Taurine prevents arsenic-induced cardiac oxidative stress and apoptotic damage: Role of NF-κB, p38 and JNK MAPK pathway

Cardiac dysfunction is a major cause of morbidity and mortality worldwide due to its complex pathogenesis. However, little is known about the mechanism of arsenic-induced cardiac abnormalities and the use of antioxidants as the possible protective agents in this pathophysiology. Conditionally essential amino acid, taurine, accounts for 25% to 50% of the amino acid pool in myocardium and possesses antioxidant properties. The present study has, therefore, been carried out to investigate the underlying mechanism of the beneficial role of taurine in arsenic-induced cardiac oxidative damage and cell death. Arsenic reduced cardiomyocyte viability, increased reactive oxygen species (ROS) production and intracellular calcium overload, and induced apoptotic cell death by mitochondrial dependent caspase-3 activation and poly-ADP ribose polymerase (PARP) cleavage. These changes due to arsenic exposure were found to be associated with increased IKK and NF-κB (p65) phosphorylation. Pre-exposure of myocytes to an IKK inhibitor (PS-1145) prevented As-induced caspase-3 and PARP cleavage. Arsenic also markedly increased the activity of p38 and JNK MAPKs, but not ERK to that extent. Pre-treatment with SP600125 (JNK inhibitor) and SB203580 (p38 MAPK inhibitor) attenuated NF-κB and IKK phosphorylation indicating that p38 and JNK MAPKs are mainly involved in arsenic-induced NF-κB activation. Taurine treatment suppressed these apoptotic actions, suggesting that its protective role in arsenic-induced cardiomyocyte apoptosis is mediated by attenuation of p38 and JNK MAPK signaling pathways. Similarly, arsenic intoxication altered a number of biomarkers related to cardiac oxidative stress and other apoptotic indices in vivo and taurine supplementation could reduce it. Results suggest that taurine prevented arsenic-induced myocardial pathophysiology, attenuated NF-κB activation via IKK, p38 and JNK MAPK signaling pathways and could possibly provide a protection against As-induced cardiovascular burden.     

Resveratrol induces apoptosis of human malignant B cells by activation of caspase-3 and p38 MAP kinase pathways

Red wine polyphenol, trans-resveratrol (trans-3,4',5-trihydroxy stilbene), has potent chemopreventive effects against various tumors. In this study, we found for the first time that resveratrol rapidly induces S phase cell cycle arrest of human malignant B cells including myeloma cells in dose- and time-dependent manners, followed by S phase cell cycle arrest through ATM/Chk pathway. Resveratrol-induced apoptosis occurs in association with the activation of caspase-3 and the loss of mitochondrial transmembrane potentials. In addition, resveratrol induces the phosphorylation of p38 MAP kinase, and specific inhibition of p38 MAP kinase abolishes the resveratrol-induced apoptosis, indicating that activation of the p38 MAP kinase pathway is required for inducing apoptosis in malignant B cells. These results suggest that resveratrol may have potential as a novel therapeutic agent for the patients with B cell malignancies including multiple myeloma.     

金粉蕨素拮抗血管内皮细胞氧化应激损伤及机制

目的 :研究金粉蕨素 (onychin ,Ony)对血管内皮细胞氧化应激损伤的影响及可能机制。方法 :培养人脐静脉血管内皮细胞株 (ECV30 4 ) ,经Ony处理后 ,用过氧化氢 (H2 O2 )对其损伤 ;用MTT比色法和乳酸脱氢酶测定法分别检测损伤组和处理组细胞增殖活性和功能状态 ;用Western Blot法检测磷酸化ERK1 2和p38、P90RSK蛋白的表达。结果 :不同浓度的Ony(0 .3、1、3、10 μmol·L-1)促进H2 O2 损伤的内皮细胞增殖 ,减少LDH释放 ,并呈浓度依赖性。Ony(3μmol·L-1)抑制H2 O2 诱导的磷酸化p38表达 ,30min时最明显 ,但并不影响H2 O2 对ERK的激活以及ERK下游蛋白激酶P90RSK的表达。而阳性对照药genistein虽可增加内皮细胞增殖活性和减少功能损伤 ,但明显抑制H2 O2 诱导的磷酸化ERK表达及其下游蛋白激酶P90RSK。结论 :Ony拮抗血管内皮细胞氧化应激损伤可能与抑制p38磷酸化有关。     

