Gill alterations of whiteleg shrimp (Litopenaeus vannamei) exposed to cadmium under different experimental salinities.

BACKGROUND: Heavy metals are one of the most important environmental pollutants in marine coastal ecosystems. Cadmium is a heavy metal that enters to marine environments via industrial wastes and oil production activities. OBJECTIVES: This study were done to determine the toxicity of cadmium to Litopenaeus vannamei and to evaluate the histological changes in gill tissues after exposure to sublethal concentrations of cadmium at different salinities. METHODS: For this reason, toxicity test was done to determine the lethal concentration (LC50) of cadmium for whiteleg shrimp. According to the calculated LC50 amount, sublethal doses of cadmium were used to determine its histological effects in different salinity during 2 weeks exposing period. RESULTS: LC50 of cadmium for 96 h for whiteleg shrimp was 6.56 mg/L. Histological alterations in the gill were observed in L. vannamei after 14 days exposure to different concentrations of cadmium and salinity. Histopathological index was increased in a dose-dependent manner. CONCLUSION: Our findings showed that doses lower than 2 mg/L have repairable effects on gill structure, but the concentration of 2 mg/L cadmium leaves irreparable and destructive effects on the gill tissue.

Impacts of sublethal concentrations of 17 α-ethinylestradiol (EE2) on growth, reproductive performance, and survival in red cherry shrimp Neocaridina davidi (Crustacea, Atyidae) during consecutive spawnings.

This study was conducted for the first time to investigate the long-term impacts of sublethal concentrations of 17 α-ethinylestradiol (EE2) on growth, survival, and reproductive performances in a model shrimp, the red cherry (Neocaridina davidi), females during five successive spawning steps for 7.5 months. Females were distributed in eighteen aquariums and continuously exposed to EE2 at six nominal concentrations of 0 (control), 0.02, 0.2, 2, 20, and 200 µg/L. Growth indices increased up to 0.2 µg/L and then sharply declined up to 200 µg/L. Most reproductive indices significantly decreased at levels > 0.02-0.2 µg/L with increasing EE2 levels. The highest absolute, relative, and actual fecundity values were recorded in the control, with the lowest value at 200 µg/L. With increasing EE2 levels, mean egg volume showed an increasing trend from the third spawning event onwards. Except for the time required to reach the first spawning, inter-spawning intervals considerably decreased with increasing EE2 levels at > 0.2 µg/L, especially from the third spawning stage onwards. Survival of exposed females significantly decreased with increasing EE2 levels. Unlike the body size, the juvenile's survival rates in all exposed treatments were considerably lower than the control. Females at concentrations 0.02-0.2 µg/L gained more body weight and length but produced fewer eggs with lower hatching percentages during five consecutive spawns. The results suggest that EE2 depending on the concentrations can cause unbalanced growth, reduce reproductive performances, especially from the third stage of spawning onwards, and reduce survival rates in brooders and subsequent offspring. In terms of growth, survival, and reproductive indices over successive spawns in ecotoxicology studies, the concentrations of 0.02-0.2 µg/L can be considered as chronic levels, but higher levels may have detrimental effects.

Immunotoxic effects of metal-based nanoparticles in fish and bivalves.

There is a global research interest in metal nanoparticles (MNPs) due to their diverse applications, rapidly increasing use, and increased presence in the aquatic environment. Currently, most MNPs in the environment are at levels unlikely to cause overt toxicity. Sub-lethal effects that MNPs may induce, notable immunotoxicity, could however have significant health implications. Thus, deciphering the immunological interactions of MNPs with aquatic organisms constitutes a much-needed area of research. In this article, we critically assess the evidence for immunotoxic effects of MNPs in bivalves and fish, as key wildlife sentinels with widely differing ecological niches that are used as models in ecotoxicology. The first part of this review details the properties, fate, and fundamental physicochemical behavior of MNPs in the aquatic ecosystem. We then consider the toxicokinetics of MNP uptake, accumulation, and deposition in fish and bivalves. The main body of the review then focuses on immune reactions in response to MNPs exposure in bivalves and fish illustrating their immunotoxic potential. Finally, we identify major knowledge gaps in our current understanding of the implications of MNPs exposure for immunological functions and the associated health consequences for bivalves and fish, as well as the general lessons learned on the immunotoxic properties of the emerging class of nanoparticulate contaminants in fish and bivalves.

