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At least 1,153 records · Page 64Linked to original sources
PubMed2005

Inhibition of cell differentiation by quinolones in micromass cultures of rat embryonic limb bud and midbrain cells.

Micromass cultures (MMC) of rat embryonic limb bud (LB) and midbrain (CNS) cells were applied to compare the developmental toxicity of three quinolone antimicrobials: norfloxacin (Nor), enrofloxacin (Enr) and ciprofloxacin (Cip). Cultures were exposed for 5 days to seven concentrations of drugs. Cytotoxicity was assessed by quantifying neutral red uptake; differentiation-by quantifying alcian blue uptake (LB) or by image analysis of Gill's haematoxylin stained foci (CNS). Both, LB and CNS cultures showed dose-dependent reduction in total cell number and differentiation. To distinguish specific effect on differentiation, IC(50) for proliferation (P) and differentiation (D) were calculated and P/D ratios were compared. In LB cultures all three drugs were cytotoxic (P/D ratios were 1). In CNS cultures P/D ratios were 1 (up to 2.7 for Nor, up to 4.4 for Enr and up to 16 for Cip) what can suggest specific action on differentiation. Ciprofloxacin was the most toxic and CNS cells were more sensitive than LB. The ranges of IC(50)-D values (microg/ml) were as follows: Nor (79-14), Enr (127-179), Cip (91-101) in LB cultures; Nor (22-52), Enr (38-91), Cip (3-17) in CNS cultures. With one exception (Cip in CNS culture) all drugs were classified as weak embryotoxic.

Animals↗
PubMed2005

Ecotoxicological evaluation of diethanolamine using a battery of microbiotests.

In order to investigate the potential ecotoxicity of diethanolamine (DEA), a battery of model systems was developed. DEA is widely used as a chemical intermediate and as a surface-active agent in cosmetic formulations, pharmaceuticals and agricultural products. DEA was studied using ecotoxicological model systems, representing four trophic levels, with several bioindicators evaluated at different exposure time periods. The battery included bioluminescence inhibition of the bacterium Vibrio fischeri, growth inhibition of the alga Chlorella vulgaris and immobilization of the cladoceran Daphnia magna. Cell morphology, total protein content, neutral red uptake, MTS metabolization, lysosomal function, succinate dehydrogenase activity, G6PDH activity, metallothionein levels and EROD activity were studied in the hepatoma fish cell line PLHC-1, derived from Poeciliopsis lucida. The systems most sensitive to DEA were both D. magna and V. fischeri, followed by C. vulgaris and the fish cell line PLHC-1. The most prominent morphological effect observed in PLHC-1 cultures exposed to DEA was the induction of a marked steatosis, followed by death at high concentrations, in some cases by apoptosis. The main biochemical modification was a nearly three-fold increase in metallothionein levels, followed by the stimulations of lysosomal function and succinate dehydrogenase and G6PDH activities. Judging by the EC(50) values in the assay systems, DEA is not expected to produce acute toxic effects in the aquatic biota. However, chronic and synergistic effects with other chemicals cannot be excluded.

Aliivibrio fischeri↗
PubMed2005

Mutagenic and cytotoxic effect of planifolin: a naphthopyranone dimer isolated from Paepalanthus planifolius.

A naphthopyranone dimer, named planifolin, was isolated from a methylene chloride extract of the capitula of Paepalanthus planifolius Koern. The molecule (C(31)H(26)O(10)) appeared to be made up of two monomeric portions, semi-vioxanthin and paepalantine (an isocoumarin), linked by an ether bond, and it may possess several kinds of biological activity that can be related to its polyphenolic structure. Short-term tests that detect genetic damage can afford the information needed to evaluate carcinogenic risks of chemicals to humans. The Ames test, recommended for testing the mutagenicity of chemical compounds with potential pharmacological application, was used in the present study. The mutagenic activity was evaluated in Salmonella typhimurium strains TA100, TA98, TA102 and TA97a and the cytotoxic effect in McCoy cells. The in vitro cytotoxicity of planifolin to McCoy cells, tested in microculture with neutral red, showed a significant cytotoxic index (CI(50)) of 12.83 microg/mL. Planifolin showed mutagenic activity for TA100, TA98 and TA97a. The results indicate that this new naphthopyranone dimer causes mutations by substitution and by addition and deletion of bases in the sequence of DNA. Moreover, its mutagenic potential was increased by metabolic activation.

