Oxidative Stress-related Responses Research Articles

Gadolinium ecotoxicity is enhanced in a warmer and acidified changing ocean as shown by the surf clam Spisula solida through a multibiomarker approach

Humans have exhaustively combusted fossil fuels, and released pollutants into the environment, at continuously faster rates resulting in global average temperature increase and seawater pH decrease. Climate change is forecasted to exacerbate the effects of pollutants such as the emergent rare earth elements. Therefore, the objective of this study was to assess the combined effects of rising temperature (Δ = + 4 °C) and decreasing pH (Δ = − 0.4 pH units) on the bioaccumulation and elimination of gadolinium (Gd) in the bioindicator bivalve species Spisula solida (Surf clam). We exposed surf clams to 10 µg L−1 of GdCl3 for seven days, under warming, acidification, and their combination, followed by a depuration phase lasting for another 7 days and investigated the Gd bioaccumulation and oxidative stress-related responses after 1, 3 and 7 days of exposure and the elimination phase. Gadolinium accumulated after just one day with values reaching the highest after 7 days. Gadolinium was not eliminated after 7 days, and elimination is further hampered under climate change scenarios. Warming and acidification, and their interaction did not significantly impact Gd concentration. However, there was a significant interaction on clam's biochemical response. The augmented total antioxidant capacity and lipid peroxidation values show that the significant impacts of Gd on the oxidative stress response are enhanced under warming while the increased superoxide dismutase and catalase values demonstrate the combined impact of Gd, warming & acidification. Ultimately, lipid damage was greater in clams exposed to warming & Gd, which emphasizes the enhanced toxic effects of Gd in a changing ocean.

Neuroprotective Effect of Dexmedetomidine against Postoperative Cognitive Decline via NLRP3 Inflammasome Signaling Pathway

Dexmedetomidine (Dex), widely used as a sedative in surgical procedures and intensive care units, induces sympatholytic, anxiolytic, analgesic, and sedative effects. Postoperative cognitive dysfunction (POCD) is routinely observed in postoperative care following surgery and general anesthesia. The NLRP3 inflammasome complex plays a critical role in innate immune response by detecting pathogenic microorganisms and activating pro-inflammatory cytokines. Although there are numerous protective effects of Dex among the neurological diseases, specific mechanisms including NLRP3 inflammasome-mediated neuroinflammation via oxidative stress response in a POCD model are not fully understood. Here, we investigated whether Dex exhibits neurocognitive effects through the NLRP3 inflammasome signaling in a POCD mouse model using a neurobehavioral test and ELISA analysis. We also confirmed the level of oxidative stress-related response in the in vitro system in the POCD model. Furthermore, we evaluated the NLRP3 inflammasome complex by immunoprecipitation analysis. In summary, the results of the present study indicated that Dex showed a neuroprotective effect in the POCD model by reducing oxidative stress response through NLRP3 inflammasome-mediated neuroinflammation.

Antibladder Cancer Effects of Excavatolide C by Inducing Oxidative Stress, Apoptosis, and DNA Damage In Vitro.

Excavatolide C (EXCC) is a bioactive compound derived from the gorgonian octocoral Briareum excavatum, and its anticancer effects are rarely addressed, particularly for bladder cancer. This investigation aimed to explore the potential impacts of EXCC on inhibiting the proliferation of three kinds of bladder cancer cells (5637, BFTC905, and T24). EXCC inhibits bladder cancer cell proliferation based on 48 h ATP assay. This antiproliferation function is validated to be oxidative stress dependent. Cellular and mitochondrial oxidative stresses were upregulated by EXCC, accompanied by depleting glutathione and mitochondrial membrane potential. These antiproliferation and oxidative stress events were suppressed by N-acetylcysteine (NAC), indicating that EXCC has an oxidative stress-regulating function for antiproliferation of bladder cancer cells. Oxidative stress-related responses such as apoptosis, caspase activation, and DNA damage were upregulated by EXCC and reverted by NAC. Taken together, the antiproliferation function of EXCC provides a potential treatment against bladder cancer cells via oxidative stress modulation.

