Publications (4) View all
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Article: T-2 toxin induced skin inflammation and cutaneous injury in mice.
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ABSTRACT: T-2 toxin is one of the most toxic among several trichothecenes involved in both human and animal poisoning cases. We investigated the biochemical and histological alterations behind inflammation and cutaneous injury caused by T-2 toxin. Swiss albino mice were exposed to T-2 toxin topically at doses of 0.5, 1 and 2 LD50 (2.97, 5.94 and 11.88mg/kg respectively) and observed till 3, 24 and 72h. Topical application of T-2 toxin resulted in skin oxidative stress in terms of increased reactive oxygen species generation, lipid peroxidation and neutrophil mediated myeloperoxidase activity. The histological alterations include degenerative changes like vacuolation, ballooning of basal keratinocytes and infiltration of inflammatory cells in dermis. The mRNA levels of skin pro-inflammatory cytokines TNF-α, IL-6, and IL-1β showed significant up regulation. Anti-inflammatory cytokines IL-10 showed significant up regulation at 24h whereas IL-4 showed down regulation for all the doses and time points. Gelatin zymography and immunoblot analysis of matrix metalloproteinases (MMP)-9 and 2 indicated MMP activation and their role in degenerative skin histological changes. Time dependent increase in inducible nitric oxide synthase levels was seen. Immunoblot analysis revealed significant increase in the levels of phosphorylated p38 mitogen activated protein kinase (MAPK). Flow cytometry analysis of propidium iodide stained epidermal cells showed increase in sub-G1 population at all the doses and time points indicating apoptosis. In summary, T-2 toxin induced skin inflammation and cutaneous injury is mediated through oxidative stress, activation of myeloperoxidase, MMP activity, increase in inflammatory cytokines, activation of p38 MAPK and apoptosis of epidermal cells leading to degenerative skin histological changes.Toxicology 08/2012; · 3.68 Impact Factor -
Article: Evaluation of protective efficacy of CC-2 formulation against topical lethal dose of T-2 toxin in mice.
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ABSTRACT: T-2 toxin is the type-A trichothecene and a common contaminant of food and cereals, produced by Fusarium species. T-2 toxin easily penetrates skin due to its lipophilic nature and causes skin irritation and blisters in humans. Physical protection of the skin and airway is the only proven effective method of protection. To date, no chemical antidotes are available to prevent T-2 induced lethality. In the present study, we evaluated the protective efficacy of 20% N,N'-dichloro-bis(2,4,6-trichlorophenyl) urea (CC-2) formulation against lethal topical exposure dose of T-2 toxin in mice. None of the animals exposed to only T-2 toxin at lethal dose of 2 and 4 LD50 (11.8 and 23.76 mg/kg body weight) survived beyond 36 and 16 h, respectively. CC-2 application at 5 and 15 min post-exposure protected mice 100% from lethality at 2 LD50. Survival rate was 100% and 50% at 4LD50 dose if CC-2 was applied dermally within 5 and 15 min post-exposure. Recovery profile of surviving animals after 2LD50 T-2 toxin exposure at 1, 3, 7, and 14 days was assessed in terms of hepatic GSH, lipid peroxidation, serum ALP, ALT and AST. Hepatic lipid peroxidation significantly increased in all groups exposed to T-2 toxin by 3 day but normalized by day 7. A delayed GSH depletion was noted in surviving animals on day 7 but recovered by day 14. ALT and AST levels were elevated in all CC-2 protected mice on day 1 and normalized by day 3. ALP level decreased till day 7 in all protected groups. The biochemical variables recovered to control values by 14th day. GC-MS analysis after in vitro interaction of CC-2 formulation with T-2 toxin had shown that nearly 86% of T-2 toxin is decontaminated in 5 min but 8-10% of T-2 toxin was still present even after 60 min of interaction. Results of our study suggest that CC-2 may be an effective dermal decontaminant against lethal topical exposure of T-2 toxin.Food and chemical toxicology: an international journal published for the British Industrial Biological Research Association 01/2012; 50(3-4):1098-108. · 2.99 Impact Factor -
Article: Alteration of blood brain barrier permeability by T-2 toxin: Role of MMP-9 and inflammatory cytokines.
