Cytotoxicity effects induced by Zearalenone metabolites, alpha Zearalenol and beta Zearalenol, on cultured Vero cells.

Zearalenone (Zen) is a non-steroidal estrogenic mycotoxin produced by several species of Fusarium. It has been implicated in several mycotoxicosis in farm animals and in humans. The major metabolites of this mycotoxin in various species are alpha and beta Zearalenol. In vivo, Zen is mainly reduced to these alcoholic metabolites which cause reproductive tract disorders and impaired fertility due to their estrogenic activities. In this study, we examined the cytotoxicity of alpha and beta Zearalenol in cultured cells. For this purpose, the MTT assay was carried out and the influence of alpha and beta Zearalenol on protein and DNA syntheses was assessed. To evaluate the cell stress caused by these two metabolites, oxidative stress measured by MDA induction and stress protein induction (Hsp 70, Hsp 27) were tested. Results showed that alpha and beta Zearalenol were metabolites that caused cytotoxicity by inhibiting cell viability, protein and DNA syntheses and inducing oxidative damage and over-expression of stress proteins. However, the Zen metabolites exhibited lower toxicity than Zen, with beta zearalenol being the more active of the two metabolites.

Cactus (Opuntia ficus-indica) cladodes prevent oxidative damage induced by the mycotoxin zearalenone in Balb/C mice.

Zearalenone (ZEN) is one of the most widely distributed fusarial mycotoxins which is encountered at high incidence in many foodstuffs. ZEN was associated with different reproductive disorders in animals. Several in vivo studies have shown that ZEN is hepatotoxic, haematotoxic and causes several alterations of immunological parameters. Furthermore, evidence of its cytotoxicity and genotoxicity has recently emerged from several reports. The aim of the current study was (i) to find out whether oxidative stress could be relevant for ZEN induced toxicity in vivo using Balb/c mice and (ii) to evaluate the safety and efficacy of cactus cladodes Opuntia ficus to prevent the deleterious effects of ZEN. To this end, the effect of a single dose of ZEN (40 mg/kg b.w.) alone and with extract of cactus cladodes (25, 50 and 100 mg/kg b.w.) on the induction of oxidative stress was monitored in kidney and liver by measuring the MDA level, the protein carbonyls generation, the catalase activity and the expression of the heat shock proteins (Hsp). Our results clearly showed that ZEN induced significant alterations in all tested oxidative stress markers. Oxidative damage seems to be a key determinant of ZEN induced toxicity in both liver and kidney of Balb/c mice. The combined treatment of ZEN with the lowest tested dose of cactus extracts (25 mg/kg b.w.) showed a total reduction of ZEN induced oxidative damage for all tested markers. It could be concluded that cactus cladodes extract was effective in the protection against ZEN hazards. This could be relevant, particularly with the emergent demand for natural products which may counteract the detrimental effects of oxidative stress and therefore prevent multiple human diseases.

Cytotoxicity and oxidative damage in kidney cells exposed to the mycotoxins ochratoxin a and citrinin: individual and combined effects.

ABSTRACT Ochratoxin A (OTA) and citrinin (CTN) are two mycotoxins, quite common contaminants, that can occur jointly in a wide range of food commodities. Both mycotoxins have several toxic effects but both share a significant nephrotoxic potential since OTA and CTN were reported to be responsible for naturally occurring human and animal kidney diseases. Considering the concomitant production of OTA and CTN, it is very likely that humans and animals are always exposed to the mixture rather than to individual compounds. Therefore, the aim of the present study was to investigate, using kidney cell culture (Vero cells), whether cytotoxicity and essentially oxidative cell damage (a key determinant of renal diseases) are enhanced by combination of both mycotoxins as compared to their effect separately. To this end, we have assessed their effects individually or combined on cell proliferation using three different cell viability assays (MTT, Trypan Blue, and Neutral Red). In addition, the role of oxidative stress was investigated by measuring the malondialdehyde (MDA) level and the expression of the heat shock protein Hsp 70. Our results clearly showed that cultured renal cells respond to OTA and CTN exposure by a moderate and weak inhibition of cell proliferation and induction of oxidative stress, respectively. However, when combined, they exert a significant increase in inhibition of cell viability as well as the induction of MDA level and Hsp 70 expression. OTA and CTN combination effects are clearly of synergistic nature. The enhanced induction of oxidative stress observed with OTA and CTN simultaneously could be relevant to explain the molecular basis of the renal diseases induced by these mycotoxins.