Boat noise impacts early life stages in the Lusitanian toadfish: A field experiment

Marine traffic is the most common and chronic source of ocean noise pollution. Despite the evidence of detrimental effects of noise exposure on fish, knowledge about the effects on the critical early life stages - embryos and larvae - is still scarce. Here, we take a natural habitat-based approach to examine potential impacts of boat noise exposure in early life stages in a wild fish population of the Lusitanian toadfish (Halobatrachus didactylus). In-situ experiments were carried out in the Tagus estuary, an estuary with significant commercial and recreational boat traffic. Nests with eggs were exposed to either ambient (control) or boat noise (treatment), for 1 fortnight. Eggs were photographed before being assigned to each treatment, and after exposure, to count number of eggs and/or larvae to assess survival, and sampled to study development and oxidative stress and energy metabolism-related biomarkers. Data concerns 4 sampling periods (fortnights) from 2 years. Results indicate that offspring survival did not differ between treatments, but boat noise induced a detrimental effect on embryos and larvae stress response, and on larvae development. Embryos showed reduced levels of electron transport system (ETS), an energy metabolism-related biomarker, while larvae showed higher overall stress responses, with increased levels of superoxide dismutase (SOD) and DNA damage (oxidative stress related responses), ETS, and reduced growth. With this study, we provided the first evidence of detrimental effects of boat noise exposure on fish development in the field and on stress biomarker responses. If these critical early stages are not able to compensate and/or acclimate to the noise stress later in the ontogeny, then anthropogenic noise has the potential to severely affect this and likely other marine fishes, with further consequences for populations resilience and dynamics.

O-192 Modulating hypoxia and oxidative stress in human ovarian tissue xenografts using adipose tissue-derived stem cells

Abstract Study question To investigate whether adipose tissue-derived stem cells (ASCs) modulate hypoxia and oxidative stress in human ovarian tissue transplants to reduce early follicle loss. Summary answer ASCs protect the follicle pool by mitigating the hypoxia-related response through HIF1↑ signaling in human xenografts and enhancing revascularization by ensuring faster tissue reperfusion. What is known already ASCs are known for their angiogenic potential and capacity to boost angiogenesis by secreting growth factors and differentiating into vessels in numerous models of wound healing in regenerative medicine. In a 2-step ovarian tissue xenotransplantation involving grafting inside a fibrin scaffold two weeks prior to transplantation, ASCs reduced follicle loss after short- and long-term grafting, as well as abnormal follicle activation, by increasing reoxygenation and revascularization in human xenografts. Study design, size, duration Prospective experimental study. Cryopreserved ovarian cortex from five adult women was transplanted to 30 nude mice, with or without ASCs (ASC group; OT group). Ovarian grafts were retrieved on days 3 (n = 5), 10 (n = 5) and 21 (n = 5). One piece of ovarian tissue per patient was fixed for analysis after thawing to serve as non-grafted controls. Participants/materials, setting, methods The 10 animals grafted for 21 days underwent in vivo microdialysis evaluation to investigate direct reactive oxygen species (ROS) kinetics. Analyses of ovarian grafts at all time points and non-grafted controls included immunolabeling for double CD34 (revascularization by host and graft components), immunofluorescence for HIF1α (hypoxia-related response), Nrf2 (oxidative stress-related response) and 8OHdG (oxidative stress-related DNA damage), and gene expression (RT-qPCR) for VEGF-A (neoangiogenesis), SOD2 (antioxidant activity) and Nrf1 (mitochondrial biogenesis). Main results and the role of chance ROS peaked sooner in the ASC group (day 2, p < 0.0001) than the OT group (day 10, p = 0.01) after grafting, indicating earlier tissue reperfusion. Total vascularization was stable in the ASC group at all time points, but lower in the OT group 3 days after grafting (p = 0.01) due to a drop in both host and graft vascular components. HIF1α expression, detected mainly in follicles, was significantly lower in primordial follicles in the ASC group than the OT group on days 3 (p = 0.008) and 10 (p = 0.01). VEGF gene expression rose significantly (around 40x) in both groups on day 3 and persisted significantly longer in the ASC group (10 days) than the OT group (3 days) (p = 0.04), emphasizing the role of ASCs as enhancers of proangiogenic factors. There was no upturn in the oxidative stress-related response (Nrf2 pathway) nor DNA damage (8OHdG) to follicles in any of the grafted groups over time, while a modest increase in both markers was observed only in the stroma after 21 days. Neither was there any major increase in SOD2 and Nrf1 gene expression, suggesting no significant activation of the Nrf2 pathway for cytoprotection from oxidative stress. Limitations, reasons for caution Although Nrf2 signaling activation was detected in human granulosa cell cultures in increasing ROS concentrations, our findings did not confirm its role in tissue damage modulation after ovarian tissue transplantation. Further studies may evidence the involvement of other pathways that modulate oxidative stress after transplantation. Wider implications of the findings The role of ASCs in protecting the follicle pool appears to be related to a decrease in hypoxia and faster ovarian graft revascularization and reperfusion, sustained by an increase in VEGF for a longer period after grafting. There was no evidence of oxidative stress-related damage, irrespective of the transplantation strategy. Trial registration number