Chrysin protects against cisplatin-induced colon. toxicity via amelioration of oxidative stress and apoptosis: probable role of p38MAPK and p53

Cisplatin, an antineoplastic drug, is widely used as a foremost therapy against numerous forms of cancer but it has pronounced adverse effects viz., nephrotoxicity, ototoxicity etc. CDDP-induced emesis and diarrhea are also marked toxicities that may be due to intestinal injury. Chrysin (5,7-dihydroxyflavone), a natural flavone commonly found in many plants possesses multiple biological activities, such as antioxidant, anti-inflammatory and anti-cancer effects. In the present study, we investigated the protective effect of chrysin against CDDP-induced colon toxicity. The plausible mechanism of CDDP-induced colon toxicity and damage includes oxidative stress, activation of p38MAPK and p53, and colonic epithelial cell apoptosis via upregulating the expression of Bak and cleaved caspase-3. Chrysin was administered to Wistar rats once daily for 14 consecutive days at the doses of 25 and 50 mg/kg body weight orally in corn oil. On day 14, a single intraperitoneal injection of cisplatin was given at the dose of 7.5 mg/kg body weight and animals were euthanized after 24 h of cisplatin injection. Chrysin ameliorated CDDP-induced lipid peroxidation, xanthine oxidase activity, glutathione depletion, decrease in antioxidant (catalase, glutathione reductase, glutathione peroxidase and glucose-6 phosphate dehydrogenase) and phase-II detoxifying (glutathione-S-transferase and quinone reductase) enzyme activities. Chrysin also attenuated goblet cell disintegration, expression of phospho-p38MAPK and p53, and apoptotic tissue damage which were induced by CDDP. Histological findings further supported the protective effects of chrysin against CDDP-induced colonic damage. The results of the present study suggest that the protective effect of chrysin against CDDP-induced colon toxicity was related with attenuation of oxidative stress, activation of p38MAPK and p53, and apoptotic tissue damage.     

Induction of apoptosis by a stilbene analog involves bax translocation regulated by p38 MAPK and Akt

trans-Stilbenes have been reported to induce cytochrome P450 1B1 (CYP1B1) inhibition and cell death, however, the molecular mechanisms of the effects are not fully understood. We report here that (1-(2-{3-[2-(2,4-dimethoxy-phenyl)-vinyl]-5-methoxy-phenoxy}ethyl)-1H-imidazole), a synthetic stilbene analog (SA) significantly suppressed TCDD-stimulated CYP1B1 mRNA expression. In HL-60 cells, SA induced apoptosis through activation of p38 MAPK and inactivation of Akt, which in turn activated Bad and mitochondrial death signaling pathway, as evidenced by Bax translocation and cytochrome c release. Expression of dominant negative p38 MAPK or constitutively active Akt significantly prevented cell death and mitochondrial Bax translocation, implicating that p38 MAPK and Akt signaling pathways play crucial roles in stilbene-induced apoptosis of HL-60 cells. These results suggest that SA induces apoptotic cell death as well as CYP1B1 inhibition and may thus be beneficial in cancer prevention.     

