Hepatotoxic responses of 4-nonylphenol on African catfish (Clarias gariepinus): antixoidant and histochemical biomarkers

Toxicogenomic profiling of endocrine disruptor 4-Nonylphenol in male catfish Heteropneustes fossilis with respect to gonads

Toxicogenomics study reveals information of gene activity and proteins within the particular cells or tissue of an organism in response to toxic substances. 4-Nonylphenol is a potent environmental contaminant and endocrine disruptor. This study elucidates the toxic and xeno-estrogenic effect of 4-Nonylphenol from the cellular level to the gene level by in vivo and in silico approach. In vivo, studies show that exposure of 4-Nonylphenol at a low dose 64µgL- 1 and a high dose of 160µgL- 1 for 30 days to 60 days of duration during pre-spawning to the spawning period in testes of Heteropneustes fossilis causes cellular level toxicity i.e., dose and duration dependent clumping of spermatocytes. Dose and duration-dependent decrease in superoxide dismutase(SOD), Catalase, glutathione peroxidase(GPx) and increase in lipid peroxidase (LPO) level in testes. There was a dose and duration-dependent decrease in total antioxidant status and increased level of total oxidant status in the testicular tissue of H. fossilis along with an increase in cortisol level 0.4-NP caused alteration in antioxidant enzyme levels impedes the first line of defense mechanism in the body of an organism. There was a dose-dependent increase in necrosis percentage in testicular cells, cell death, and an increase in total ROS (reactive oxygen species) in a dose-dependent manner in testicular cells of H. fossilis. 4-NP causes gene level toxicity i.e., increased DNA migration or DNA fragmentation. Upregulation of gene expression of gonadal aromatase (CYP19a1a) and downregulation of the 3-beta-hydroxysteroid dehydrogenase (3-β HSD) gene in testes were observed. In silico studies also confirmed the interacting potency of 4-NP with steroid enzyme 3- β HSD and CYP19a1a. Present investigations shows that exposure to water bodies contaminated with xenoestrogens like 4-NP has significantly reduced reproductive parameters like fertilization, fecundity, hatching, and larval survival in numerous fish species.4-NP causes alteration in gene expression of the proteins which are very crucial for reproduction and maintenance of maleness. Due to chronic exposure to 4-NP, it becomes a toxicant causing tissue cell death. So, the harmful impact of 4-NP on reproduction in teleost fish is concerning, not just for the fish themselves but for the entire ecosystem. Therefore, efforts should be made to reduce the contamination of water bodies with xenoestrogens.

Maternal exposure to chronic, low-dose nonylphenol in zebrafish: Disruption of ovarian health, reproductive function, and embryogenesis

Nonylphenol (NP), a non-ionic surfactant and potent endocrine disruptor, is known for its environmental persistence, biotic accumulation potential and toxicity. Nonetheless, mechanisms underlying NP modulation of female fertility with potential impact on embryogenesis in the unexposed offspring remain elusive. This study investigates the effects and toxic mechanisms of maternal exposure to NP at varying concentrations (50 and 100 μg/L) on zebrafish (Danio rerio), specifically focusing on ovarian health, reproductive parameters, and early developmental potential in the F1 generation. Our findings indicate a higher accumulation of NP in the ovaries compared to muscle tissue. Further, chronic (28 days) NP exposure promotes ovarian reactive oxygen species (ROS) accumulation, activates the MAPK (JNK, p38 MAPK, ERK1/2) pathways, AP-1 induction, and elevated expression of pro-inflammatory cytokines (Tnf-α, Il-1β, Il-6) triggering inflammation. Besides, heightened follicular atresia in NP-treated ovaries relates to increased Bax/Bcl2 ratio, cleaved caspase 3 and Parp1 activation prompting apoptosis. While it showed higher affinity to zebrafish ERα (in silico analysis), NP exposure in vivo promotes a robust increase in ovarian ERα but abrogated ERβ expression and a significant alteration in fshr and lhcgr transcripts. While attenuated StAR and P450 aromatase expression at both mRNA and protein levels and reduced igf3 expression reveal impaired ovarian microenvironment, NP-induced dysregulated NO/NOS/cyclooxygenase signaling and attenuation of hCG-induced p34cdc2 activation and oocyte maturation correspond well with decreased fecundity and fertilization efficiency. Intriguingly, maternal exposure to NP resulted in delayed embryogenesis, developmental aberrations, and reduced hatching rates in the unexposed offspring, risking F1 generation. Collectively, this study provides mechanistic insights into the detrimental influence of maternal exposure to NP on ovarian dysfunction, reproductive insufficiency and embryotoxicity.

