Vinay Lomash

Curcumin encapsulated in chitosan nanoparticles: a novel strategy for the treatment of arsenic toxicity.

Water-soluble nanoparticles of curcumin were synthesized, characterized and applied as a stable detoxifying agent for arsenic poisoning. Chitosan nanoparticles of less than 50 nm in diameter containing curcumin were prepared. The particles were characterized by TEM, DLS and FT-IR. The therapeutic efficacy of the encapsulated curcumin nanoparticles (ECNPs) against arsenic-induced toxicity in rats was investigated. Sodium arsenite (2mg/kg) and ECNPs (1.5 or 15 mg/kg) were orally administered to male Wistar rats for 4 weeks to evaluate the therapeutic potential of ECNPs in blood and soft tissues. Arsenic significantly decreased blood δ-aminolevulinic acid dehydratase (δ-ALAD) activity, reduced glutathione (GSH) and increased blood reactive oxygen species (ROS). These changes were accompanied by increases in hepatic total ROS, oxidized glutathione, and thiobarbituric acid-reactive substance levels. By contrast, hepatic GSH, superoxide dismutase and catalase activities significantly decreased on arsenic exposure, indicative of oxidative stress. Brain biogenic amines (dopamine, norepinephrine and 5-hydroxytryptamine) levels also showed significant changes on arsenic exposure. Co-administration of ECNPs provided pronounced beneficial effects on the adverse changes in oxidative stress parameters induced by arsenic. The results indicate that ECNPs have better antioxidant and chelating potential (even at the lower dose of 1.5 mg/kg) compared to free curcumin at 15 mg/kg. The significant neurochemical and immunohistochemical protection afforded by ECNPs indicates their neuroprotective efficacy. The formulation provides a novel therapeutic regime for preventing arsenic toxicity.

Evaluation of DNA damage and cytotoxicity induced by three commonly used organophosphate pesticides individually and in mixture, in rat tissues

Organophosphate pesticides are among the most widely used synthetic chemicals for controlling a wide variety of pests. Chlorpyrifos (CPF), methyl parathion (MPT), and malathion (MLT) are among the most extensively used organophosphate (OP) pesticides. The main target of action of OP compounds is the central and peripheral nervous system, although it has also been postulated that these compounds in both acute and chronic intoxication, disturb the redox processes and thus induce oxidative stress. The excessive generation of reactive oxygen species (ROS) causes damage to all vital macromolecules including lipids, proteins, and DNA. This study was aimed to investigate the genotoxicity and cytotoxicity of CPF, MPT, and MLT when given singly or in combination. The DNA damage was measured by alkaline single‐cell gel electrophoresis or comet assay and expressed as DNA damage index. The results showed that both acute and chronic exposure with CPF, MPT, and MLT, caused significantly marked DNA damage in rat tissues namely, liver, brain, kidney, and spleen, when measured 24 hour posttreatment. It was also observed that MPT caused highest level of DNA damage and brain was maximally affected by these OP compounds. When these pesticides were given in mixture, the damage was not the sum of damage caused by individual pesticide, confirming that these pesticides do not potentiate the toxicity of each other. When the DNA damage was measured 48 and 72 hour posttreatment, the damage was partially repaired. Pesticide exposure also caused histopathological changes in rat tissues.

Fluoride-induced changes in haem biosynthesis pathway, neurological variables and tissue histopathology of rats

This study intended to determine the effects of various concentrations of fluoride (1, 10, 50 and 100 ppm) in drinking water for a period of 12 weeks on changes in haem biosynthesis pathway, oxidative stress and neurological variables supported by histopathological observations and fluoride in rats. The data indicates significant alterations in the parameters related to haeme synthesis pathway like inhibition of blood δ‐aminolevulinic acid dehydratase, δ‐aminolevulinic acid synthetase, oxidative stress like depletion of glutathione (GSH) and increase in oxidized glutathione (GSSG) and thiobarbituric acid reactive substances. These changes were accompanied by depletion in GSH:GSSG ratio, whole brain biogenic amine levels and a dose‐dependent increase in fluoride concentration. Interestingly and most significantly, these changes were more pronounced at lower concentrations of fluoride compared with higher fluoride dose. Biochemical changes were supported by the histological observations, which also revealed that at high concentrations of fluoride, toxic effects and damages to organs were more pronounced. These changes support our earlier findings regarding the role of decreased ionic mobility of fluoride ion at higher concentrations, leading to less pronounced toxicity. Copyright

Expression profile of Japanese encephalitis virus induced neuroinflammation and its implication in disease severity.