Resveratrol prevents the expression of glaucoma markers induced by chronic oxidative stress in trabecular meshwork cells

Elevated intraocular pressure (IOP) constitutes the best characterized risk for primary open-angle glaucoma (POAG). Elevated IOP is believed to result from an increase in aqueous humor outflow resistance at the level of the trabecular meshwork (TM)/Schlemm’s canal. Malfunction of the TM in POAG is associated with the expression of markers for inflammation, cellular senescence, oxidative damage, and decreased cellularity. Current POAG treatments rely on lowering IOP, but there is no therapeutic approach available to delay the loss of function of the TM in POAG patients. We evaluated the effects of chronic administration of the dietary supplement resveratrol on the expression of markers for inflammation, oxidative damage, and cellular senescence in primary TM cells subjected to chronic oxidative stress (40% O₂). Resveratrol treatment effectively prevented increased production of intracellular reactive oxygen species (iROS) and inflammatory markers (IL1α, IL6, IL8, and ELAM-1), and reduced expression of the senescence markers sa-β-gal, lipofuscin, and accumulation of carbonylated proteins. Furthermore, resveratrol exerted antiapoptotic effects that were not associated with a decrease in cell proliferation. These results suggest that resveratrol could potentially have a role in preventing the TM tissue abnormalities observed in POAG.     

Di(2-ethylhexyl) phthalate promotes hepatic fibrosis by regulation of oxidative stress and inflammation responses in rats

Di(2-ethylhexyl) phthalate (DEHP) is an environmental pollutant that is widely used in medical and consumer products. An epidemiological study has suggested that a large daily intake of DEHP from phthalate-contaminated food may be a risk factor for liver dysfunction. Long-term exposure to DEHP is associated with liver disease and exacerbates the progression of chronic liver injury. However, the effect of DEHP on hepatic fibrosis is rarely studied. In the present study, we sought to determine the effect of DEHP on carbon tetrachloride (CCl4)-induced liver fibrosis, and to further examine the molecular mechanisms. We found that DEHP exposure remarkably promoted liver inflammation, necrosis and fibrosis, and increased expression of the protein associated with liver inflammation and fibrogenesis, including α-SMA, COL-Ⅰ, COL-Ⅲ, TGF-β1, P-Smad2, P-Smad3, P-p38 and P-p65. The similar trend was observed in the LX-2 cells. Furthermore, DEHP exposure induced oxidative stress and inflammatory cytokine production. Taken together, DEHP might play a fibrotic role in hepatic fibrosis rats and TGF-β1-stimulated LX-2 cells in vitro which was related to TGF-β1/Smad and p38MAPK/NF-κB signal pathway.     

Cobalt oxide nanoparticles induced oxidative stress linked to activation of TNF‐α/caspase‐8/p38‐MAPK signaling in human leukemia cells

The purpose of this study was to determine the intracellular signaling transduction pathways involved in oxidative stress induced by nanoparticles in cancer cells. Activation of reactive oxygen species (ROS) has some therapeutic benefits in arresting the growth of cancer cells. Cobalt oxide nanoparticles (CoO NPs) are an interesting compound for oxidative cancer therapy. Our results showed that CoO NPs elicited a significant (P <0.05) amount of ROS in cancer cells. Co‐treatment with N‐aceyltine cystine (an inhibitor of ROS) had a protective role in cancer cell death induced by CoO NPs. In cultured cells, the elevated level of tumor necrosis factor‐alpha (TNF‐α) was noted after CoO NPs treatment. This TNF‐α persuaded activation of caspase‐8 followed by phosphorylation of p38 mitogen‐activated protein kinase and induced cell death. This study showed that CoO NPs induced oxidative stress and activated the signaling pathway of TNF‐α‐Caspase‐8‐p38‐Caspase‐3 to cancer cells. Copyright © 2015 John Wiley & Sons, Ltd.     