Prefeeding of Clarias gariepinus with Spirulina platensis counteracts petroleum hydrocarbons-induced hepato- and nephrotoxicity

Petroleum aromatic hydrocarbons are considered one of the most dangerous aquatic pollutants due to their widespread across water bodies, persistence, and extension to the food chain. To our knowledge, there hasn't been any research investigating the hepatorenoprotective effects of Spirulina platensis (SP) against toxicity induced by these environmental toxicants in fish. Thus, we decided to explore its potential safeguarding against benzene and toluene exposure in adult Clarias gariepinus. To achieve this objective, fish were divided into five groups (60 per group; 20 per replicate). The first group served as a control. The second and third groups were intoxicated with benzene and toluene at doses of 0.762 and 26.614 ng/L, respectively for 15 days. The fourth and fifth groups (SP + benzene and SP + toluene, respectively) were challenged with benzene and toluene as previously mentioned following dietary inclusion of SP at a dose of 5 g/kg diet for 30 days. The marked increase in liver metabolizing enzymes, glucose, total protein, albumin, globulin, albumin/globulin ratio, and creatinine confirmed the hepato- and nephrotoxic impacts of benzene and toluene. These outcomes were coupled with cytopathological affections and excessive collagen deposition. The incorporation of SP in ration formulation, on the contrary, restored the previously mentioned toxicological profile due to its antioxidant and cytoprotective attributes. Regardless of SP intervention, the renal tissues still displayed histo-architectural lesions, because of insufficient dose and timeframe. Additional research will be required to identify the ideal SP remediation regimen.

Gallic acid rescues uranyl acetate induced-hepatic dysfunction in rats by its antioxidant and cytoprotective potentials

BACKGROUND

The liver was identified as a primary target organ for the chemo-radiological effects of uranyl acetate (UA). Although the anti-oxidant and anti-apoptotic properties of gallic acid (GA) make it a promising phytochemical to resist its hazards, there is no available data in this area of research.

METHODS

To address this issue, eighteen rats were randomly and equally divided into three groups. One group was received carboxymethyl cellulose (vehicle of GA) and kept as a control. The UA group was injected intraperitoneally with UA at a single dose of 5 mg/kg body weight. The third group (GA + UA group) was treated with GA orally at a dose of 100 mg/kg body weight for 14 days before UA exposure. UA was injected on the 15th day of the experiment in either the UA group or the GA + UA group. The biochemical, histological, and immunohistochemical findings in the GA + UA group were compared to both control and UA groups.

RESULTS

The results showed that UA exposure led to a range of adverse effects. These included elevated plasma levels of aspartate aminotransferase, lactate dehydrogenase, total protein, globulin, glucose, total cholesterol, triglycerides, low-density lipoprotein cholesterol, and very-low-density lipoprotein and decreased plasma levels of high-density lipoprotein cholesterol. The exposure also disrupted the redox balance, evident through decreased plasma total antioxidant capacity and hepatic nitric oxide, superoxide dismutase, reduced glutathione, glutathione-S-transferase, glutathione reductase, and glutathione peroxidase and increased hepatic oxidized glutathione and malondialdehyde. Plasma levels of albumin and alanine aminotransferase did not significantly change in all groups. Histopathological analysis revealed damage to liver tissue, characterized by deteriorations in tissue structure, excessive collagen accumulation, and depletion of glycogen. Furthermore, UA exposure up-regulated the immuno-expression of cleaved caspase-3 and down-regulated the immuno-expression of nuclear factor-erythroid-2-related factor 2 in hepatic tissues, indicating an induction of apoptosis and oxidative stress response. However, the pre-treatment with GA proved to be effective in mitigating these negative effects induced by UA exposure, except for the disturbances in the lipid profile.

CONCLUSIONS

The study suggests that GA has the potential to act as a protective agent against the adverse effects of UA exposure on the liver. Its ability to restore redox balance and inhibit apoptosis makes it a promising candidate for countering the harmful effects of chemo-radiological agents such as UA.

