Short-Term PCB (Aroclor 1254) Toxicity on Few Phosphatases in Mice Brain

The present communication reports the dose and duration dependent toxicity of a PCB, Aroclor 1254, to a few ion dependent ATPases, Acid phosphatase, Alkaline phosphatase and Glucose-6-phosphatase in the whole brain tissue of mice. Two groups of mice were subjected to two sublethal doses (0.1 and 1 mg kgbw⁻¹ day⁻¹) of PCB orally and exposed for 4, 8 or12 days. A separate control group received the corn oil vehicle for the same exposure times. The observed results indicated exposure duration dependent changes in the enzymatic levels in the brain. The results suggest that the alteration in the enzymatic activity was possibly due to imposed oxidative stress generated by Aroclor 1254 on membrane-bound ion-dependent ATPases and other phosphatases in the brain tissue.     

Combination of chlorogenic acid and salvianolic acid B protects against polychlorinated biphenyls-induced oxidative stress through Nrf2

Caffeic acid derivatives (CADs) are well-known phytochemicals with multiple physiological and pharmacological activities. This study aimed to investigate the combined protective effects of CADs on PCB126-induced liver damages and oxidative stress in mice. Here, we used chemiluminescence and chose chlorogenic acid (CGA), salvianolic acid B (Sal B) as the best antioxidants. Then, mice were intragastrically administered with 60 mg/kg/d CGA, Sal B, and CGA plus Sal B (1:1) for 3 weeks before exposing to 0.05 mg/kg/d PCB126 for 2 weeks. We found that pretreatment with CGA, Sal B, and CGA plus Sal B effectively attenuated liver injury and cytotoxicity caused by PCB126, but improved the expressions of superoxide dismutase (SOD), glutathione reduced (GSH), heme oxygenase-1 (HO-1) and nuclear factor E2-related factor 2 (Nrf2), CGA plus Sal B especially, was found to have the best effects that indicated a synergetic protective effect. Taken together, as the Nrf2 regulates the cyto-protective response by up-regulating the expression of antioxidant genes, we suggested that CGA plus Sal B had a combined protection on PCB126-induced tissue damages and that the Nrf2 signaling might be involved.     

Can garlic oil ameliorate diabetes-induced oxidative stress in a rat liver model? A correlated histological and biochemical study

This study aimed to characterise the structural changes in liver of an alloxan-induced diabetic rat and to explain such changes in terms of the biochemical changes in free radicals and antioxidants. In addition, it aimed to determine the potential ability of garlic oil to alter these changes. The study groups were: control (n = 12), alloxan-induced diabetic rats (n = 10) and alloxan-induced diabetic rats treated with garlic oil (10 mg/kg body weight (n = 10)). Markers of oxidative stress were assessed. Small pieces of the liver were processed for transmission electron microscopic study. Garlic oil caused a significant decrease in levels of LPO in plasma (0.26 vs 0.53), erythrocyte lysate (14.4 vs 24.8) and liver tissue homogenate (1.04 vs 2.08), whereas those of thiols were significantly elevated (1.2 vs 0.46), (24 vs 15) in plasma and erythrocyte lysate respectively. SOD activity and G-S-T activity were significantly elevated in erythrocyte lysate (5.7 vs 3.3) (377 vs 179) and liver homogenate (1.4 vs 0.5) (752 vs 623) respectively after garlic oil administration. Ultrastructural study of the liver confirmed the ability of garlic to retard lipid peroxidation of cellular membranes induced by oxidative stress associated with diabetes. Therefore, garlic could normalise oxidative stress in alloxan-induced diabetic rats.     

Gallic acid attenuates chromium-induced thyroid dysfunction by modulating antioxidant status and inflammatory cytokines