Dual role of resveratrol in modulation of genotoxicity induced by sodium arsenite via oxidative stress and apoptosis

The potential benefits of resveratrol as an anticancer (proapoptosis) and antioxidant (pro-survival) compound have been studied extensively. However, the role of resveratrol in modulation of the toxicity induced by sodium arsenite (NaAsO₂) is still unclear. In the present study, we examined the effects of resveratrol on NaAsO₂-induced cytotoxicity, DNA and chromosomal damage, cell cycle progression, apoptosis and oxidative stress in human lung adenocarcinoma epithelial (A549) cell line at concentrations from 1 to 20 μM after 24 h exposure. Our results revealed that at 1 and 5 μM, resveratrol was found to exert benefit effects, promoting cell viability and proliferation over 24 h NaAsO₂ exposure, whereas, resveratrol was showed to inhibit cell survival under the same condition at 20 μM. Corresponding to the opposing effect of resveratrol at low vs. high concentrations, DNA and chromosomal damage, cell apoptotic rate and level of oxidative stress were also alleviated by lower concentrations (1, 5 μM) of resveratrol, but exacerbated by higher concentration (20 μM) resveratrol. Our study implicates that resveratrol is the most beneficial to cells at 1 and 5 μM and caution should be taken in applying resveratrol as an anticancer therapeutic agent or nutraceutical supplement due to its concentration dependent effect.     

Protection by genistein on cortical neurons against oxidative stress injury via inhibition of NF-kappaB,JNK and ERK signaling pathway

Abstract

Context: Genistein, one of the isoflavones derived from soybean seeds, has been reported to exert multiple bioactivities. However, the mechanism of its action on the central nervous system is not fully understood.

Objective: To investigate the cytoprotection of genistein and its molecular mechanism against H₂O₂-induced cell death in primary rat cortical neurons.

Materials and methods: Genistein (0.01, 0.1, and 1?μM) were added into the primary rat neurons 24?h before and co-cultured with 500?μM H₂O₂ for 1?h. Neuronal injury was assessed by MTT, lactate dehydrogenase (LDH) assay, and Hoechst33258 staining. Intracellular reactive oxygen species (ROS) generation induced by H₂O₂ was determined. Neuronal apoptosis was evaluated by Bcl-2/Bax ratio as well as by caspase-9 and caspase-3 activities. The protein levels and phosphorylation of NF-κB/p65, IκB, JNK, and ERK were detected by western blots.

Results: Genistein pretreatment attenuated H₂O₂-mediated neuronal viability loss, nuclear condensation, and ROS generation in a concentration-dependent manner. Genistein exerted anti-apoptotic effects by reversing the apoptotic factors Bcl-2 and Bax ratio, along with the suppression of caspase-9 and caspase-3 activities. In addition, genistein down-regulated the expression of NF-κB/p65, and suppressed the phosphorylation of p65 and IκB. Genistein also inhibited H₂O₂-induced activation of the MAPK-signaling pathway including JNK and ERK.

Discussion and conclusion: The results indicated that genistein effectively protects cortical neurons against oxidative stress at least partly via inactivation of NF-κB as well as MAPK-signaling pathways, and suggested the possibility of this antioxidant for the prevention and treatment of stroke.     

Resveratrol pretreatment alleviates NLRP3 inflammasome-mediated cardiomyocyte pyroptosis by targeting TLR4/MyD88/NF-κB signaling cascade in coronary microembolization-induced myocardial damage

