Liver fibrosis is associated with cutaneous inflammation in the imiquimod-induced murine model of psoriasiform dermatitis.

BACKGROUND: Psoriasis exhibits several extracutaneous manifestations. Little is known about hepatic parameters specifically associated with psoriasis. OBJECTIVES: To study whether psoriasiform dermatitis is associated with liver injury. METHODS: We studied liver parameters of inflammation and fibrosis in a murine model of psoriasiform dermatitis induced by topical application of imiquimod for 9 weeks. RESULTS: Topical treatment with imiquimod induced a form of psoriasiform dermatitis reminiscent of the human disorder, characterized by thickened and scaly skin, psoriasiform epidermal hyperplasia, altered keratinocyte differentiation and cutaneous overexpression of interleukin-17A. Mice with dermatitis displayed hepatitis, as shown by elevation of plasma transaminase levels, as well as portal and periportal hepatitis, characterized by T-lymphocyte (CD3ε+ ) and polymorphonuclear cell (Gr1+ ) infiltrates. The hepatitis progressed towards liver fibrogenesis, as shown by excessive Sirius red staining, which is consistent with the expression of α-smooth muscle actin by hepatic stellate cells. CONCLUSIONS: These results indicate that liver inflammation and fibrosis are associated with experimental psoriasiform dermatitis. Our results suggest that psoriatic inflammation may be associated with specific liver injury.

The automated micronucleus assay for early assessment of genotoxicity in drug discovery.

Recent publications on the automated in vitro micronucleus assay show predictive values higher than 85% for the classification of in vitro aneugens, clastogens and non-genotoxic compounds. In the present work, the CHO-k1 micronucleus assay in combination with cellular imaging was further evaluated. Firstly, the effect of a range of S9 concentrations on micronucleus formation and cytotoxicity was investigated. Subsequently, the reproducibility and predictivity of the micronucleus assay on CHO-k1 cells was investigated with a set of four compounds. Then, a larger set of compounds (n=44) was tested on CHO-k1 cells and inter-laboratory correlation was calculated. Finally, cellular imaging was compared with flow cytometry for in vivo assessment of micronucleus formation. The concentration of S9 had a significant impact on micronucleus formation and cytotoxicity. In addition, calculations of relative cell count (RCC) and cytokinesis-block proliferation index (CBPI) showed to be complementary to cytotoxicity assessment. The CHO-k1 micronucleus assay correctly classified the four reference compounds, with a dose-response relationship and low variability. Based on a larger set of compounds, the assay proved to be reliable with a sensitivity of 94% (n=31) and a specificity of 85% (n=13). A correlation coefficient of 97% was obtained when the lowest observable adverse effect levels (LOAELs) from our study were compared with those published by Diaz et al. (2007) [10]. In conclusion, the in vitro CHO-k1 micronucleus assay combined with cellular imaging is a predictive assay appropriate for genotoxicity screening at early stages of drug development. In addition, for in vivo assessment of micronucleus formation, we preferred to use flow cytometry rather than cell imaging.

Carcinogenic potency of perfluorooctane sulfonate (PFOS) on Syrian hamster embryo (SHE) cells.

Perfluorooctane sulfonate (PFOS) is the degradation product of many fluoroderivatives and a widespread environmental contaminant. Its persistence, its long half-life in humans and its toxicity explain high concerns on human health side effects in future. PFOS is suspected to be a non-genotoxic carcinogen. In the present work, we assessed carcinogenic potential of PFOS by studying morphological transformation in Syrian hamster embryo (SHE) cells; cell transformation of SHE cells is an in vitro assay recommended by the Organization for Economic Cooperation and Development to detect carcinogens, genotoxic or not. Genotoxicity of PFOS and expression of PPARs genes in SHE cells were also measured. PFOS was shown to induce cell transformation (P < 0.05) at non-cytotoxic concentrations (0.2 and 2 µg/mL) (P ≤ 0.01). No genotoxic effect was recorded in the range of PFOS concentrations tested (2 × 10(-4) to 50 µg/mL) using the single-cell gel electrophoresis (comet) assay after 5 and 24 h of exposure. The expression of PPARs genes was measured by qPCR within the first 24 h and after 7 days of PFOS treatment. Results indicated an increased expression of ppar-ß/δ isoform as early as 24 h. After 7 days, the increase of ppar-ß/δ mRNA was significant at the concentrations inducing cell transformation (0.2 and 2 µg/mL), while overexpression of ppar-γ and ppar-α did not closely relate to effective concentrations. The results indicate that PFOS behave as a non-genotoxic carcinogen and impacted PPARs genes. Its cell transforming potential paralleled an increased expression of ppar-ß/δ.