Hexavalent chromium-mediated oxidative stress causes severe organ damage. The present study was designed to investigate the possible thyroprotective effect and underlying mechanisms of gallic acid using rat model of potassium dichromate-induced thyroid dysfunction. Forty adult male albino rats were divided into 4 groups: control, gallic acid (20 mg GA/kg b. wt), potassium dichromate (2 mg PD/kg b. wt) and the fourth group was co-treated with PD and GA. PD-injection resulted in decreased serum free triiodothyonine (FT3), free thyroxine (FT4) with concomitant significant increase in thyroid stimulating hormone (TSH) levels. Superoxide dismutase (SOD), glutathione-S-transferase (GST) activities and their respective mRNA expression and reduced glutathione (GSH) content were significantly decreased. Thyroid nitrosative stress marker (NO level and iNOS mRNA and protein expression) and pro-inflammatory cytokines (serum TNF-α, IL-6 and thyroid TNF-α, IL-6 and COX-2 gene and protein expression levels) were disturbed. Histopathological changes revealed distended, collapsed and degenerated follicles with vacuolated cytoplasm. GA co-treatment attenuated pro-inflammatory cytokines, the thyroid expression of iNOS, TNF-α, IL-6 and COX-2, decreased the elevated lipid peroxidation biomarkers and NO level and up- regulated SOD and GST mRNA expression levels. In conclusion, GA has shown strong modulatory potential against PD-induced inflammation and oxidative stress in albino rats.     

Oxidative stress responses to carboxylic acid functionalized single wall carbon nanotubes on the human intestinal cell line Caco-2

Carbon nanotubes (CNT) are among the more promising nanomaterials due to their potential applications. In this sense, the adverse effects that CNT can induce are of concern. In particular, carboxylic acid functionalized single wall carbon nanotubes (COOH-SWCNT) have shown to reduce cell viability and induce morphological effects on the human intestinal cell line Caco-2, but little is known about the toxic mechanisms involved. The aim of the present study was to investigate the oxidative stress responses of this cell line after 24 h exposure to COOH-SWCNT. Biomarkers assayed included lipid peroxidation (LPO), reactive oxygen species (ROS) generation, and enzymatic and non-enzymatic antioxidant defences. Results showed an increase in ROS from 100 μg/mL reaching 5.2-fold the basal value at the highest concentration assayed. An induction of catalase, superoxide dismutase and glutathione peroxidase activities was also observed, meanwhile glutathione reductase showed a reduced activity at 1000 μg/mL. Glutathione (GSH) levels also decreased (2.5-fold) at the highest level of exposure. Therefore, the antioxidant defences could not overwhelm the oxidative insult caused by COOH-SWCNT and LPO products increased in a concentration-dependent manner. We can conclude that oxidative stress plays a role in the pathogenicity induced by COOH-SWCNT on Caco-2 cells at the concentrations assayed.     

Increased oxidative stress and apoptosis in peripheral blood mononuclear cells of fructose-fed rats

BackgroundMeasuring of oxidative stress in peripheral blood mononuclear cells is a suitable model of dietary induced systemic oxidative stress. Thus, we aimed to evaluate whether a chronic high fructose intake could induce oxidative damage in peripheral blood and bone marrow mononuclear cells of rats.MethodsAnimals were randomly assigned to the following groups: Control group (standard rat chow and tap water n = 8), and Fructose group (standard rat chow and a 10% fructose solution in the drinking water n = 8). Reactive oxygen species and cytokines were measure using flow cytometry in peripheral blood and bone-marrow mononuclear cells. Apoptotic cell death and the advanced oxidation protein products (AOPP) were also determined.ResultsWe observed a significant increase in ROS production in peripheral blood mononuclear cells of fructose group as compared to control rats. Apoptosis and the AOPP were higher in those animals underwent high fructose intake. Serum levels of IL-6 and IL-12 were also increased after 12 weeks of high fructose intake.ConclusionWe concluded that fructose intake leads to systemic oxidative stress and pro-inflammatory condition which affect peripheral blood mononuclear cells and bone-marrow mononuclear cells viability.     

Oxidative stress mediates dibutyl phthalateinduced anxiety-like behavior in Kunming mice

Among all phthalate esters, dibutyl phthalate (DBP) is only second to di-(2-ethylhexyl) phthalate (DEHP) in terms of adverse health outcomes, and its potential cerebral neurotoxicity has raised concern in recent years. DBP exposure has been reported to be responsible for neurobehavioral effects and related neurological diseases. In this study, we found that neurobehavioral changes induced by DBP may be mediated by oxidative damage in the mouse brain, and that the co-administration of Mangiferin (MAG, 50 mg/kg/day) may protect the brain against oxidative damage caused by DBP exposure. The results of ethological analysis (elevated plus maze test and open-field test), histopathological examination of the brain, and assessments of oxidative stress (OS) in the mouse brain showed that there is a link between oxidative stress and anxiety-like behavior produced by DBP at higher doses (25 or 125 mg/kg/day). Biomarkers of oxidative stress encompass reactive oxygen species (ROS), glutathione (GSH), malondialdehyde (MDA) and DPC coefficients (DPC). MAG (50 mg/kg/day),administered as an antioxidant,can attenuatetheanxiety-like behavior of the tested mice.     