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.

Selective induced apoptosis and cell cycle arrest in MCF7 and LNCap cell lines by skin mucus from round goby (Neogobius melanostomus) and common carp (Cyprinus carpio) through P53 expression.

The skin mucus in lower vertebrates such as fish with strong innate immune system has many unique and valuable bioactive compounds that can be used for inducing apoptosis in cancer cells. This study was looking for the cytotoxic potential of mucus from the two fish species, including round goby (Neogobius melanostomus) and common carp (Cyprinus carpio), and inducing apoptosis in MCF7 and LNCaP cancer cell lines via influencing P53 gene expression and cell cycle arrest. Results showed that the both mucus types have cytotoxic effects on the both cancer cell lines whereas they have no severe effect on normal primary fibroblast cells. In addition, round goby mucus and common carp mucus selectively induced apoptosis in the LNCaP and MCF7 cells, respectively, through up-regulating P53 gene and arresting cell cycle at the G1 phase. Taken together, this study suggested that the both mucus types can selectively influence P53 pathway and induce apoptosis in especial cancer cells. The skin mucus derived from round Goby and common Carp can be a promising candidate for investigation about apoptosis and molecular targeting therapy in cancer.

Using ovarian and brain cell culture from the Mullet, Liza klunzingeri, to assess the inhibitory effects of benzo[a]pyrene on aromatase activity.

We assessed the toxic effects of benzo[a]pyrene (BaP) on cell viability, aromatase (Aro) activity and steroid production using ovarian and brain cell cultures obtained from Mullet, Liza klunzingeri. The brain and ovary were minced and digested, and the cells were suspended in Leibovitz's L-15 medium supplemented with 15% and 20% fetal bovine serum. The cell suspensions were seeded on 25-cm2 cell-culture flasks at 1 × 106 cells/mL and incubated at 25 °C for 2 weeks. A BaP concentration of 10-5 mol/L was accepted as the half-maximal inhibitory concentration. Ovarian and brain cells were exposed to different concentrations of BaP [0 (control), 10-6 , 2 × 10-6 , 3 × 10-6 mol/L] and incubated at 30 °C. At different sampling times (0, 12, 24 and 48 h) 40 ng/105 cells of 1,4,6-androstatriene-3,17-dione (ATD) was added to each well. Aro activity, 17ß-estradiol (E2) and ATD production were determined. The sensitivity of the cultivated ovarian and brain cells to BaP increased dose dependently. BaP was a potent inhibitor of Aro activity at 2 × 10-6 and 3 × 10-6 mol/L, both in the cultivated brain and ovarian cells at different sampling times, with 10-6 mol/L BaP found to be the least potent Aro inhibitor. E2 production decreased from cultivated ovarian and brain cells treated by different concentrations of BaP. In conclusion, BaP is able to change the activity of Aro and disrupt the biosynthesis of estrogens, and thus affects reproduction in fish.

Exposure of liver cell culture from the orange-spotted grouper, Epinephelus coioides, to benzo[a]pyrene and light results in oxidative damage as measured by antioxidant enzymes.

