Exposure to crude oil during spill events causes a variety of pathologic effects in birds, including oxidative injury to erythrocytes, which is characterized in some species by the formation of Heinz bodies and subsequent anemia. However, not all species appear to develop Heinz bodies or anemia when exposed to oil, and there are limited controlled experiments that use both light and electron microscopy to evaluate structural changes within erythrocytes following oil exposure. In this study, we orally dosed zebra finches (Taeniopygia guttata) with 3.3 or 10 mL/kg of artificially weathered Deepwater Horizon crude oil or 10 mL/kg of peanut oil (vehicle control) daily for 15 days. We found that birds receiving the highest dosage experienced a significant increase in reticulocyte percentage, mean corpuscular hemoglobin concentration, and liver mass, as well as inflammation of the gastrointestinal tract and lymphocyte proliferation in the spleen. However, we found no evidence of Heinz body formation based on both light and transmission electron microscopy. Although there was a tendency for packed cell volume and hemoglobin to decrease in birds from the high dose group compared to control and low dose groups, the changes were not statistically significant. Our results indicate that additional experimental dosing studies are needed to understand factors (e.g., dose- and species-specific sensitivity) and confounding variables (e.g., dispersants) that contribute to the presence and severity of anemia resulting from oil exposure in birds.

Observational studies have indicated that low-to-moderate exposure to cadmium (Cd), lead (Pb), and mercury (Hg) adversely affects birth anthropometry, but results are inconclusive. The aim of this study was to elucidate potential impact on birth anthropometry of exposure to Cd, Pb, and Hg in pregnant women, and to identify the main dietary sources. In the NICE (Nutritional impact on Immunological maturation during Childhood in relation to the Environment) birth-cohort in northern Sweden, blood and urine were collected from pregnant women in early third trimester. Cd, Pb and Hg were measured in erythrocytes (n = 584), and Cd also in urine (n = 581), by inductively coupled plasma mass spectrometry. Dietary data were collected through a semi-quantitative food frequency questionnaire administered in mid-third trimester. Birth anthropometry data were extracted from hospital records. In multivariable-adjusted spline regression models, a doubling of maternal erythrocyte Cd (median: 0.29 μg/kg) above the spline knot of 0.50 μg/kg was associated with reduced birth weight (B: −191 g; 95% CI: −315, −68) and length (−0.67 cm; −1.2, −0.14). The association with birth weight remained when the analysis was restricted to never-smokers. Likewise, a doubling of erythrocyte Hg (median 1.5 μg/kg, mainly MeHg) above 1.0 μg/kg, was associated with decreased birth weight (−59 g; −115, −3.0), and length (−0.29 cm; −0.54, −0.047). Maternal Pb (median 11 μg/kg) was unrelated to birth weight and length. Erythrocyte Cd was primarily associated with intake of plant derived foods, Pb with game meat, tea and coffee, and Hg with fish. The results indicated that low-level maternal Cd and Hg exposure were associated with poorer birth anthropometry. Further prospective studies in low-level exposed populations are warranted.

Nickel and cobalt are essential elements that become toxic at high concentrations. Little is known about nickel and cobalt toxicity in aquatic animals. This study aimed to investigate acute and chronic toxicity of nickel and cobalt in Japanese flounder (Paralichthys olivaceous), with emphasis on oxidative stress reactions, histopathological changes, and differences in gene expression. The lethal concentration for 50% mortality (LC₅₀) in 3 and 8 cm Japanese flounder exposed to nickel for 96 h was found to be 86.2 ± 0.018 and 151.3 ± 0.039 mg/L; for cobalt exposure, LC₅₀ was 47.5 ± 0.015 and 180.4 ± 0.034 mg/L, respectively. Chronic nickel and cobalt exposure caused different degrees of oxidative enzyme activity changes in gill, liver, and muscle tissues. Erythrocyte deformations were detected after acute or chronic exposure to nickel and cobalt. the nickel and cobalt exposure also caused pathological changes such as spherical swelling over other gill patches, rod-like proliferations in the gill patch epithelial cell layer, and disorder in hepatocyte arrangement, cell swelling, and cytoplasm loosening. RNA-Seq indicated that there were 184 upregulated and 185 downregulated genes in the liver of Japanese flounder exposed to 15 mg/L nickel for 28 d. For cobalt, 920 upregulated and 457 downregulated genes were detected. Among these differentially expressed genes, 162 were shared by both nickel and cobalt exposure. In both nickel and cobalt, pathways including fatty acid elongation, steroid biosynthesis, unsaturated fatty acid biosynthesis, fatty acid metabolism, PPAR signaling, and ferroptosis were significantly enriched. Taken together, these results aided our understanding of the toxicity of nickel and cobalt in aquatic animals.