Alpha-lipoic acid protects oxidative stress,changes in cholinergic system and tissue histopathology during co-exposure to arsenic-dichlorvos in rats

We investigated protective efficacy of α-lipoic acid (LA), an antioxidant against arsenic and DDVP co-exposed rats. Biochemical variables suggestive of oxidative stress, neurological dysfunction, and tissue histopathological alterations were determined. Male rats were exposed either to 50 ppm sodium arsenite in drinking water or in combination with DDVP (4 mg/kg, subcutaneously) for 10 weeks. α-Lipoic acid (50 mg/kg, pos) was also co-administered in above groups. Arsenic exposure led to significant oxidative stress along, hepatotoxicity, hematotoxicity and altered brain biogenic amines levels accompanied by increased arsenic accumulation in blood and tissues. These altered biochemical variables were supported by histopathological examinations leading to oxidative stress and cell death. These biochemical alterations were significantly restored by co-administration of α-lipoic acid with arsenic and DDVP alone and concomitantly. The results indicate that arsenic and DDVP induced oxidative stress and cholinergic dysfunction can be significantly protected by the supplementation of α-lipoic acid.     

Effect of styrene exposure on plasma parameters,molecular mechanisms and gene expression in rat model islet cells

Styrene is an aromatic hydrocarbon compound present in the environment and have primary exposure through plastic industry. The current study was designed to evaluate styrene-induced toxicity parameters in rat plasma fasting blood glucose (FBG) level, oral glucose tolerance, insulin secretion, oxidative stress, and inflammatory cytokines in cellular and molecular levels. Styrene was dissolved in corn oil and administered at different doses (250, 500, 1000, 1500, 2000 mg/kg/day and control) to each rat, for 42 days. In treated groups, styrene significantly increased fasting blood glucose, plasma insulin (p < 0.001) and glucose tolerance. Glucose tolerance, insulin resistance and hyperglycemia were found to be the main consequences correlating gene expression of islet cells. Styrene caused a significant enhancement of oxidative stress markers (p < 0.001) and inflammatory cytokines in a dose and concentration-dependent manner in plasma (p < 0.001). Moreover, the activities of caspase-3 and −9 of the islet cells were significantly up-regulated by this compound at 1500 and 2000 mg/kg/day styrene administrated groups (p < 0.001). The relative fold change of GLUD1 was downregulated (p < 0.05) and upregulated at 1500 and 2000 mg/kg, respectively (p < 0.01). The relative fold changes of GLUT2 were down regulated at 250 and 1000 mg/kg and up regulated in 500, 1500 and 2000 mg/kg doses of styrene (p < 0.01). The expression level of GCK indicated a significant upregulation at 250 mg/kg and downregulation of relative fold changes in the remaining doses of styrene, except for no change at 2000 mg/kg of styrene for GCK. Targeting genes (GLUD1, GLUT2 and GCK) of the pancreatic islet cells in styrene exposed groups, disrupted gluconeogenesis, glycogenolysis pathways and insulin secretory functions. The present study illustrated that fasting blood glucose, insulin pathway, oxidative balance, inflammatory cytokines, cell viability and responsible genes of glucose metabolism are susceptible to styrene, which consequently lead to other abnormalities in various organs.     

Supplementation with nanomolar concentrations of verbascoside during in vitro maturation improves embryo development by protecting the oocyte against oxidative stress: a large animal model study

The effects of verbascoside (VB), added at nanomolar concentrations during in vitro maturation (IVM) of juvenile sheep oocytes, on in vitro embryo development and its mechanisms of action at the oocyte level were analyzed. Developmental rates, after IVM in the presence/absence of VB (1 nM for 24 h; 1 nM for 2 h; 10 nM for 2 h), were evaluated. The bioenergetic/oxidative status of oocytes matured after IVM in the presence/absence of 1 nM VB for 24 h was assessed by confocal analysis of mitochondria and reactive oxygen species (ROS), lipid peroxidation (LPO) assay, and quantitative PCR of bioenergy/redox-related genes. The addition of 1 nM VB during 24 h IVM significantly increased blastocyst formation and quality. Verbascoside reduced oocyte ROS and LPO and increased mitochondria/ROS colocalization while keeping mitochondria activity and gene expression unchanged. In conclusion, supplementation with nanomolar concentrations of VB during IVM, in the juvenile sheep model, promotes embryo development by protecting the oocyte against oxidative stress.     

