Cholinesterase activity and histopatological changes in the Mediterranean crab, Carcinus maenas, exposed to environmental contaminants

Marine environments are continuously being threatened by a large number of pollutants including heavy metals and organophosphorous pesticides from anthropogenic sources. These compounds can cause a serious environmental problem. The present study aimed: (1) to measure sensitivity of acetylcholinesterase (AChE) activity to in vivo exposure to the organophosphorous chlorpyriphos-ethyl (CPF) and to the heavy metals cadmium (Cd) and copper (Cu) and (2) to use the histopathological lesions as tissue biomarkers for biomonitoring of different contaminations. The results clearly showed that the AChE activity in different tissues (digestive gland, muscle and eyes) of Carcinus maenas was relatively sensitive to the concentrations of CPF and tended to have different patterns in response to Cd, Cu and Cu+Cd mixture exposure. The transfer of treated crabs to the clean sea water allowed to recover totally or partially the lost activity depending on selected tissues and contaminant exposure (metals or organophosphorous compounds). Histopathological biomarkers in C. maenas exposed to different contaminants showed the presence of different lesions which altered the digestive gland after 7 days of contamination

Study of lipid profile and parieto-temporal lipid peroxidation in AlCl3 mediated neurotoxicity. modulatory effect of fenugreek seeds

<p>Abstract</p> <p>Background</p> <p>Peroxidation of lipid (LPO) membrane and cholesterol metabolism have been involved in the physiopathology of many diseases of aging brain. Therefore, this prospective animal study was carried firstly to find out the correlation between LPO in posterior brain and plasmatic cholesterol along with lipoprotein levels after chronic intoxication by aluminium chloride (AlCl₃). Chronic aluminum-induced neurotoxicity has been in fact related to enhanced brain lipid peroxidation together with hypercholesterolemia and hypertriglyceridemia, despite its controversial etiological role in neurodegenerative diseases. Secondly an evaluation of the effectiveness of fenugreek seeds in alleviating the engendered toxicity through these biochemical parameters was made.</p> <p>Results</p> <p>Oral administration of AlCl₃to rats during 5 months (500 mg/kg bw i.g for one month then 1600 ppm via the drinking water) enhanced the levels of LPO in posterior brain, liver and plasma together with lactate dehydrogenase (LDH) activities, total cholesterol (TC), triglycerides (TG) and LDL-C (Low Density Lipoproteins) levels. All these parameters were decreased following fenugreek seeds supplementation either as fenugreek seed powder (FSP) or fenugreek seed extract (FSE). A notable significant correlation was observed between LPO_brainand LDL-C on one hand and LDH_liveron the other hand. This latter was found to correlate positively with TC, TG and LDL-C. Furthermore, high significant correlations were observed between LDH_brainand TC, TG, LDL-C, LPO_brainas well as LDH_liver.</p> <p>Conclusion</p> <p>Aluminium-induced LPO in brain could arise from alteration of lipid metabolism particularly altered lipoprotein metabolism rather than a direct effect of cholesterol oxidation. Fenugreek seeds could play an anti-peroxidative role in brain which may be attributed in part to its modulatory effect on plasmatic lipid metabolism.</p

Assessment of Oxidative Stress and Histopathological Biomarkers in the Parablennius Incognitus Fish as Potential Contamination Indicators of the Bay of Sousse (Tunisia)

International audienceOxidative stress and histopathological biomarkers were investigated in the gills and liver of Parablennius incognitusfishes. Individuals sampled in the bay of Sousse were compared to fishes from a reference site, i.e. GhdamsiIsland (Tunisia). Severe biochemical and histological alterations were observed in fishes from Sousse bay andassociated with urban discharges contamination. Several tissue alterations were also observed in gills, particularlylamellar epithelium detachment, disorganization of pillar cells, and hypertrophy of chloride cells. In the liver wenoted particularly hypertrophy of hepatocytes, congestion and dilation of the central vein and sinusoid capillaries,pyknotic nucleus, and hepatic steatosis. The high reduction of superoxide dismutase and catalase activities in gillsand of superoxide dismutase and glutathione peroxidase activities in the liver of contaminated fishes may explainthe increase of lipoperoxidation in both organs of P. incognitus. The integrated biomarker response values found inindividuals from the contaminated site were in good agreement with alteration of physico-chemical parameters andwith the high level of Cd concentrations detected in water of the stressful place, i.e. the bay of Sousse. Oxidativestress and histopathological alterations were sensitive biomarkers to discriminate between fishes from the pollutedSousse bay site and those from the reference site, suggesting their potential utility in bio monitoring

Mercury accumulation and its effects on molecular, physiological, and histopathological responses in the peacock blenny Salaria pavo