The Mediterranean basin is a hotspot of mercury (Hg) contamination owing to intense anthropogenic emissions, volcanic activity and oligotrophic conditions. Little work has been done to assess the sources of Hg exposure for seabirds and, particularly, the physiological consequences of Hg bioaccumulation. In this study, we (i) describe the individual and temporal variation in blood concentration of total Hg (THg) over three breeding seasons, (ii) identify the factors that affect the THg exposure and (iii) determine the individual- and population-level connections between THg and blood-based markers of oxidative status in chicks of Scopoli’s shearwaters (Calonectris diomedea) breeding on the island of Linosa in the southern Mediterranean. We carried out the work on chicks near fledging because they are fed with prey captured near the colony, thus their Hg levels reflect local contamination. The concentration of THg in erythrocytes varied from 0.23 to 4.29 μg g⁻¹ dw. Chicks that were fed upon higher trophic level prey (i.e., higher δ¹⁵N values) had higher THg levels. Individual variation in THg concentrations was not explained by parental identity, sex nor δ¹³C values. There was significant variation in THg among chicks born from the same mother in different years. We found significant correlations between THg and markers of oxidative status; however, these correlations were no longer significant when we took into account the annual variation in mean values of all metrics. Males with higher values of body condition index had higher blood THg, while THg and body condition index were not correlated in females. Our data indicate that THg levels were moderate to high if compared to other seabirds. However, there is little evidence for harmful short-term detrimental effects owing to THg exposure.

The present experiment was conducted to explicate the genotoxic effects of profenofos, an organophosphate insecticide, on the erythrocytes of silver barb (Barbonymus gonionotus). Silver barb were exposed to a solution of 10% and 50% of lethal concentrations (LC₅₀) of profenofos as sub-lethal concentrations at different days (1, 7, 15, and 30 d), along with a control (0% profenofos). Subsequent recovery patterns were assessed allowing the fish exposed to profenofos free water for the same period that they were exposed to profenofos. Our results revealed that with the progression of time and concentration, fish exposed to profenofos showed significantly (p < .05) higher level of erythrocytic nuclear abnormalities (ENA) such as micronuclei, bi-nuclei, degenerated nuclei, notched nuclei, nuclear bridge and nuclear buds, as well as erythrocytic cellular abnormalities (ECA) such as echinocytic, elongated, fusion, spindle, tear-drop and twin shaped cells. After exposure, the silver barb recovered spontaneously, and the abnormal erythrocytic parameters were normalized with a concentration- and duration-dependent fashion. Therefore, these abnormalities and their recovery can be used to assess the toxic levels of pesticides on aquatic organisms. There is great potential to use this technique as in vivo to predict susceptibility of aquatic animals to environmental pollution.

Benzo[a]pyrene (BaP) is a bio-accumulative toxic compound found in the atmosphere, water, and soil that may affect the life cycle of amphibians. In this study, a few contamination biomarkers, such as hepatic melanomacrophages (MMs), mast cells, erythrocyte micronuclei (MN) and white blood cells were used to determine how BaP acts in these cells in the anurans Physalaemus cuvieri and Leptodactylus fuscus. Animals of both species were divided into three treatment groups: 1 day, 7 days and 13 days, subcutaneously injected 2 mg/kg BaP diluted in mineral oil and control group with only mineral oil. After 7 days, BaP caused the frequency of MN to increase in both species while reducing melanin area. The micronucleus frequency increased due to the genotoxicity of BaP, while the decreasing melanin area may be related to the inhibition of tyrosinase activity, an enzyme responsible for regulating melanogenesis, decreasing the synthesis of melanin. The mast cell density increased in all groups and in both species as a response to the inflammatory action of BaP. These cells respond to nonspecific inflammatory effects leading, therefore, to this response in all treatments. The percentage of leukocytes remained unchanged probably due to great intraspecific variability. Additionally, the leukocyte profiles of both species were characterized and the differences were attributed to extrinsic factors. In short, BaP can affect the integrity of several organs and tissues, and cell functions leading to the conclusion that this compound is hepatotoxic, genotoxic and immunotoxic for anurans.