Neurotoxicity of 4-nonylphenol in adult zebrafish: Evaluation of behaviour, oxidative stress parameters and histopathology of brain

Nonylphenol and its derivatives use as plasticizer or additives in manufacturing industries. Effluents originated from industrial areas are being added to soil, ground water, river and marine water intentionally or unintentionally. Complex mixture of these contaminants enter the food chain and produce sub-lethal deleterious effects mainly on nervous and reproductive systems of aquatic animals and human beings. The information pertaining to oxidative stress-mediated alterations in brain of zebrafish would be helpful to understand the toxicity potential of such compounds in aquatic animals. The aim of the present study was to evaluate the behavioural changes, status of oxidative stress markers; sod, cat, and NF-E2-related factor 2 (nrf2) mRNA gene expression profile; and histopathological changes in the brain of adult zebrafish exposed to 4-nonylphenol (4NP) at concentration of 100 and 200 μg/L of water for 21 days. Zebrafish were divided into four groups viz; control (C1), vehicle (C2, ethanol 10 μg/L of water), treatment 1 (T1, 4-NP, 100 μg/L) and treatment 2 (T2, 4-NP, 200 μg/L). Both exposure levels of 4-NP adversely affected the exploratory behaviour of zebrafish and produced anxiety-like symptom. Concentration-dependent reduction in activity of superoxide dismutase and catalase; and glutathione level, with increased level of malondialdehyde recorded in the brain of exposed zebrafish. Gene expression analysis showed down regulation of sod, cat, nrf2 genes in brain of zebrafish from toxicity groups indicating 4-NP induced oxidative stress in brain. However, noticeable histological alterations were not observed in 4-NP exposed brain of zebrafish.

Impact of porous microsponges in minimizing myotoxic side effects of simvastatin

Simvastatin (SV) is a poorly soluble drug; its oral administration is associated with a significant problem: Myopathy. The present study aims to formulate SV microsponges that have the potential to minimize the myotoxicity accompanying the oral administration of the drug. SV microsponges were prepared by exploiting the emulsion solvent evaporation technique. The % entrapment efficiency (%EE) of the drug approached 82.54 ± 1.27%, the mean particle size of SV microsponges ranged from 53.80 ± 6.35 to 86.03 ± 4.79 µm in diameter, and the % cumulative drug release (%CDR) of SV from microsponges was significantly higher than that from free drug dispersion much more, the specific surface area of the optimized microsponges formulation was found to be 16.6 m²/g revealed the porosity of prepared microsponges. Histological and glycogen histochemical studies in the skeletal muscles of male albino rats revealed that microsponges were safer than free SV in minimizing myotoxicity. These findings were proven by Gene expression of Mitochondrial fusion and fission (Mfn1) & (Fis1) and (Peroxisome proliferator-activated receptor gamma co-activator 1α) PGC-1α. Finally, our study ascertained that SV microsponges significantly decreased the myotoxicity of SV.

Nigella sativa seeds mitigate the hepatic histo-architectural and ultrastructural changes induced by 4-nonylphenol in Clarias gariepinus

Due to its prevalence in aquatic environments and potential cytotoxicity, 4-nonylphenol (4-NP) has garnered considerable attention. As a medicinal plant with numerous biological activities, Nigella sativa (black seed or black cumin) seed (NSS) is widely utilized throughout the world. Consequently, this study aimed to examine the potential protective effects of NSS against 4-NP-induced hepatotoxicity in African catfish (Clarias gariepinus). To achieve this objective, 18 fish (351 ± 3 g) were randomly divided into three equal groups for 21 days. The first group serves as a control which did not receive any treatment except the basal diet. The second and third groups were exposed to 4-NP at a dose of 0.1 mg L-1 of aquarium water and fed a basal diet only or supplemented with 2.5% NSS, respectively. The histological, histochemical, and ultrastructural features of the liver were subsequently evaluated as a damage biomarker of the hepatic tissue. Our results confirmed that 4-NP was a potent hepatotoxic agent, as 4-NP-intoxicated fish exhibited many lesions. Steatohepatitis, ballooning degeneration, sclerosing cholangitis, and coagulative necrosis of melanomacrophagecenters (MMCs) were observed. Hemosiderin, lipofuscin pigments, and proliferation of fibroblasts, kupffer cells, and telocytes were also demonstrated in the livers of 4-NP-intoxicated fish. In addition, decreased glycogen content and increased collagen deposition were observed in the hepatic tissue. Hepatocytes exhibited ultrastructural alterations in the chromatin, rough endoplasmic reticulum, smooth endoplasmic reticulum, mitochondria, lysosomes, and peroxisomes. Co-administration of 2.5% NSS to 4-NP-intoxicated fish significantly reduced these hepatotoxic effects. It nearly preserved the histological, histochemical, and ultrastructural integrity of hepatic tissue.