Among the various toxicants discharged into aquatic environments, benzo (a) pyrene (BaP) has been shown to effect on the antioxidant system of fish and the evaluation of its impact on biota is of considerable concern. The aim of the present study was to use the primary hepatocyte culture obtained from the orange-spotted grouper, Epinephelus coioides, to evaluate the adverse effects of benzo (a) pyrene (BaP) on cell viability and liver antioxidant system. BaP was selected for its high ability to produce reactive oxygen species (ROS) and oxidative stress. The liver was minced by a scalpel and digested in the PBS solution with 0.1% collagenase IV at room temperature for 20 min. Then, the cell suspension was transferred to a plate contained an equal amount of Leibovitz's L-15 medium with 20% fetal bovine serum (FBS), 100 IU mL-1 of penicillin and 100 µg mL-1 streptomycin. 5 mL of cell suspension were plated into sterile 25 cm2 tissue culture flasks at the density of 1.5 × 106 cell/ml L-15 and incubated at 30 °C for two weeks. The medium was renewed after 24-48 h. The number of the liver cells was adjusted to 4 × 106 after two weeks. 10-4 mol l-1 was verified by MTT assay as the IC50 of BaP. Then, hepatocytes were exposed to three concentrations of BaP (10-5, 2 × 10-5, 3 × 10-5 mol L-1) and incubated for 24 h. Samples were collected after 6, 12 and 24 h and the amounts of SOD, CAT, GPx, LPO, LDH, AST, ALT, ALP and total protein were analyzed. The results showed that, 10-5 mol L-1 of BaP was not significantly toxic to cultivated hepatocytes, however, the sensitivity of cells to BaP increased in a dose-related pattern. The activity of the antioxidant enzymes (SOD, CAT and GPx) and liver enzymes (ALT, AST, ALP, LDH) significantly increased, though the amount of LPO, total antioxidant power and total protein decreased dose-dependently in BaP-exposed cells. In conclusion, according to the finding of the present study, BaP has a high potential to induce the oxidative stress in primary liver cell culture of E. coioides.

Immunotoxicity of estrogen and nonylphenol on apoptosis and expression of ERs in goldfish macrophage: Opening new avenue for discovering the role of experimental model systems and sexes.

The expression of estrogen receptors (ERs) and their roles in important cell processes such as apoptosis in the macrophages exposed to estrogen/xenoestrogen have remained a complex secret. This study focused on the expression of estrogen receptors (ERs) and the stimulation of apoptosis in the macrophages from the two sexes of goldfish (Carassius auratus) exposed to 17-ßestradiol (E2) and nonylphenol (NP) under in vivo and in vitro conditions. For the in vivo experiment, fish were exposed to NP (10-6 M and 10-7 M) and E2 (10-6 M) for 24 days. Then, the head kidney macrophages from the male and the female goldfish were isolated and assayed. For the in vitro experiments, the macrophages derived from the two sexes were cultured in L-15 medium and exposed to E2 (150 nM) and NP (10 nM and 150 nM) for 3 days. The results showed that the three isoforms of ERs (ERα, ERß1, ERß2) were expressed in the goldfish macrophages. After the exposure of macrophages to NP and E2, sex-specific increase of ERs expression and apoptosis were observed (P < 0.05). The expression of ERα after NP treatment showed the highest alteration, with the response being concentration-dependent. The most alteration of ERs expression were observed in the in vivo experiment. This study provides insight to understand how exposure of the goldfish macrophages to E2 and NP can up-regulate the transcript levels of estrogen receptor subtypes and stimulate apoptosis.

Spontaneously contracting cell aggregates derived from grass carp heart as a promising tool in in vitro heart research.