Benzene is widely employed in the field of production, and its toxicity on biological systems has received increasing attention. Cell proliferation is a major life characteristic of living organisms. KLF15 and NOTCH1 are mature and classical genes in cell proliferation studies, particularly in the area of tumor investigation. The aim of this study was to investigate the effect and mechanism of VNN3 on cell proliferation induced by 1,4-benzoquinone (1,4-BQ), an important metabolite of benzene, and obtain a sensitive biomarker for the hazard screening and health care of benzene exposure. Normally growing AHH-1 cells were cultured in vitro and were incubated with different concentrations of 1,4-BQ (0, 10, 20, and 40 μM) for 24 h. A CCK-8 assay was used to assess the cell viability, whereas EdU was used to detect the cell proliferation of AHH-1 cells. The expression of VNN3, KLF15 and NOTCH1 was detected by real-time PCR. Moreover, a lentiviral model was constructed in AHH-1 cells to interfere with VNN3 expression. The results showed that 1,4-BQ clearly increased the expression of VNN3. Moreover, 1,4-BQ dose-dependently inhibited cell proliferation and caused increased KLF15 expression; in contrast, the NOTCH1 expression decreased in AHH-1 cells. Furthermore, following interference with the VNN3 expression, the cell proliferation inhibition and the expression of KLF15 and NOTCH1 were rescued. To further investigate the action of VNN3 in benzene hematotoxicity, we assessed it in benzene-exposed workers. The results showed that there was a remarkable correlation between the VNN3 expression and hemogram, which included RBC, NEUT and HGB. In addition, analysis of the KLF15 and NOTCH1 expression showed that the VNN3 expression was related to cell proliferation, which was consistent with the in vitro results. In conclusion, VNN3 influences cell proliferation induced by 1,4-BQ by regulating the expression of KLF15 and NOTCH1. VNN3 may represent a potential biomarker of benzene toxicity.

Metal exposure can produce oxidative stress by disrupting the prooxidant/antioxidant balance. It has been suggested that calcium (Ca) may provide protection against metal toxicity in the organism. The objective of this study is to explore the effects of Ca availability and metal pollution on oxidative stress biomarkers in pied flycatcher (Ficedula hypoleuca) nestlings. For this purpose, we performed a Ca-supplementation experiment with birds inhabiting a Ca-poor and metal-polluted area in SW Finland. An array of oxidative stress biomarkers (GSH, GSH:GSSG ratio, GPx, GST, CAT, SOD, lipid peroxidation and protein carbonylation) was measured in red blood cells. The effects of antioxidant molecules and oxidative damage on nestling size, growth, fledging success and fledgling number were evaluated. We observed an up-regulation of GST activity and increased protein carbonyl content in the polluted zone, probably related to a combination of higher metal exposure and reduced food quantity and quality in this area. As expected, birds from the unpolluted zone showed higher GSH:GSSG ratio but, unexpectedly, also showed signs of higher lipid peroxidation (not statistically significant, p = 0.056), both responses likely being related with the lower Ca availability. Our study suggests that different measures of oxidative damage are affected by different factors: while damage to proteins was the target of metal exposure/food limitation, poor Ca availability may enhance damage to lipids in growing birds. The intercorrelations found between Ca in plasma, metal exposure and the different oxidative stress biomarkers show that the antioxidant defense is finely regulated to cope with increased oxidative challenges. Finally, our results suggest that the antioxidant status during early development, conditioned by environmental pollution and Ca availability, is one factor affecting nestling survival and fledgling number.

The comparative accumulation of C₄–C₁₅ perfluorinated sulfonates (PFSAs) and carboxylates (PFCAs), and several precursors (e.g., perfluorooctane sulfonamide, N-methyl-FOSA, and fluorotelomer unsaturated acids and alcohols) was examined in tissues (liver, brain, muscle, and adipose), plasma/red blood cells (RBCs) and whole egg clutches (yolk and albumen) of female herring gulls collected in 2010 from Chantry Island, Lake Huron of the Laurentian Great Lakes. Highest mean ∑PFSA concentrations were in yolk, followed by adipose, liver, plasma, muscle, RBCs, and brain. Highest mean ∑PFCA concentrations were in yolk, followed by brain, plasma, liver, RBC, adipose and muscle. PFOS accounted for >88% of ∑PFSA in all samples; the liver, plasma/RBCs, muscle and adipose PFCA patterns were dominated by C₈–C₁₁ PFCAs, whereas C₁₀–C₁₅ PFCAs in brain and yolk. Among PFSAs and PFCAs there is tissue-specific accumulation, which could be due to a number of pharmacokinetic processes.

Because of its toxicity and its ubiquity within aquatic compartments, uranium (U) represents a significant hazard to aquatic species such as fish. In a previous study, we investigated some biological responses in zebrafish either exposed to depleted or to enriched U (i.e., to different radiological activities). However, results required further experiments to better understand biological responses. Moreover, we failed to clearly demonstrate a significant relationship between biological effects and U radiological activity. We therefore chose to herein examine U bioaccumulation and induced effects in zebrafish according to a chemical dose–response approach. Results showed that U is highly bioconcentrated in fish, according to a time- and concentration-dependent model. Additionally, hepatic antioxidant defenses, red blood cells DNA integrity and brain acetylcholinesterase activity were found to be significantly altered. Generally, the higher the U concentration, the sooner and/or the greater the effect, suggesting a close relationship between accumulation and effect.