The effect of nonylphenol exposure on the stimulation of melanomacrophage centers, estrogen and testosterone level, and ERα gene expression in goldfish

The present study tried to measure the formation of melanomacrophage centers (MMCs) in various organs of male and female goldfish exposed to nonylphenol (NP) and aimed to assess its relationship with the main sexual hormones, estrogen receptor expression, and the pigment content of the MMCs. Immature goldfish were exposed to 10^-6 and 10^-7 M NP for 25 days. After obtaining blood for measuring testosterone and estrogen (E2) levels, tissue samples were collected from various organs for histological studies, quantifying pigments using ImageJ software and chemical analysis, and measuring ERα gene expression. Results showed that the order of forming MMCs in various organs exposed to NP was liver > spleen > kidney, and the order of ERα gene expression was liver > testes > spleen > kidney in the male, and liver > spleen > kidney > ovaries in the female. Among the three pigments present in MMCs after exposure to the two doses of NP, melanin was more obvious (especially in the liver) and increased mostly in a dose-dependent manner in both sexes (especially in the male). Chemical analyses confirmed these results. Measurement of testosterone and E2 level in male and female goldfish showed that NP had more effect on the concentration of these hormones in male fish, indicating more endocrine-disrupting potential of NP against the male fish. Generally, the increase of melanin content of melanomacrophage centers coincided with the increase of ERα gene expression and decrease of testosterone level in goldfish after exposure to NP.

The protective role of lycopene against toxic effects induced by the herbicide Harness® and its active ingredient acetochlor on the African catfish Clarias gariepinus (Burchell, 1822)

The effects of Harness® toxicity on fish health are little known. So, current work aimed to study the impact of sub-lethal doses of Harness® (an acetochlor-based herbicide) on the African catfish, Clarias gariepinus, and also investigated the potential role of lycopene (LYCO) administration in alleviating Harness® negative effects. Fish were divided into five groups in triplicates as follows: group 1 (control) received no treatment, group 2 was exposed to 10 μm Harness®/L, group 3 was orally administered 10 mg LYCO/kg body weight and exposed to 10 μm Harness®/L, group 4 was exposed to 100 μm Harness®/L, and group 5 was orally administered 10 mg LYCO/kg body weight and exposed to 100 μm Harness®/L for 2 weeks. Some hemato-biochemical parameters, genotoxicity, and histopathological changes were assessed at the end of this period. Sub-lethal doses of Harness® altered the shape of erythrocytes in contrast to the control sample. Also, hematological parameters of exposed fish exhibited a significant (P < 0.05) reduction in the values of red blood cell count (RBCs), hemoglobin (Hb), hematocrit (HCT), and platelets (PL), as well as an insignificant (P > 0.05) drop in mean corpuscular volume (MCV). Harness® was also found to cause genotoxicity as well as histopathological alterations. LYCO administration decreased hemato-biochemical changes and returned them to near-normal levels. The findings showed that LYCO administration (10 mg LYCO/kg body weight) decreased Harness® toxicity in C. gariepinus and alleviated its destructive effects.