In situ assessment of phytotechnologies for multicontaminated soil management.

Due to human activities, large volumes of soils are contaminated with organic pollutants such as polycyclic aromatic hydrocarbons, and very often by metallic pollutants as well. Multipolluted soils are therefore a key concern for remediation. This work presents a long-term evaluation of the fate and environmental impact of the organic and metallic contaminants of an industrially polluted soil under natural and plant-assisted conditions. A field trial was followed for four years according to six treatments in four replicates: unplanted, planted with alfalfa with or without mycorrhizal inoculation, planted with Noccaea caerulescens, naturally colonized by indigenous plants, and thermally treated soil planted with alfalfa. Leaching water volumes and composition, PAH concentrations in soil and solutions, soil fauna and microbial diversity, soil and solution toxicity using standardized bioassays, plant biomass, mycorrhizal colonization, were monitored. Results showed that plant cover alone did not affect total contaminant concentrations in soil. However, it was most efficient in improving the contamination impact on the environment and in increasing the biological diversity. Leaching water quality remained an issue because of its high toxicity shown by micro-algae testing. In this matter, prior treatment of the soil by thermal desorption proved to be the only effective treatment.

Comparison of a genomic and a multiplex cell imaging approach for the detection of phospholipidosis.

Phospholipidosis (PLD) is a topic of concern in drug development because it may be associated with toxicological consequences. The aim of the study was to determine the best method to screen proprietary compounds with regard to their potential to induce PLD. Two in vitro approaches, a genomic method previously evaluated in our laboratory and a fluorescent cell based approach to detect PLD were compared using HepG2 cells. The same set of reference compounds (15 PLD inducing, 7 non-PLD inducing and 4 additional compounds) were used to compare both approaches. The same sensitivity (15/15) and similar specificity (7/7 versus, 6/7 for the genomic approach) were obtained. In addition, 11 proprietary compounds were tested in 4-day exploratory rat toxicity studies as well as in both in vitro approaches. Two of the 11 compounds induced alveolar foamy macrophages and lung vacuolization in vivo and were considered as PLD inducers. Sensitivity (2/2) and specificity (7/9) were better with the fluorescent method than with the genomic approach (1/2 and 3/9, respectively). In conclusion, compared to the genomic approach, the fluorescent method is the test of choice for screening compounds at an early stage of drug development. Indeed, the fluorescent method is more adapted to medium throughput, detects the positive reference compounds at lower (8/15) or equal (7/15) concentrations, allows multiplexing and is associated with higher sensitivity and specificity to predict lung foamy macrophages and vacuolization in vivo. Nevertheless, to confirm our conclusion, it would be necessary to compare the predictivity of both in vitro approaches by using a wide range of reference and proprietary compounds, with information on their potential to induce PLD under in vivo conditions.

Perfluorooctanoic acid (PFOA) acts as a tumor promoter on Syrian hamster embryo (SHE) cells.

Perfluorooctane sulfonate (PFOS) (C(8)F(17)SO(3)) and perfluorooctanoic acid (PFOA) (C(8)HF(15)O(2)) are synthetic chemicals widely used in industrial applications for their hydrophobic and oleophobic properties. They are persistent, bioaccumulative, and toxic to mammalian species. Their widespread distribution on earth and contamination of human serum raised concerns about long-term side effects. They are suspected to be carcinogenic through a nongenotoxic mode of action, a mechanism supported by recent findings that PFOS induced cell transformation but no genotoxicity in Syrian hamster embryo (SHE) cells. In the present study, we evaluated carcinogenic potential of PFOA using the cell transformation assay on SHE cells. The chemical was applied alone or in combination with a nontransformant concentration of benzo[a]pyrene (BaP, 0.4 µM) in order to detect PFOA ability to act as tumor initiator or tumor promoter. The results showed that PFOA tested alone in the range 3.7 × 10(-5) to 300 µM did not induce SHE cell transformation frequency in a 7-day treatment. On the other side, the combination BaP/PFOA induced cell transformation at all PFOA concentrations tested, which revealed synergistic effects. No genotoxicity of PFOA on SHE cells was detected using the comet assay after 5 and 24 h of exposure. No significant increase in DNA breakage was found in BaP-initiated cells exposed to PFOA in a 7-day treatment. The whole results showed that PFOA acts as a tumor promoter and a nongenotoxic carcinogen. Cell transformation in initiated cells was observed at concentrations equivalent to the ones found in human serum of nonoccupationally and occupationally exposed populations. An involvement of PFOA in increased incidence of cancer recorded in occupationally exposed population cannot be ruled out.