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ABSTRACT: T-2 toxin is a cytotoxic fungal secondary metabolite produced by different species of Fusarium such as F. sporotichioides, F. poae, F. equiseti, F. acuminatum etc. This class of mycotoxins causes a number of pathologies including nervous disorders, cardiovascular alterations, immunodepression and hemostatic derangements. In the present study, mechanism of T-2 toxin induced alteration of blood-brain barrier (BBB) permeability was assessed in terms of oxidative stress, gene expression of MMP-9, MMP-2 and their inhibitors TIMP-1 and TIMP-2, activation of inflammatory cytokines in both brain and peripheral tissue spleen. Gel zymography was used to show the activity of MMP-9 and MMP-2. The percutaneous exposure of 1 LD50 T2 toxin caused a reversible alteration in BBB permeability as observed by extravasation of Evans blue dye. Maximum dye level was observed on day 3 and reduced by day 7. A significant GSH depletion was observed on days 1 and 3. Brain ROS and lipid peroxidation levels increased significantly on 1 and 3 days and decreased by day 7. The SOD levels in brain showed significantly higher activity on 3 days (4-fold) and 7 days (5-fold) of toxin exposure compared to control. A similar trend was observed with catalase enzyme levels. The gene expression analysis of cNOS and iNOS showed varying levels of expression on different time points of post exposure. MMP-9 expression was significantly high on days 3 and 7 in brain with corresponding alteration in TIMP-1. MMP-2 and TIMP-2 showed no effect. Gene expression analysis of the inflammatory cytokines, IL-1α, IL-1β, IL-6 and TNF-α showed elevated levels on day 7 in brain. As spleen plays an important role in inflammatory response we analyzed MMP-9, MMP-2 and inflammatory cytokines in spleen. The MMP-9 was activated on day 7. MMP-2 activity was found to be elevated on 3 and 7 days and TIMP-2 mRNA level increased on 1 and 3 days in spleen. Inflammatory cytokines, IL-1 α, IL-1β, IL-6 and TNF-α showed elevated levels on days 1 and 3 in spleen indicating an early effect in spleen than in brain. In summary, the results of the study showed that the T-2 induced alteration in BBB permeability is mediated through oxidative stress, activation of MMP-9, and proinflammatory cytokines in brain as well as contribution from peripheral tissue spleen.Toxicology 02/2011; 280(1-2):44-52. · 3.68 Impact Factor -
Article: Modulation of ROS/MAPK signaling pathways by okadaic acid leads to cell death via, mitochondrial mediated caspase-dependent mechanism.
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ABSTRACT: Okadaic acid (OA) is a specific and potent protein phosphatase inhibitor and tumor promoter. The present study establishes the role of reactive oxygen species (ROS) and mitogen activated protein kinases in cell death induced by okadaic acid. The study showed that okadaic acid is cytotoxic at 10 nM with an IC50 of 100 nM in U-937 cells. The CVDE assay and mitochondrial dehydrogenase assay showed a time dependent cytotoxicity. The phase contrast visualization of the OA treated cells showed the apoptotic morphology and was confirmed with esterase staining for plasma membrane integrity. OA activated caspases-7, 9 and 3, PARP cleavage and induced nuclear damage in a time and dose dependent manner. Compromised mitochondrial membrane potential, release of cytochrome-c and apoptosis inducing factor confirms the involvement of mitochondria. A time dependent decrease in glutathione levels and a dose dependent increase in ROS with maximum at 30 min were observed. ROS scavenger-N-acetyl cysteine, mitochondrial stabilizer-cyclosporin-A, and broad spectrum caspase inhibitor Z-VAD-FMK inhibited the OA induced caspase-3 activation, DNA damage and cell death but caspase-8 inhibitor had no effect. OA activated p38 MAPK and JNK in a time dependent manner, but not ERK½. MAP kinase inhibitors SB203580, SP600125 and PD98059 confirm the role of p38 MAPK and JNK in OA induced caspase-3 activation and cell death. Over all, our results indicate that OA induces cell death by generation of ROS, and activation of p38 MAPK and JNK, and executed through mitochondrial mediated caspase pathway.Apoptosis 11/2010; 16(2):145-61. · 4.07 Impact Factor
