes in gene expression were measured using a 96-well RT(2) Profiler ™PCR Array: Human Oxidative Stress and Antioxidant Defense, which arrayed 84 genes functionally involved in cellular OS response. 47 (55.95%) genes were found to be significantly upregulated in patients with mustard lung compared with controls (p<0.05), whereas 7 (8.33%) genes were significantly downregulated (p<0.05). Among the most upregulated genes were OS responsive-1 (OXSR1), forkhead box M1 (FOXM1), and glutathione peroxidase-2 (GPX2), while metallothionein-3 (MT3) and glutathione reductase (GSR) were the most downregulated genes. Expression of hypoxia-induced genes (CYGB and MB), antioxidants and reactive oxygen species (ROS)-producing genes were significantly altered, suggesting an increased oxidative damage in mustard lungs. Mustard lungs were characterized by hypoxia, massive production of ROS, OS, disruption of epithelial cells, surfactant dysfunction, as well as increased risk of lung cancer and pulmonary fibrosis. Oxidative stress induced by ROS is the major mechanism for direct effect of SM exposure on respiratory system. Antioxidant treatment may improve the main features of mustard lungs.