The influence of thermal desorption on genotoxicity of multipolluted soil.

A multipolluted soil sampled from a former coking plant in Lorraine (France) was evaluated for its genotoxic effects on coelomocytes of the Eisenia fetida earthworm using the comet assay. The biological efficiency of thermal desorption of the contaminated soil was also investigated. The untreated polluted soil was shown to be genotoxic to earthworms. Although thermal desorption reduced the concentration of PAHs by 94% (Sigma(16 PAHs)=1846 and 101 mg/kg before and after thermal desorption, respectively), the treatment did not eliminate the genotoxicity of soil pollutants to earthworms but increased it. The concentration of non-volatile metals did not change after thermal desorption. Among metals found in the treated soil, cadmium, chromium and nickel could explain the genotoxicity of the contaminated soil after thermal desorption. The treatment could increase the bioavailability and genotoxicity of heavy metals, through a modification of the soil's organic matter, the speciation of heavy metals and their binding to organic matter. This study underlines the importance of measuring biological effects, in order to evaluate the risk associated with formerly contaminated soils and the efficiency of remediation.

Morphological cell transformation of Syrian hamster embryo (SHE) cells by the cyanotoxin, cylindrospermopsin.

Cylindrospermopsin (CYN) is a cyanotoxin which has been implicated in human intoxication and animal mortality. Genotoxic activity of this hepatotoxin is known but its carcinogenic activity remains to be elucidated. In this work, CYN was assessed for its cell-transforming activity using the Syrian hamster embryo (SHE) cell transformation assay. This in vitro assay is used to evaluate the carcinogenic potential of chemical, physical and biological agents in SHE cells, which are primary, normal, diploid, genetically stable and capable of metabolic activation. We demonstrated that CYN induced a significant increase in morphological cell transformation in SHE cells following a 7-day continuous treatment in the range of non-cytotoxic concentrations 1 x 10(-7)-1 x 10(-2) ng/mL.

Bioavailability of chemical pollutants in contaminated soils and pitfalls of chemical analyses in hazard assessment.

Decision-making for remediation of industrial wastelands are still based on the concentrations of pollutants of concern measured in soils. In this work, two soils polluted by polycyclic aromatic hydrocarbons (PAHs) and metals were investigated for their toxicity on earthworms (Eisenia fetida), collembolae (Folsomia candida), and higher plants (Brassica chinensis, Lactucca sativa and Avena sativa) in order to study the relationships between chemical contamination and biological effects. Although the level of contamination by PAHs was elevated and commensurate in the two soils, their toxicity profile was quite different. Soil A affected survival and reproduction of invertebrates and growth of higher plants. Surprisingly, soil B, heavily contaminated by metals in addition to PAHs, was devoid of toxicity. Our results indicate that toxicity cannot simply be extrapolated from pollutant concentrations in a complex matrix in which bioavailability of pollutants may be reduced by ageing. Moreover, the use of toxicity data obtained from spiked soils characterized by readily bioavailable pollutants can also be called into question for such extrapolations. Predicting biological effects therefore requires biological tools to avoid any erroneous conclusions that can be drawn from sole extrapolation of analytical results.

2,4-Dichlorophenoxyacetic acid: effects on Syrian hamster embryo (SHE) cell transformation, c-Myc expression, DNA damage and apoptosis.

2,4-Dichlorophenoxyacetic acid (2,4-D) is a selective, systemic auxin-type herbicide extensively used throughout the world. The present research was aimed at studying effects of low and non-cytotoxic concentrations of 2,4-D on SHE cells in relation with carcinogenicity. Effects were studied on Syrian hamster morphological cell transformation, c-Myc expression - both at the gene and protein level - DNA damage and apoptosis. 2,4-D significantly induced cell transformation at 11.5 microM and 23 microM (i.e. 2.5 microg/mL and 5 microg/mL). An increase in the expression of the transcription factor c-Myc, measured by use of RT-PCR with respect to mRNA level and by Western blotting for protein level was registered at these concentrations, as well as genotoxic effects evaluated with the single-cell gel electrophoresis (Comet) assay. Consequences for apoptosis of 2,4-D treatment were also investigated. The fluorochrome acridine orange was used to study DNA fragmentation as a marker of apoptosis. No effect on apoptosis was found at 2,4-D concentrations that induced cell transformation. This was confirmed by the unchanged expression of Bcl-2 and Bax, two regulator genes of the mitochondrial pathway of apoptosis. Our results demonstrate the transforming and genotoxic effects of low concentrations of 2,4-D in mammalian cells. This information contributes to a better understanding of the mechanism of 2,4-D toxicity in mammalian cells and demonstrates that 2,4-D should be considered as potentially hazardous to humans.

