Effects of 4-nonylphenol on blood cells of the African catfish Clarias gariepinus (Burchell, 1822)

Effects of 2,4-dichlorophenol on non-specific immunity, histopathological lesions, and redox balance in African Catfish, clarias gariepinus (Burchell, 1822)

The toxic effects of 2, 4-dichlorophenol (2, 4-DCP) on aquatic organisms are well-established; however, the details regarding the mechanisms underlying the toxicity, especially immunotoxicity are poorly understood. Consequently, the aim of this study was to investigate the histopathologic, oxidative stress and immunotoxic effects attributed to exposure to sublethal concentrations of 2,4-DCP in the African catfish, Clarias gariepinus. Juvenile C. gariepinus were exposed to 0.4, 0.8, or 1.6 mg/L 2, 4-DCP for 28 days after which blood and head kidney were extracted for the determination of various nonspecific innate immune parameters while the liver was excised for histopathology examination and measurement of oxidative stress biomarkers. Control fish were maintained in water spiked 10 µL/L ethanol, representing the solvent control. A significant increase was noted in the activities of lactate dehydrogenase and superoxide dismutase as well as in levels of lipid peroxidation and DNA fragmentation in a dose-dependent manner, with higher adverse effects observed at the highest concentration tested (1.6 mg/L). The total white blood cells (WBC) count was significantly elevated in fish exposed to 2,4-DCP compared to control. Myeloperoxidase content was decreased significantly in fish exposed to 2,4-DCP especially at the highest concentration (1.6 mg/L) compared to controls. The respiratory burst activity did not differ markedly amongst groups. Histopathological lesions noted included edema, leucocyte infiltration, and depletion of hemopoietic tissue in the head kidney of exposed fish. There was significant upregulation in the mRNA expression of tumor necrosis factor (TNF-α) and heat shock protein 70 (HSP 70) but downregulation of major histocompatibility complex 2 (MHC 2) in exposed fish. Data demonstrated that exposure to 2,4-DCP resulted in histopathological lesions, oxidative stress, and compromised immune system in C. gariepinus.

Deleterious effects of polypropylene released from paper cups on blood profile and liver tissue of Clarias gariepinus: bioremediation using Spirulina

Despite numerous studies on microplastics, the biological impacts of polypropylene microplastics (PP-MPs) and its toxicity on freshwater fish have yet to be fully revealed. The purpose of this research was to look at the potentially harmful effects of PP-MPs in freshwater African catfish Clarias gariepinus and bioremediation using Spirulina. After acclimatization to laboratory conditions, 108 fish (125 ± 3 gm and 27 ± 2 cm) were assigned into triplicate six experimental groups (12 fish/group), a control group, Spirulina group (SP), PP-MP-treated groups (0.14 and 0.28 mg/l PP-MPs), and PP-MP + Spirulina-treated groups (0.14 mg/l PP-MPs + 200 mg/L SP and 0.28 mg/l PP-MPs +200 mg/L SP) for 15-day exposure and 45-day recovery after that. The hematological parameters exhibiting significance (RBCs, Hct, Hb, and MCV) or non-significance (MCH and MCHC) either decreased with the increase in PP-MP doses from 0.0 in the control to 0.28 mg/L red blood cells (RBCs), hematocrit (Hct), mean corpuscular hemoglobin (MCH), mean corpuscular hemoglobin concentration (MCHC), hemoglobin (Hb) and platelets or increased with such an increase in doses (mean corpuscular volume (MCV)). The liver enzyme activity, aspartate aminotransferase (AST), alkaline phosphatase (ALP), and alanine aminotransferase (ALT) exhibited non-significant (p ≥ 0.05) or significant (p < 0.05) increases in (0.14 and 0.28 mg/L) PP-MP-exposed groups, respectively, except ALP. Furthermore, there was a significant (p < 0.05) or non-significant (p ≥ 0.05) increase in 0.14 and 0.28 mg/l PP-MP +200 mg/L-exposure groups, respectively, compared to the control group and the same exposure group without Spirulina. In comparison to the control group, PP-MPs (0.14 and 0.28 mg/L) induced a significant (p < 0.05) increase in the percentage of poikilocytosis and nuclear abnormalities of RBCs. The liver tissue from fish exposed to PP-MPs exhibited varying degrees of pathological changes. These results indicated that these pathological changes increased with PP-MP concentration, suggesting that the effect of PP-MPs was dose-dependent. After 45 days of recovery under normal conditions, it was obvious that there was a significant improvement in the percentage of poikilocytosis and nuclear abnormalities of RBCs, as well as a non-significant improvement in hemato-biochemical parameters and liver tissue.

Assessing haematological parameters and probable toxicity analysis in two coastal fish species at harbouring areas of Digha coastal belt, West Bengal, India

Coastal ecosystems are vital for maintaining the biodiversity and human livelihoods, but they are increasingly subjected to anthropogenic pressures, including pollution from various sources. Present work intends to assess the possible threats in coastal ecosystem as well as coastal fish species, in particular, through haematological parameters caused due to exposure of environmental contaminants like polycyclic aromatic hydrocarbons (PAHs), potentially toxic metals (PTMs), etc. This study analysed the haematological parameters and probable toxicity levels in two important coastal fish species, viz., Mystus sp. and Mugil sp. widely available in Digha coastal belt. Different haematological parameters, such as WBCs (White Blood Cells), Lym (Lymphocytes), Gran (Granulocytes), Mid (Monocytes), RBCs (Red Blood Cells), HCT (Haematocrit) value, MCV (Mean Corpuscular Volume), MCH (Mean Corpuscular Haemoglobin), MCHC (Mean Corpuscular Haemoglobin Concentration), RDW- CV (Red Cells Distribution Width-Co-efficient of Variation), RDW- SD (Red Cells Distribution Width-Standard Deviation), PLT (Total Platelet Count), MPV (Mean Platelet Volume), PDW- SD (Platelet Distribution Width-Standard Deviation), PDW- CV (Platelet Distribution Width-Co-efficient of Variation), PCT (Plateletcrit), PLCR (Platelet Large Cell Ratio), PLCC (Platelet Large Cell Count) and many others were measured directly through Erba H360 Haematology Analyser, simultaneously air dried blood smear was stained by Haematoxylin-Eosin(H-E) and Giemsa stain for assessing morphometric alterations of RBCs, WBCs, platelets as well as to determine the differential counts of WBCs by observing through Leica DM2000 microscope. Evidence of several abnormalities in the erythrocyte's nucleus (ENAs) and the abundance of abnormal celled erythrocytes (ECAs), carcinoma (lymphoproliferative disorder, polycythaemia vera, Hodgkin lymphoma and non-Hodgkin lymphoma), elevation of WBCs content, Lym %(Lymphocyte percentage), Eo(Eosinophils), monocytes, HCT and gross depletion of Ne(Neutrophils), basophils, and PLCR levels indicated a sign of major impact of contamination to two intoxicated fishes which may also affect the human being through food chain and may result into leukaemia in mammalian species, finally. However, comprehensive evaluation of the long-term impacts of the contaminants like PAHs and/or PTMs, etc., on fish populations, human health risk and coastal ecosystem is required to be addressed.

Cytotoxicity and immunological impact of Trypanosoma sp. infection on blood parameters of wild African catfish, Clarias gariepinus

Fish trypanosomiasis is a common blood parasitic disease transmitted by aquatic invertebrates, such as leeches. This study aims to shed light on the cytotoxicity of Trypanosoma sp. on erythrocytes and its impacts on the innate immune response (serum lysozyme activity, nitric oxide production, phagocytic activity, serum total protein, and globulin) in wild African catfish, Clarias gariepinus. One hundred catfish were examined using blood smears stained with Giemsa and confirmed with PCR. The prevalence of infection was found to be 10% by microscope detection and 15% by PCR. The morphological identification of Trypanosoma as Trypanosoma mukasai was determined. Additionally, this study included previously undescribed features of Trypanosoma, such as the width of the anterior and posterior body, the length of the posterior pale region, and the number of folds. Various alterations in erythrocytes were observed, totaling 54.57%. Nuclear abnormalities, including fragmented nuclei, eccentric nuclei, and micronuclei, were also reported. Infected fish showed a reduction in serum total protein and globulin levels, while nitric oxide production, lysozyme activity, and phagocytic activity exhibited a significant increase compared to non-infected fish. We believe that our findings will contribute valuable data to the morphological and molecular identification of Trypanosoma sp. in African catfish, as well as their cytotoxic impact.