Chronic exposure to nonylphenol induces oxidative stress and liver damage in male zebrafish (Danio rerio): Mechanistic insight into cellular energy sensors, lipid accumulation and immune modulation

Nonylphenol (NP), an environmentally persistent and toxic endocrine-disrupting chemical with estrogenic properties, has severe implications on humans and wildlife. Accumulating evidence demonstrates the toxic response of NP on the developmental process, nervous system, and reproductive parameters. Although NP exposure has been implicated in chronic liver injury, the underlying events associated with hepatic pathophysiology remain less investigated. Using male zebrafish (Danio rerio) as the model, the present study investigates the impact of environmentally relevant concentrations of NP (50 and 100 μg/L, 21 days) on hepatic redox homeostasis vis-à-vis cellular energy sensors, inflammatory response, and cell death involving a mechanistic insight into estrogen receptor (ER) modulation. Our results demonstrate that congruent with significant alteration in transcript abundance of antioxidant enzymes (SOD1, SOD2, Catalase, GPx1a, GSTα1), chronic exposure to NP promotes ROS synthesis, more specifically superoxide anions and H₂O₂ levels, and lipid peroxidation potentially through elevated NOX4 expression. Importantly, NP perturbation of markers associated with fatty acid biosynthesis (srebf1/fasn) and cellular energy-sensing network (sirt1/ampkα/pgc1α) indicates dysregulated energy homeostasis, metabolic disruption, and macrovesicular steatosis, albeit with differential sensitivity at the dose level tested. Besides, elevated p38-MAPK phosphorylation (activation) together with loss of ER homeostasis at both mRNA (esr1, esr2a, esr2b) and protein (ERα, ERβ) levels suggest that NP modulation of ER abundance may have a significant influence on hepatic events. Elevated expression of inflammatory markers (TLR4, p-NF-κB, TNF-α, IL-6, IL-1β, and NOS2) and pro-apoptotic and necrotic regulators, e.g., Bax, caspase- 8, -9 and cleaved PARP1 (50 kDa), indicate chronic inflammation and hepatotoxicity in NP-exposed males. Collectively, elevated oxidative stress, metabolic dysregulation and immune modulation may lead to chronic liver injury in organisms exposed to metabolic disrupting chemicals.

Nonylphenol and cyproterone acetate effects in the liver and gonads of Lithobates catesbeianus (Anura) tadpoles and juveniles

Environmental pollution plays an important role in amphibian population decline. Contamination with endocrine disrupting chemicals (EDCs) is particularly worrying due to their capacity to adversely affect organisms at low doses. We hypothesized that exposure to EDCs such as 4-nonylphenol (NP) and cyproterone acetate (CPA) could trigger responses in the liver and gonads, due to toxic and endocrine disrupting effects. Growth rate may also be impaired by contamination. We investigated sublethal effects of a 28-day exposure to three different concentrations of NP and CPA on liver pigmentation, gonadal morphology, body mass, and length of tadpoles and juveniles Lithobates catesbeianus. Liver pigmentation and the gonadal morphologies of treated tadpoles did not differ from control, but growth rate was impaired by both pollutants. Juveniles treated with 10 μg/L NP and 0.025 and 0.25 ng/L CPA displayed increased liver melanin pigmentation, but gonadal morphologies, sex ratios, and body mass were not affected after treatments. The increase in liver pigmentation may be related to defensive, cytoprotective role of melanomacrophages. The decreased growth rate in tadpoles indicates toxic effects of NP and CPA. Thus, contamination with NP and CPA remains a concern and sublethal effects of different dosages of the compounds on native species should be determined.

Multigenerational reproduction and developmental toxicity, and HPG axis gene expression study on environmentally-relevant concentrations of nonylphenol in zebrafish

Nonylphenol (NP) is a toxic xenobiotic compound, which is persistent in the aquatic environment and is extremely toxic to aquatic organisms. Although the exact molecular mechanisms of its toxic effect are well understood, the multigenerational reproduction and multigenerational - gene expression changes caused by NP still remain unclear. The following work investigated the effect of NP on four consecutive generations of zebrafish by examining their growth and several reproductive parameters, the degree of gonad damage, and the expression of related reproduction related genes. The results showed that high concentrations (20 and 200 μg·L^-1) of NP could decrease growth and induce gonad damage in zebrafish. In addition, gnrh2 and gnrh3 genes were up-regulated, and fshβ and lhβ genes were downregulated in the hypothalamus in male zebrafish; while in female fish, the fshβ and lhβ were upregulated in P and F1 generations, and then down-regulated in the F2 generation. Meanwhile, the cyp19a1a gene was downregulated in the gonad of male fish, while the genes of fshr, lhr and esr showed a downward trend in females. Compared to P generation, F2 generation was more tolerant to higher NP concentrations (20 and 200 μg·L^-1), as was also more sensitive to lower concentrations of NP (2 μg·L^-1). Consequently, stress and damage caused by environmentally-relevant concentrations of aquatic pollutants in a vertebrate model were measured and predicted. Prevention and control measures can be actively and effectively proposed, which might be transversal to other exposed organisms, including humans. After several generations, typical transgenerational genetic phenomena might occur, which should be addressed by further studies.