Evaluation of 8-hydroxy-2-deoxyguanosine and NFkB activation,oxidative stress response,acetylcholinesterase activity,and histopathological changes in rainbow trout brain exposed to linuron

Linuron is a widely used herbicide to control grasses and annual broad leaf weeds. It is known that linuron has toxic effects on different organisms. However, the toxic effects of linuron on aquatic organisms, especially fish, is completely unknown. Thus, we aimed to investigate changes in 8-hydroxy-2-deoxyguanosine (8-OHdG) and nuclear factor kappa B (NFkB) activity, histopathological changes, antioxidant responses and acetylcholinesterase (AChE) activity in rainbow trout brain after exposure to linuron. Fish were exposed to 30 μg/L, 120 μg/L and 240 μg/L concentrations of linuron for twenty-one days. Brain tissues were taken from fish for 8-OHdG and NFkB activity, histopathological examination and determination of superoxide dismutase (SOD), catalase (CAT) enzyme activity, lipid peroxidation (LPO), and reduced glutathione (GSH) levels. Our data indicated that high linuron concentrations caused a decrease in GSH levels, SOD and CAT activities in brain tissues (p < 0.05). LPO levels were significantly increased by 240 μg/L linuron. All concentrations caused a significant inhibition in brain AChE enzyme activity (p < 0.05). Immunopositivity was detected for 8-OHdG and NFkB, and linuron exposure caused histopathological damage to the brain tissues. The results of this study can provide useful information for understanding of linuron-induced toxicity.     

Possible involvement of nitric oxide mechanism in the neuroprotective effect of rutin against immobilization stress induced anxiety like behaviour,oxidative damage in mice

Dietary supplements are widely used to manage stress and related consequences. However, the exact pathological mechanism and cellular cascades involved in the action of these supplements are not properly understood so far. Therefore, the present study has been designed to explore the neuroprotective mechanism of rutin against immobilization stress-induced anxiety-like behavioural and oxidative damage in mice. Laboratory Animal Centre A-strain (laca) mice were used in the present study. Rutin (20, 40, and 80 mg/kg), l-arginine (100 mg/kg), l-nitroarginine methyl ester (l-NAME) (5 mg/kg) and vitamin-E (50 mg/kg) were administered for 5 days before 6 h immobilization stress on 6th day. Various behavioural parameters (mirror chamber test, locomotor activity) followed by biochemical parameters (lipid peroxidation, nitrite concentration, reduced glutathione and catalase) in brain and then serum corticosterone level were assessed. 6 h immobilization stress produced anxiety-like behavioural in mirror chamber test, raised corticosterone level and oxidative stress (as evidenced by rise in lipid peroxidation, nitrite concentration, depletion of reduced glutathione and catalase activity) significantly as compared to naive group. 5 days pre-treatment with rutin (40 and 80 mg/kg) causes a significant attenuation of locomotor activity, corticosterone level, oxidative stress as compared to control. Further, l-arginine (100 mg/kg) pre-treatment significantly reversed the protective effect of rutin (40 mg/kg) in 6 h immobilized animals. However, l-NAME (5 mg/kg) pre-treatment with rutin (40 mg/kg) potentiated their protective effect which was significant as compared to their effect per se. The present study suggests the involvement of nitric oxide mechanism in the neuroprotective effect of rutin against immobilization stress-induced anxiety-like behaviour and oxidative damage in mice.     