Modulating hypoxia and oxidative stress in human xenografts using adipose tissue-derived stem cells

To investigate whether adipose tissue-derived stem cells (ASCs) modulate hypoxia and oxidative stress in human ovarian tissue transplants. Prospective experimental study SETTING: Gynecological research unit in a university hospital PATIENT(S): Cryopreserved ovarian cortex from 5 adult women. Thirty mice were grafted with frozen-thawed human ovarian tissue, with or without ASCs (2-step/ASCs+ovarian tissue [OT] group and OT group). The ovarian grafts were retrieved on days 3 (n = 5), 10 (n = 5), and 21 (n = 5). The 10 animals grafted for 21 days underwent invivo evaluations using microdialysis. One piece of ovarian tissue per patient was fixed for analysis after thawing (non-grafted controls). Direct reactive oxygen species were collected every second day after grafting by means of microdialysis. Analyses of ovarian fragments included immunolabeling for double CD34 (revascularization by host and graft components); immunofluorescence for hypoxia-inducible factor 1α (hypoxia-related response), nuclear factor erythroid 2-related factor 2 (oxidative stress-related response), and 8-hydroxy-deoxyguanosine (oxidative stress-related DNA damage); and gene expression (quantitative reverse transcription polymerase chain reaction) for vascular endothelial growth factor-A (neoangiogenesis), superoxide dismutase 2 (antioxidant activity), and nuclear respiratory factor 1 (mitochondrial biogenesis). Reactive oxygen species peaked earlier in the ASC group (day 2) compared with that in the OT group (day 10) after grafting. Total vascularization was stable in the ASC group at all time points, while it was lower in the OT group 3 days after grafting. Hypoxia-inducible factor 1α expression, also detected in non-grafted controls, was significantly lower in the ASC group than in the OT group on days 3 and 10. The increase in VEGF gene expression lasted significantly longer in the ASC group than in the OT group. There was no significant upturn in the oxidative stress-related response (nuclear factor erythroid 2-related factor 2 pathway) or oocyte DNA damage (8-hydroxy-deoxyguanosine) in any of the grafted groups. Use of ASCs allows faster ovarian graft reperfusion and mitigates the hypoxia-related response through rapid revascularization, sustained by prolonged increase in vascular endothelial growth factor after grafting. No evidence of oxidative stress-related damage was detected irrespective of the transplantation strategy.

Cardiopulmonary Bypass Suppresses Forkhead Box O3 and Downstream Autophagy in the Diabetic Human Heart

Autophagy is an integral component of cellular homeostasis and metabolism. The exact mechanism of impaired autophagy in diabetes mellitus is unknown. Forkhead Box O3 (FOXO3α) is a key regulator of oxidative stress-related responses. We hypothesize FOXO3α is a direct upstream regulator of the autophagy pathway, and its upregulation is compromised in diabetic patients during stress of cardiopulmonary bypass (CPB). The study enrolled 32 diabetic and 33 nondiabetic patients undergoing a cardiac surgical procedure on CPB. Right atrial tissue and serum samples were collected before and after CPB per protocol. A set of key components were quantitatively assessed and compared by microarray, immunoblotting, and immunohistochemistry studies. Data were analyzed using paired or unpaired student test. A P of <.05 or less was considered significant. Serum microarray showed FOXO3α was upregulated in the diabetic vs nondiabetic group after CPB (P= .033), autophagy-related 4B gene and Beclin 1 gene were greatly upregulated in the nondiabetic group (P= .028 and P= .002, respectively). On immunoblotting, there was upregulation of FOXO3α in the nondiabetic patients after CPB (P= .003). There were increased levels of Beclin-1, Bcl-2, and light chain 3B after CPB in the nondiabetic group only (P= .016, P= .005, P= .002, respectively). Sirtuin 1, Unc-51-like autophagy activating kinase 1 (ULK1), peroxisome proliferator-activated receptor gamma coactivator 1α (PGC1α), and mammalian target of rapamycin (mTOR) were not significantly changed in the nondiabetic group after CPB. Compared with nondiabetic patients, there was no significant upregulation of FOXO3α in diabetic patients, which could possibly explain the lack of upregulation of the autophagy process after CPB. FOXO3α could potentially serve as a therapeutic target to improve cellular homeostasis.

Test of Arabidopsis Space Transcriptome: A Discovery Environment to Explore Multiple Plant Biology Spaceflight Experiments.