Animals↗
PubMed2006

Modulation of cadmium chloride toxicity by sulphur amino acids in hepatoma cells.

Cadmium is a toxic metal and no effective antidote exists at present. The aim of this study was to examine whether sulphur amino acids, involved in glutathione synthesis, can modulate cadmium toxicity in vitro. Two hepatoma cell lines (HepG2 and HTC cells) were exposed to cadmium chloride (0-100 microM) for 8h in control media or in media containing 1mM of homocysteine, cysteine or cystathionine. Cell viability was then assessed with the neutral red assay. In order to assess the mechanism by which homocysteine and cysteine modulate cadmium toxicity their ability to scavenge reactive oxygen species was determined as well as the potential to increase intracellular glutathione levels. The ability of the sulphur amino acids to prevent cadmium uptake by HTC and HepG2 cells was also assessed. The results indicate that homocysteine and cysteine protect efficiently both cell lines from cadmium chloride toxicity whereas cystathionine protects efficiently HTC cells but not HepG2 cells. This effect was shown to be dependent on the dose of each amino acid and increased protection from cadmium was observed with increasing concentrations of homocysteine and cysteine. Both amino acids prevented the formation of reactive oxygen species only when they were administered together with cadmium chloride. In addition homocysteine and cysteine did not increase intracellular glutathione levels. The results indicate that the mechanism by which sulphur amino acids protect from cadmium toxicity in vitro is due to the reduced uptake of the metal by the cells possibly by direct binding to the -SH group of the amino acids.

Cadmium Chloride↗
PubMed2006

Effects of repeated ochratoxin exposure on renal cells in vitro.

In the present study an in vitro model of subchronic repeated exposure to OTA and OTB was employed to generate ochratoxin-derived subpopulations of human and porcine proximal tubular cells (HKC, IHKE, PKC, LLC-PK1). These cell subpopulations were subsequently used to investigate effects on cell proliferation rates, expression of marker proteins (cytokeratins, vimentin) and the acute cytotoxicity of OTA and OTB (MTT reduction, neutral red uptake, cell number). The hypothesis was tested whether repeated exposure at moderate concentrations of these toxins could provide for a reduced sensitivity of selected cell subpopulations to subsequent toxin exposure. Despite the observed increased cell population doubling times and the reduced sensitivity toward OTA and OTB exposure of some cell types, with the exception of the primary human epithelial cells, no overt changes in the expression of cytokeratin and vimentin could be determined. The presented data, however suggest that repeated exposure of renal epithelial cells to ochratoxins A or B will provide for a subpopulation of cells with reduced ochratoxin-sensitivity and alterations in growth characteristics.

Animals↗
PubMed2006

Primary culture of rat hepatocytes in 96-well plates: effects of extracellular matrix configuration on cytochrome P450 enzyme activity and inducibility, and its application in in vitro cytotoxicity screening.