The synergetic effects of 4-nonylphenol and polyethylene microplastics in Cyprinus carpio juveniles using blood biomarkers

Microplastics are widely distributed in aquatic ecosystems along with other chemical pollutants. Therefore, it is vital to study the health-hazardous effects of MPs in combination with 4-nonylphenol (4-NP), which is a highly abundant industrial waste and a critical alkylphenol endocrine disruptor. We investigated the effects of the exposure to polyethylene microplastics (PE-MPs), 4-NP, and their combination on blood biomarkers in Cyprinus carpio juveniles. Four study groups were treated for 15 consecutive days: (1) control group, (2) 10 mg/L PE-MP group, (3) 10 mg/L PE-MPs + 200 µg/L 4-NP group, and (4) 200 µg/L 4-NP group, followed by 15 days of recovery. Biochemical analyses showed that creatine kinase, lactate dehydrogenase, glucose, liver enzymes, total protein, and A/G ratios were significantly increased after exposure to PE-MPs, 4-NP, and the combination. Hematological parameters (RBC's, Hb, Ht, neutrophil percentage, and WBC's) were significantly decreased in the three exposure groups, whereas mean corpuscular volume and lymphocyte percentages were significantly increased. The 15-day recovery period improved most hematobiochemical parameters and PE-MP accumulation indices. Taken together, we demonstrated the hazardous effects of PE-MP and 4-NP combinations on C. carpio blood parameters and highlighted their potential risk to human health.

Hematological Consequences of Polyethylene Microplastics Toxicity in Male Rats: Oxidative stress, Genetic, and Epigenetic links

Microplastics (MPs) pollution is a newly emerging environmental issue. MPs can accumulate within animals and humans, which can pose a serious health threat. Petroleum-based polyethylene (PE) is one of the most popular plastics. Accordingly, its exposure rates have steadily increased over the years. This study aimed to analyze the effects of PE-MPs on the hematological system of albino rats and the epigenetic effect. Five groups of adult male eight-weeks-old rats received either distilled water, corn oil, 3.75mg/kg PE-MPs, 15mg/kg PE-MPs, or 60mg/kg of PE-MPs, daily by oral gavage for 35 days. PE-MPs significantly increased the body weights of the rats and lipid peroxidation, with concomitant reduction of superoxide dismutase activity and depletion of reduced glutathione, thus adversely affecting oxidants/antioxidants balance. Moreover, PE-MPs increased the % of abnormal RBCs, irregular cells, tear drop cells, Schistocyte cells, and folded cells. The genotoxic effects on DNA were evident by increased DNA damage, confirmed by the comet assay, in addition to increased DNA methylation. The effects of PE-MPs have been shown to be dose correlated. In conclusion, this study provides evidence of dose-related PE-MPs-induced hematological, genotoxic, and epigenetic effects in mammals, and thus emphasizes the potentially hazardous health effects of environmental PE-MPs.

Haemato-biochemical, mutagenic, and histopathological changes in Oreochromis niloticus exposed to BTX

The study of the DNA damage response in erythrocytes after exposure to volatile organic compounds (VOCs) can present evidence for its potential effect as genotoxic- biomarkers for environmental pollution. Although VOCs are dangerous pollutants, still little is known about hemotoxic, cytotoxic, and genotoxic effects of such pollutants on fish. We optimized an assay method for apoptosis and DNA damage in erythrocytes of adult tilapia fish after 15 days exposure to benzene (0.762 ng/L), toluene (26.614 ng/L), and xylene (89.403 ng/L). The highest level of apoptosis and DNA damage were recorded in benzene-exposed fish, as was the highest level of histopathological alterations in gills, liver, and kidney. The imbalance of the antioxidants profile explained the stress-case reported in exposed fish. These results suggest that hemotoxic, cytotoxic, genotoxic, and tissue damage were recorded after exposure to BTX in Oreochromis niloticus.

Alkylphenols cause cytotoxicity and genotoxicity induced by oxidative stress in RTG-2 cell line

Alkylphenols ethoxylates are industrial surfactants, and the release in the environmental matrices produces degraded products, of which nonylphenol (NP) and octylphenol (OP) were the most common. They can be classified as endocrine disruptors since the estrogenic potential is widely recognized, but some others toxic aspects are in discussion. This study aimed to evaluate the toxicity of NP, OP, and mixtures of both through cellular, biochemical and genetic biomarkers in fish gonadal cell line RTG-2 exposed to nominal concentrations of 0.05; 0.5; 5; 50, and 100 μg mL^-1 of each chemical and their mixtures of 0.05, 0.5; 5 μg mL^-1 concentrations. After 24 h, the cells were collected for cytotoxic (neutral red - NR; crystal violet - CV, resazurin assay - RA and lactate-dehydrogenase - LDH), antioxidant system (glutathione-s-transferase - GST; superoxide-dismutase - SOD; glutathione-peroxidase - GPx and malondialdehyde - MDA) and genotoxic assays (alkaline comet assay and Fpg-modified alkaline comet assay). The chemicals and their mixtures were cytotoxic at 50 and 100 μg mL^-1, in general aspect, but LDH showed cytotoxicity since 0.05 μg mL^-1. The GST and SOD showed an activity increase trend in most tested groups, while GPx decreased at 5 μg mL^-1 of the mixture. The MDA increase in all groups resulted in lipid peroxidation. The reactive oxygen species caused DNA damage for all groups. The tested chemicals and concentrations have been found in the freshwater systems. They can induce cell toxicity in several parameters that could impair the gonadal tissues considering the RTG-2 responses.

The Effect of Neonicotinoids Exposure on Oreochromis niloticus Histopathological Alterations and Genotoxicity

This study aimed to examine the side effects of selected neonicotinoids (Acetamiprid, Aceta, and Imidacloprid, Imid) on Oreochromis niloticus juveniles. The acute toxicity, Probit method, revealed an LC₅₀ of 195.81 and 150.76 ppm for Aceta/96 h and Imid/72 h respectively. The fish were divided into three groups that were exposed, for 21 days (n = 5/replicate), to 1/10 of the LC₅₀ of either neonicotinoids, however, the third was an unexposed control group. Results of erythrocytic micronucleus (MN), and nuclear abnormalities (NA) showed that Aceta and Imid exposure caused a significant (p < 0.05) increase in MN by ~ 2.2 and ~ 10 folds, respectively relative to control. NAs occurred at the order of kidney-shaped > budding > binucleated in Aceta, however, budding > binucleated > kidney-shaped was noticed in the Imid group. Histopathological changes in gills, liver, and muscles were observed significantly in both exposed groups with more severity in the Imid group. Collectively, Aceta and Imid have potential genotoxicity and histopathological alterations in O. niloticus.

Cytotoxicity, redox and immune status in African catfish, Clarias gariepinus (Burchell, 1822) exposed to bisphenol A (BPA) and its analogues

The objective of the study was to determine the comparative toxicities and immune dysfunction in the African catfish, Clarias gariepinus, exposed to bisphenol A (BPA) and its two analogues: bisphenol AP (BPAP) and bisphenol P (BPP). Juveniles of C. gariepinus were exposed to sublethal concentrations (70 and 140 μg/L) of BPA, BPAP and BPP for 7, 14 or 21 days after which various endpoints which are indicative of cytotoxicity, oxidative stress and haematological and innate immune parameters were determined in the liver homogenates or blood plasma. The exposure of C. gariepinus to BPA and its analogues caused significant increased activities of lactate dehydrogenase, catalase and superoxide dismutase. The exposed fish had increased levels of DNA fragmentation, lipid peroxidation, white blood cells, nitric oxide and respiratory burst, while the red blood cell counts and the percentage packed cell volume decreased significantly in the exposed fish compared to control. The toxic effects elicited by the bisphenols were both concentration- and duration-dependent. Generally, BPA exerted the most toxic effects on the fish, followed by BPAP, while BPP exerted the least toxic effects to C. gariepinus. Summarily, the findings indicated that BPA and its two analogues studied in the research are capable of causing cytotoxicity, oxidative stress and immune dysfunction in C. gariepinus.