Recent advances in the routine access to space along with increasing opportunities to perform plant growth experiments on board the International Space Station have led to an ever-increasing body of transcriptomic, proteomic, and epigenomic data from plants experiencing spaceflight. These datasets hold great promise to help understand how plant biology reacts to this unique environment. However, analyses that mine across such expanses of data are often complex to implement, being impeded by the sheer number of potential comparisons that are possible. Complexities in how the output of these multiple parallel analyses can be presented to the researcher in an accessible and intuitive form provides further barriers to such research. Recent developments in computational systems biology have led to rapid advances in interactive data visualization environments designed to perform just such tasks. However, to date none of these tools have been tailored to the analysis of the broad-ranging plant biology spaceflight data. We have therefore developed the Test Of Arabidopsis Space Transcriptome (TOAST) database (https://astrobiology.botany.wisc.edu/astrobotany-toast) to address this gap in our capabilities. TOAST is a relational database that uses the Qlik database management software to link plant biology, spaceflight-related omics datasets, and their associated metadata. This environment helps visualize relationships across multiple levels of experiments in an easy to use gene-centric platform. TOAST draws on data from The US National Aeronautics and Space Administration’s (NASA’s) GeneLab and other data repositories and also connects results to a suite of web-based analytical tools to facilitate further investigation of responses to spaceflight and related stresses. The TOAST graphical user interface allows for quick comparisons between plant spaceflight experiments using real-time, gene-specific queries, or by using functional gene ontology, Kyoto Encyclopedia of Genes and Genomes pathway, or other filtering systems to explore genetic networks of interest. Testing of the database shows that TOAST confirms patterns of gene expression already highlighted in the literature, such as revealing the modulation of oxidative stress-related responses across multiple plant spaceflight experiments. However, this data exploration environment can also drive new insights into patterns of spaceflight responsive gene expression. For example, TOAST analyses highlight changes to mitochondrial function as likely shared responses in many plant spaceflight experiments.

SCD \u2013 Stem Cell Differentiation Toward Osteoblast Onboard the International Space Station

Microgravity produces a variety of physical, chemical, and biological cues leading to an intricate and largely unresolved network of mechanosensitive molecules, transduction pathways, oxidative stress-related responses, and adaptations. The bone loss observed in astronauts and animal models after spaceflight is attributable to alterations in the bone tissue formation that depends on the continuous remodelling through the activities of bone-resorbing osteoclasts of hematopoietic lineage and bone-forming osteoblast of mesenchymal origin. Focusing on osteogenic differentiation, we present the results of the ”SCD - Stem Cells Differentiation” experiment, aiming to determine how human bone marrow stem cells (hBMSCs) react to a prolonged (approx. 2 weeks) exposure to microgravity in terms of growth, and differentiation when treated with a physiological osteo-inducer as 1,25-dihydroxy vitamin D (Vit D3). The experiment was selected by the European Space Agency and transferred to ISS with the Soyuz-TMA- 16M (ISS 42S). It was carefully prepared because experiments performed on ISS remain a uniquely exceptional means of clarifying the microgravitational effects on osteogenesis, often only partially activated and detectable under simulated conditions. Because of the substantial reduction in calcification observed (about 50% inflight vs. on-ground control), we looked at significantly affected pathways in hBMSCs grown in microgravity vs. on-ground controls. Genome-wide expression changes were assessed via microarray and next generation sequencing (NGS) and integrated with exosomal mi-RNA measurements. Multi-scale pathway analysis of the omics datasets revealed evidence of cell cycle arrest, occurring with a number of osteogenic gene markers, but without indications of adipogenesis, senescence and/or apoptosis.

In vitro lung toxicity of indoor PM10 from a stove fueled with different biomasses