Ecotoxicity of a polycyclic aromatic hydrocarbon (PAH)-contaminated soil.

Soil samples from a former cokery site polluted with polycyclic aromatic hydrocarbons (PAHs) were assessed for their toxicity to terrestrial and aquatic organisms and for their mutagenicity. The total concentration of the 16 PAHs listed as priority pollutants by the US Environmental Protection Agency (US-EPA) was 2634+/-241 mg/kgdw in soil samples. The toxicity of water-extractable pollutants from the contaminated soil samples was evaluated using acute (Vibrio fischeri; Microtox test, Daphnia magna) and chronic (Pseudokirchneriella subcapitata, Ceriodaphnia dubia) bioassays and the EC values were expressed as percentage water extract in the test media (v/v). Algal growth (EC50-3d=2.4+/-0.2% of the water extracts) and reproduction of C. dubia (EC50-7d=4.3+/-0.6%) were the most severely affected, compared to bacterial luminescence (EC50-30 min=12+/-3%) and daphnid viability (EC50-48 h=30+/-3%). The Ames and Mutatox tests indicated mutagenicity of water extracts, while no response was found with the umu test. The toxicity of the soil samples was assessed on the survival and reproduction of earthworms (Eisenia fetida) and collembolae (Folsomia candida), and on the germination and growth of higher plants (Lactuca sativa L.: lettuce and Brassica chinensis J.: Chinese cabbage). The EC50 values were expressed as percentage contaminated soil in ISO soil test medium (weight per weight-w/w) and indicated severe effects on reproduction of the collembola F. candida (EC50-28 d=5.7%) and the earthworm E. fetida (EC50-28 d=18% and EC50-56 d=8%, based on cocoon and juvenile production, respectively). Survival of collembolae was already affected at a low concentration of the contaminated soil (EC50-28 d=11%). The viability of juvenile earthworms was inhibited at much lower concentrations of the cokery soil (EC50-14 d=28%) than the viability of adults (EC50-14 d=74%). Only plant growth was inhibited (EC50-17d=26%) while germination was not. Chemical analyses of water extracts allowed us to identify inorganic water-extractable pollutants as responsible for toxicity on aquatic species, especially copper for effects on D. magna and C. dubia. The soil toxicity on collembolae and earthworms could be explained by 4 PAH congeners-fluorene, phenanthrene, pyrene, and fluoranthene. Yet, toxicity of the cokery soil as a whole was much lower than toxicity that could be deduced from the concentration of each congener in spiked soils, indicating that pollutants in the soil became less bioavailable with ageing.

Artificial streams in the assessment of environmental hazard of chemicals.

Artificial streams are dynamic mesocosms, simulating aquatic systems and rivers. They are useful to study ecotoxicity of chemicals and their effects on flora and fauna colonizing the streams or introduced into the channels. These artificial rivers can also be used to study the influence of ecological and hydrodynamic parameters, such as the kind of substrate of river and flow rate. Responses of the bivalve Unio tumidus to substrate type (silt, sand, and pebbles) and water flow rate (high and low) were investigated after 15 and 35 days in the channels, in order to optimize the experimental conditions for ecotoxicity study with methyl methacrylate (MMA). The toxicological effects of different concentrations of MMA on bivalves and on communities of invertebrates and diatoms were determined after several weeks of exposure at a high flow rate. Biomarkers responses measured in the digestive gland and the gills of U. tumidus were the activities of detoxification systems as early indicators of toxicity and lipid peroxidation as a marker of cytotoxicity. Effects of MMA resulted in a decrease in antioxidant activities. Disturbances in bivalves appeared at lower concentrations than in communities. This indicates sensitivity of the biomarkers studied, which are predictive indicators of ecotoxicity.

Toxicity of nonylphenol on the cnidarian Hydra attenuata and environmental risk assessment.