Broiler welfare is preserved by long-term low-dose oral exposure to zinc oxide nanoparticles: preliminary study

The potential public health risk through utilizing of zinc oxide nanoparticles (ZnO NPs) in food constitutes the major obstacle to the expansion of nanoparticle (NP) in food industry. Liver histology, bone marrow and liver genotoxicity, immunity, and oxidant status were investigated upon long-term ZnO NPs feed supplementation. One hundred and sixty male IR (Indian River) chicks were randomly allocated to one of the four dietary treatments: control, ZnO NPs at 10, 20, or 40 mg/kg for 42 days. This study revealed non-significant hepatic histopathological alterations and DNA damage and the treatment had no influence on body and organ weights, liver enzymes, lipid peroxidation (MDA), IgG, IgM, and interferon gamma (IFN-γ). This study suggests that low-dose (< 40 mg/kg diet) long-term ZnO NPs supplementation to broiler chicks has no observed potential adverse effects on normal histology of the liver, blood physiology, immune system, and DNA damage of liver and bone marrows, which are critical features for validating ZnO NPs for use in food. Further studies are required to evaluate the probable withdrawal period of ZnO NPs before approval as a dietary supplement in broiler or livestock diets.

Cytoprotective effect of Nigella sativa seed on 4-nonylphenol-induced renal damage in the African catfish (Clarias gariepinus)

4-Nonylphenol (4-NP) is a nephrotoxic substance that is highly prevalent in aquatic environments. Nigella sativa seed (NSS) has many biological activities and is widely used throughout the world as a medicinal product. Therefore, in the present study, we investigated the cytoprotective effect of NSS on 4-NP-induced renal damage in African catfish (Clarias gariepinus). Thirty fish were divided into five equal groups: an untreated control group and four groups that were challenged with 4-NP at a dose of 0.1 mg L-1 of aquarium water and fed a basal diet supplemented with 0%, 1%, 2.5%, and 5% NSS, respectively, for 3 weeks. Histological, histochemical, and ultrastructural features of the kidney were then assessed as biomarkers for renal tissue damage. Our results confirmed that 4-NP was a potent cytotoxic agent for the kidney tissue and induced renal damage, with 4-NP-intoxicated fish showing necrosis in the epithelial cells of the renal corpuscles, renal proximal convoluted tubules, and intertubular hematopoietic tissue, as well as loss of or a decrease in microvilli, a decrease in mitochondria, and an increase in the lysosomes in the epithelial cells of the proximal convoluted tubules. The kidneys of 4-NP-intoxicated fish also showed increased numbers of Perls' Prussian blue-positive melanomacrophage centers and intraepithelial T-lymphocytes in the proximal convoluted tubules and plasma cells. The administration of NSS to 4-NP-challenged fish significantly minimized the cytotoxic effect of 4-NP, maintaining the normal kidney structure, with concentrations of 2.5% and 5% of feed being most effective for protecting the kidney against 4-NP-induced renal damage.

Bisphenol A-induced oxidative stress, hepatotoxicity and altered estrogen receptor expression in Labeo bata: impact on metabolic homeostasis and inflammatory response