Studies on the protective role of lycopene against polychlorinated biphenyls (Aroclor 1254)-induced changes in StAR protein and cytochrome P450 scc enzyme expression on Leydig cells of adult rats

Polychlorinated biphenyls (PCBs) are ubiquitous and persistent environmental contaminants that disturb normal endocrine functions, including gonadal functions in humans and mammals. PCBs (Aroclor 1254) - induced toxic manifestations are associated with the production of free radicals. Lycopene belongs to the group of natural carotenoids, which are found in many fruits, vegetables and other green plants. Lycopene, the most potent antioxidant protects against oxidative damage. The present study was conducted to elucidate the protective role of lycopene against Aroclor 1254-induced changes in Leydig cellular steroidogenic acute regulatory (StAR) protein, cytochrome P450 side chain cleavage (P450 scc) enzyme expression and 3β-hydroxy steroid dehydrogenase (3β-HSD) activity. The rats were divided into four groups. Each group consists of six animals. Group I rats were administered with corn oil intraperitoneally (i.p.) for 30 days. Group II rats were treated with Aroclor 1254 (i.p.) 2 mg kg^?1 body weight (bwt) day^?1 for 30 days. Group III rats were treated with Aroclor 1254 (i.p.) 2 mg kg^?1 bwt day^?1 along with simultaneous supplementation of lycopene 4 mg kg^?1 bwt day^?1 (gavage) for 30 days. Group IV rats administered with lycopene alone at the dose of 4 mg kg^?1 bwt day^?1 (gavage) for 30 days. After 24 h of the last treatment, animals were decapitated, blood was collected and serum testosterone level was estimated by radioimmunoassay (RIA). Testes were removed and Leydig cells were isolated in aseptic condition. StAR protein, cytochrome P450 scc enzyme expression were studied by Western blot analysis and 3β-HSD activity was estimated spectrophotometrically. Aroclor 1254 treatment significantly reduced the serum testosterone level. Simultaneous supplementation of lycopene maintained the serum testosterone to near normal. Aroclor 1254 exposure decreased Leydig cellular StAR protein, cytochrome P450 scc enzyme expression and activity of 3β-HSD. However, simultaneous supplementation of lycopene improved Leydig cellular StAR protein, cytochrome P450 scc expression and activity of 3β-HSD. These results suggested that lycopene have ameliorative role against Aroclor 1254 induced Leydig cell dysfunction.     

Pioglitazone ameliorates methotrexate-induced renal endothelial dysfunction via amending detrimental changes in some antioxidant parameters,systemic cytokines and Fas production

Methotrexate (MTX) is widely used in treatment of cancers and autoimmune diseases. However, nephrotoxicity is one of its most important side effects. The peroxisome proliferator-activated receptor gamma agonist, pioglitazone, is known to exert antiinflammatory and reno-protective effects in various kidney injuries. The purpose of this study was to investigate the potential involvement of endothelial damage in MTX-induced renal injury and to elaborate the possible protective effect of pioglitazone against MTX-induced endothelial impairment. Compared with saline-treated rats, treatment with MTX (7 mg/kg for 3 days) caused significant elevations in serum levels of urea and creatinine, increased renal nitrate/nitrite level and impaired renovascular responsiveness of isolated perfused kidney to endothelium-dependent vasodilations induced by acetylcholine (0.01–2.43 nmol) and isoprenaline (1 μmol). These effects were abolished by concurrent treatment with pioglitazone (2.5 mg/kg, for 5 days starting 2 days before MTX). Alternatively, MTX treatment did not affect endothelium-independent renovascular relaxation induced by sodium nitroprusside (0.001–10 μmole). The possibility that alterations in renal antioxidants, circulating cytokine and apoptotic factor (Fas) levels contributed to MTX-pioglitazone interaction was assessed. Pioglitazone treatment abrogated renal oxidative stress (decreased reduced glutathione and catalase activity and increased malondialdehyde), elevated serum cytokine (interleukin-6, interleukin-10, tumor necrosis factor-alpha and transforming growth factor-beta1) and Fas induced by MTX. Histologically, MTX caused defused tubular cells swelling and vacuolization associated with endothelial damage in renal arterioles. These effects disappeared upon co-treated with pioglitazone. Collectively, pioglitazone abolished MTX-induced endothelium dysfunction and nephrotoxicity via ameliorating oxidative stress and rectifying cytokines and Fas abnormalities caused by MTX.     