Percutaneous coronary intervention and acute coronary syndrome are both closely tied to the frequently occurring complication of coronary microembolization (CME). Resveratrol (RES) has been shown to have a substantial cardioprotective influence in a variety of cardiac diseases, though its function and potential mechanistic involvement in CME are still unclear. The forty Sprague–Dawley rats were divided into four groups randomly: CME, CME + RES (25 mg/kg), CME + RES (50 mg/kg), and sham (10 rats per group). The CME model was developed. Echocardiography, levels of myocardial injury markers in the serum, and histopathology of the myocardium were used to assess the function of the cardiac muscle. For the detection of the signaling of TLR4/MyD88/NF-κB along with the expression of pyroptosis-related molecules, ELISA, qRT-PCR, immunofluorescence, and Western blotting were used, among other techniques. The findings revealed that myocardial injury and pyroptosis occurred in the myocardium following CME, with a decreased function of cardiac, increased levels of serum myocardial injury markers, increased area of micro-infarct, as well as a rise in the expression levels of pyroptosis-related molecules. In addition to this, pretreatment with resveratrol reduced the severity of myocardial injury after CME by improving cardiac dysfunction, decreasing serum myocardial injury markers, decreasing microinfarct area, and decreasing cardiomyocyte pyroptosis, primarily by blocking the signaling of TLR4/MyD88/NF-κB and also reducing the NLRP3 inflammasome activation. Resveratrol may be able to alleviate CME-induced myocardial pyroptosis and cardiac dysfunction by impeding the activation of NLRP3 inflammasome and the signaling pathway of TLR4/MyD88/NF-κB.     

Assessment of the neurotoxic mechanisms of decabrominated diphenyl ether (PBDE-209) in primary cultured neonatal rat hippocampal neurons includes alterations in second messenger signaling and oxidative stress

2′,2′,3′,3′,4′,4′,5′,5′,6′,6′,-decabrominated diphenyl ether (PBDE-209) is the most widely used polybrominated diphenyl ethers (PBDEs) globally. Some animal experiments have found that PBDE-209 caused developmental neurotoxicity. But detailed mechanisms are less well understood. Our experiments were conducted to research the potential neurotoxic mechanisms of PBDE-209 in primary cultured neonatal rat hippocampal neurons by measuring cell viability, apoptotic rate, expression of P38 mitogen-activated protein kinases (MAPKs), calcium ion concentration, oxidative stress, nitrous oxide (NO) content, and global gene DNA methylation levels. The neurons were exposed to different PBDE-209 concentrations (0, 10, 30 and 50 μg/ml). The difference between the experimental groups and control groups was significant (P < 0.05). PBDE-209 increased the rate of apoptosis, expression of P38 MAPK, calcium ion concentration, reactive oxygen species (ROS) level, malondialdehyde (MDA) content and NO content (P < 0.05). In addition, PBDE-209 deceased cell viability, activity of superoxide dismutase (SOD) and the levels of global gene DNA methylation (P < 0.05). The results suggested that PBDE-209 could affect secondary messengers, cause oxidative stress and decrease global gene DNA methylation levels. These actions may contribute to the mechanism of PBDE-209 neurotoxicity.     

Total saponins isolated from Radix et Rhizoma Leonticis suppresses tumor cells growth by regulation of PI3K/Akt/mTOR and p38 MAPK pathways

Both PI3K/AKT/mTOR and mitogen activated protein kinase (MAPK) signaling cascades played an important role in tumorigenesis, a more complete understanding of these signaling pathways allowed the development of new therapeutic strategies. Total saponins isolated from Radix et Rhizoma Leonticis (RLTS) was recognized with anticancer properties. In a murine hepatocellular carcinoma H22 cell-bearing mouse model, RLTS exhibited significant inhibitory effect on tumor growth. Here, we investigated the role of RLTS on the PI3K/AKT/mTOR signaling pathway and MAPK pathways in liver and lung cancer cells. Results obtained showed RLTS inhibited cell proliferation and induced cell apoptosis in vitro, which attributed to the inhibition on the activation of PI3K/AKT/mTOR cascade and its related signaling molecules, such as activated VEGFR and NF-κB, and activation of p38 MAPK in tumor cells. Additional, RLTS inhibited cell migration and downregulated proteins that mediated metastasis including CXCR4, MMP2 and MMP9. Overall, these findings suggested that RLTS interfered with multiple signaling cascades involved in tumorigenesis and had potential in cancer therapy.     