Bisphenol A (BPA), a weak estrogenic endocrine disruptor and a well-known plasticizer, has the potential to perturb diverse physiological functions; however, its impact on immune and metabolic function in aquatic vertebrates is relatively less understood. The present study aims to investigate the impact of BPA on hepatotoxicity, metabolic and immune parameters vis-à-vis estrogen receptor expression modulation in a freshwater teleost, Labeo bata (Cyprinidae, Cypriniformes). The 96-h median lethal concentration of BPA in L. bata has been determined as 4.79 mg/L. Our data demonstrate that congruent with induction of plasma vitellogenin (VTG), chronic exposure to sub-lethal BPA (2 and 4 μM/L) attenuates erythrocyte count, hemoglobin concentration, packed cell volume, mean corpuscular hemoglobin, but not leukocyte number. Further, a significant increase in MDA, concomitant with diminished catalase and heightened GST activity corroborates well with hepatic dystrophic changes, appearance of fatty liver (macrovesicular steatosis) and elevated serum lipids (triglyceride, cholesterol, LDL, VLDL) in BPA-treated groups. Interestingly, a differential regulation of estrogen receptor (ER) subtypes at transcript and protein level signifies negative influence of BPA on hepatic ERα/ERβ homeostasis in this species. While at a lower dose it promotes Akt phosphorylation (activation), BPA at the higher dose attenuates ERK1/2 phosphorylation (activation), suggesting potential alteration in insulin sensitivity. Importantly, dose-dependent decrease in hepatic TNF-α, IL-1β, iNOS (NOS2) expression and nitric oxide (NO) level corresponds well with progressive decline in p-NF-κB, p-p38 MAPK, albeit with differential sensitivity, in BPA-exposed groups. Collectively, BPA exposure has wide-spread negative influence on hematological, biochemical and hepatic events in this species.

De novo transcriptomic analysis predicts the effects of phenolic compounds in Ba River on the liver of female sharpbelly (Hemiculter lucidus)

This work aimed at predicting the toxic effects of phenolic compounds in Ba River on the health of female sharpbelly (Hemiculter lucidus) by the de novo transcriptomic analysis of the liver. Sharpbelly, a native fish living in freshwater ecosystem of East Asia, were sampled upstream, near, and downstream of a wastewater discharge to the Ba river. Based on the occurrence of bisphenol A (BPA), nonylphenol (NP), and 4-tert-octylphenol (4-t-OP) in the water and fish sampled from each site, up-, mid-, and down-stream were interpreted as control, high, and low treatment groups, respectively. In the mid-stream group the Fulton's condition factor (CF) and body weight were remarkably increased by approximate 20%; the gonado-somatic index (GSI) and hepatosomatic index (HSI) in mid-stream fish showed a similar increasing trend but lacking of statistical difference. Exposure to wastewater effluent caused 160 and 162 differentially expressed genes (DEGs) in up-mid and down-mid stream groups, respectively. Two sets of DEGs were primarily enriched in the signaling pathways of drug metabolism, endocrine system, cellular process, and lipid metabolism in the mid-stream sharpbelly, which may alter the fish behavior, disrupt the reproductive function, and lead to hypothyroidism, hepatic steatosis, etc. Taken together, our results linked the disrupted signaling pathways with activities of phenolic compounds to predict the potential effects of wastewater effluent on the health of wild fish.

Disruptive effects of nonylphenol on reproductive hormones, antioxidant enzymes, and histology of liver, kidney and gonads in Caspian trout smolts

The endocrine-disrupting effect of pollutants such as alkylphenols has been considered a major concern during recent years. Although the effects of nonylphenol on the reproductive hormones of fish have been investigated in several studies, the effect of this endocrine disruptor on reproductive hormones of immature fish and salmonid smolts has been less addressed. The present work studied the effects of 1, 10 and 100 μg/l concentrations of nonylphenol on the levels of plasma reproductive hormones and liver antioxidant enzymes as well as on histopathology of reproductive and non-reproductive organs of male and female Caspian brown trout (Salmo trutta caspius) smolts after 21 days of exposure. The results of the present study showed that environmentally relevant concentrations of nonylphenol affected plasma levels of sex steroids; gonadotropins, phosphorus, estradiol to testosterone ratio, and also caused histopathological lesions in liver, kidney and testis tissues of immature Caspian brown trout during smolting. Nonylphenol significantly increased the levels of estradiol in plasma of both male and female smolts exposed to nonylphenol compared with the control groups. Exposure to nonylphenol decreased testosterone and FSH levels in both genders. It has also increased plasma levels of LH in females but did not affect LH levels in male fish. Liver SOD and CAT content was decreased in nonylphenol-exposed smolts. Therefore, the release of this economically valuable and endangered species into the rivers contaminated with nonylphenol should be avoided as it can have significant effects on the development and reproductive function of smolts.