Regarding challenges in isolation and maintenance of cultured heart cells, introduction of new in vitro heart model that is stable and exhibits long-term spontaneously contracting cell aggregates (SCCs), whose electrophysiological properties are comparable to the human heart, is required. This research aimed to establish cardiac primary cells and to evaluate the effects of culture conditions. Also the effect of fish age on beating SCC and cardiac cell morphology were studied. Twelve healthy grass carps (Ctenopharyngodon idella) were divided into four groups based on their age. Non-enzymatic explant culture was used and heart explants were incubated at 21-31 °C for 60 days. After proliferation of the cardiac primary cells, changes in their morphology and their beatings were recorded. The results showed that the explants derived from different age of grass carp fish are fully viable and proliferative with formation of SCC for a long period of time. By increasing the number of adhered cells, the cardiac primary cells became more flat and elongated. Increasing the medium temperature and fetal bovine serum concentration in culture medium led to decline and enhancement in beat frequencies of heart cell aggregates, respectively. Also, grass carp heart explant had high potential in regeneration (especially in young fish) and thus high feasibility to generate stable long-term cultures. In general, it seems that explant culture of heart from grass carp can be considered as a promising tool in heart research area.

Interruption of immune responses in primary macrophages exposed to nonylphenol provides insights into the role of ER and NF-KB in immunotoxicity of Persian sturgeon.

The severe decline in population of sturgeons due to pollution highlighted poor understanding about the immunotoxicological responses of sturgeons. This study was designed in three experiments to find out how nonylphenol (NP) interrupts some pro-inflammatory immune parameters in macrophages from Persian sturgeon (Acipencer persicous) as the oldest vertebrate model conserving intact innate immune system. After determination of IC50 values of NP (200 µM), some pro-inflammatory immune parameters and induced apoptosis in macrophages at low dose (10 nM) and high dose (100 nM) of NP and of 17ß estradiol (E2) (positive control) were determined after 6, 24 and 48 h of the exposure (as the first experiment). The two doses of NP induced pro-inflammatory reaction and apoptosis with strong correlations, whereas this result was observed more obviously in high dose of E2. In the second experiments, the macrophages were exposed to the two doses of NP along with estrogen receptor alpha (ERα) antagonist, which consequently decreased the induction of pro-inflammatory reactions. Similarly, in the third experiment, NF-KB and ERα antagonists were used and pro-inflammatory reactions decreased compared to the control group (P < 0.05). Decreasing correlation between immune parameters following the second and third experiments verified interaction between ERα and NF-KB pathways. Thus, NP could be immune disrupter and apoptosis inducer in sturgeon macrophages in vitro, even in low dose. For the first time, this study revealed that NP can induce pro-inflammatory reactions in macrophages derived from sturgeons.

Optimization of macrophage isolation from the Persian sturgeon and the Caspian kutum fish: a comparative study.

The aim of this research was a comparative study on the isolation and culture of head kidney macrophages derived from Acipenser persicous and Rutilus frisii kutum as teleost and chondrostei species of fish. The macrophages were isolated by density gradient sedimentation, followed by adherence to a plastic surface. They exhibited strong phagocytic activity against bacteria. The effect of cell density, incubation time, FBS percentage, pH and temperatures on the cell number and viability were determined and compared. Also, the effect of light/dark regimen on viability, adherence, release of reactive oxygen species (ROS) and nitric oxide (NO) in the macrophages was determined. The results showed that the Caspian kutum macrophages were more sensitive to FBS percentage and cell density whereas the Persian sturgeon macrophages were more sensitive to pH of the cell culture media. The adherence and viability of the macrophages from both fish species firstly increased (P < 0.05) after exposure to a light/dark regimen, but then significantly decreased as did ROS and NO productions. For the first time, this study has determined the optimal conditions for primary culture of macrophages derived from sturgeons, and shows the unique effect of light on the biology of fish immune cells.

CYP1A gene expression as a basic factor for fipronil toxicity in Caspian kutum fish.

