Microcystin-leucine-arginine (MC-LR), as a most common and deleterious variant among all structural analogues of Microcystins (MCs), can cause male reproductive dysfunction. However, its toxic effects on prostate in adult mice have not been invested in detail. In this study, we observed that MC-LR could enter prostate tissues and induce focal hyperplasia and prostate inflammation. Moreover, increased levels of prostate specific antigen (PSA) and prostate acid phosphatase (PAP) in serum of mice following chronic exposure to MC-LR were detected. We also examined increased expression of forkhead box protein M1 (FOXM1) and PSA in human prostate epithelial cells (RWPE-1) treated with MC-LR at low levels, and FOXM1 could regulate PSA expression. Furthermore, MC-LR also induced expression of CyclinD1 via FOXM1/Wnt/β-catenin signaling pathways in RWPE-1 cells, promoting proliferation of prostate epithelial cells, resulting in prostatic hyperplasia in vivo. As a foreign substance, MC-LR also induced immune reaction in RWPE-1 cells mediated by NF-κB pathway, promoting production of pro-inflammatory cytokines and chemokines. Collectively, these findings demonstrated that MC-LR may induce prostatic hyperplasia and prostatitis in mice following chronic low-dose exposure to MC-LR. This work may provide new perspectives in developing new diagnosis and treatment strategies for MC-LR-induced prostatic toxicity.

Recently, health damage to children exposed to synthetic polyurethane (PU) running tracks has aroused social panic in China. Some possible toxic volatiles may be responsible for these damages. However, the exact cause remains unclear. We have detected a low concentration of sulfur dioxide (SO₂; 1.80–3.30 mg/m³) on the surface of the PU running track. Surprisingly, we found that SO₂ was generated from the PU running track, and even such a low concentration of SO₂ could induce severe lung inflammation with hemorrhage, inflammatory cell infiltration, and inflammatory factor secretion in mice after 2-week exposure. Prolonged exposure (5 weeks) to the SO₂ caused chronic pulmonary inflammation and pulmonary fibrosis in the mice. Peripheral hemogram results showed that platelet concentration increased significantly in the SO₂ group compared to that in the control group, and the proportion of blood neutrophils and monocytes among total leukocytes was more imbalanced in the SO₂ group (16.6%) than in the control group (8.0%). Further histopathology results of sternal marrow demonstrated that hematopoietic hyperplasia was severely suppressed with increased reticular stroma and adipocytes under SO₂ exposure. These data indicate that a low concentration of SO₂ generated spontaneously from PU running track outdoors as a secondary product is still harmful to health, as it impairs the respiratory system, hematopoiesis, and immunologic function. This indicates that the low-concentration SO₂ could be a major cause of diseases induced by air pollution, such as chronic obstructive pulmonary disease.

This paper is a part of a multi-disciplinary research “Application of Decentralized On-Site Water Treatment System in Egypt for Use in Agriculture and Producing Safe Fish and Animal Proteins”.The project aimed to investigate the environmental impact of implementing sewage water before and after treatment using the effluent of the on-site decentralized Japanese' Johkasou system, in agriculture and producing fish protein. The aim is to establish such system in Egypt to strengthen the sanitary conditions of water resources. In the present study, the impact of the sewage pollution in some fish farms at El-Fayyum, Port Said and El-Dakahlia governorates in Egypt was carried out. Water and fish (Oreochromis niloticus and Mugil cephalus) samples were collected from private fish farms of such localities. Bacteriological and chemical examination of water samples revealed the existence of coliforms and many other bacterial species of significant human health hazards. The chemical parameters of water showed a marked deviation from normal levels while examination of fish flesh specimens indicated contamination with Streptococcus Sp., Staphylococcus Sp., and Salmonella in all examined localities. Other bacterial isolates of human health importance (Morganella morganii, Pseudomonas cepacia and Enterococcos durans) were identified. The parasitological examination revealed the presence of encysted metacercariae (EMC); Diplostomatidae, Prohemistomatidae and Heterphyidae. Moreover, two protozoan parasites (Mxyoboulus tilapiae and Ichthyophthirius multifilis) were also recorded. The histopathological examination revealed mild tissue reaction in case of bacterial infection and severe pathological lesions in different organs in case of EMC infection. Lamellar hyperplasia and mononuclear cell infiltration in branchial tissue was common findings. In skeletal muscles, atrophy of muscle fibres, myolysis and myophagia were detected.