Biomass combustion significantly contributes to indoor and outdoor air pollution and to the adverse health effects observed in the exposed populations. Besides, the contribution to toxicity of the particles derived from combustion of different biomass sources (pellet, wood, charcoal), as well as their biological mode of action, are still poorly understood. In the present study, we investigate the toxicological properties of PM10 particles emitted indoor from a stove fueled with different biomasses.PM10 was sampled by gravimetric methods and particles were chemically analyzed for Polycyclic Aromatic Hydrocarbons (PAHs) and elemental content. Human lung A549 cells were exposed for 24 h to 1–10 μg/cm2 PM and different biological endpoints were evaluated to comparatively estimate the cytotoxic, genotoxic and pro-inflammatory effects of the different PMs.Pellet PM decreased cell viability, inducing necrosis, while charcoal and wood ones mainly induced apoptosis. Oxidative stress-related response and cytochrome P450 enzymes activation were observed after exposure to all the biomasses tested. Furthermore, after pellet exposure, DNA lesions and cell cycle arrest were also observed. The severe genotoxic and pro-necrotic effects observed after pellet exposure were likely the consequence of the high metal content. By administering the chelating agent TPEN, the genotoxic effects were indeed rescued. The higher content in PAHs measured in wood and charcoal PMs was likely the reason of the enhanced expression of metabolizing and oxidative stress-related enzymes, like CYP1B1 and HO-1, and the consequent increase in apoptotic cell death.These data suggest that combustion particles from different biomass sources may impact on lung cells according to different pathways, finally producing different toxicities. This is strictly related to the PM chemical composition, which reflects the quality of the combustion and the fuel in particular. Further studies are needed to clarify the role of particle dimension and the molecular mechanisms behind the harmful effects observed.

Photosynthetic and antioxidant responses of the tropical intertidal seagrasses Halophila ovalis and Thalassia hemprichii to moderate and high irradiances

AbstractThis study investigated photosynthetic and oxidative stress-related responses to moderate (500 μmol photons m−2s−1) and high irradiances (1500 μmol photons m−2s−1) in two tropical intertidal seagrasses,Halophila ovalisandThalassia hemprichii. Exposure to high irradiance for 3 h resulted in a large decline in the maximum quantum yield of photosystem II (Fv/Fm) and in the effective quantum yield of photosystem II (ΦPSII) but induced non-photochemical quenching (NPQ) and chloroplast clumping inH. ovalis.Thalassia hemprichii, however, showed only a minor decrease in Fv/Fm and ΦPSII, and no change in either NPQ or the intracellular arrangement of chloroplasts. The irradiance did not affect reactive oxygen species (ROS) or superoxide dismutase (SOD) activity in either seagrass, whereas high irradiance enhanced ascorbate peroxidase (APX) activity inH. ovalis. The results from a subsequent experiment using an oxidative stress inducer, methyl viologen (MV), also showed a higher degree of Fv/Fm inhibition inH. ovalis. These results show thatH. ovalisis much more physiologically responsive to high irradiances and oxidative stress thanT. hemprichiiand that its photoprotective mechanisms involve NPQ, APX and reduction of the amount of light absorbed through the clumping of its chloroplasts.

187 - Exercise Program for Chronic Kidney Disease Improves Pathophysiological Condition with a Shift of Oxidative Stress

Exercise program for patients with chronic kidney disease currently recognized as a useful method to improve multiple factors of patients’ condition, however there still remains systemic risks including cardiovascular events. We examined the risk of oxidative stress brought by the intra-dialysis exercise program using electron spin resonance-based multiple radical scavenging (MULTIS) method. Thirty-nine stable hemodialysis (HD) patients of multiple dialysis centers were examined. The renal rehabilitation program was aerobic training using the lower limb ergo-meter twice a week during HD, with Borg scale 11 to 13 and the work time was 15 to 60 min. Eleven patients of them continued the program up to 9 mo. Oxidative stress was evaluated by MULTIS method measuring serum scavenging activities against five reactive oxygen species. Inflammatory cytokines were also measured. The patients received the renal rehabilitation showed significant increase of daily activity, exercise tolerance and muscular strength, accompanied with decreases of systolic blood pressure, LDL and HDL, and an improvement of HD efficiency (Kt/V). The serum alkylperoxyl radical (ROO•) and hydroxyl radical (•OH) scavenging activities were significantly increased by the exercise program within the 3 and 9 mo., respectively. To the contrary, superoxide (O2•‒) and alkoxyl radical (RO•) scavenging activities was decreased. An increase of TNF-a was detected in the patients with the exercise program. No severe unfavorable effects were confirmed during the program. These results indicate that the effects of renal rehabilitation are mostly recognized as favorable, while decreases of O2•‒ and RO• scavenging activities accompanied with an increase of TNF-a should be concerned. The oxidative stress related responses of HD patients are different from healthy subjects.

