Toxic effects of the mycotoxin zearalenone and its derivatives on in vitro maturation of bovine oocytes and 17 beta-estradiol levels in mural granulosa cell cultures.
Moulds parasites of livestock foodstuffs alter the quality of grains by synthesizing mycotoxins. Zearalenone (ZEA) and its derivatives (alpha- and beta-zearalenol, zeranol, taleranol and zearalanone) are produced by fungi of the genus Fusarium and, after ingestion via contaminated cereals, may lead to fertility disturbances and other reproductive pathologies. Zearalenone, alpha-zearalenol and zearalanone were tested, at levels ranging from 0.3 to 30 microg/ml, in order to evaluate the effect on the in vitro maturation (IVM) rate of bovine oocytes and on the formation of 17 beta-estradiol in supernatants of mural granulosa cells (GC) cultures. These compounds induced dose-dependent oocyte maturation delay and chromatin abnormalities. Maturation of oocytes to metaphase II (M II) was inhibited in oocytes cultured in the presence of 30 microg/ml ZEA, alpha-zearalenol or zearalanone, with a significant increase in chromatin abnormalities occurring in the presence of ZEA (P<0.05) and alpha-zearalenol (P< 0.001). In preliminary trials on 17 beta-estradiol formation, at the same testing concentration, higher levels of 17 beta-estradiol were found in the presence of alpha-zearalenol (mean value 1.6 ng/ml) with respect to ZEA and zearalanone (mean estradiol concentrations of 0.06 and 0.5 ng/ml, respectively). These data demonstrate a negative effect of ZEA and its derivatives on meiotic progression of bovine oocytes, possibly attributable to a toxic mechanism not related to the binding affinity of these compounds to estrogen receptor sites, and support previous observations that alpha-zearalenol acts as a stronger estrogenic inducer than the original molecule (ZEA).
Minervini
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F
Institute of Toxins and Mycotoxins, CNR, Viale Einaudi 51, 70125 Bari, Italy. itmpfm10@area.cnr.it
Dell'Aquila
M E
ME
Maritato
F
F
Minoia
P
P
Visconti
A
A
D000826:Animal Testing Alternatives; D000818:Animals; D002417:Cattle; D002467:Cell Nucleus / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000378:metabolism*; D004968:Estrogens, Non-Steroidal / Q000633:toxicity*; D005260:Female; D006107:Granulosa Cells / Q000187:drug effects* / Q000378:metabolism; D008540:Meiosis / Q000187:drug effects; D009865:Oocytes / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism / Q000473:pathology; D015025:Zearalenone / Q000031:analogs & derivatives / Q000633:toxicity*; D015029:Zeranol / Q000031:analogs & derivatives* / Q000633:toxicity
D004968:Estrogens, Non-Steroidal; C029659:zearalenol; D004958:Estradiol; D015025:Zearalenone; D015029:Zeranol