Basal level enzyme activities and enzyme inducibility were compared for rat hepatocytes that were cultured in 96-well plates with three different extracellular matrix configurations: single layer (SL) collagen type I, SL Matrigel, and collagen/Matrigel (C/M) sandwich. Overall, C/M sandwich and SL Matrigel plates were both superior to SL collagen type I plates in maintaining enzyme activities and inducibility and C/M sandwich plates had higher induced activity for CYP3A enzymes than SL Matrigel plates did. Cytotoxicity of nine reference compounds to rat hepatocytes (C/M sandwich configuration), rat hepatoma H4IIE and mouse fibroblast Balb/c 3T3 (3T3) cells was evaluated in 96-well plates using neutral red uptake (for 3T3) and tetrazolium salt MTS assays (for H4IIE and rat hepatocytes). For compounds chlorpromazine, quinidine, trichlorfon, thiopental, and antipyrine, the absolute differences in cytotoxicity LogIC(50) values obtained from different cell types were relatively small and without an obvious trend. The DeltaLogIC(50) values between cultured hepatocytes and the cell lines were much larger for acetaminophen and cyclophosphamide (1.35 < or =/DeltaLogIC(50)/ < or = 3.40), and for clofibrate and thioacetamide (not cytotoxic in hepatocytes at their highest dose levels). These large differences were likely the result of metabolism of these compounds in rat hepatocytes. The relationship between in vitro cytotoxicity LogIC(50) values and in vivo mouse or rat oral acute LogLD(50) values showed that compared to the cell lines, cultured rat hepatocytes improved correlation for acetaminophen and cyclophosphamide. The potential benefit of conducting in vitro cytotoxicity screening using a combination of permanent cell lines and cultured hepatocytes would allow us to obtain mechanistic insight on bioactivation, as well as improve the predictability of metabolism-mediated toxicity.

3T3 Cells↗
PubMed2004

Assessment of the potential irritation and photoirritation of novel amino acid-based surfactants by in vitro methods as alternative to the animal tests.

The ultraviolet-A radiation damage effects on skin and eyes will be increased by phototoxic compounds which could be present in pharmaceutical or cosmetic formulations. Great efforts have been made in the last years to find surfactants to replace those with phototoxic potential in commercial use. Series of different in vitro models for phototoxicity, included to validated neutral red uptake (NRU) 3T3 phototoxicity assay are useful screening tools. The phototoxic effects of a novel family of glycerol amino acid-based surfactant compounds were examined via these assays. Human red blood cells and two immortalised cell lines, murine fibroblast cell line 3T3, and one human keratinocyte cell line, HaCaT, were the in vitro models employed to predict potential photoirritation. The phototoxic end-points assessed were hemolysis (human red blood cell test) and resazurin transformation to resorufin and NRU in cell culture methods. The results suggest that no phototoxic effects by any new amino acid derived-surfactants, could be identified.

Amino Acids↗
PubMed2005

Cytotoxicity of trichloroethylene and perchloroethylene on normal human epidermal keratinocytes and protective role of vitamin E.

Trichloroethylene (TCE) and perchloroethylene (PERC), the most common alkenyl halides, have been extensively used in industry, and can cause skin damage. To evaluate their cytotoxic potential on skin, the effects of these agents on the normal human epidermal keratinocytes (NHEK) were investigated. Their action on cell viability, membrane integrity and lipid peroxidation (LPO) was assessed by neutral red uptake (NRU) assay, lactate dehydrogenase (LDH) release test and measurement of malondialdehyde (MDA) levels and superoxide dismutase (SOD) activity. In addition, the protective effect of antioxidatant vitamin E on the cytotoxicity was also studied. Incubation of NHEK with various concentrations (0.01-31.6 mM) of TCE or PERC caused a dose-dependent decrease in cell viability, with 80% reduction at 31.6 mM. NR50 values from the cytotoxicity assay was found to be 4.53 and 2.16 mM for TCE and PERC, respectively. A time- and concentration- dependent release of LDH were observed at 1, 2, 3, 4 h after cells were exposed to different doses of TCE or PERC. These agents also caused an increase of MDA, whilst an inhibition of SOD activity, in a concentration-dependent manner. Pre-treatment of the cells with vitamin E at 10-200 mM dose-dependently attenuated the cytotoxic effect of TCE or PERC. Pre-treatment with vitamin E also reversed subsequent TCE or PERC-induced release of LDH, elevation of lipid peroxidation and decline of anti-oxidant enzyme activities. These results suggest that TCE and PERC could induce cytotoxicity to NHEK associated with oxidative stress and antioxidatant vitamin E could effectively protect NHEK from TCE- or PERC-induced cytotoxicity, which may be associated to the superoxide scavenging effect and enhancement of anti-oxidant enzyme activities.