Abstract 517: Differential Redox Profiles Due to Endothelial Heterogeneity During Oxidative Stress

Atherosclerosis, a chronic inflammatory disease characterized by plaque formation in vascular walls results in perfusion complications culminating in ischemia and induced angiogenesis. Interestingly, atherosclerosis is known largely to be an arterial disease with a preference in vascular beds, often affecting more arteries than veins. A significantly different pattern exists between the endothelial cells of these major blood vessels, highlighting the possibility of intrinsic differences between arterial and venous micro-environments including vascular endothelial cells themselves leading to variable responses during pathogenesis. Although isolated primary cells have been shown to lose some in-vivo characteristics under cell culture conditions, our data proves that these heterogeneous cell types retain the ability to differentially sense redox states. Oxidative stress is one of the key players associated with progression of atherosclerosis, marked by over-production of reactive oxygen species (ROS) and reduction in endogenous antioxidants such as glutathione (GSH). GSH, a major free radical scavenger prevents ROS damage by reducing ROS while being oxidized into glutathione disulfide (GSSG). GSSG is then recycled back to its reduced form under normal physiological conditions, hence maintaining an optimum GSH:GSSG ratio. This ratio is known to be deregulated during redox imbalance seen with oxidative stress during disease, due to decreasing GSH and increasing GSSG levels. Our experiments using Mouse Aorta Endothelial Cells (MAECs) and mouse Vena Cava Endothelial cells (VCECs) to represent arterial and venous endothelial cells display differences in this GSH:GSSG ratio as well, implicating differential redox states within these vessel types. Additionally, differences in oxidative stress related responses with regards to cell proliferation, migration, adhesion molecule expression and leukocyte recruitment in endothelial cells of arteries and veins further highlight the possibility of drastically different predispositions to atherosclerosis. Thus, endothelial cell heterogeneity between arteries and veins may lead to differential redox profiles and altered physiological functions during oxidative stress.

NADPH Oxidase-Dependent Mechanism Explains How Arsenic and Other Oxidants Can Activate Aryl Hydrocarbon Receptor Signaling.

The mechanisms explaining arsenic toxicity are not well understood, but physiological consequences of stimulated aryl hydrocarbon receptor (AHR) signaling both directly and through cross-talk with other pathways have been indicated. The aim of this study was to establish how arsenic interacts with AHR-mediated transcription. The human hepatoma cell line (HepG2-XRE-Luc) carrying a luciferase reporter under the control of two AHR response elements (AHREs) and immortalized human keratinocytes (HaCaT) were exposed to sodium arsenite (NaAsO2; As(3+)), alone or in combination with the endogenous high affinity AHR ligand 6-formylindolo[3,2-b]carbazole (FICZ). Luciferase activity, cytochrome P4501A1 (CYP1A1) activity, oxidative stress-related responses, metabolic clearance of FICZ, and NADPH oxidase (NOX) activity as well as nuclear factor (erythroid-derived 2)-like 2 (Nrf2)-dependent gene expression were measured. Arsenic inhibited CYP1A1 enzyme activity and reduced the metabolic clearance of FICZ. Arsenic also led to activated CYP1A1 transcription but only in cells grown in medium containing trace amounts of the endogenous ligand FICZ, pointing to an indirect mechanism of activation. Initially, arsenic caused dose-dependent inhibition of FICZ-activated AHR signaling, disturbed intracellular GSH status, and increased expression of oxidative stress-related genes. Silencing of NOX4, addition of N-acetylcystein, or pretreatment with arsenic itself attenuated the initial dose-dependent inhibition of AHR signaling. Arsenic pretreatment led to elevated GSH levels and sensitized the cells to ligand-dependent AHR signaling, while silencing of Nrf2 significantly reduced arsenic-mediated activation of the AHR. In addition, influence of NOX on AHR activation was also observed in cells treated with the SH-reactive metals cadmium, mercury, and nickel. Together, the results suggest that SH-reactive agents via a new and possibly general NOX/H2O2-dependent mechanism can interfere with the endogenous regulation of the AHR.

Neurotoxicity and biochemical responses in the earthworm Pheretima hawayana exposed to TiO2NPs

Serious concerns have been expressed about potential risks of manufactured TiO2NPs. In this research, toxicity of nanoparticulate and bulk TiO2 were examined to the earthworm Pheretima hawayana. The 24-h median lethal concentration (LC50) and sublethal endpoints were assessed. Both NPs and their bulk counterparts were toxic. The 24-h LC50 for TiO2NPs (145.36mgkg−1) was highly toxic than that of bulk TiO2 (357.77mgkg−1). The aim of the present work is to evaluate the suitability of P. hawayana and its biochemical responses to be used as a bioindicator organism and biomarkers of TiO2 toxicity. Earthworms were exposed to three sublethal concentrations of TiO2NPs (1, 10 and 100µgkg−1) for 28 days to test acetylcholinesterase (AChE), antioxidant enzymes (superoxide dismutase: SOD and catalase: CAT) activities and MDA content. The response of the antioxidant enzymes combined with AChE inhibition and MDA accumulation indicated that TiO2NPs could induce significant impairments to the earthworms at the actual environment tested concentrations. The results pointed out the high sensitivity of the antioxidant and oxidative stress related responses to TiO2NPs exposure, demonstrating their usefulness in environmental monitoring and risk assessment. The study highlights also the usefulness of earthworm P. hawayana as potential bioindicator species for assessing the risk of nanoparticles environmental contamination.