International audienceFor humans, fish consumption is the major source of mercury (Hg) exposure. The aim of this study was to assess the effect of Hg in the peacock blenny Salaria pavo, a species of the family of blennies that was used as indicator of water pollution. We performed a sublethal contamination of fish to 66 μg HgCl2 L−1 during 1, 4, 10 and 15 days but Hg concentration measured in the experimental water was much lowerthan the nominal concentration. Hg was also measured in both gill and liver tissues and displays a significant increase of its concentration in gills after 1 day of exposure followed by a decrease throughout the experiment. In the liver, Hg burden reaches its maximum at day 4 followed also by a decrease. Partial-length cDNA of mt1, mt2, gpx, cat, mnsod and cuznsod was characterized. Results from mRNA expression levels displayed an up-regulation of mt1, gpx and mnsod while a downregulation of cat was observed. Several biomarker activities were determined in gills and liver and exposure to Hg affected all antioxidant enzymes in gills. EROD, GST and GPx significantly decreased, while CAT levels increased from 4 days of Hg exposure. No lipid peroxidation (LPO) induction was observed in gills of exposed fish. Regarding the liver, the activity of all enzymes increased significantly from the beginning of the experiment. LPO induction was, however, induced after 4 days only. The histological analysis also performed indicated that fish exhibited several damages in gills and liver, mainly in relation to circulatory disturbances in the gills and regressive changes in the liver. All biomarkers assessed showed that peacock blennies are able to detoxify Hg from gill and liver tissues by developing various defense mechanisms

Effects of Hg sublethal exposure in the brain of peacock blennies Salaria pavo : Molecular, physiological and histopathological analysis

International audienceMarine environments are affected by large amounts of toxicants among those mercury (Hg). The aim of this study was to assess potential neurotoxic effects of Hg in the peacock blenny Salaria pavo. A sublethal contamination to 66 μg HgCl2 L-1 over periods of 1, 4, 10 and 15 days was performed. Total Hg concentrations measured in the brain highlighted the detection of Hg at days 1 and 4 following the exposure but no concentration of the metal was further detected. Partial-length cDNA of genes coding ABC transporters (abcb1, abcc1, abcc2, abcg2) and acetylcholinesterase (ache) were characterized. Results from mRNA expression levels displayed an up-regulation of abcb1 mRNA while a down-regulation of abcc1 and abcc2 mRNA was observed. No change in abcg2 and ache mRNA expression was noted throughout the experiment. At each sampling time, Hg exposure did not affect the activity of the AChE enzyme. The histological analysis indicated that fish exhibited several damages in the optic tectum and the cerebellum and 3 reaction patterns were identified for each organ: circulatory disturbances, regressive and progressive changes. Molecular, physiological and histological biomarkers assessed in the present study highlighted that peacock blennies were able to detoxify Hg from the brain tissue by developing defense mechanisms. More globally, neurotoxic effects of a sublethal Hg exposure in the brain of peacock blennies and the adaptation capacity of this species were evaluated

Transcriptomic, Biochemical, and Histopathological Responses of the Clam Ruditapes decussatus from a Metal-Contaminated Tunis Lagoon

International audienceThis study was designed to investigate the molecular (transcriptional expression), biochemical (oxidative stress and neurotoxicity), and histopathological effects of metal contamination in the gill of clams (Ruditapes decussatus) sampled from the Tunis lagoon. The concentrations of five heavy metals (Cd, Pb, Hg, Cu, and Zn) in surface sediments and their accumulation in soft tissues of R. decussatus were evaluated in three sites (Z1, Z2, and Z3). A metal contamination state of Tunis lagoon sediments was noted with spatial variations with relatively high levels at Z2. Biomarker analyses showed an increase in glutathione S-transferase and catalase activities and lipid peroxidation levels and a decrease in acetylcholinesterase activity in the studied sites. Molecular investigation showed a significant overexpression of: cytochrome c oxidase subunit I, ribosomal RNA 16S, Cu/Zn superoxide dismutase, heat shock protein 70, and metallothioneins in the three sampling sites. Moreover, our data were correlated to severe and diverse histopathological alterations in the clam gills. The principal component analysis showed that the Z2 region is more affected by metal contamination than Z1 and Z3 regions. Current field results suggest the use of several combined biomarkers at different cell levels instead of individual ones in monitoring programs

Cadmium exposure exerts neurotoxic effects in peacock blennies Salaria pavo

International audienceCadmium (Cd) is considered as an important factor involved in several neurological disturbances. The aim of this study was to assess the effects of Cd in the brain of peacock blennies Salaria pavo, a species used as a bioindicator of water pollution. A sublethal contamination of 2 mg CdCl2 L⁻¹ was performed over periods of 1, 4, 10 and 15 days. Total Cd accumulation was measured in brains and displayed low concentrations throughout the experiment. Partial-length cDNA of different ATP-binding cassette transporters (abcb1, abcc1, abcc2, abcg2 proteins) and acetylcholinesterase (ache) were characterized. mRNA expressions profiles displayed an up-regulation of abcc2 mRNA after 4 days of Cd exposure only while abcg2 mRNA was down-regulated after 10 days only. For AChE, the mRNA transcription and the activity of the enzyme were followed and highlighted that Cd exerted an inhibitory effect on the nervous information transmission. At the histological level, fish exhibited pathological symptoms in the optic tectum and the cerebellum and results showed that the cerebellum was the most affected organ