Immunological and hemato-biochemical effects on catfish (Clarias gariepinus) exposed to dexamethasone

Dexamethasone (glucocorticoid) was recently shown to be a life-saving drug for the treatment of SARS-CoV-2 disease. Water and sediments can be contaminated by sewage treatment plants when this product is widely used. Accordingly, we evaluated the effects of dexamethasone as pharmaceutical residue on Clarias gariepinus, following exposure and post-exposure recovery on blood biochemical, antioxidant, and cytokine markers. Three experimental groups were examined. Control, fish exposed to 0.3 mg/L of dexamethasone, and fish exposed to 3 mg/L of dexamethasone for 7 days, followed by a 15-days recovery period. Hematological indices, such as red blood cell number, hemoglobin (Hb), platelets, mean corpuscular hemoglobin concentration, and large lymphocytes, were significantly declined following the exposure to dexamethasone compared to control. In contrast, hematocrit (Ht), mean corpuscular volume, monocytes, small lymphocytes, and mean corpuscular hemoglobin increased significantly depending on the dose–concentration. Liver and kidney functions, other biochemical parameters (albumin and globulin), cortisol, and cytokine (IL-1β and IL-6) concentrations increased significantly after exposure to dexamethasone compared to control. Antioxidants and acetylcholinesterase enzymes were significantly decreased in catfish treated with dexamethasone cumulatively with doses. After a recovery period, blood biochemical, antioxidant, and cytokine markers were still elevated compared with the control group. In conclusion, dexamethasone at concentrations present in water bodies causes deleterious effects on blood biomarkers, biochemical, and antioxidant as well as immune upregulation in catfish until after depuration period.

Reproductive Toxicity and Recovery Associated With 4-Non-ylphenol Exposure in Juvenile African Catfish (Clarias garepinus)

Although, the effects of 4-non-ylphenol (4-NP) on fish's reproductive hormones were assessed in several studies using adult models, however, the effect of this endocrine disruptor on immature fish's reproductive hormones was not addressed commonly. We aimed to study the apoptosis induction, hematotoxicity, reproductive toxicity, and the recovery associated with 4-NP exposure in juvenile African catfish [Clarias garepinus) using some hormones [17β-estradiol (E2), testosterone (T), follicle-stimulating hormone (FSH), and luteinizing hormone (LH)] and gonad histology as biomarkers. The toxic effects of 4-NP have been studied in many animal models, but there is still limited knowledge about the dose-dependent damage caused by 4-NP exposure in juvenile Clarias gariepinus. A healthy juvenile C. gariepinus was categorized into four groups (n = 3/group; three replicates in each group). The first group was the control, and the other three groups were subjected to 4-NP concentrations as 0.1, 0.2, and 0.3 mg/L for 15 days; they were left for a recovery period of another 15 days. The reproductive hormones of C. gariepinus exposed to 4-NP for 15 days exhibited significant variations between the treatment groups and the control (P < 0.05), which were evident in E2 and T-values, whereas FSH, LH, total protein, and lipid peroxidation values showed non-significant differences among all groups at P < 0.05. Such a situation referred to the fact that the 15-day recovery period was insufficient to remove the impacts of 4-NP doses in concern. The trend of dose-dependent increase/decrease was recorded for T, E2, FSH, and LH. The histopathological alterations of 4-NP treated in gonad tissues were recorded in juvenile C. gariepinus, reflecting their sensitivity to 4-NP estrogenic-like effects. Overall, our results investigate that recovery has improved the reproductive toxicity caused by 4-NP in juvenile C. garepinus. Significant variations between the treated groups and the control group (P < 0.05) were evident in hematological parameters except for hemoglobin (Hb), mean corpuscular volume (MCV), mean corpuscular hemoglobin (MCH), and mean corpuscular hemoglobin concentration (MCHC). The parameters exhibiting significance decreased with such increased doses [red blood cells (RBCs), hematocrit (Hct), and white blood cells (WBCs)]. Similar patterns of significant variations toward the increase or decrease were recorded following the 15-day recovery period. Apoptotic frequency in erythrocytes and brain cells has increased significantly with increased 4-NP exposure, indicating that 4-NP caused cytotoxic effects, such as apoptosis in a dose-dependent manner. However, these cellular alterations greatly decreased after the 15-day recovery period.

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.

Influence of the Linear Alkylbenzene Sulfonate (LAS) on hematological and biochemical parameters of Nile Tilapia, Oreochromis niloticus

The acute toxicity of household detergent (Ariel) on blood parameters and histology of Oreochromis niloticus was investigated using static bioassay for 96 h. Linear alkylbenzenesulfonate (LAS) is an anionic surfactant widely used in detergents and cleaners, both in industrial and household applications. LAS contaminating aquatic ecosystems as a potential toxic pollutant, was investigated in the present study for acute toxicity. The fish samples were divided into six groups, including 20 fish in each group. Normal feed was given to control group without detergents treatment. Hematological parameters (RBC count, Hb, Ht and platelets) were significantly declined, while WBC count showed a highly significant increase. Compared with the control group, significant elevation of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) was recorded in fish treated with different concentrations of detergent. Catalase (CAT), Superoxide dismutase (SOD) activities and Reduced Glutathione (GSH) concentration showed a highly significant reduction. Total proteins showed significant decrease, while total lipids, cholesterol and triglycerides significantly increased. The mean lethal concentration (LC₅₀) for 96 h of Ariel was at concentration 10 mg/L. Relative percentage of detergent residues in fish muscles was increased with higher detergent concentrations. In conclusion, exposure to detergents resulted in great alterations in the histological structure of liver and gills.

Low Dose-Rate Irradiation of Gamma-Rays-Induced Cytotoxic and Genotoxic Alterations in Peripheral Erythrocytes of p53-Deficient Medaka (Oryzias latipes)

Morphological alterations and nuclear abnormalities in fish erythrocytes have been used in many studies as bioindicators of environmental mutagens including ionizing radiation. In this study, adult Japanese medaka (Oryzias latipes) were irradiated with gamma rays at a low dose rate (9.92 μGy/min) for 7 days, giving a total dose of 100 mGy; and morphological alterations, nuclear abnormalities, and apoptotic cell death induced in peripheral erythrocytes were investigated 8 h and 7 days after the end of the irradiation. A variety of abnormalities, such as tear-drop cell, crenated cell, acanthocyte, sickled cell, micronucleated cell, eccentric nucleus, notched nucleus, and schistocyte, were induced in the peripheral erythrocytes of the wild-type fish, and a less number of abnormalities and apoptotic cell death were induced in the p53-deficient fish. These results indicate that low dose-rate chronic irradiation of gamma rays can induce cytotoxic and genotoxic effects in the peripheral erythrocytes of medaka, and p53-deficient medaka are tolerant to the gamma-ray irradiation than the wild type on the surface.

Non-Clinical Investigation of Tuberculosis Drugs: Conjugated Norbornene- Based Nanocarriers Toxic Impacts on Zebrafish

INTRODUCTION:

Rifampicin conjugated (R-CP), and rifampicin -isoniazid dual conjugated (RI-CP) norbornene-derived nanocarriers are newly designed for pH stimuli-responsive delivery of tuberculosis (TB) drugs. Its biosafety level is yet to be well established.

OBJECTIVES:

To assess the impacts of the nanocarriers on liver cells using zebrafish animal model and human liver cell line model (HepG2).

METHODS:

Initially, lethal dose concentration for the norbornene-derived nanocarrier systems in zebrafish was determined. The toxic effects were analysed at the sub-lethal drug concentration by histopathological study, total GSH level, gene expression and DNA damage in zebrafish liver cells. Fish erythrocyte nuclear abnormalities were also evaluated. Cell viability and oxidative stress level (ROS generation) after exposure to the nanoconjugates was determined using HepG2 cell in the in vitro study.

RESULTS:

In vivo studies of both R-CP and RI-CP showed 100% mortality at 96 hours for exposure concentration >100mg/l and showed toxic changes in zebrafish liver histology, GSH, and DNA damage levels. A noticeable upregulated PXR, CYP3A and cyp2p6 genes was observed in RI-CP exposure than in RIF or R-CP molecules. The in vitro study revealed a dose-dependent effect on cell viability and ROS generation for RIF, R-CP and RI-CP exposures in HepG2 cells.

CONCLUSION:

The current study reports that the rifampicin conjugated (R-CP) and rifampicin-isoniazid conjugated (RI-CP) norbornene derived nanocarriers exhibit enhanced toxic responses in both adult zebrafish and HepG2 cells. The pH-sensitive norbornene derived nanocarriers on conjugation with different drugs exhibited varied impacts on hepatic cells. Hence the present investigation recommends a complete metabolomics analysis and norbornene carrier-drug interaction study to be performed for each drug conjugated norbornene nanocarrier to ensure its biosafety.