Immunotoxic effects of thymus in mice following exposure to nanoparticulate TiO2

Titanium dioxide nanoparticles (TiO₂ NPs) have been extensively used in industry, medicine, and daily life, and have shown potential toxic effects for animals or humans. We noted that the effects of TiO₂ NPs on the immune system and its mechanism of action in animals or humans have not been elucidated. Thus, mice were exposed to the TiO₂ NPs (0, 1.25, 2.5, or 5 mg kg^?1 body weight) for 9 consecutive months. Exposure to TiO₂ NPs was accumulated in the thymus, leading to a decrease in body weight and increases in the weight of the thymus or thymus indices. In the blood, exposure to TiO₂ NPs significantly decreased white blood cell, red blood cell, reticulocyte, haemoglobin, and mean corpuscular haemoglobin concentration; and increased mean corpuscular volume, mean corpuscular haemoglobin, platelets, and mean platelet volume. The reductions of lymphocyte subsets, including CD3+, CD4+, CD8+, B cell, and natural killer cell, were observed in the TiO₂ NP‐treated mouse thymus. Appearance of starry‐sky aspect of the cortex that is given by the body of macrophages, bleeding, severe hemolysis or congestion, fatty degeneration, and cell apoptosis or necrosis were observed in the thymus following TiO₂ NPs exposure. Importantly, TiO₂ NPs increased expression of nucleic factor‐κB(NF‐κB), IκB kinase1/2, interleukin‐1β, interleukin ?4, regulated upon activation normal T‐cell expressed and secreted, cyclooxygenase 2, neutrophil gelatinase‐associated lipocalin, purinergic receptors‐7, interferon‐inducible protein 10, hypoxia inducible factor 1‐α, p‐c‐Jun N‐terminal kinase, p‐p38, and p‐extracellular signal‐regulated kinase 1/2 protein, respectively; whereas suppressed expression of IκB, peroxisome proliferater‐activated receptor‐γ, trefoil factor 1, peroxisome proliferator activated receptor gamma coactivator‐1α, and prostaglandin E2 proteins in the thymus, respectively. Taken together, these results suggest that TiO₂ NPs exerts toxic effects on lymphoid organs and T cell and innate immune cell homeostasis in mice and that these immunotoxic potential effects may result from the activation of NF‐κB‐mediated mitogen‐activated protein kinases (MAPKs) pathway.     

The role of GSH in microcystin‐induced apoptosis in rat liver: Involvement of oxidative stress and NF‐κB

Microcystins (MCs) are potent and specific hepatotoxins produced by cyanobacteria in eutrophic waters, representing a health hazard to animals and humans. The objectives of this study are to determine the relationship between oxidative stress and NF‐κB activity in MC‐induced apoptosis in rat liver and the role of glutathione (GSH). Sprague‐Dawley rats were intraperitoneally (i.p.) injected with microcystin‐LR (MC‐LR) at 0.25 and 0.5 LD₅₀ with or without pretreatment of buthionine‐(S,R)‐sulfoximine (BSO), a specific GSH synthesis inhibitor. MC‐LR induced time‐dependent alterations of GSH levels in rat liver. Increased malondialdehyde (MDA) and significant changes of antioxidant enzymes including GSH peroxidase (GPX) and GSH reductase (GR) were also observed, particularly at 24 h post‐exposure. The results indicated that acute exposure to MC‐LR induced oxidative stress, and GSH depletion (BSO pretreatment) enhanced the level of oxidative stress. Furthermore, the modulation of pro‐apoptotic gene p53 and Bax and anti‐apoptotic gene Bcl‐2 was observed in 0.5 LD₅₀ group at 24 h, and the alteration was more pronounced by BSO injection before MC‐LR treatment, suggesting that GSH played a protective role against MC‐induced toxicity. Additionally, electrophoretic mobility shift assay (EMSA) showed that NF‐κB was induced at 0.25 LD₅₀ but inhibited at 0.5 LD₅₀. The above results indicated that the possible crosstalk of oxidative stress and NF‐κB activity was associated with MC‐LR‐induced hepatocytes apoptosis in vivo. Our data will provide a new perspective for understanding the mechanisms of MC‐induced liver injury. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 552–560, 2016.     

