Assessment of the estrogenic effects of zearalenone after treatment with ozone utilizing the mouse uterine weight bioassay

The ability of ozone gas (O-3) to detoxify zearalenone (ZEN), a commonly oc curring estrogenic mycotoxin, was assessed utilizing the mouse uterine weig ht bioassay. Solutions containing 12 ppm ZEN in water were ozonated for var ying time periods (0, 0.5, and 5 min), then extracted with chloroform and e vaporated to dryness. The residue was redissolved in acetonitrile and analy zed for ZEN. High-performance liquid chromatography (HPLC) analysis oi aliq uots indicated a rapid degradation and decline in parent ZEN level with inc reasing time of ozone treatment. The acetonitrile solution containing the d egraded ZEN residue was added to a known volume of corn oil and evaporated under nitrogen to eliminate the acetonitrile in the oil. Eighteen-day-old p repubertal female mice (B6C3F1 strain) were gavaged daily with the test che micals in 50 mu l of corn oil between d 18 and 23. Initial dose-response st udies showed that a concentration of 60 mu g ZEN/mouse/d produced uterine w eights that were significantly higher than the uterine weights of control a nimals (2.7 times higher than that of the solvent control). Treatment group s for the ozonation study included: DES, 0.1 mu g (positive control), untre ated ZEN (60 mu g), extraction control for ZEN (60 mu g), 0.5 min ozone-tre ated ZEN (60 mu g), 5 min ozone-treated ZEN (60 mu g), solvent control (50 mu l), and absolute control. Results showed the uterine weights of animals receiving the ozone-treated ZEN were not significantly affected. These find ings were in agreement with HPLC analyses and suggested that ozone can prev ent the estrogenic effects of this important mycotoxin in mice, importantly , ozone treatment of contaminated whole grains may enable the practical det oxification and control of ZEN. Also, the mouse uterine weight bioassay may be useful in assessing the efficacy of other detoxification strategies for estrogenic chemicals.