Soil contaminants can cause direct harm to lizards due to their regular swallowing of soil particles. As the world’s fastest growing insecticide with long half-life in soil, the endocrine disrupting effect of neonicotinoids on lizards deserves more attention. In this report, we assessed the endocrine disrupting effect of imidacloprid on Eremias argus during 28 days of continuous exposure. Among the imidacloprid and its metabolites, only the metabolite 6-chloropyridic acid had a significant accumulation in the gonads and was positively correlated with its blood concentration. Imidacloprid might cause endocrine disrupting effects on lizards in two ways. First, the desnitro metabolites of imidacloprid could accumulate in the brain, inhibited the secretion of gonadotropin-releasing hormone, and ultimately affected the feedback regulation of hypothalamic-pituitary-gonadal related hormones. Secondly, imidacloprid severely inhibited the gene expression of the corresponding enzymes in the gonadal anti-oxidative stress system, causing histological damage to the gonads and ultimately affecting gonadal function. Specifically, exposure to imidacloprid resulted in abnormal arrangement of spermatogenic epithelial epithelium, hyperplasia of epididymal wall, and oligospermia of male lizard. Meanwhile, gene expressions of cyp17, cyp19, and hsd17β were severely inhibited in the imidacloprid exposure group, consistent with decreased levels of testosterone and estradiol in plasma. Imidacloprid exposure could cause insufficient androgen secretion and less spermatogenesis in male lizards. The risk of imidacloprid exposure to female lizards was not as severe as that of male lizards, but it still inhibited the expression of cyp19 in the ovaries and led to a decrease in the synthesis of estradiol. This study firstly reported the endocrine disruption of imidacloprid to lizards, providing new data for limiting the use of neonicotinoids.

Novel brominated flame retardants (NBFRs) are now ubiquitous in the environment with the extensive production and application. In the present study, pentabromotoluene (PBT), hexabromobenzene (HBB) and decabromodiphenyl ethane (DBDPE) were spiked into the sediments where mudsnails (Bellamya aeruginosa) were cultivated. In the 35-day enrichment process, the highest concentration of the three NBFRs measured in mudsnail is 2.0 mg/kg, 22 mg/kg and 5.2 mg/kg dry weight (dw), respectively. The average enrichment of NBFRs in viscera was about 3 times of pleopod with the same mass. Meanwhile, the parent mudsnails can transfer NBFRs to their offspring. The removal half-life of the three NBFRs was in the range of 2.6 and 5.7 days according to the first-order kinetic equation. Several degradation products of the NBFRs were detected in mudsnail samples, which were exposed to single substance. 2,4,6-tribromotoluene was identified as degradation product of PBT; 1,2,4,5-tetrabromobenzene and 1,2,4-tribromobenzene were identified as debromination products of HBB. Possible degradation pathways were further proposed. Additionally, mudsnails after exposed to 50 mg/kg of NBFRs were observed under a scanning electron microscope, indicating that shrinkage, tissue hyperplasia and perforation occurred on the visceral surface. Such damage might be related to the accumulation of more pollutants in mudsnails viscera. As one of the few studies to explore the biological process of NBFRs, our observation could provide a scientific basis for evaluating the environmental risks of NBFRs to benthic organisms.

To examine the effects of BaP on tissue apoptosis, laboratory studies were conducted using juvenile Chinese rare minnows (Gobiocypris rarus) exposed to 1, 5, 20, and 80 μg/L of BaP for 28 days. The post-treatment pathological findings in the liver were associated with hepatocyte swelling, karyopyknosis, and karyorrhexis. Moreover, an increase in the goblet cells in the intestine, epithelial hyperplasia of the gills and fusion of gill lamellae were observed. Significant increases in hepatocyte apoptosis using the TUNEL stain were observed in the liver tissue but not in the intestine and gills. In addition, BaP exposure significantly up-regulated the mRNA levels of cyp1a1, p53, bax, bcl-2, and caspase-9 in the liver following the 5, 20, and 80 μg/L treatments, whereas the apaf-1 was significantly down-regulated following all treatments. Moreover, the activities of caspase 3 and caspase 8 were markedly elevated, whereas the protein expression levels of Apaf-1 were down-regulated following the 20 and 80 μg/L treatments. Taken together, our results suggested that BaP strongly induces tissue-specific apoptosis in vivo, leading to significant pathological changes. The responsiveness of apoptotic-related genes demonstrates that BaP induced apoptosis in the liver may be through a mitochondria-independent pathway.