Impacts of microplastics on reproductive performance of male tilapia (Oreochromis niloticus) pre-fed on Amphora coffeaeformis

This study examines the potential defending effects of the diatom, Amphora coffeaeformis, as a feed additive versus the deleterious effects (mainly on gonads) caused by microplastics (MPs) in Nile tilapia, Oreochromes niloticus. Groups of male tilapia were pre-fed diets with four different supplementation levels of A. coffeaeformis (0%, 2.5%, 5%, and 7.5%) for 70 days, then exposed to 10 mg/L MPs for 15 days. Thereafter, samples were taken from the four experimental groups and the control fish group, for evaluating blood picture, erythrocytes alterations, biochemical parameters, catalase (CAT), superoxide dismutase (SDO), and total antioxidant capacity (TAC). In addition, male reproductive performance was assessed by quantifying the follicle-stimulating hormone (FSH), luteinizing hormone (LH), and testosterone (T), also testicular sections and GSI% were also assessed. The results showed that the number of leucocytes were significantly (p < 0.05) higher, but the number of red blood cells (RBCs), the level of Hemoglobin (Hb), the percentage of Hematocrit (Ht), the number of platelets, and the eosinophil percentages were significantly decreased (p < 0.05) when fish exposed to MPs. Biochemical parameters (ALP, glucose, uric acid, albumin, and A/G ratio) were significantly increased after MP exposure compared with the control group. Furthermore, MPs induced a significant decline in both serum LH and T levels. Testicular, histological, degenerative changes and testis-ova were found in the MP-exposed fish. Thus, A. coffeaeformis supplementation displayed ameliorative properties that detoxified the negative effects of MPs. This study provides a better understanding of the reproductive injuries caused by MPs exposure and evidence for the use of A. coffeaeformis as a natural remedy in freshwater tilapia.

Chitosan nanoparticles alleviated endocrine disruption, oxidative damage, and genotoxicity of Bisphenol-A- intoxicated female African catfish

Bisphenol-A (BPA) is widely used in production of plastic products. It can reach the ecosystems affecting aquatic organisms most likely fishes. The purpose of this study was to study the toxic effects of BPA on the biochemical variables and oxidative stress in female African catfish, Clarias gariepinus and to estimate the protective role of chitosan nanoparticles (CSNPs) against BPA toxicity. Five groups in triplicates of fish were divided as follows: group I was control, group II was treated with CSNPs (0.66 ml/L), group III was exposed to BPA (1.43 μg/L), group IV was treated with BPA (1.43 μg/L) plus CSNPs (0.33 ml/L), and group V was treated with BPA (1.43 μg/L) plus CSNPs (0.66 ml/L) for 30 days. Blood and liver tissue samples were collected at the end of experiment for the biochemical and oxidative stress biomarkers analyses. Results exhibited that serum Follicle Stimulating Hormone (FSH) and 17-β Estradiol (E2) were significantly decreased in female catfish. While, serum Testosterone (T.) and Luteinizing Hormone (LH) were increased after exposure to BPA. Marked increment in superoxide dismutase (SOD) and malondialdehyde (MDA) levels of hepatic tissue of catfish exposed to BPA. Furthermore, significant reduction in hepatic catalase (CAT), glutathione peroxidase (GSH-px), total antioxidant capacity (TAC), reduced glutathione (GSH), and glutathione S-transferase (GST) levels were decreased significantly in BPA-exposed catfish compared to the control group. However, administration of female C. gariepinus with the low and high doses (0.33 ml/L and 0.66 ml/L) of CNPs restored the biochemical parameters to be close to the normal values of the control group and also, reduced oxidative stress induced by BPA toxicity. This improvement was evident in fish administrated with the high CSNPs dose (0.66 ml/L) compared to catfish exposed to BPA in group (III). Furthermore, the percentage of hepatic DNA damage was detected in group III exposed to BPA alone. However, it was declined after co- administration with both the low and high doses of CSNPs. The study has revealed that treatment with CSNPs has antagonistic functions against the toxicity of BPA in female African catfish.

Microplastics-Induced Eryptosis and Poikilocytosis in Early-Juvenile Nile Tilapia (Oreochromis niloticus)

This study aims to assess the impact of microplastics (MPs) on erythrocytes using eryptosis (apoptosis) and an erythron profile (poikilocytosis and nuclear abnormalities), considered to be novel biomarkers in Nile tilapia (Oreochromis niloticus). In this study, four groups of fish were used: The first was the control group. In the second group, 1 mg/L of MPs was introduced to the samples. The third group was exposed to 10 mg/L of MPs. Finally, the fourth group was exposed to 100 mg/L of MPs for 15 days, following 15 days of recovery. The fish treated with MPs experienced an immense rise in the eryptosis percentage, poikilocytosis, and nuclear abnormalities of red blood cells (RBCs) compared with the control group in a concentration-dependent manner. Poikilocytosis of MP-exposed groups included sickle cell shape, schistocyte, elliptocyte, acanthocyte, and other shapes. Nuclear abnormalities of the MPs-exposed groups included micronuclei, binucleated erythrocytes, notched, lobed, blebbed, and hemolyzed nuclei. After the recovery period, a greater percentage of eryptosis, poikilocytotic cells, and nuclear abnormalities in RBCs were still evident in the groups exposed to MPs when crosschecked with the control group. The results show concerning facts regarding the toxicity of MPs in tilapia.

Nonylphenol exposure in Labeo rohita (Ham.): Evaluation of behavioural response, histological, haematological and enzymatic alterations

The impact of acute and chronic exposure of nonylphenol (NP) on behaviour, histopathology, haematology and biochemical parameters of Labeo rohita (Hamilton, 1822) was investigated in the current study. The 96 h LC₅₀ of NP for L. rohita was estimated to be 0.548 mg L^-1. Acute toxicity of NP induced several behavioural alternations. Further, sub-lethal NP exposure for a period of sixty days to 1/10th (0.0548 mg L^-1), 1/15th (0.0365 mg L^-1) and 1/20th (0.0274 mg L^-1) of 96 h LC₅₀ resulted a reduction in total erythrocyte count and haemoglobin content whereas the total leukocyte count was observed to increase significantly. Among the biochemical parameters, blood glucose level increased, but there was significant decrease in total serum protein, albumin and globulin level. Significant alterations occurred in the histological architecture of gill tissue in NP exposed groups. The catalase and superoxide dismutase activity in gill tissues were elevated significantly while the concentration dependent inhibition of acetylcholinesterase activity was observed on 20th, 40th and 60th day of NP exposure. An increased glutathione-S-transferase activity in gill tissue was also observed in NP exposed groups. The present ecotoxicological study provides a reliable indication for the obligation to control the use and safe disposal of NP.

Impact of copper and zinc mixture on haematological parameters of rainbow trout (Oncorhynchus mykiss): acute exposure and recovery

Significant changes in composition of rainbow trout Oncorhynchus mykiss blood cells types were induced after 4-days exposure with mixture of Cu²⁺ and Zn²⁺ at 0.25, 0.125 and 0.06 parts of LC₅₀ in comparison to control group. The highest concentration of metal mixture (0.25 of LC₅₀) significantly induced elevation of the number of monocytes and poly-segmented neutrophils. Treatment with 0.125 parts of LC₅₀ concentration increased the number of thrombocytes, monocytes and non-segmented neutrophils. The most diluted mixture resulted in significant induction of thrombocytes, monocytes, non- and poly segmented neutrophils. Analysis of leucocyte cell types in the O. mykiss blood samples after 4-days of exposure at all applied mixture parts showed signs of monocytosis and neutrophilia. Comparison of different types of leucocytes' percentages (leukogram) in fish after 4-days exposure to metal mixture and after 4, 8, and 12-days recovery periods showed that, values of neutrophils even after the 12-days recovery period at all tested parts of LC₅₀, and monocytes after exposure with the highest (0.25) used part of LC₅₀ were not restored to control group levels. Depuration and recovery processes in treated fish are concentration and recovery period dependent.

Genotoxicity, oxidative stress, and biochemical biomarkers of exposure to green synthesized cadmium nanoparticles in Oreochromis niloticus (L.)