Cell Survival↗
PubMed2006

Resveratrol induces apoptotic cell death in rat H4IIE hepatoma cells but necrosis in C6 glioma cells.

Resveratrol (trans-3,5,4',-trihydroxystilbene) is assumed to possess cancer-preventive and cancer-therapeutic properties. The aim of this project was to analyze cellular effects of resveratrol in metabolically active H4IIE rat hepatoma cells in comparison to metabolically poorly active C6 rat glioma cells. Resveratrol is rapidly taken up by both cell types and acts as a potent intracellular antioxidant. On the other hand, resveratrol in higher concentrations is relatively toxic to both cell lines as measured by the neutral red accumulation assay. In H4IIE cells, resveratrol concentrations rapidly decline to very low levels during the first hours of incubation due to formation of resveratrol glucuronides. The first resveratrol effect found at 3h after the start of resveratrol treatment was the induction of mild DNA damage as detected by the comet assay. Cell death was caused via induction of apoptosis as detected by caspase activation, oligonucleosomal DNA fragmentation and formation of apoptotic nuclei. Following DNA damage, resveratrol led to an activation of caspases 2 and 8/10 at 6h and consequently of caspase 3 at 12h, but failed to activate caspase 9. In contrast to H4IIE cells, resveratrol is not metabolised in C6 glioma cells and accumulates to concentrations which are assumed to drive the cell into necrosis. This suggests that the mode of cell death caused by resveratrol and the usefulness of resveratrol for cancer prevention and treatment critically depends on the metabolic capacity of the tumor cell to be eradicated.

Animals↗
PubMed2006

Cytotoxic effect of ciprofloxacin in primary culture of rat astrocytes and protection by Vitamin E.

The aim of this study was to investigate the possible cytotoxic and oxidative stress inducing effects of ciprofloxacin (CPFX) on primary cultures of rat astrocytes. The cultured cells were incubated with various concentrations of CPFX (0.5-300mg/l), and cytotoxicity was determined by neutral red (NR) and MTT assays. Survival profile of cells was biphasic in NR assay: CPFX did not cause any alteration at any concentration for 7h, whereas < or =50mg/l concentrations induced significant cell proliferation in incubation periods of 24, 48, 72, and 96h. However, cell proliferation gradually decreased at higher concentrations, and 200 and 300mg/l of CPFX exposure was found to be significantly (p<0.05) cytotoxic at all time periods. With MTT assay, no alteration was noted for incubation period of 7h, as observed with NR assay. But, cell viability decreased with approximately > or =50mg/l CPFX exposure in all other time periods. Cell proliferation was only seen in 24h of incubation with 0.5 and 5mg/l CPFX. Vitamin E pretreatment of cell cultures were found to be providing complete protection against cytotoxicity of 300mg/l CPFX in 96h incubation when measured with both NR and MTT assays. The SOD pretreatment was partially protective with NR assay, but no protection was noted when measured with MTT. A significant enhancement of lipid peroxidation was observed with the cytotoxic concentration of the drug, but total glutathione content and catalase activity of cells did not change. The data obtained in this study suggest that, in accordance with our previous results with fibroblast cells, CPFX-induced cytotoxicity is related to oxidative stress. And the biphasic effect of CPFX possibly resulted from the complex dose-dependent relationships between reactive oxygen species, cell proliferation, and cell viability.

Animals↗
PubMed2006

Cytotoxicity and related effects of T-2 toxin on cultured Vero cells.