The aim of this study was to assess the effects of fipronil insecticide on the Caspian kutum fish at different levels of biological organizations and to find possible relationship between these biomarkers. Different doses of fipronil (65, 130 and 200 mg/kg) were intraperitoneally administered to the fish for 2 weeks. After 7 and 14 days of exposure, alterations in organ-somatic index, tissue and DNA structure, oxidative stress and CYP1A gene expression in gill, liver, brain and kidney were studied. Determination of these parameters in the liver showed that the degree of tissue change (DTC), comet tail, superoxide dismutase (SOD) and relative CYP1A mRNA expression increased mostly in a time dependent manner whereas in the kidney increased mostly in a dose dependent manner. These parameters in the gill increased more in time and dose dependent manner. Apart from the changes in CYP1A expression and oxidative stress, no alterations was observed in the brain. Multiple regression analysis showed that the CYP1A had the most correlation with the organ-somatic index (R2 = 0.76) and comet tail (R2 = 0.89) in the liver, and with DTC (R2 = 0.93) and oxidative stress (R2 = 0.87) in the kidney. Generally, this study showed that CYP1A gene expression can be considered as one basic factor for fipronil toxicity in this fish. However, other possible factors also should be considered for future research.

Effects of the environmental endocrine disrupting compound benzo[a]pyrene on thyroidal status of abu mullet (Liza abu) during short-term exposure.

Benzo[a]Pyrene (BaP) is a ubiquitous polycyclic aromatic hydrocarbon (PAH) that has been shown to disrupt the metabolism of thyroid hormone. Then, the present investigation aimed to study the effects of BaP on thyroid function in Liza abu. Fish were injected with 2, 10 and 25 mg/kg-bw of BaP. Samples were taken from blood, thyroid and muscle tissues at days 1, 2, 4, 7, and 14. Blood was evaluated for changes in the plasma levels of TSH, T3 and T4. Also, BaP bioaccumulation in the fish muscle was measured. Thyroid tissues were processed for routine histology. BaP concentration in the muscle of treated fish reached a maximum level after 4 days. Exposure of fish to BaP resulted in a significant decrease in T3 and T4 plasma level and increase in TSH concentration up to day 4. Also some pathological alterations were observed in BaP-exposed fish such as hemorrhage and increased number of large follicles with squamous epithelium. In conclusion, according to the results of the present investigation, short term exposure to sublethal concentrations of BaP significantly affected thyroid function in fish. The results revealed BaP ability to alter thyroid function.

Using cell apoptosis, micronuclei and immune alternations as biomarkers of phenanthrene exposure in yellowfin seabream (Acanthopagrus latus).

In the present study, the apoptosis and tissue changes in the spleen, as well as humoral immune-related parameters, micronuclei (MN) induction in blood cells and Ethoxyresorufin-O-deethylase (EROD) activity were investigated in yellowfin seabream (Acanthopagrus latus) after short-term exposure to phenanthrene (Phe). The fish were intraperitoneally injected with different concentrations (2, 20 and 40 mg kg-1) of Phe and tissue and blood samples were collected 1, 4, 7 and 14 days after injection. The concentrations of Phe in the fish liver increased 4 days after the experiment. EROD activity showed a pattern consistent with Phe concentration in the liver. Apoptotic index in the spleen increased dose dependently in Phe-exposed fish. Exposure to Phe caused significant decrease in the plasma level of immunoglobulin M, phagocytic and respiratory burst activity after 4 days of exposure. The frequency of MN in the erythrocytes of the treated fish was significantly higher than control. The main pathological alterations in the spleen included the increase in melanomacrophage centers (MMCs), destroyed red blood cell and hemorrhage. The degree of tissue changes in the spleen of the exposed fish ranged from slight to moderate damage. The size and number of MMCs in the spleen were significantly higher in Phe-treated fish compared to the control. Our results showed that Phe could suppress immune responses in fish, induce cell apoptosis, histological changes in the spleen and MN formation. This may suggest those parameters consider as useful biomarkers for monitoring of the health status of fish during exposure to Phe.

Comparison of waterborne and intraperitoneal exposure to fipronil in the Caspian white fish (Rutilus frisii) on acute toxicity and histopathology.