The considerable increment in the use of Nanoparticles in the industry has been recognized as an environmental concern today. Therefore, this study aimed to investigate the toxicity effects of green synthesized cadmium nanoparticles [Cd]^NPs using Moringa oleifera leaves extract on multi-biomarkers in Oreochromis niloticus after four weeks of exposure. The results showed that LC₅₀ values of [Cd]^NPs for 24, 48, 72 and 96 h were 2.17, 1.75, 1.49 and 1.22 mg l^-1, respectively. There was a significant decrease in the number of white and red blood cells, hemoglobin, hematocrit, mean corpuscular hemoglobin concentration value in fish exposed to [Cd]^NPs. The mean corpuscular volume and neutrophils were increased. [Cd]^NPs exposure to fish has led to cytotoxic and genotoxic changes in the erythrocytes. Significant changes were observed in the cortisol, triiodothyronine, and thyroxine levels of the fish exposed to [Cd]^NPs. The activities of aspartate aminotransferase and alanine aminotransferase increased. Glucose, total lipids, urea, and creatinine levels increased in the serum of fish exposed to [Cd]^NPs, whereas total protein contents and alkaline phosphatase activity decreased. A significant reduction was observed in glycogen, total antioxidant levels, and superoxide dismutase, catalase and glutathione S-transferase activities of fish exposed to [Cd]^NPs. In contrast, the [Cd]NPs exposure resulted in a significant increase in DNA fragmentation percentages, lipid peroxidation, and carbonyl protein levels in different tissues. The results of the present study confirmed that [Cd]^NPs has the toxicity potential to cause Cyto-genotoxicity, oxidative damages, changes in the hematological and biochemical changes, and endocrine disruptor in the fish.

Toxicity of polystyrene nanoplastics in Ctenopharyngodon idella juveniles: A genotoxic, mutagenic and cytotoxic perspective

The increased contamination of surface water with plastic waste is proportional to the increased consumption of products that use them as raw material. However, the impact of these residues on aquatic biota remains limited, mainly when it comes to nanoplastics (NPs). Thus, the aim of the current study is to test the hypothesis that the exposure of Ctenopharyngodon idella juveniles to polystyrene nanoplastics (PS NPs) at low concentrations (0.04 ng/L, 34 ng/L and 34 μg/L), for 20 days, leads to DNA damage and has mutagenic and cytotoxic effects on their erythrocytes. Comet assay enabled observing that DNA damage (inferred from the greater tail length, DNA percentage in the tail and Olive tail moment) induced by PS NPs has increased as the pollutant concentrations have increased, as well as that the formation of micronuclei and other nuclear abnormalities was equitable in animals exposed to this pollutant. On the other hand, there were significant changes in erythrocyte shape and size, oxidative stress generation (NO levels, lipid peroxidation, hydrogen peroxide), antioxidant system inhibition (mediated by total hepatic glutathione) and PS NPs accumulation in the liver and brain of animals exposed to higher concentrations of it. Therefore, the current study has confirmed the initial hypothesis and enhanced the knowledge about the genotoxic, mutagenic and cytotoxic potential of PS NPs in freshwater fish at early developmental stage, relating these effects to biochemical changes and significant accumulation of these nanomaterials. Besides, it is a warning about the (eco) toxicological risk represented by these nanopollutants in aquatic environments. CAPSULE: Polystyrene nanoplastics are capable of inducing DNA damage, mutagenic and cytotoxicity changes in fish.

Blood Biochemical and Erythrocytic Morpho-pathological Consequences of Naphthalene Intoxication in Indian Teleost, Anabas testudineus (Bloch)

Anabas testudineus (Bloch) was exposed to 0.71 mg/L and 1.42 mg/L (25 and 50% of LC₅₀ value respectively) naphthalene, a polycyclic aromatic hydrocarbon (PAH), for 21 days. Blood biochemical parameters and erythrocytic morphological alterations were assessed to describe the naphthalene toxicity. Biochemical analysis showed a significant increase in glutamic pyruvic transaminase, GPT (576.7 ± 11.79 and 608.9 ± 12.08 U/L, respectively) and alkaline phosphatase, ALP (12.9 ± 0.69 and 13.4 ± 0.64 U/L, respectively) activities under two doses compared with control. Protein and albumin (ALB) content in blood decreased significantly, in comparison with control value in the tune of 22.67 ± 1.04 and 23.97 ± 1.24 g/dl, respectively and 10.7 ± 0.79 and 11.1 ± 0.67 g/dl, respectively. Erythrocytes showed varied symptomatic morphological changes under naphthalene exposure, which included severe denaturation, swelling in cells, appearance of sickle and tear drop cells, and cellular vacuolation. In particularly, the changes were more prominent under higher naphthalene exposure. Following the results, it has been able to establish that GPT, ALP, protein and ALB, and the morphological manifestations of erythrocytes would be good tools of biomarker in monitoring toxicological paradigm, especially to naphthalene exposure in aquatic bodies.

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.

Digital light microscopy to characterize the scales of two goatfishes (Perciformes; Mullidae)

The normal and lateral line scales from above the head and four flank regions were investigated in two goatfishes by using light microscopy to evaluate the microscopic characteristics of scale surface ornamentation from different body parts of these fishes and to add new morphological data for their discrimination. The body scales were removed and digital images captured with a Dino-Lite digital camera connected to a Leica compound microscope. The presence of both transverse and longitudinal radii was a distinctive characteristic for the scales of studied goatfishes. The most distinctive features of the key scales discriminating the two goatfishes were the scale shape, the presence of irregular grooves in scale surface, the presence of transverse radii in the lateral fields, and the availability of lepidont at the anterior field. The lateral line scale ornamentations were almost similar in two species; however, the lateral line canal was branching in Parupeneus heptacanthus. Scale extension index indicated that in both species, the dimension of normal key scales tends to the right, while the dimension of lateral line scales tends to the left. This study accentuated that scales from different body regions may exhibit variation in surface ornamentations, that scale morphology could successfully be used to discriminate the examined goatfishes, and that the use of fish scale microscopy is an easy and relatively rapid method and does not require fish sacrifice. Since fish identification is essential for the conservation and management of species, the use of scale morphology to this purpose appears particularly promising.

DNA alterations in blood cells of Channa punctatus after acute exposure to 4-Nonylphenol

The DNA damaging effect of 4-nonylphenol was evaluated in blood cells of fish Channa punctatus by using single gel electrophoresis assay (SGEA). Fish were exposed to three sublethal concentrations (0.15 mg/l, 0.31 mg/l and 0.63 mg/l) of 4-NP which were calculated after LC50 determination. Exposure was given for 96 hours and blood sampling was done after 24, 48, 72 and 96 hours. Tail moment (TM), tail intensity (TI), tail length (TL) and olive tail moment (OTM) were used as parameters for assessing DNA damage. Comet assay results indicated significant DNA fragmentation in blood cells of C. punctatus as a significant increase in the values of all parameters was observed when exposured to different concentrations of 4- NP. Highest damage was observed at 24 h of exposure followed by a decrease in value at 48 and 72 h while at 96 h of exposure increase in the value of all the parameters were observed. On the other hand, after exposure to different concentrations highest damage was seen after treatment with 0.31 mg/l of NP. Owing to the results, the blood cells of C. punctatus show great sensitivity for 4-NP and can be used as bio-indicator for genotoxicity testing.

γ-H2AX foci as indication for the DNA damage in erythrocytes of medaka (Oryzias latipes) intoxicated with 4-nonylphenol

The present study aimed to investigate the genotoxicity in erythrocytes induced after exposure of medaka (Oryzias latipes) to 4-nonylphenol (4-NP). Adult female medaka fish were exposed to 4-NP at three sublethal concentrations for 15 days to compare their sensitivity with that of catfish as an aquatic model. Comet assay and γ-H2AX were used as biomarkers to detect DNA damage in erythrocytes. Exposure to 4-NP resulted in an increase in the tail moment in a dose-dependent manner. The highest level of DNA damage was recorded after exposure to 100 μg/l 4-NP. The number of foci was increased after exposure to 4-NP, indicating damage to DNA. The present results confirmed the high level of morphological alterations and apoptosis of erythrocytes detected in the first part of this study. 4-NP induced genotoxic effects in medaka, which were found to be more sensitive than catfish after exposure to 4-nonylphenol. Graphical abstract.