Mitigation of 5-Fluorouracil induced renal toxicity by chrysin via targeting oxidative stress and apoptosis in wistar rats

5-Fluorouracil (5-FU) is a potent antineoplastic agent commonly used for the treatment of various malignancies. It has diverse adverse effects such as cardiotoxicity, nephrotoxicity and hepatotoxicity which restrict its wide and extensive clinical usage. It causes marked organ toxicity coupled with increased oxidative stress and apoptosis. Chrysin (CH), a natural flavonoid found in many plant extracts, propolis, blue passion flower. It has antioxidative and anti-cancerous properties. The present study was designed to investigate the protective effects of CH against 5-FU induced renal toxicity in wistar rats using biochemical, histopathological and immunohistochemical approaches.Rats were subjected to prophylactic oral treatment of CH (50 and 100 mg/kg b.wt.) for 21 days against renal toxicity induced by single intraperitoneal administration of 5-FU (150 mg/kg b.wt.). The possible mechanism of 5-FU induced renal toxicity is the induction of oxidative stress; activation of apoptotic pathway by upregulation of p53, bax, caspase-3 and down regulating Bcl-2. However prophylactic treatment of CH decreased serum toxicity markers, increased anti-oxidant armory as well as regulated apoptosis in kidney. Histopathological changes further confirmed the biochemical and immunohistochemical results. Therefore, results of the present finding suggest that CH may be a useful modulator in mitigating 5-FU induced renal toxicity.     

Effects of insecticides fenitrothion,endosulfan and abamectin on antioxidant parameters of isolated rat hepatocytes

Fenitrothion, endosulfan and abamectin are insecticides that affect various organs in humans and animals. The present study was conducted to investigate their cytotoxicity in isolated male rat hepatocytes. The study suggests that incubation of hepatocytes with 10 or 100 μM of each insecticide for 2 h significantly decreased the cell viability. Increased leakage percentage of lactate dehydrogenase (LDH), alanine transaminase (ALT) and aspartate aminotranferase (AST) were detected in hepatocytes due to the same dose of insecticide exposure confirmed membrane damage of hepatocytes. Fenitrothion (100 μM) increased the cellular lipid peroxidation (LPO) levels more than the other insecticides. The activities of the antioxidant enzymes like superoxide dismutase (SOD), glutathione peroxidise (GSH-Px) and glutathione-S-transferase (GST) were decreased by fenitrothion incubation more than endosulfan and abamectin. The same treatment reduced the level of antioxidant glutathione (GSH) and increased the level of LPO. The activities of glutathione-S-transferase (GST) and gamma glutamyl transpeptidase (γ-GT) were more affected by fenitrothion and endosulfan, respectively, indicating an oxidative stress. There was negative correlation coefficient among GSH, GST and γ-GT. A significant correlation was also found between γ-GT and cell viability. The present study revealed that fenitrothion showed varying pathological signs depending on the dose; high dose caused marked damage of isolated hepatocytes in the oxidative and antioxidant parameters. Endosulfan induced cell membrane damage of the hepatocytes more than abamectin and fenitrothion as indicated by increasing the leakage percentages of LDH, ALT, AST and γ-GT. Therefore, hepatotoxicity of insecticides increased in a time and dose-dependent manner and depended on the class of the insecticide.     

Effects of paraoxon on serum biochemical parameters and oxidative stress induction in various tissues of Wistar and Norway rats

This study investigates the effects of different doses of paroxon (POX), an active metabolite of the organophosphate pesticide parathion, on some serum biochemical parameters and induction of oxidative stress in various tissues of female Wistar and Norway rats. The rats were intraperitoneally treated with 0.3, 0.7, 1 and 1.5 mg/kg of POX. The parameters were evaluated after 24 h. The results showed that the decreased glutathione level and catalase, glutathione-S-transferase and lactate dehydrogenase activities in tissues of Wistar rat were higher than Norway rat at higher doses of POX. At these concentrations, POX increased superoxide dismutase activity, malondialdehyde level and some serum biochemical indices. In conclusion, POX induces the production of free radicals and oxidative stress in a dose-dependent manner. Induction of oxidative stress in POX-treated rats is in the order of brain > liver > heart> kidney > spleen. Wistar rat is found to be more sensitive to the toxicity of POX compared to Norway rat.     