BACKGROUND Host immune response particularly through the induction of proinflammatory cytokines and chemokines in Japanese encephalitis virus infection has not been clearly understood in relation with pathogenicity and disease severity. The newly identified host mediators of pathogenesis could be the future target for diagnostic and therapeutics purpose. OBJECTIVES We investigated the mechanism of JE virus induced pathogenesis in terms of proinflammatory cytokine and chemokine secretion at molecular level in young one-week-old BALB/c mouse after subcutaneous administration of JEV. STUDY DESIGN Histopathology of brain was done to observe the morphological changes after JEV infection and genes relevant to macrophage activation, chemokine secretion, inflammatory cell infiltration, and blood-brain barrier permeability were examined at their gene and protein expression level for various time points after infection. RESULTS At 6-day post-infection 100% mortality was observed. At 5-day post-infection, there was a robust expression of proinflammatory cytokines and chemokines with increased number of infiltrating inflammatory cells into the brain. Histopathology data confirms the infiltration of leucocytes and there was a marked upregulation in expression of genes relevant to infiltration. The expression pattern of macrophage receptor CLEC5A/DAP-12 signaling has shown the involvement in this robust neuroinflammation. CONCLUSIONS This is the first report that shows the involvement of monocyte and macrophage receptor CLEC5A in severe inflammatory response in JEV infection of brain. This study at gene expression level provides a hypothesis of neuroinflammation, a new lead in development of appropriate therapeutic, and prophylactics against Japanese encephalitis.

Aloe vera gel alleviates cardiotoxicity in streptozocin-induced diabetes in rats

Objectives Persistent hyperglycaemia results in oxidative stress along with the generation of oxygen free radicals and appears to be an important factor in the production of secondary complications in diabetes. The aim of this work was to evaluate markers of oxidative stress in heart tissue along with the protective, antioxidant and antidiabetic activity of 30% Aloe vera gel in diabetic rats.

Effects of co-exposure to arsenic and dichlorvos on glutathione metabolism, neurological, hepatic variables and tissue histopathology in rats

The individual toxic effects of arsenic and organophosphate pesticides are known but there is a lack of data on their combined effects. The present study investigates the toxic effects following combined exposure to organophosphate and arsenic on: (i) alterations in brain biogenic amines, (ii) oxidative stress and its correlation with glutathione linked enzymes, cell death and histopathological observations, and (iii) arsenic concentration in soft tissues. Rats were exposed to arsenic (1 mg kg−1 body weight, orally) and dichlorvos (4 mg kg−1 body weight, subcutaneously) either individually or in combination for 16 weeks. Arsenic alone and in combination with DDVP led to a significant increase in reactive oxygen species (ROS), thiobarbituric acid reactive substance (TBARS), glutathione peroxidase (GPx) and glutathione-S-transferase (GST) activities accompanied by a decreased glutathione reductase, reduced and oxidized glutathione (GSH and GSSG) levels in tissues. Arsenic and DDVP also produced a significant depletion in brain biogenic amines; however, acetylcholinesterase (AChE) activity increased moderately on arsenic exposure. Arsenic and DDVP co-exposure exhibited synergism in the case of ROS while no such effect was noted in the case of TBARS. Interestingly, combined exposure to arsenic and DDVP resulted in more pronounced toxic effects compared to their individual effects based on various biochemical variables, cell death (TUNEL assay) and histopathological observations. Interestingly, brain arsenic levels decreased on co-exposure to arsenic and DDVP accompanied with prominent elevation of liver arsenic content in co-exposed groups. The present study thus provides some interesting observations on the interaction between arsenic and DDVP including (i) co-exposure to arsenic and DDVP might lead to significant oxidative stress and (ii) their co-exposure produced synergistic effects on some liver variables but some antagonistic effects on the brain.