Genotoxicity induced by hexavalent chromium leading to eryptosis in Ctenopharyngodon idellus

The initiation of eryptosis as a result of genotoxic action of Cr(VI), seen through micronucleus and comet assay in the peripheral erythrocytes of Ctenopharyngodon idellus was evaluated through RT-qPCR. For this, fish was exposed to sublethal concentration of hexavalent chromium (5.30 and 10.63 mg/L), and the blood was sampled on different endpoints (15, 30 and 45 days). Accumulation of chromium in the erythrocytes was also studied, which depicted a significant increase in toxicant concentration and time dependent manner. Both concentrations of hexavalent chromium induced DNA damage, visible in the form of comet tails. The presence of micronuclei in the erythrocytes was accompanied with occurrence of nuclear bud (NBu), lobed nucleus (Lb), notched nucleus (Nt), vacuolated nucleus (Vn), binucleated cell (Bn) as nuclear abnormalities; and acanthocytes (Ac), echinocytes (Ec), notched cells (Nc), microcytes (Mc) and vacuolated cytoplasm (Vc) as cytoplasmic abnormalities. The expression of genes related to intrinsic apoptotic pathway induced by Cr(VI) presented significant (p < 0.05) upregulation in the expression of p53, Bax, Apaf-1, caspase9 and caspase3, and downregulation of Bcl2; inferring the initiation of apoptotic pathway. The ration of Bax and Bcl2 also appended the apoptotic state of the erythrocytes. From the present investigation, it can be concluded that genotoxicity induced by hexavalent chromium lead to eryptosis in C. idellus.

Evaluation of Erythrocyte Morphometric Indices in Juvenile Red Spotted Grouper, Epinephelus akaara under Elevated Water Temperature

Higher thermal exposure can influence the blood cell morphology and count. Hence, based on the previous results (Rahman et al., 2019), the present study evaluated the morphometric indices of erythrocytes and their nucleus under different water temperatures (25°C, 28°C, 31°C, and 34°C) to investigate their use as an indicator of thermal stress in red spotted grouper, Epinephelus akaara. 180 healthy specimens of E. akaara were exposed to four temperature conditions (25°C as control, 28°C, 31°C, and 34°C) for 42 days, following 2 weeks of acclimation at 25°C. Erythrocyte major axis (EL), erythrocyte minor axis (EW), nucleus major axis (NL), and nucleus minor axis (NW) were examined from the blood smears on each sampling day (i.e., 2, 7, and 42 days of thermal exposure). EL and NL were significantly decreased, whereas EW and NW were increased at higher water temperature (31°C and 34°C). The major-minor axis proportions of erythrocytes and their nucleus (EL/EW; NL/NW) were decreased with increasing water temperature (31°C and 34°C). The strong relationships were observed among the morphometric indices of erythrocytes and their nucleus, especially in EL vs. NL and EW vs. NW. This study reveals that elevated water temperature (31°C and 34°C) can influence the major and minor axis morphometry of erythrocytes and their nucleus in red spotted grouper. These indices may be used as stress indicators to monitor the health status of E. akaara and probably for other fish species.

Hepatotoxic effects of silver nanoparticles on Clarias gariepinus; Biochemical, histopathological, and histochemical studies

The current study investigates the hepatotoxic effects of two acute doses of silver nanoparticles (AgNPs) and silver nitrate (AgNO3) on African catfish (Clarias garepinus) using biochemical, histopathological, and histochemical changes and the determination of silver in liver tissue as biomarkers. AgNPs-induced impacts were recorded in some of these characteristics based on their size (20 and 40 nm) and their concentration (10 and 100 μg/L). Concentrations of liver enzymes (Aspartic aminotransferase; AST, Alanine aminotransferase; ALT), alkaline phosphatase (ALP), total lipids (Tl), Glucose (Glu) and Ag-concentration in liver tissue exhibited a significant increase under stress in all exposed groups compared to the control group. The total proteins (Tp), albumin (Al), and globulin (Gl) concentrations exhibited significantly decrease in all treated groups compared to the control group. At tissue and cell levels, histopathological changes were observed. These changes include proliferation of hepatocytes, infiltrations of inflammatory cells, pyknotic nuclei, cytoplasmic vaculation, melanomacrophages aggregation, dilation in the blood vessel, hepatic necrosis, rupture of the wall of the central vein, and apoptotic cells in the liver of AgNPs-exposed fish. As well as the depletion of glycogen content in the liver (feeble magenta coloration) was observed. The size and number of melanomacrophage centers (MMCs) in liver tissue showed highly significant difference in all exposed groups compared to the control group. Recovery period for 15 days led to improved most alterations in the biochemical, histopathological, and histochemical parameters induced by AgNPs and AgNO3. In conclusion, one can assume liver sensitivity of C. garepinus for AgNPs and the recovery period is a must.

Protective effect of p53 knockout on 4-nonylphenol-induced nephrotoxicity in medaka (Oryzias latipes)

In the past few decades, environmental pollutants have become common because of misused nonionic surfactants and detergents. Nonylphenol ethoxylates (NPs) are one of the most important contaminants of water. Therefore, the present study aimed to investigate the protective blocking effect of apoptosis (deficient P53 gene) on 4-nonylphenol (4-NP)-induced nephrotoxicity of medaka (Oryzias latipes). We divided 36 fish into six groups: two different control groups of wild type (Wt; Hd-rR) control and p53 (-/-) control, and four different treated with 4-nonylphenol (50 μg/L and 100 μg/L) for 15 days. Histology, immunochemistry, and TUNEL assays confirmed that 4-NP causes nephrotoxicity. Our results showed that 4-NP administration significantly disturbed the kidney structure and function and 4-NP-treated fish showed dilated glomerular vessels, had less glomerular cellular content, decreased expression of glomerular proteins, and an increased level of apoptosis compared with a Wt control group (P < 0.05). As p53 is an apoptotic inducer, some protection in p53-deficient medaka was found as nephrotoxic effects of 4-NP were minimized significantly. Our study demonstrated for the first time to our knowledge that 4-NP induces apoptosis, causing nephrotoxicity in medaka. We found that blocking apoptosis blocking was able to protect the kidney from the toxic effects of 4-NP.

Dose-specific biochemical and erythrocytic alterations of anthracene exposure on blood of Anabas testudineus (Bloch)

The present work is designed to compare the chronic toxicity of anthracene [one of the major constituents of polycyclic aromatic hydrocarbons (PAHs)] on Anabas testudineus (Bloch), in an air-breathing carnivorous fish, in laboratory condition under the exposure of two doses of LC₅₀ value, i.e., 0.0075 mg/l (T1), i.e., 25% and 0.015 mg/l (T2) i.e., 50% for 21 days. A comprehensive comparison was recorded based on biochemical parameters and evaluated the erythrocytic alterations of blood components of the fish. It revealed an enhanced trend of activity of glutamic pyruvic transamin (GPT) 470.7 ± 12.32, 546.6 ± 13.22, 599.4 ± 13.09 U/L and alkaline phosphatase (ALP) 9.2 ± 0.61, 10.4 ± 0.86, 10.9 ± 0.74 U/L in control, T1 and T2 respectively; and reverse trend of protein (PRO) 26.63 ± 1.32, 22.15 ± 1.13, 22.29 ± 1.02 g/dl and albumin (ALB) 11.9 ± 0.71, 9.65 ± 0.91, 10.05 ± 0.94 g/dl in control, T1 and T2 respectively. Under T1 and T2 exposure conditions, it displayed the maximum alterations and appearance of tear drop-like cells (Tr), sickle cells (Sk), swelled cells (Sc) and vacuolated cells (Va) in comparison to control condition. An exclusive experimentation of the present work suggested that biochemical parameters and erythrocytic alterations may be useful tool as biomarkers to monitor the long term toxicological effects, especially to anthracene a constituent of PAHs, in any aquatic environment.

Hemotoxic effects of some herbicides on juvenile of Nile tilapia Oreochromis niloticus

Recently, the residues of some common and widely used herbicides (acetochlor, bispyribac-sodium, bentazon, bensulfuron-methyl, halosulfuron-methyl, and quinclorac) were detected in the surface water, soil, sediments, and fish tissues as the agricultural drainage problems. In this study, juveniles of Nile tilapia Oreochromis niloticus were exposed to sub-lethal concentrations of these herbicides as 2.625, 0.800, 36.00, 2.50, 1.275, and 11.250 mg/l for acetochlor, bispyribac-sodium, bentazon, bensulfuron-methyl, halosulfuron-methyl, and quinclorac respectively for 96 h. Some hemato-biochemical parameters were evaluated. In comparison with the control group, sub-lethal concentrations of all tested herbicides induced alterations in the shape of erythrocytes. Also, in all tested herbicides, hematological parameters of exposed fish exhibited a significant decrease in red blood cell count except bentazon. However, all tested herbicides showed an insignificant reduction in mean corpuscular hemoglobin concentration and total white blood cells except bensulfuron-methyl. For biochemical parameters, most tested herbicides induced a significant increase in levels of cholesterol, albumin, globulin, albumin/globulin ratio, activity of alkaline phosphatase (ALP), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and total plasma protein (only with acetochlor), urea, and creatinine (except bentazon and halosulfuron-methyl that exhibited non-significant decrease in creatinine level) compared with the control. In conclusion, the fish blood profiles can be used as good biomarkers for laboratory study to assess the toxicity of the tested rice herbicides at a sub-acute level especially acetochlor on O. niloticus. Graphical Abstract.

