Antioxidant defense system and oxidative status in Antarctic fishes: The sluggish rockcod Notothenia coriiceps versus the active marbled notothen Notothenia rossii.

Adaptive responses of antioxidant defense systems (ADS) to changes in increased levels of activity are critical, especially in Antarctic fishes. The benthopelagic marbled notothen (Notothenia rossii) shows higher spontaneous activity than the benthonic and sluggish rockcod (N. coriiceps). Therefore, we hypothesize that species-related responses of ADS would occur to counteract different rates of reactive oxygen species formation in these two Antarctic fish. Here we evaluated ADS and oxidative damage in tissues (brain, gills, liver and white muscle) of the two Antarctic fish. Despite no significant differences in lipid and protein oxidative damage were observed, we actually found species- and tissue-specific differences in ADS. Gill metallothionein-like proteins (MTLP) and liver reduced glutathione (GSH) concentrations were higher in N. coriiceps than in N. rossii. Brain and gill antioxidant capacity against peroxyl radicals (ACAP); gill enzyme [glutamate-cysteine ligase (GSL), superoxide dismutase (SOD) and catalase (CAT)] activity; liver GCL and SOD activity; and white muscle CAT activity were higher in N. rossii than in N. coriiceps. Therefore, the more active fish (N. rossii) maintains higher activities of enzymes involved in superoxide ions (O2.-) detoxification and GSH production in peripheral tissues (gills, liver and white muscle). This allows the more active fish (N. rossii) to keep levels of lipid and protein oxidative damage similar to those observed in the sluggish fish (N. coriiceps). It is worth noting that the more active fish also shows a higher brain antioxidant capacity, which could involve other non-enzymatic antioxidants like vitamins C and E. In contrast, N. coriiceps shows lower consumption of non-enzymatic antioxidants in peripheral tissues than N. coriiceps. As hypothesized, our results indicate that differences in ADS profiles between fish species are likely related to their habits and metabolic rates. This would imply in different fish abilities to deal with oxidative stress associated with increasing seawater temperature.

Effects of increasing temperature on antioxidant defense system and oxidative stress parameters in the Antarctic fish Notothenia coriiceps and Notothenia rossii.

Antioxidant defense system (ADS) and oxidative stress parameters were evaluated in the Antarctic fish Notothenia rossii and N. coriiceps exposed to increasing temperature. Acclimated fish were kept at 0°C or exposed to 4°C for 1day (N. rossii) or to 2 and 4°C for 1 and 6 days (N. coriiceps). Measurements were assessed in brain, gills, liver, white muscle and erythrocytes. Parameters analyzed included antioxidant capacity against peroxyl radicals (ACAP); reduced glutathione (GSH) and metallothionein-like proteins (MTLP) concentration; superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione-S-transferase (GST) and glutamate-cysteine ligase (GCL) activity; lipid peroxidation (LPO) level and protein carbonyl (PC) concentration. Increased liver GST activity was observed in N. rossii exposed to 4°C for 1day. Increased muscle GPx activity was observed in N. coriiceps after exposure to 2°C for 1day. Reduced gill GPx activity and increased liver SOD activity were observed after exposure to 4°C for 1day. In N. coriiceps, increased gill GCL activity and reduced gill GPx activity, as well as reduced liver MTLP were observed after exposure to 2°C for 6 days. Reduced brain SOD activity and increased brain LPO; reduced gill ACAP, GSH concentration and GPx activity, as well as increased gill GCL activity; reduced liver ACAP, MTLP, SOD activity, GST activity and increased liver and erythrocytes LPO were observed after exposure to 4°C for 6 days. These findings indicate that ADS is more responsive to short-term increasing temperature in the sluggish N. coriiceps than in the active N. rossii. However, responses of N. coriiceps to long-term increasing temperature were transient and did not prevent tissue oxidative damage. Considering the predicted increase in temperature in the Southern Ocean over the next decades, our findings suggest that Antarctic fishes are sensitive to ocean warming, displaying tissue oxidative damage associated with the thermal stress.