Mitogen‐activated protein kinase signaling and its association with oxidative stress and apoptosis in lead‐exposed hepatocytes

Lead toxicity has become a serious public health concern all over the world. Previous studies have shown that lead induces biochemical and structural changes in liver. However, although lead is known to alter liver functions, the underlying molecular mechanisms of hepatotoxicity are not yet clear. We hypothesized that a correlation exists between oxidative stress, apoptosis and mitogen‐activated protein kinases (MAPKs) in lead‐exposed liver. Wistar rats were treated with 0, 0.5%, and 1% lead acetate for 3d, 14d, and 35d and sacrificed the next day. On 4d, oxidative stress and apoptosis were correlated with downregulated expressions of ERK1/2 and p38‐MAPKα/β, and upregulated expressions of JNK1/3 in males. In females, the correlation was with downregulated expressions of ERK1/2 and upregulated expressions of p38‐MAPKα/β and JNK1/3. On 15d, the correlation was observed with upregulated expressions of p38‐MAPKα/β in males and downregulated expressions of p38‐MAPKα/β in females. In both sexes, a correlation was observed with upregulated expressions of ERK1/2 and JNK1/3 in 1% groups. On 36d, the correlation was observed with downregulated expressions of p38‐MAPKα/β in males and their upregulated expressions in females. Time‐dependent increase in lipid peroxidation on 15d and 36d correlated with upregulated expressions of p38‐MAPKα/β in females and ERK1/2 in 1% groups in both sexes. The lower dose induced more apoptosis up to 15d in females and the higher dose induced in males on 36d. Generally, the female livers had more p38‐MAPKα/β than the male livers. On 36d, the female livers showed more p38‐MAPKα/β and JNK1/3 than the male livers. In conclusion, although not clearly defined, a correlation exists among oxidative stress, apoptosis, and the MAPKs in lead‐exposed hepatocytes. The sex‐dependent effects may be due to differences in hormonal or other physiological mechanisms. In lead‐exposed hepatocytes, the apoptosis may be induced via oxidative stress‐mediated alterations in the MAPKs. © 2013 Wiley Periodicals, Inc. Environ Toxicol 30: 513–529, 2015.     

Neurobehavioral impairments, generation of oxidative stress and release of pro-apoptotic factors after chronic exposure to sulphur mustard in mouse brain

Recent global events have focused attention on the potential threat of international and domestic chemical terrorism, as well as the possibility of chemical warfare proliferation. Sulphur mustard (SM) is one of the potent chemical warfare agents (CWA), which initiates a cascade of events that converge on the redox mechanisms common to brain injury. The present study was designed to examine the effects of chronic SM exposure on neurobehavioral impairments, mitochondrial oxidative stress in male Swiss Albino mice and its role in inducing apoptotic neuronal cell death. The animals were divided into four groups (control, low, medium and high dose) of 5 animals each. Exposure to SM was given percutaneously daily for 12 weeks. The results demonstrated impairment in neurobehavioral indices viz. rota rod, passive avoidance and water maze tests in a dose dependent manner. There was a significant increase in lipid peroxidation and protein carbonyl content whereas, decrease in the activity of manganese superoxide dismutase (MnSOD), glutathione reductase and glutathione peroxidase suggesting impaired antioxidant defense system. Immunoblotting of cytochrome c, Bcl-2, Bax and activation of caspase-3 suggest induction of apoptosis in a dose dependent manner. Finally, increased p53 expression suggests that it may target the mitochondrial pathway for inducing apoptosis in response to DNA damage signals. In conclusion, chronic SM exposure may have the potential to generate oxidative stress which may trigger the release of cytochrome c as well as caspase-3 activation in neurons leading to cell death by apoptosis in a dose dependent manner which may in the end be responsible for the disruption of cognitive functions in mice.