Characterization of chikungunya virus induced host response in a mouse model of viral myositis.

While a number of studies have documented the persistent presence of chikungunya virus (CHIKV) in muscle tissue with primary fibroblast as the preferable cell target, little is known regarding the alterations that take place in muscle tissue in response to CHIKV infection. Hence, in the present study a permissive mouse model of CHIKV infection was established and characterized in order to understand the pathophysiology of the disease. The two dimensional electrophoresis of muscle proteome performed for differential analysis indicated a drastic reprogramming of the proteins from various classes like stress, inflammation, cytoskeletal, energy and lipid metabolism. The roles of the affected proteins were explained in relation to virus induced myopathy which was further supported by the histopathological and behavioural experiments proving the lack of hind limb coordination and other loco-motor abnormalities in the infected mice. Also, the level of various pro-inflammatory mediators like IL-6, MCP-1, Rantes and TNF-α was significantly elevated in muscles of infected mice. Altogether this comprehensive study of characterizing CHIKV induced mouse myopathy provides many potential targets for further evaluation and biomarker study.

T-2 toxin induced skin inflammation and cutaneous injury in mice.

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 11.88 mg/kg respectively) and observed till 3, 24 and 72 h. 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.

Oxidative stress and tissue pathology caused by subacute exposure to ammonium acetate in rats and their response to treatments with alpha-ketoglutarate and N-acetyl cysteine

Ammonia is a widely used industrial chemical that is recognized as a potent neurotoxin and environmental pollutant. The present study addresses the oxidative stress and tissue pathology caused by 4 weeks of exposure to ammonium acetate (AMA; 100 mg/kg daily; orally) in rats, and their response to oral treatments with alpha-ketoglutarate (A-KG; 1.0 g/kg), a potential cyanide antidote, and/or N-acetyl cysteine (NAC; 10 mg/kg), an antioxidant. The organ–body weight index of brain and liver was significantly increased by AMA but kidney was unaffected. Also, plasma ammonia levels were significantly elevated without any concomitant change in blood gas status and hematology but levels of catalase, superoxide dismutase, glutathione peroxidase, glutathione reductase and reduced glutathione (GSH) in the brain and liver were diminished, accompanied by elevated levels of malondialdehyde. Levels of glutathione disulfide (GSSG) were unaffected, but the ratio of GSH:GSSG was reduced. Plasma alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase and total bilirubin were raised but urea, uric acid and creatinine levels were not altered. AMA also caused temporal, hepatic and renal pathology. However, the renal pathology was not supported by any biochemical alterations. A-KG or NAC alone afforded less protection against AMA as compared to both given together. The protective efficacy of A-KG can be ascribed to its ability to detoxify ammonia and additionally both A-KG and NAC have antioxidant properties as well. The study suggests a new therapeutic regimen for ammonia poisoning.

Designing of mouse model: a new approach for studying sulphur mustard-induced skin lesions.

This study was planned to design a mouse model for studying sulphur mustard (SM)-induced skin injury. SM was applied dermally at dose of 5 or 10 mg kg(-1) in polyethyleneglycol-300 (PEG-300) or dimethylsulphoxide (DMSO) or acetone once. The changes in body weight, organ body weight indices (OBWI) and haematological and oxidative stress parameters were investigated over a period of 3-7 days and supported by histopathological observations. Exposure to SM in PEG-300 or DMSO resulted in a significant depletion in body weight, OBWI, hepatic glutathione (GSH) and elevation in hepatic lipid peroxidation, without affecting the blood GSH and hepatic oxidised glutathione (GSSG) levels. Interestingly, no aforesaid change was observed after dermal application of SM diluted in acetone. These biochemical changes were supported by the histological observations, which revealed pronounced toxic effect and damage to liver, kidney and spleen after dermal application of SM diluted in PEG-300 or DMSO. The skin showed similar microscopic changes after dermal application of SM in all the three diluents, however; the severity of lesions was found to be time and dose dependent. It can be concluded that dermal exposure of SM diluted in acetone can be used to mimic SM-induced skin toxicity without systemic toxicity in a mouse model.