T-2 toxin belongs to a group of mycotoxins synthesized by Fusarium fungi that are widely encountered as natural contaminants of certain important agricultural commodities particularly, cereals. Upon exposure, T-2 toxin causes severe human and animal diseases. It is considered to be a major causative agent in fatal alimentary toxic aleukia (ATA) in humans. In this study, cytotoxicity and apotosis induction by T-2 toxin was investigated in vitro on Vero cell line using the MTT and the neutral red viability assays, the induction of lipid peroxidation, the decrease of macromolecule levels (protein, DNA and RNA), DNA fragmentation and caspase-3-dependent apoptosis induction. Our results showed that T-2 toxin reduced cell viability correlated to an impairment of macromolecule levels. It also increased MDA formation, induced DNA fragmentation showed by DNA laddering patterns on agarose gel electrophoresis. This fragmentation is in relation with apoptosis induction which was confirmed by activation of caspase-3, and depletion of the mitochondrial membrane potential reflecting a mitochondrial dysfunction.

Animals↗
PubMed2006

Effects of combinations of Fusarium mycotoxins on the inhibition of macromolecular synthesis, malondialdehyde levels, DNA methylation and fragmentation, and viability in Caco-2 cells.

We studied the interactive effects of either binary or tertiary mixtures of Fusarium mycotoxins, deoxynivalenol (DON), zearalenone (ZEA), and fumonisin B1 (FB1) on the human intestinal cell line, Caco-2, using the endpoints including malonedialdehyde (MDA) production, inhibition of protein and DNA syntheses, DNA methylation, DNA fragmentation, and cell viability as measured by the neutral red (NR) test. The mixtures of mycotoxins reduce cellular viability in increasing order: [FB1+ZEA]<[FB1+DON]<[ZEA+DON]<[FB1+DON+ZEA] in NR test. Because FB1 antagonizes the effects of estrogenic Zearalenone, FB1 was assayed against estradiol. In NR assay, mixture of FB1 and estradiol and/or ZEA improves Caco-2 cells viability in contrast to individual effects. Mixtures of ZEA or FB1 and DON, display synergistic effects in lipid peroxidation. The ability of the toxins to inhibit DNA synthesis is 45%, 70%, and 43% for 10 microM of ZEA, DON, and FBI, respectively. Their binary mixtures (at 10 microM each), inhibit DNA synthesis by 35%, 62%, and 65%, far less than additive effects. Surprisingly, the tertiary mixture (10 microM each) only inhibits DNA synthesis by 25%. ZEA, DON, and FB1 induce DNA fragmentation individually. However, mixtures of these mycotoxins always damage DNA to a greater extent. Each individual mycotoxin (10 microM) raises the percentage of 5-methylcytosine (m5dC) in DNA from 4.5% to 9%, while the combination does not increase this rate any further. Altogether, the data indicate that mixtures of Fusarium toxins are able to induce lipid peroxidation, DNA damage, DNA fragmentation, DNA methylation, and cytotoxicity in Caco-2 cells, and suggest a potential promoter effect in human intestinal cells.

Apoptosis↗
PubMed2006

Cytotoxicity of Lachesis muta muta snake (bushmaster) venom and its purified basic phospholipase A2 (LmTX-I) in cultured cells.