Genotoxic effects of 4-nonylphenol and Cyproterone Acetate on Rana catesbeiana (anura) tadpoles and juveniles

Genotoxic analyses are commonly used in ecotoxicological studies as early biomarkers to investigate the potential effects of environmental contaminants on biological models. Several pollutants can induce DNA damage and, therefore, counting micronuclei and other nuclear abnormalities are efficient tools to evaluate genotoxicity. Some pollutants such as 4-nonylphenol (NP), a detergent used mainly in industries, and Cyproterone Acetate (CPA), an antiandrogenic medicine, have already shown genotoxic effects on some vertebrates. However, although amphibians are considered bioindicators of environmental quality and their populations are declining worldwide, the effects of these compounds on anurans are not yet known and, therefore, we believe that it is important to investigate such effects on anurans. Since water contamination is one of the ultimate causes of amphibian decline, ecotoxicological studies are important to discuss the appropriate solutions to avoid species extinction. Thus, this study investigates the genotoxic effects on Rana catesbeiana tadpoles and juveniles after being exposed to 1, 10 and 100 μg/L NP and 0.025, 0.25 and 2.5 ng/L CPA, by counting the nuclear abnormalities after exposure. The laboratory experiments lasted 28 days. The experimental conditions were the same except for the water volume since tadpoles and juveniles exhibit different habits at different developmental stages. Compared to juveniles, tadpoles were more susceptible to both compounds as indicated by the increased nuclear abnormalities observed in the highest NP concentration and all tested CPA concentrations. The juveniles, on the other hand, responded only to the two highest CPA concentrations. We concluded that CPA, even at very low concentrations, is extremely harmful to both anuran developmental stages and, particularly, to tadpoles. The significant effects observed on tadpoles is an important outcome of this study since 100 μg/L or higher NP concentrations are frequently detected in the environment.

Ameliorative effect of Spirulina platensis against lead nitrate-induced cytotoxicity and genotoxicity in catfish Clarias gariepinus

The present study was designed to investigate the protective role of dietary supplementation of Spirulina platensis (SP) against cytotoxic and genotoxic effects of lead nitrate in Clarias gariepinus. Four groups of fishes were used: first group as control which fed on basal diet, second group fed on basal diet and exposed to (1 mg/L of lead nitrate), third group fed on diet containing 0.25% SP and exposed to (1 mg/L of lead nitrate), and fourth group fed on diet containing 0.5%SP and exposed to (1 mg/L of lead nitrate). Fish samples were taken at 2nd and 4th week of exposure. The hematological indices of lead nitrate-exposed group were decreased significantly compared to the control group at 2nd and 4th week of exposure. Lead nitrate caused a significant increase in the percentage of poikilocytosis, micronuclei, and apoptotic cells as well as comet tail length and olive tail moment compared with the control group at 2nd and 4th week of exposure. The highest level of damage was found on 4th week of exposure with all parameters. Dietary inclusion of SP ameliorated these cytotoxic and genetic changes, as well as this amelioration was concentration and time dependent. Consequently, the present study proposed that the addition of SP to the fish diet can be used as a promising protective agent to oppose cytotoxic and genotoxic effects of lead nitrate in aquaculture. Graphical abstract.

Changes in Blood Cell Morphology and Number of Red Spotted Grouper, Epinephelus akaara in Response to Thermal Stress

Rising of water temperature due to global warming is a great concern to aquaculturists and fishery biologists. Hence, the present study aimed to investigate the effects of high water temperature on juvenile red spotted grouper, Epinephelus akaara based on the evaluation of stress responses in blood. E. akaara juveniles were exposed to different thermal conditions (25℃, 28℃, 31℃, and 34℃) for 6 weeks following 2 weeks of acclimation at 25℃. Blood cell morphology and number were examined at three sampling points (2, 7, and 42 days) from a total of 180 fish. Major erythrocytic cellular abnormalities (ECA) observed in blood smears of thermally stressed groups (31℃ and 34℃) after 6 weeks were echinocytes, teardrop-like cells, swollen cells and vacuolated cells. Both red and white blood cell number (RBC and WBC) were significantly (p<0.05) elevated in 31℃ and 34℃ group after 6 weeks thermal exposure. Differential leucocytes number showed significant increases in neutrophil (N) and decreases in lymphocytes (L) in the highest temperature (34℃). Different N:L ratio was observed at different thermal conditions which can be used as a reliable alternative to measure stress response. Taken together, these results suggest that higher temperature (31℃ and 34℃) can interfere the immune system of red spotted grouper by altering the blood cell morphology and number.

Cytotoxic and hemotoxic effects of silver nanoparticles on the African Catfish, Clarias gariepinus (Burchell, 1822)

The present study investigates the hemotoxic and cytotoxic impacts of two acute doses of silver nanoparticles (AgNPs) on the African catfish, Clarias garepinus in comparison to the impact of AgNO₃ and the control fish. AgNPs-induced impacts were recorded on some biological and hematological indices of that species on the bases of their size (20 and 40 nm) and concentration (10 and 100 µg) but no significant interaction. AgNO₃ had very low impact on these indices in comparison to AgNPs. Recovery period for 15 days was found to be valid to remove AgNPs and AgNO₃ toxicity for most indices. The condition factor exhibited stability under stress whereas the hepatosomatic index was more sensitive to AgNPs. The AgNPs-induced hematological changes recorded were corresponding with different blood cell alterations which increased in frequency from the control and AgNO₃ to 40 nm/100 µg; such blood cell alterations disappeared to great extent after recovery period of 15-days in a reverse order.

Protective effects of a novel pyrazolecarboxamide derivative against lead nitrate induced oxidative stress and DNA damage in Clarias gariepinus

Pyrazole derivatives display diverse biological and pharmacological activities. The aim of this study is to investigate the antioxidant properties of a novel pyrazolecarboxamide derivative (4-amino-N-[(4-chlorophenyl)]-3-methyl-1-phenyl-1H-thieno [2, 3-c] pyrazole-5-carboxamide) in African catfish, Clarias gariepinus, exposed to 1 mg/L PbNO₃. Fish were intramuscularly injected with pyrazole-5-carboxamidederivative according to the following groupings: Group 1 (control), Group 2 (1 mg/L lead nitrate), Group 3 (1 mg/L lead nitrate + 5 mg pyrazole derivative/kg body weight), and Group 4 (1 mg/L lead nitrate + 10 mg pyrazole derivative/kg body weight) for two weeks and four weeks. Lead nitrate (1 mg/L) caused significant elevation of serum aspartate aminotransferase (AST), alanine aminotransferase (ALT), creatinine, uric acid, cholesterol, and glucose-6-phosphate dehydrogenase (G6PDH) compared to the control group after two and four weeks of exposure, while serum total lipids, alkaline phosphatase (ALP), and lactate dehydrogenase (LDH) were significantly reduced compared to the control group. Furthermore, levels of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) and total antioxidant capacity (TAC) were reduced in group 2 compared to the control group. However, in group 2, hepatic lipid peroxidation (LPO) and DNA fragmentation percentage were significantly increased compared to the control group. Histopathological changes in the liver of lead-exposed groups included marked disturbance of hepatic tissue organization, degeneration of hepatocytes, dilation of blood sinusoids and the central vein as well as necrosis. Injection of pyrazole derivative for two weeks and four weeks reversed alterations in biochemical parameters, antioxidant biomarkers, lipid peroxidation, hepatic DNA damage, and histopathological changes in liver tissue induced by 1 mg/L lead nitrate. This amelioration was higher in response to high-dose pyrazole derivative (10 mg) at the fourth week of exposure, showing concentration-and time-dependency. Overall, the sensitized derivative pyrazolecarboxamide is likely a useful tool to minimize the effects of lead toxicity due to its potent antioxidant activity.