Fipronil is an effective insecticide widely used in agriculture with potential ecotoxicological consequences. The median lethal dose (LD50) and concentration (LC50) of fipronil in 16.3 g Caspian white fish, Rutilus frisii kutum fingerlings were determined. To determine the LD50, a total of 133 fish were assigned to 19 tanks (7 fish/tank) including one control and 6 treatment groups (300, 450, 550, 650, 750, 850 mg/kg). Fish were injected intraperitoneally and monitored at 96 h. The LD50 of fipronil was 632 mg/kg suggesting it was slightly toxic to the Caspian white fish. To determine LC50, 114 fish were assigned to 19 tanks (6 fish/tank) including one control and 6 treatment groups (300, 400, 500, 600, 700, 800 µg/L). The LC50 of fipronil was 572 µg/L, which was highly toxic to the fish. The degree of tissue change (DTC) in vital organs from moribund fish exposed via waterborne exposure showed severe damage (DTC: 71 ± 52 for 700 µg/L) in the gill, including aneurisms, extensive fusion and necrosis. The fish exposed through the intraperitoneal route seemed to have severe lesions (DTC: 66 ± 50 for 750 mg/kg) in the kidney, involving hemorrhage, tubular degeneration and necrosis. The liver had no significant differences in DTC values between the two routes and showed pyknosis and sinusoid dilation. Hematoxylin and eosin staining did not show any histological alterations in the brain but nissl staining showed some alterations in distribution of purkinje cells. Generally, this study showed that the route of exposure to fipronil not only affects its acute toxicity but also determines the main target organs of toxicity and histopathological alterations in Caspian white fish.

Using a liver cell culture from Epinephelus coioides as a model to evaluate the nonylphenol-induced oxidative stress.

The present study aimed to use primary liver cell culture derived from the orange-spotted grouper, Epinephelus coioides, to assess the toxic effects of nonylphenol (NP) on the hepatocyte viability and the liver antioxidant system. E. coioides was selected due to its commercial importance. NP was used in this study because of its high potential of producing oxidative stress due to increased reactive oxygen species (ROS). A liver of E. coioides was digested with PBS containing 0.1% collagenase IV. The digested cells were moved to Leibovitz L-15 culture medium with 20% fetal bovine serum (FBS), 100IUmL-1 penicillin, 100µgmL-1 streptomycin. Aliquots of cell suspension were seeded as a monolayer into sterile 25cm2 tissue culture flasks and incubated at 30°C for 14days. The medium, containing non-attached cells, was removed after 24 to 48h and a new medium was added. The IC50 of 10-4molL-1 was determined for nonylphenol using MTT assay. Cells were then incubated with L-15 medium containing 10-5, 2×10-5, 3×10-5molL-1 of NP and samples were taken after 6, 12 and 24h of incubation for analysis of LPO, SOD, CAT, GPx, LDH, AST, ALT, and ALP. Based on the results, the lowest concentration of NP was not markedly cytotoxic to primary hepatocytes and the cell sensitivity to NP increased dose-dependently. The activities of SOD, CAT and GPx decreased significantly, while activities of LPO, LDH, AST, ALT and ALP, increased significantly in a dose-related pattern in NP-treated cells. In conclusion, this study revealed that NP could induce the oxidative stress in cultivated hepatocytes of E. coioides during a short-term exposure. NP toxicity is mainly due to the induction of the reactive oxygen species (ROS), which lead to cell membrane disruption, damage of cellular metabolism, and interference with cellular macromolecules.

Assessment of immune status of yellowfin seabream (Acanthopagrus latus) during short term exposure to phenanthrene.