Human envenoming by Lachesis muta muta venom, although infrequent, is rather severe, being characterized by pronounced local tissue damage and systemic dysfunctions. Studies on the pharmacological actions of L. m. muta venom are relatively scant and the direct actions of the crude venom and its purified phospholipase A(2) (PLA(2)) have not been addressed using in vitro models. In this work, we investigated the cytotoxicity of L. m. muta venom and its purified PLA(2) isoform LmTX-I in cultured Madin-Darby canine kidney (MDCK) and in a skeletal muscle (C2C12) cell lines. As revealed by neutral red dye uptake assay, the crude venom (10 or 100 microg/ml) induced a significant decrease in cell viability of MDCK cells. LmTX-I at the concentrations tested (70-270 microg/ml or 5-20 microM) displayed no cytotoxicity in both MDCK and C2C12 cell lines. Morphometric analysis of Feulgen nuclear reaction revealed a significant increase in chromatin condensation (pyknosis), apparent reduction in the number of mitotic nuclei and nuclear fragmentation of some MDCK cells after incubation with L. m. muta venom. Monolayer exposure to crude venom resulted in morphological changes as assessed by scanning electron microscopy. The staining with TRITC-labelled phalloidin showed a marked disarray of the actin stress fiber following L. m. muta venom exposure. In contrast, LmTX-I had no effect on nucleus and cell morphologies as well as on stress fiber organization. These results indicate that L. m. muta venom exerts toxic effects on cultured MDCK cells. The LmTX-I probably does not contribute per se to the direct venom cytotoxicity, these effects are mediated by metalloproteinases/disintegrins and other components of the venom.

Animals↗
PubMed2005

Investigation of cytotoxic, genotoxic, mutagenic, and estrogenic effects of the flame retardants tris-(2-chloroethyl)-phosphate (TCEP) and tris-(2-chloropropyl)-phosphate (TCPP) in vitro.

The organophosphorus esters tris-(2-chloroethyl)-phosphate (TCEP) and tris-(2-chloropropyl)-phosphate (TCPP) have been widely used as flame retardants and fire preventing agents, e.g. in polyurethane foams. We investigated the cytotoxic, genotoxic, mutagenic, and estrogenic potentials of TCEP and TCPP, using different in vitro models. Cytotoxic effects were evaluated by neutral red uptake and genotoxicity with the alkaline single cell gel electrophoresis (Comet assay), both in V79 (hamster fibroblasts) cells. Mutagenicity was tested in the Ames assay with Salmonella typhimurium using the strains TA 97 a, 98, 100, 102, 104, 1535, 1537, and 1538, with and without metabolic activation by S9-rat liver homogenate. Estrogenic or anti-estrogenic effects were examined with the recombinant yeast reporter gene assay, and in human endometrial cancer Ishikawa cells by induction of alkaline phosphatase. In V79 cells TCEP was weakly cytotoxic at concentrations above 10 microM in the presence of S9-rat liver homogenate whereas TCPP showed cytotoxicity above 1mM in the presence of S9. Both substances did not induce DNA strand breaks in the alkaline version of the Comet assay neither without an external enzymatic metabolizing system, nor in the presence of S9-mix. Additionally, no mutagenic potential could be detected for TCEP and TCPP in eight Salmonella strains using concentrations up to 1mM in the presence and absence of S9. Hormonal activity shown as induction of estrogenic or anti-estrogenic effects could not be detected in the two in vitro test systems.

Animals↗
PubMed2006

Role of trace elements in cadmium chloride uptake in hepatoma cell lines.

Cadmium coexists with other metals in various products. Releases of cadmium in the environment occur in parallel to the release of other metals including copper, iron and zinc which also have an essential role in human homeostasis as they participate in various biochemical pathways. We studied the interaction of iron, copper, zinc and calcium channel blockers (nifedipine and verapamil) with cadmium chloride in two hepatoma cell lines (HepG2 and HTC cells) in order to determine if these trace elements can affect CdCl(2) uptake and interfere with its toxicity. Both cell lines were initially exposed to CdCl(2) (0-200 microM) for 2h and the uptake of the metal was determined. Cadmium chloride uptake by HepG2 and HTC cells shows an increase with increasing doses of the metal. Cells were also pretreated with 100 uM of FeCl(2) or ZnCl(2) or CuCl(2) or with a nifedipine/verapamil (100 uM) mixture for 2h and then exposed to 200 uM CdCl(2) for 1h in the presence of the trace elements. The uptake of CdCl(2) was determined as well as the membrane integrity (LDH leakage assay), the cell viability (neutral red assay) and cell proliferation (protein assay). Zinc and calcium channel blockers inhibited the uptake of cadmium chloride by both cell lines. On the other hand iron loading resulted in increased uptake of CdCl(2) by both cell lines whereas copper loading increased the uptake of cadmium chloride from HTC cells and inhibited the uptake by HepG2 cells. These findings are of importance when the effects of cadmium on living organisms are examined since co-exposure to cadmium and other metals can occur.