Polychlorinated biphenyl exposure alters the expression profile of microRNAs associated with vascular diseases

Exposure to persistent organic pollutants, including polychlorinated biphenyls (PCBs) is correlated with multiple vascular complications including endothelial cell dysfunction and atherosclerosis. PCB-induced activation of the vasculature subsequently leads to oxidative stress and induction of pro-inflammatory cytokines and adhesion proteins. Gene expression of these cytokines/proteins is known to be regulated by small, endogenous oligonucleotides known as microRNAs that interact with messenger RNA. MicroRNAs are an acknowledged component of the epigenome, but the role of environmentally-driven epigenetic changes such as toxicant-induced changes in microRNA profiles is currently understudied. The objective of this study was to determine the effects of PCB exposure on microRNA expression profile in primary human endothelial cells using the commercial PCB mixture Aroclor 1260. Samples were analyzed using Affymetrix GeneChip® miRNA 4.0 arrays for high throughput detection and selected microRNA gene expression was validated (RT-PCR). Microarray analysis identified 557 out of 6658 microRNAs that were changed with PCB exposure (p < 0.05). In-silico analysis using MetaCore database identified 21 of these microRNAs to be associated with vascular diseases. Further validation showed that Aroclor 1260 increased miR-21, miR-31, miR-126, miR-221 and miR-222 expression levels. Upregulated miR-21 has been reported in cardiac injury while miR-126 and miR-31 modulate inflammation. Our results demonstrated evidence of altered microRNA expression with PCB exposure, thus providing novel insights into mechanisms of PCB toxicity.     

Protection of cisplatin-induced spermatotoxicity,DNA damage and chromatin abnormality by selenium nano-particles

Cisplatin (CIS), an anticancer alkylating agent, induces DNA adducts and effectively cross links the DNA strands and so affects spermatozoa as a male reproductive toxicant. The present study investigated the cellular/biochemical mechanisms underlying possible protective effect of selenium nano-particles (Nano-Se) as an established strong antioxidant with more bioavailability and less toxicity, on reproductive toxicity of CIS by assessment of sperm characteristics, sperm DNA integrity, chromatin quality and spermatogenic disorders. To determine the role of oxidative stress (OS) in the pathogenesis of CIS gonadotoxicity, the level of lipid peroxidation (LPO), antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) and peroxynitrite (ONOO) as a marker of nitrosative stress (NS) and testosterone (T) concentration as a biomarker of testicular function were measured in the blood and testes. Thirty-two male Wistar rats were equally divided into four groups. A single IP dose of CIS (7 mg/kg) and protective dose of Nano-Se (2 mg/kg/day) were administered alone or in combination. The CIS-exposed rats showed a significant increase in testicular and serum LPO and ONOO level, along with a significant decrease in enzymatic antioxidants levels, diminished serum T concentration and abnormal histologic findings with impaired sperm quality associated with increased DNA damage and decreased chromatin quality. Coadministration of Nano-Se significantly improved the serum T, sperm quality, and spermatogenesis and reduced CIS-induced free radical toxic stress and spermatic DNA damage.In conclusion, the current study demonstrated that Nano-Se may be useful to prevent CIS-induced gonadotoxicity through its antioxidant potential.     

Taurine reverses endosulfan-induced oxidative stress and apoptosis in adult rat testis

The present study was aimed to investigate the mechanistic aspect of endosulfan toxicity and its protection by taurine in rat testes. Pre-treatment with taurine (100 mg/kg/day) significantly reversed the decrease in testes weight, and the reduction in sperm count, motility, viability and daily sperm production in endosulfan (5 mg/kg/day)-treated rats. Sperm chromatin integrity and epididymal L-carnitine were markedly decreased by endosulfan treatment. Endosulfan significantly decreased the level of serum testosterone and testicular 3β-HSD, 17β-HSD, G6PDH and LDH-X. Sperm Δψm and mitochondrial cytochrome c content were significantly decreased after endosulfan. Testicular caspases-3, -8 and -9 activities were significantly increased but taurine showed significant protection from endosulfan-induced apoptosis. Oxidative stress was induced by endosulfan treatment as evidenced by increased H₂O₂ level and LPO and decreased the antioxidant enzymes SOD, CAT and GPx activities and GSH content. These alterations were effectively prevented by taurine pre-treatment.In conclusion, endosulfan decreases rat testes weight, and inhibits spermatogenesis and steroidogenesis. It induces oxidative stress and apoptosis by possible mechanisms of both mitochondria and non-mitochondria pathways. These data provide insight into the mode of action of endosulfan-induced toxicity and the beneficial role provided by taurine to counteract endosulfan-induced oxidative stress and apoptosis in rat testis.