Alkylphenols and their derivatives, alkylphenol polyethoxylates (APEs), are synthetic chemicals of concern owing to their endocrine properties. Nonylphenol (NP) is a critical APE metabolite because of its recalcitrance to biodegradation, toxicity, and ability to bio-accumulate in aquatic organisms. Studies of NP effects in vertebrates demonstrated estrogenic disrupting properties in fish, birds, reptiles, and mammal cells in which NP displaces the natural estrogen from its receptor. Less is known on its toxicity toward invertebrates. Effects on reproduction have been reported, but toxicity on development has been poorly documented thus far. We investigated NP toxicity on survival and regeneration of the freshwater coelenterate Hydra attenuata. Hydra is known for its regenerative capacity and its sensitivity to chemical pollution. It has been used for over 20 years to screen for teratogenicity of chemicals (Johnson et al. (1982) Teratog Carcinog Mutagen 2:263-276). Our results showed that hydra appeared as one of the most sensitive species to acute and chronic toxicity of NP compared to several freshwater invertebrates. Regeneration was disrupted at NP concentrations lower than those affecting survival. Toxicity thresholds of NP for aquatic vertebrates and invertebrates are also reported and discussed in the context of environmental risk assessment and of water quality objectives recommended for surface waters in industrialized countries. NP levels have decreased during the last decade because of a voluntary agreement of surfactant producers and users. At present, concentrations of NP found in surface waters are far below 1 microg/L in Europe, but can reach several microg/L when wastewater treatment plant inefficiency occurs.

DNA damage (comet assay) and 8-oxodGuo (HPLC-EC) in relation to oxidative stress in the freshwater bivalve Unio tumidus.

The relationships between DNA damage and oxidative stress in the digestive gland, gills and haemocytes of the freshwater bivalve Unio tumidus were investigated. Two markers of genotoxicity were measured: DNA breaks by means of the comet assay, and oxidative DNA lesions by means of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) measured using high-performance liquid chromatography (HPLC) coupled to electrochemical detection. Lipid peroxidation was evaluated by measuring malondialdehyde (MDA) tissue levels. Effects were studied after exposure of bivalves for 6 days to benzo[a]pyrene (B[a]P) (50 and 100 microg l(-1)) and ferric iron (20 and 40 mg l(-1)), applied alone or in combination. Lipid peroxidation in the digestive gland and gills resulted from exposure to Fe3+ or B[a]P whatever the concentrations tested. DNA oxidatively formed lesions were induced in the two tissues at a higher level after B[a]P exposure than after Fe3+ treatment. No significant dose-response relationship was found with the two compounds and no synergistic effect was observed between Fe3+ and B[a]P. The gills appeared less sensitive than the digestive gland to DNA lesions expressed as 8-oxodGuo and comet results. Good correlations were noted between 8-oxodGuo and comet. MDA and DNA damage did not correlate as well, although it was stronger in the digestive gland than in the gills. Production of mucus by the gills likely served to prevent lesions by reducing the bioavailability of the chemicals tested, which could explain that dose-effect relationships and synergistic effects were not observed.

Di-(2-ethylhexyl)phthalate (DEHP) increases Bcl-2/Bax ratio and modifies c-myc expression in Syrian hamster embryo (SHE) cells.

The objective of this work was to study the anti-apoptotic properties of the non-genotoxic rodent carcinogen, di(2-ethylhexyl)phthalate (DEHP) in Syrian hamster embryo (SHE) cells. We demonstrated that a 24 h pre-treatment of SHE cells with 50 microM DEHP inhibited apoptosis triggered by growth factors deprivation. The RNA expression levels of the regulator genes involved in the apoptotic pathway, bcl-2, bax and of c-myc were measured using Western blotting and RT-PCR. We showed that a 24 h treatment of SHE cells with 50 microM DEHP increased (P < 0.05) the bcl-2 expression, while c-myc expression was decreased. No effect on bax expression was observed in the range of 10-50 microM. The defective regulation of apoptosis caused by DEHP treatment could contribute to its carcinogenicity.

The INSERM expert review on glycol ethers: findings and recommendations.

The use of glycol ethers and their effects on health have recently attracted the attention of the French health authorities. At their request, INSERM, the French Institute of Health and Medical Research, conducted a collective expertise review on glycol ethers in 1999. INSERM Expertise Reviews are independent procedures performed by experts from several disciplines, to guarantee the objectivity and the relevance of the report. During several work sessions, the experts carried out a critical analysis of and reviewed studies concerning the toxicity of glycol ethers. This process resulted in a series of recommendations and conclusions. All these data have been published in the form of a report and have been used to help the public authorities to make decisions on how to prevent risks for professionals and consumers.