Antioxidant and oxidative stress related responses in the Mediterranean land snail Cantareus apertus exposed to the carbamate pesticide Carbaryl

The aim of the present work was to study the alterations of the antioxidant defenses and the overall susceptibility to oxidative stress of the terrestrial snail Cantareus apertus exposed to the carbamate pesticide Carbaryl at a low environmentally realistic concentration.The animals were exposed to Lactuca sativa soaked for 1h in 1μM Carbaryl. The temporal dynamics of the responses was assessed by measurements at 3, 7 and 14days of exposure.C. apertus exposed to Carbaryl activates a number of enzymatic antioxidant responses, represented by the early induction of catalase, glutathione peroxidase, glutathione reductase, followed by a delayed induction of superoxide dismutase. Concomitantly, a derangement of the total oxyradical scavenging of the tissues was observed, suggesting an overall impairment of the tissue capability to neutralize ROS probably resulting from the overall negative balance between enzymatic antioxidant defense capability and oxidative stress intensity. This negative balance exposed the animals to the risk of oxidative stress damages including genotoxic damage. Compared to acetylcholinesterase inhibition, the antioxidant responses developed to Carbaryl exposure at the low concentration utilized showed a greater percentage variation in exposed organisms.The results pointed out the high sensitivity of the antioxidant and oxidative stress related responses to Carbaryl exposure at an environmental realistic concentration, demonstrating their usefulness in environmental monitoring and risk assessment. The study highlights also the usefulness of the terrestrial snail C. apertus as potential bioindicator species for assessing the risk of pesticide environmental contamination.

The effects of helium based atmospheric pressure cold plasma (APCP) on wound healing

Cold plasmas have been proposed for many applications in medicine, such as tissue disinfection and wound healing. Their antibacterial effects have been well demonstrated and depend mainly to the action of reactive oxygen species or ROS, but the molecular mechanisms promoting tissue regeneration in wound healing are not yet fully understood. We previously reported that the applications of 2-5 min of atmospheric pressure cold plasma (APCP) generated by helium ionization is effective in the inactivation bacteria without any visible changes in cells and tissues (1) and the aim of the presented study is to ascertain if the same doses of APCP are able to promote wound healing. At this purpose we tested the effects of APCP exposure on dermal fibroblasts viability obtained from 3 different donors by means of MTT and Tunnel test, in presence or absence of a potent antioxidant such as 5mM N-acetylcystein (NAC). To define the cellular response to APCP, we then analyzed by real-time PCR the expression changes of selected genes involved in oxidative stress-related response (OGG1, GPX1) and wound repair (IL1beta, IL6, TNFα, FGF2, TGFβ, SMAD3, α-SMA, collagen I) in the plasma treated cells cultures. Our results demonstrated that in all the three different fibroblasts cultures, 2 min APCP application did not cause any variation of viability 2 h after treatment and increased significantly after 24 h (p<0.05). In fibroblasts of two donors we also found at this time a significant increase of viability of cell exposed for 2 min to APCP when compared to the untreated control. Moreover, NAC pretreatment positively affected the viability of one cell preparations. Evaluation of apoptosis (Tunel test) on all fibroblast preparations treated with 2 min APCP and monitored after 24 h revealed that the number of apoptotic nuclei was comparable to those detected in untreated cells. RT-PCR analysis of cells two hours after APCP treatment revealed only a transient increasing in GPX1, IL6, FGF2 and TNFα mRNA levels. In conclusion, cell exposure of 2 min APCP, a dose that inactivates skin pathogens, maintain or increase their viability, but revealed a transitory alteration of the expression of some genes involved in oxidative stress and wound repair.