Maternal Transfer of Bisphenol A During Nursing Causes Sperm Impairment in Male Offspring.

The health effects of environmental chemicals on animals and humans are of growing concern. Human epidemiological and animal study data indicate that reproductive disorders and diseases begin early during prenatal and postnatal development. An increase of human male reproductive disturbance in the past several decades was associated to chemicals called endocrine disruptors (ED). Bisphenol A (BPA) is a ubiquitous organic environmental contaminant with ED activity. This study verified the effect of BPA exposure via breast milk during the lactation (early postnatal) period in male mice. Dams were exposed to oral BPA (300, 900, and 3000 µg/kg/BW/day) during the breastfeeding period (21 days). BPA at all concentrations significantly impaired sperm parameters in adult mice (8 months old), but mitochondrial functionality was more affected at BPA 3000. The acrosome membrane parameter was affected by BPA concentrations from 900 to 3000, and DNA integrity showed pronounced impairment at BPA 900 and 3000. BPA 3000 treatment also induced testicular degeneration and complete aplasia in some seminiferous tubules. Testicular oxidative damage was observed, and the total antioxidant capacity was impaired in BPA 900 and 3000 treatment groups. Taken together, the present study demonstrated long-term adverse effects of BPA in male mice, including reduced sperm quality, antioxidant capacity, and changes in testicular tissue. Our results clearly demonstrate the danger of BPA transferred via lactation on sperm quality registered even after a long time-elapsed from exposure to this harmful chemical.

Effects of seasonality and moult cycle on the proliferation of nerve cells and on the labelling of ecdysone receptors in an estuarine crab.

Decapod crustaceans show proliferation of the nerve cells in the olfactory lobe throughout their lives. However, the regulation of this process is still poorly understood, since it may vary with endogenous and exogenous factors. The objective of the present investigation was to quantify the proliferation of nerve cells and number of nerve cells with ecdysone receptors in the clusters of the central olfactory system in Neohelice granulata, according to moult stages and in different seasons (summer and winter). Three injections of bromodeoxyuridine (BrdU) were administered to the crabs. Brains were sectioned by microtome and fixed on slides for immunohistochemistry with anti-BrdU and anti-EcR antibodies. The proliferation of nerve cells was higher in winter than in summer, probably because in winter the crabs do not breed and the premoult and postmoult periods are longer. Crabs in postmoult exhibited more BrdU-labelled cells than crabs in premoult or intermoult in winter, because of a greater number of mitoses related to an increase in body size and addition of olfactory receptor neurons. The number of EcR-labelled cells was higher in premoult than in postmoult or intermoult in winter. The proliferation of nerve cells is regulated seasonally and according to moult stages.

The impact of polar fraction of the fine particulate matter on redox responses in different rat tissues.

Particulate matter (PM) contains different chemical substances that have been associated with health effects and an increased risk of mortality due to their toxicity. In this study, fine particulate matter (PM2.5) samples were collected in a region with rural characteristics (Seropédica (Se)) and another with some industries (Duque de Caxias (DC)) (Brazil, RJ). Rats were exposed to PM2.5 extracts daily for 25 days at different dilutions: 10×, 5×, and a concentrated solution (CS). Biochemical analyses were investigated for total antioxidant capacity (ACAP), lipid peroxidation (LPO) levels, reduced glutathione (GSH) concentration, activity of glutamate cysteine ligase (GCL), and activity of glutathione S-transferase (GST). The liver showed a significant increase in GCL (DC-5×, DC-CS and Se-CS) and GST activities (DC-CS and Se-CS) in both regions when compared to the control group. In the renal cortex, GCL activity decreased in most of the tested groups while GST activity increased only in the 5× groups of both regions (DC and Se). In the renal medulla, GCL activity decreased for Se-10× and DC-CS but increased for Se-5×, and GST activity increased in the Se-10×, DC-5×, and DC-CS groups. Lung GCL increased in all groups for both regions. Moreover, this organ also showed an increase in GST activity when higher metal concentrations were present (5× and CS). TBARS levels were increased for all tissues in most tested concentrations. These data indicate that soluble compounds (e.g., metals) from PM2.5 sampled in areas with different pollution indexes can change the redox status and cause damage to different tissues.