Animals↗
PubMed2006

An experimental in vitro model for dynamic direct exposure of human cells to airborne contaminants.

The aim of this study was to establish a dynamic in vitro model for direct exposure of human cells to gaseous contaminants to investigate the cellular responses to airborne chemical exposures. Nitrogen dioxide (NO2) was selected as a model gas compound. Standard test atmospheres were generated (2.5-10 ppm), using a dynamic direct dilution method. Human cells including: A549 pulmonary type II-like epithelial cell lines and skin fibroblasts were grown on porous membranes. Human cells on snapwell inserts were placed in horizontal diffusion chambers and exposed to various airborne concentrations of NO2 directly at the air/liquid interface for 1 h at 37 degrees C. Cytotoxicity of the test gas was investigated using the MTS (3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium), NRU (neutral red uptake) and ATP (Adenosine triphosphate) assays. Dose-dependent effects of NO2 were observed in human cells tested which resulted in a significant reduction of cell viability at concentrations normally encountered in workplace environments (p<0.05). Our findings suggest that the dynamic direct exposure method can be used for in vitro inhalational and dermal toxicity studies and potentially as an advanced technology for biomonitoring of airborne contaminants in future occupational and environmental toxicity assessments.

Air Pollutants↗
PubMed2006

Genotoxicity assessment of deoxynivalenol in the Caco-2 cell line model using the Comet assay.

The genotoxic risk associated with deoxynivalenol (DON), a prevalent trichothecene mycotoxin which contaminates cereal-based products has not yet been deeply explored. In this work, the alkaline version of the Comet assay was used to evaluate DNA damage stemming from DON exposure in both dividing and differentiated Caco-2 cells, an epithelial intestinal cell line. To avoid false positive results, cytotoxic and apoptotic thresholds were firstly established using the MTS and neutral red assays and the Hoestch staining method, respectively. Dividing cells were found to be more sensitive to DON than differentiated cells and the lowest IC(10) (0.5 microM) obtained for dividing cells exposed for 72 h was used as the highest working concentration in the genotoxicity study. Both differentiated and dividing cells responded with a dose-dependent relationship to DON in terms of DNA damage in the 0.01-0.5 microM range. These results demonstrated the existence of a genotoxic potential for DON at low concentrations compatible with actual exposure situations and calls for additional studies to determine the functional consequences which could be taken into account for the risk assessment of this food contaminant.

Apoptosis↗
PubMed2006

Lysosomes as the target of yessotoxin in invertebrate and vertebrate cell lines.

The toxic effects of the algal polyether phycotoxin yessotoxin (YTX) are studied in the insect fat body IPLB-LdFB and the mouse fibroblast NIH3T3 cell lines. Our experiments confirm the cytotoxic action exerted by the toxin in both insect and mammalian cells, but morphological observations, TUNEL experiments and electrophoretic evalution of DNA integrity failed to evidence a clear pro-apoptotic role for YTX. In both IPLB-LdFB and NIH3T3 cell lines, neutral red and acridine orange stainings, together with evaluation of acid phosphatase activity demonstrate that YTX first damages lysosomal vesicles. This is then followed by a progressive depolymerization of actin microfilaments, as shown by phalloidin fluorescent immunostaining. Overall, our data identify in early lysosomal damage and the subsequent cytoskeletal disruption two common steps related to YTX toxicity towards metazoan cells.

3T3 Cells↗