The aim of the present investigation was to assess the immune status in yellowfin seabream (Acanthopagrus latus) exposed to different concentrations of phenanthrene (Phe) for 14days. In addition, the Phe accumulation in the fish muscle was measured during the experiment. Fish were injected with different concentrations (0, 2, 20 and 40mg/kg) of Phe and samples were taken from tissue and blood of fish 1, 4, 7 and 14days after injection. Exposure of fish to Phe caused a significant decrease in white blood cells, C3 and C4 levels, lysosomal membrane stability, lysozyme activity after 4days and antibacterial activity after 7days of the experiment. In contrast, cortisol level significantly increased after 4days. The concentration of Phe in fish muscle increased rapidly after 4days. The main tissue changes observed in the head kidney including increase in melanomacrophage centers (MMCs), empty spaces between cells and hemorrhage. The degree of tissue changes ranged from normal to moderate in Phe-treated fish. The size and number of MMCs in treated fish were significantly higher than control. In conclusion, Phe toxicity in yellowfin seabream can induce increased cortisol level, tissue changes and immune suppression.

Environmentally induced tissue responses of hematopoietic system in abu mullet (Liza abu) and tiger tooth croaker (Otolithes ruber) from the Persian Gulf.

The present investigation aimed to assess the possibility of using plasma levels of erythropoietin (EPO) hormone and tissue changes of hematopoietic organs as biomarkers of environmental pollution in abu mullet (Liza abu) and tiger tooth croaker (Otolithes ruber) collected from Musa Creek (northwest of the Persian Gulf). 120 L. abu and O. ruber were collected from five stations at the Musa Creek: Petrochemical, Ghanam, Doragh, Zangi and Patil stations. Blood samples were obtained from the caudal vein. Tissue samples were also taken from the spleen and head kidney, and tissue sections were prepared according to routine histological methods. The concentrations of Hg, Pb, Zn, Cu, and Cd were also measured in the sediment samples. The minimum level of EPO and the most severe tissue changes were determined in fish collected near a Petrochemical station. This station is adjacent to the Imam Khomeini Petrochemical Complex and receives highly contaminated effluents from this complex. The highest degree of contamination (Cd) also belonged to this station. The fish collected from the Patil station represented the highest EPO level and the least tissue changes. This station exhibited a lesser degree of contamination. Based on the results, there was a significant correlation between the plasma level of EPO hormone and the degree of environmental contamination.

Evaluation of lymphoid tissue structure in Sole (Euryglossa orientalis) and Yellowfin Seabream (Acanthopagus latus) affected by environmental contaminants in the Persian Gulf.

This study sought to analyze structures of lymphatic tissues in two commercial fish species, e.g. Sole (Euryglossa orientalis) and Yellowfin Seabream (Acanthopagus latus), collected from five stations with varying levels of pollution in the Musa Creek near the Persian Gulf, e.g. Petro-chemical, Gaafari, Majidieh, Ghazaleh and Zangi Stations. Samples from Genaveh Station located outside Musa Creek were collected as controls. To correlate findings of changes in the studied tissues with local pollution status, levels of Hg, Pb, Zn, Cu and Cd were measured in sediments and water at each station. Fish were caught from the sampling stations; the spleen and head kidney were collected and sections prepared to permit histologic evaluation. The results indicated that, in both species, the most common changes were observed in fish collected near the Petrochemical station and included an increase in melano-macrophage aggregates, hemorrhage and damaged/dead red blood cells in the spleen; in the head kidney, the major findings were melano-macrophage aggregation, hemorrhage and lifting of the tubular basement membrane. No pathological alternations were noted in the spleen and head kidney of fish from the Zangi station. Samples of A. latus collected from Gaafari station and of E. orientalis from Majidieh station also had pathological changes. No significant differences were found in the tissue structures of fish recovered from the Zangi and Genaveh control stations. The concentrations for nearly all of the studied metals in sediment and water samples collected from the different stations followed the pattern: Petrochemical station ≈ Majidieh ≈ Gaafari >> Ghazaleh > Zangi Stations. From the data, it was concluded that changes in lymphoid tissues of the fish studied here "correlated" with geographical conditions and sources of pollution at the different test stations. What these changes mean to the long-term health of both species remains to be determined in ongoing studies.