Protective role of Spirulina platensis against UVA-induced haemato-biochemical and cellular alterations in Clarias gariepinus

Recently, it has become widely recognized that ultraviolet A (UVA) exposure is harmful for both aquatic and terrestrial organisms. Many studies have reported the effects of UVA on aquatic animals, especially fish, but little is known about the antioxidant role of microalgae in ameliorating the negative effects of UVA exposure. Recently, there has been great interest in using Spirulina platensis (SP) as a dietary antioxidant agent. Therefore, this study aimed to investigate the protective role of SP against UVA-induced effects by analysing haemato-biochemical alterations and erythrocyte cytotoxic and genotoxic biomarkers in African catfish (Clarias gariepinus). Fish were exposed to UVA, UVA + 100 mg/L SP extract, UVA + 200 mg/L SP extract for 3 days (UVA exposure: 1 h/day), and were not subjected to treatment (control group). The results showed the presence of some morphological malformations in red blood cells (RBCs) after UVA exposure. Additionally, nuclear abnormalities, including micronuclei, were observed. UVA induced alterations in most of the haemato-biochemical indices. Adding SP to the fish aquaria restored the haemato-biochemical parameters to their control values. In addition, SP repaired cellular damage in a dose-dependent manner. We conclude that SP plays a modulatory role in preventing and/or repairing the haemotoxic effects induced by UVA.

Immunotoxic effects of 4-nonylphenol on Clarias gariepinus: Cytopathological changes in hepatic melanomacrophages

Melanomacrophage centres (MMCs) play a key role in the immune response in fish. They are considered sensitive bio-monitoring structures with roles in the assessment of toxicant impacts. The aim of this study was to examine the potential histopathological effect of 4-nonylphenol (4-NP) on hepatic MMCs in Clarias gariepinus. To achieve this objective, adult male fish were divided randomly and equally into two groups: a control group and a group that was exposed to 4-NP (dissolved in water at a dose of 0.1 mg/L) for 21 days. The 4-NP-intoxicated hepatic MMCs contained numerous necrotic macrophages. Superoxide dismutase 2 was immuno-expressed in the hepatic MMCs in both groups, with no significant difference. Histomorphometric examination revealed that the sizes and numbers of MMCs were dramatically higher in the livers of 4-NP-exposed C. gariepinus than in control fish. Following 4-NP challenge, in the liver, the abundance of lipofuscin and haemosiderin pigments increased, and single-pigmented macrophages, aggregated groups of deformed red blood cells (RBCs) and macrophages were present near blood vessels and hepatic sinusoids. These results reveal that 4-NP exerts immunological effects on hepatic MMCs in C. gariepinus and support the utility of MMCs as a cytological biomarker for aquatic exposure to 4-NP.

The protective role of Spirulina platensis to alleviate the Sodium dodecyl sulfate toxic effects in the catfish Clarias gariepinus (Burchell, 1822)

Sodium dodecyl sulfate (SDS) as anionic surfactant is common in household and personal care products and reach in the aquatic ecosystems from different applications. Present work aimed to study the effects of SDS and the potential ameliorative influence of Spirulina platensis (SP) in the African catfish Clarias gariepinus. Fish was exposed to SDS and SP, individually or in combination in four equal groups for two weeks. The 1st group (control), 2nd group (SDS-treated), 3rd group (SDS, 0.1 mg L^-1 + SP, 100 mg L^-1 water) and 4th group (SDS, 0.1 mg L^-1 + SP, 200 mg L^-1). Serum samples were used to analyze hepatic and renal functions, electrolytes, genetic, and antioxidant biomarkers. The results revealed that SDS exposure induced hepatic and renal dysfunction, electrolytes imbalance, as well as significant disruption in enzymatic and non-enzymatic antioxidants, and increase in alterations, micronuclei and apoptosis percentages in erythrocytes. SP addition restored these biochemical and genetic variations close to control levels. Thus, the present study suggests that SP could protect the catfish against SDS-induced injury by scavenging ROS, sustaining the antioxidant status and diminishing DNA oxidative damage.

Environmental pollution and toxic substances: Cellular apoptosis as a key parameter in a sensible model like fish

The industrial wastes, sewage effluents, agricultural run-off and decomposition of biological waste may cause high environmental concentration of chemicals that can interfere with the cell cycle activating the programmed process of cells death (apoptosis). In order to provide a detailed understanding of environmental pollutants-induced apoptosis, here we reviewed the current knowledge on the interactions of environmental chemicals and programmed cell death. Metals (aluminum, arsenic, cadmium, chromium, cobalt, zinc, copper, mercury and silver) as well as other chemicals including bleached kraft pulp mill effluent (BKME), persistent organic pollutants (POPs), and pesticides (organo-phosphated, organo-chlorinated, carbamates, phyretroids and biopesticides) were evaluated in relation to apoptotic pathways, heat shock proteins and metallothioneins. Although research performed over the past decades has improved our understanding of processes involved in apoptosis in fish, yet there is lack of knowledge on associations between environmental pollutants and apoptosis. Thus, this review could be useful tool to study the cytotoxic/apoptotic effects of different pollutants in fish species.

SDS-PAGE technique as biomarker for fish toxicological studies

Although many studies on the hematological and biochemical parameters in fishes have been done, still there are some shortage in the estimation and evaluation of the baseline's values of marine and freshwater fishes. Recently, the use of hematology and biochemistry of fishes in toxicology, aquaculture, environmental pollution, feeding, and antioxidants studies has been increased. In this study we introduced the importance of those parameters and their importance as biomarkers in fish toxicology from previous literature and as new findings. Hemato-biochemical parameters were widely used in fish toxicological studies. Many researches have used the protein electrophoresis as a valid tool to determining intra and inter-specific variation among species. Protein profile was extensively used in determining the health of fish, as indicators of anemia or other diseases provide information about the existence of the disease, and in the diagnosis of disease. So, to carry out the aim of this study, we reported one of the more advanced techniques used SDS-PAGE as molecular biomarker for protein profile analysis in fish with shedding the light on the importance of hematological and biochemical parameters in fish toxicological studies.

The possible DNA damage induced by environmental organic compounds: The case of Nonylphenol

Human impact on the environment leads to the release of many pollutants that produce artificial compounds, which can have harmful effects on the body's endocrine system; these are known as endocrine disruptors (EDs). Nonylphenol (NP) is a chemical compound with a nonyl group that is attached to a phenol ring. NP-induced H₂AX is a sensitive genotoxic biomarker for detecting possible DNA damage; it also causes male infertility and carcinogenesis. We attempt to comprehensively review all the available evidence about the different ways with descriptive mechanisms for explaining the possible DNA damage that is induced by NP. We systematically searched several databases, including PubMed, Scopus, Web of Science, and gray literature, such as Google Scholar by using medical subheading (MeSH) terms and various combinations of selected keywords from January 1970 to August 2017. The initial search identified 62,737 potentially eligible studies; of these studies, 33 were included according to the established inclusion criteria. Thirty-three selected studies, include the topics of animal model (n = 21), cell line (n = 6), human model (n = 4), microorganisms (n = 1), solid DNA (n = 1), infertility (n = 4), apoptosis (n = 6), and carcinogenesis (n = 3). This review highlighted the possible deleterious effects of NP on DNA damage through the ability to produce ROS/RNS. Finally, it is significant to observe caution at this stage with the continued use of environmental pollutants such as NP, which may induce DNA damage and apoptosis.

Concentrations of toxic metals (Pb, Cd, Cr) in the tissues and their effects on diversification of Devario aequipinnatus populations

Recently, momentous consideration has being given to our natural ecosystems due to toxic metals, insidious to our environment execute as pollutants to the freshwater ecosystems. The accumulations of metals were encompassed with lead, cadmium and chromium in organs of Devario aequipinnatus. Although, the microscopic scrutinization from the gill and liver of the fish species were explored, the crucial conditions of the ecosystem. The histological study plays a key role in determining the effects of pollution. In the length-weight relationships of the regression parameters of coefficient value r², 'a' value and 'b' value were showed the negative allometric growth rate of species D. aequipinnatus. However, the nucleotide sequence blast search was performed in NCBI database. In that the species of D.aequipinnatus were closely associated with other sub-species but within same genus, and it showed the similarity range between 100% and 90% in reference to other species for phylogenetic analysis.