Changes in expression of bcl-2 and bax in Syrian hamster embryo (SHE) cells exposed to ZnCl2.

Zinc is involved in many physiological processes and plays a critical role in functional and structural cells. Zinc at concentrations ranging from 100 to 150 micromol L(-1) has been shown to induce morphological transformation of Syrian hamster embryo (SHE) cells. At these concentrations, zinc inhibited apoptosis in SHE cells. The objective of this study was to elucidate the mechanisms of action of zinc on the apoptotic pathway. Effects of 100 and 150 micromol L(-1) ZnCl(2) on the expression of two members of the Bcl-2 family of proteins and on the transcription factor c-Myc in SHE cells was investigated using RT-PCR. No effect on the proto-oncogene c-myc was observed. Up-regulation of bcl-2 expression was found and bax expression was reduced. These changes have been corroborated by immunoblotting. Effects of Zn(2+) on bcl-2/bax ratio were confirmed in apoptotic camptothecin-treated SHE cells. Cloned and sequenced cDNAs obtained from RT-PCR amplifications allowed us to check the RT-PCR products encoded the expected proteins. This study demonstrated that zinc acts in the early phases of the apoptotic process by modification of the bcl-2/bax ratio in normal and apoptotic SHE cells.

Defense systems of benthic invertebrates in response to environmental stressors.

Environmental stress factors may be responsible for biological changes in living species that are able to overcome deleterious effects depending on their detoxifying capacities. Defense systems present in every living species are involved in elimination of reactive chemical species of endogenous or exogenous origin, neutralization of their effects, repair of initial lesions, and compensation of deficient metabolic pathways. Consequently, the performance of defense systems and their inducibility will explain adaptation to environmental disturbances, whereas their alteration will augur toxicity in the exposed species. Several field studies have illustrated the relationships between antioxidants and toxicity in benthic invertebrates in rivers. They highlighted that defense systems may be useful biomarkers in mechanistic studies of ecotoxicity and in the biomonitoring of living species in polluted environments.

Relationship between two oxidative stress biomarkers, malondialdehyde and 8-oxo-7,8-dihydro-2'-deoxyguanosine, in the freshwater bivalve Unio tumidus.

This study addresses the question of the relation between cellular and genomic oxidative damages in freshwater bivalves in realistic conditions of exposure in the field. Membrane and genomic oxidative damages were studied by means of lipid peroxidation and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), respectively. Malondialdehyde (MDA) was used as an indicator of lipid peroxidation. The biomarkers were measured in the digestive gland and the gills of mussels (Unio tumidus) after 7 and 21 days of exposure in four ponds of the Moselle Basin, during three field studies conducted in 1999 and 2000. Effects measured at three sites (1R, 3C and 4M) were moderate and lipid peroxidation was slightly enhanced in mussels transferred in these ponds. In contrast, an important degradation was observed at site 2V reflected by a sharp increase in MDA and 8-oxodGuo concentrations in 2000. The biomarker responses agreed with the results of physicochemical analyses that indicated a worsening of water quality at the same site. Globally, a relationship was found between MDA increase and 8-oxodGuo formation, in the digestive gland after 7 days of exposure, and later in the gills (21 days). Responses of the digestive glands and gills to the oxidative parameters appeared correlated only after 21 days of exposure. The biomarkers selected confirmed their sensitivity for appraising the water quality of hydrosystems.

ZnCl2 induces Syrian hamster embryo (SHE) cell transformation.

In order to test the hypothesis of a relationship between apoptosis and neoplastic transformation, we studied the transforming potency of zinc, known for its antiapoptotic effects. In this study, zinc chloride (100 microM) was shown to induce morphological transformation (MT) in Syrian hamster embryo (SHE) cells. It was also tested in combination with benzo(a)pyrene (BaP), a positive control for carcinogenicity, or fomesafen, a carcinogenic pesticide with hepatic peroxisomal proliferation properties. A co-exposure of the two carcinogens with 100 microM zinc increased cell transformation in SHE cells. These results were in agreement with the theory of a relationship between the inhibition of apoptosis and induction of cell transformation. The cloning efficiency (CE) of SHE cells seeded at clonal density was raised by zinc, fomesafen and furthermore by the mixture of the two chemicals, which could be explained by the antiapoptotic action of zinc and fomesafen on SHE cells. No change in myc and bax expressions was observed in zinc-treated SHE cells.