Effects of pH on uranium uptake and oxidative stress responses induced in Arabidopsis thaliana

Uranium (U) causes oxidative stress in Arabidopsis thaliana plants grown at pH 5.5. However, U speciation and its toxicity strongly depend on environmental parameters, for example pH. It is unknown how different U species determine U uptake and translocation within plants and how they might affect the oxidative defense mechanisms of these plants. The present study analyzed U uptake and oxidative stress-related responses in A. thaliana (Columbia ecotype) under contrasted U chemical speciation conditions. The 18-d-old seedlings were exposed for 3 d to 25 µM U in a nutrient solution of which the pH was adjusted to 4.5, 5.5, 6.5, or 7.5. Results indicate that there is a different rate of U uptake and translocation at the different pHs, with high uptake and low translocation at low pH and lower uptake but higher translocation at high pH. After U exposure, an increased glutathione reductase activity and total glutathione concentration were observed in U-exposed roots, pointing toward an important role for glutathione in the root defense system against U either by chelation or by antioxidative defense mechanisms. In leaves, antioxidative defense mechanisms were activated on U exposure, indicated by increased superoxide dismutase and catalase activity. As it seems that U toxicity is influenced by pH, it is important to consider site-specific characteristics when making U risk assessments.

Changes in COX-2, iNOS and GCL gene expression in 3T3-L1 preadipocytes incubated in macrophage conditioned medium

PURPOSE: Obesity is recognized as a major risk factor for a number of diseases, including metabolic syndrome and type 2 diabetes mellitus. It is characterized with increased macrophage infiltration in adipose tissue. Macrophages secrete numerous inflammatory mediators and contribute to the increased inflammatory status of adipose tissue which is associated with increased reactive oxygen species generation and oxidative stress. In cell biology conditioned nutrient mediums (CMs) are used to assess the complex impact of the secretory products of a particular cell type on the behaviour of other cells. The aim of the present study was to examine the effect of CM obtained from J744A.1 macrophage cell culture on expression in 3T3-L1 preadipocytes of some enzymes related to antioxidant defense and the inflammatory response. MATERIAL AND METHODS: mRNA levels of inducible cyclooxygenase (COX-2), inducible NO synthase (iNOS) and glutamate-cysteine-ligase (GCL) were measured. 3T3-L1 cells were treated with increasing CM concentrations (10-30%) for 24 hours. Changes in gene expression levels were analyzed by real-time qPCR method. Calculations were performed using 2-ΔΔCt method. RESULTS: The higher CM concentration contributed to increased expression levels of the genes examined. Treatment with CM in concentrations of 10, 20 and 30% resulted in 2.3-, 2.6- and 2.7-fold increase in COX-2 expression (p&lt;0.01), respectively. Both 10% and 20% CM up-regulated iNOS by 1.7 times (p&lt;0.001). The highest CM concentration of 30% stimulated the enzyme by two times (p&lt;0.01). GCL mRNA levels were by 2.5 times higher than these of the untreated controls when stimulated with 30% CM (p&lt;0.05). CONCLUSION: CM from J744A.1 cell culture may induce inflammatory and oxidative stress-related response in 3T3-L1 preadipocytes thus demonstrating a possible link between macrophage infiltration and local inflammation in adipose tissue. Scripta Scientifica Medica 2013; 45(2): 32-35.

A mutant of the Arabidopsis thaliana LIPOXYGENASE1 gene shows altered signalling and oxidative stress related responses after cadmium exposure

Lipoxygenases (LOXes, EC 1.13.11.12) are involved in growth, development and responses to stress. Earlier results suggested a role in stress generation, signalling and/or responses when Arabidopsis thaliana is exposed to cadmium (Cd), and expression of the cytosolic LOX1 was highly upregulated in the roots after Cd exposure. To investigate the involvement of LOX1 in early metal stress responses, three-week-old wild-type and lox1-1 mutant A. thaliana plants were acutely (24 h) exposed to realistic Cd concentrations (5 and 10 μM) and several oxidative stress and signalling related parameters were studied at transcriptional and biochemical levels. Transcription of several genes encoding ROS producing and scavenging enzymes failed to be induced up to wild-type levels after Cd exposure. Expression of 9-LOX enzymes was inhibited in lox1-1 mutant roots due to lack of functional LOX1 and downregulated LOX5 expression, and the lox1-1 mutation also interfered with the expression of genes involved in jasmonate biosynthesis. LOX1 and RBOHD may be involved in stress signalling from roots to shoots, as the induction of APX2 expression, which is dependent on RBOHD activity, was disrupted in lox1-1 while RBOHD failed to be upregulated. A different pattern of H(2)O(2) production and ascorbate and glutathione levels in lox1-1 mutants after Cd exposure may have indirectly influenced gene expression patterns. Although indirect effects of the lox1-1 mutation on gene expression complicate the determination of exact sensing - signalling - response pathways, the results presented here outline a more refined LOX1 functioning in Cd-induced stress responses that could be used in studies determining the exact involvement of LOX1 in these pathways.