Biomarkers in croakers Micropogonias furnieri (Teleostei: Sciaenidae) from polluted and non-polluted areas from the Patos Lagoon estuary (Southern Brazil): evidences of genotoxic and immunological effects.

Biomarkers of exposure and effect of pollutants were analyzed in croakers Micropogonias furnieri (Teleostei: Sciaenidae) captured in winter and summer in a polluted and in a non-polluted site at the Patos Lagoon estuary (Southern Brazil). Catalase and glutathione S-transferase activities (exposure biomarkers) and lipid peroxidation (effect biomarker) were analyzed in liver samples. Other two effect biomarkers were also studied: blood cells DNA damage (through comet assay and micronucleus test) and respiratory burst measurements. In a broad view, results point to an important seasonal variation of the biochemical biomarkers analyzed. However, data obtained clearly indicate that croakers collected in winter at the polluted site were subjected to a level of clastogenic agents sufficient to generate irreversible genetic damages (mutations) and impair the fish immune system.

Toxicological effects of particulate matter (PM2.5) on rats: Bioaccumulation, antioxidant alterations, lipid damage, and ABC transporter activity.

Previous studies have demonstrated the harmful effects of atmospheric pollutants on cardiac systems because of the presence of particulate matter (PM), a complex mixture of numerous substances including trace metals. In this study, the toxicity of PM2.5 from two regions, rural (PM2.5 level of 8.5 ± 4.0 µg m(-3)) and industrial (PM2.5 level of 14.4 ± 4.1 µg m(-3)) in Brazil, was investigated through in vivo experiments in rats. Metal accumulation and biochemical responses were evaluated after rats were exposed to three different concentrations of PM2.5 in saline extract (10× dilution, 5× dilution, and concentrated). The experimental data showed the bioaccumulation of diverse trace metals in the hearts of groups exposed to PM2.5 from both regions. Furthermore, mobilization of the antioxidant defenses and an increase in lipid peroxidation of the cardiac tissue was observed in response to the industrial and rural area PM2.5. Glutathione-S-transferase activity was increased in groups exposed to the 5× and concentrated rural PM2.5. Additionally, ATP-binding cassette (ABC) transporter activity in the cardiac tissue exposed to PM2.5 was reduced in response to the 5× dilution of the rural and industrial region PM2.5. Histological analysis showed a decrease in the percentage of cardiac cells in the heart at all tested concentrations. The results indicate that exposure to different concentrations of PM2.5 from both sources causes biochemical and histological changes in the heart with consequent damage to biological structures; these factors can favor the development of cardiac diseases.

Effects of prenatal and postnatal exposure to a low dose of bisphenol A on behavior and memory in rats.

Endocrine disruptors (EDs) are increasingly common chemicals in the environment. Bisphenol A (BPA), used to manufacture polycarbonate plastics, is an ED recognized for its estrogenic, anti-estrogenic, and anti-androgenic effects. Behavior is considered a vital characteristic for an animal's life cycle. This study evaluated the effect of exposure to low doses of BPA during pregnancy and/or lactation on several aspects of rat behavior, including memory, locomotion, and the exploratory instinct. Pups at 16 weeks of age (females and males) were divided into groups according to the mother's exposure to BPA (40µg/kg/day): CON (vehicle only); PRE (during pregnancy); LAC (during lactation); PRE-LAC (during both pregnancy and lactation). In the PRE-LAC group, exposure to BPA impaired both short-term (STM) and long-term memory (LTM) in inhibitory avoidance and the object recognition task, and also affected locomotor activity and spatial memory. Some sex-specific behavioral characteristics disappeared in the LAC group. Sex-specific memory and behavior impairment were caused by BPA exposure during brain organogenesis and differentiation.