Tributyltin is a biocide used in nautical paints, aiming to reduce fouling of barnacles in ships. Despite the fact that many effects of TBT on marine species are known, studies in mammals have been limited, especially those evaluating its effect on the function of the hypothalamus-pituitary-thyroid (HPT) axis. The aim of this study was to investigate the effects of subchronic exposure to TBT on the HPT axis in female rats. Female Wistar rats received vehicle, TBT 200 ng kg−1 BW d−1 or 1000 ng kg−1 BW d−1 orally by gavage for 40 d. Hypothalamus, pituitary, thyroid, liver and blood samples were collected. TBT200 and TBT1000 thyroids showed vacuolated follicular cells, with follicular hypertrophy and hyperplasia. An increase in epithelial height and a decrease in the thyroid follicle and colloid area were observed in TBT1000 rats. Moreover, an increase in the epithelium/colloid area ratio was observed in both TBT groups. Lower TRH mRNA expression was observed in the hypothalami of TBT200 and TBT1000 rats. An increase in Dio1 mRNA levels was observed in the hypothalamus and thyroid in TBT1000 rats only. TSH serum levels were increased in TBT200 rats. In TBT1000 rats, there was a decrease in total T4 serum levels compared to control rats, whereas T3 serum levels did not show significant alterations. We conclude that TBT exposure can promote critical abnormalities in the HPT axis, including changes in TRH mRNA expression and serum TSH and T4 levels, in addition to affecting thyroid morphology. These findings demonstrate that TBT disrupts the HPT axis. Additionally, the changes found in thyroid hormones suggest that TBT may interfere with the peripheral metabolism of these hormones, an idea corroborated by the observed changes in Dio1 mRNA levels. Therefore, TBT exposition might interfere not only with the thyroid axis but also with thyroid hormone metabolism.

The aim of this study was to assess the impact of treated wastewaters on native wild Prussian carp inhabiting effluent-receiving waters (ERC) receiving municipal and sugar plant treated wastewaters, further downstream waters (DW), and a detached canal unaffected by the WWTP activities. To that end, general fish health status was determined, including plasma biochemical, haematological, oxidative stress and tissue histopathological indices, over three seasons. The greatest tissue alterations were in fall in ERC during sugar beet processing, as hypertrophy of gill epithelial and interlamellar cells, necrosis and lymphocytic infiltration, hyperplasia and hypertrophy of renal tubules, distention of hepatic sinusoids. In fall the lowest leukocytes, lymphocytes and granulocytes (2467 ± 565, 1333 ± 264, 1133 ± 488 cells/μL respectively), as well as highest plasma ALP (52.7 ± 19.39 U/L) were measured. ERC in fall had the highest ammonium (20 mg/L), nitrite (1.48 mg/L), nitrate (13.4 mg/L), and lowest dissolved O2 (1.23 mg/L). Gill, kidney and liver alterations, and the highest plasma cholesterol (9.1 ± 1.98 mmol/L) were noted in DW fish in fall. Tissue morphology during sugar cane processing seems a consequence of cellular and structural tissue integrity loss. Structural heterogeneity of gills and spleen was enhanced with increasing concentrations of heavy metals and correlated with oxidative stress (SOD 392.5 ± 77.28 U/L). Monogenean infestation was moderate in ERC fish in all seasons compared with DW fish. Prussian carp biological responses to multiple stressors, measured by the effects of WWTP on blood and tissue parameters, reached far downstream and were not of localized nature. This study demonstrated that in aquatic environments impacted with complex contaminants acting synergistically, causal relationships between biological responses and environmental stressors should be interpreted. Integrated histopathological, haematological and biochemical findings are valuable biomarkers for native fish adaptive patterns and monitoring of water quality/pollution of freshwater ecosystems.

Quantum dots (QDs) have strong adsorption capacity; therefore, their potential toxicity of the facilitated transport of other trace toxic pollutants when they co-exist to aquatic organisms has become a hot research topic. The lab study was performed to determine the developmental toxicities to the zebrafish after exposed to the combined pollution of Cadmium-telluride (CdTe) QDs and copper ion (Cu2+) compared to the single exposure. Our findings for the first time revealed that: 1) CdTe QDs facilitated the accumulation of Cu2+ in zebrafish, 2) the higher mortality, lower hatch rate, and more malformations can be clearly observed, 3) the diverse vascular hyperplasia, turbulence, and bifurcation of the exposed FLI-1 transgenic zebrafish larvae appeared together, 4) the synergistic effects played more important role during joint exposure. These observations provide a basic understanding of CdTe QDs and Cu2+ joint toxicity to aquatic organisms.

Metals, whether essential (Cu, Zn, Cr, Fe, Mn) or non-essential (Al, As, Cd, Ni, Pb, Hg) for organism metabolism, occur naturally in the marine environment and their abundance can increase due to the presence of human activities. In this study, fish were used as bio-indicators, to determine a correlation between the bio-accumulation of metals in muscle and gill tissues and the health status of fish. The study area was the Gulf of Tigullio (north-western Italy), which is impacted by various sources of metal contamination. Histopathology served as a significant tool to investigate possible alterations in gills, one of the main organs involved in fish physiology. Results highlighted some correlations between certain metals (e.g. Pb, Ni) and gill alterations (e.g. epithelial hyperplasia, epithelial lifting), providing baseline data from a pool of different fish species, which can be used for comparison purposes in further studies.