Genotoxicity evaluation of an AFB1-FB1 mixture, and its correlation with the DNA damage induced individually by both mycotoxins in Wistar rat cells.

CÁNEPA MC,; THEUMER MG,; LÓPEZ AG,; RUBINSTEIN HR

Córdoba, Argentina

Congreso; Advances in research on toxicogenic fungi and mycotoxins in South America ensuring food and feed safety in a muco-blobe context; 2006

Sixth framework programme

Objetives: To study the genotoxic effect of a mixture of aflatoxin B1 (AFB1) and fumonisin B1 (FB1) in comparison with their individual effect, and the genotoxicity of Origanum vulgare essential oil (OEO); in primary culture of rat spleen mononuclear cells (SMC) evaluated through the in vitro micronucleus technique. Methods: Animals: Male Wistar rats. AFB1 was provided by Sigma (USA). FB1 was produced by Fusarium verticillioides MRC 826 in maize. Separation and quantification of FB1 were done as previously described (1, 2). The OEO was obtained by hydrodistillation from O. vulgare fresh leaves. Normal rat SMC were obtained as described Kisaki (3). The cells were stimulated by adding Concanavalin A (ConA) and were treated with  AFB1 (TAFB1; 20 mM), FB1 (TFB1; 10 mM), the mixture of both mycotoxins (TM; at the same concentrations used in TAFB1 and TFB1) and OEO (TOEO; 10-1, 10-2, 10-3 and 10-4%). Fourty-four hours later, cytochalasin-B (Cyt-B) was added to the cells in order to block cytokinesis and these were incubated for another twenty-eight hours. The cells were fixed and micronuclei (MN) were scored in slides stained with Giemsa using a light microscope. Results: TAFB1, TFB1 and TM caused significant increase of MN frequencies with respect to the control; while no changes were observed in the TM with respect to TAFB1 and TFB1. The TOEO induced increases of MN frequencies when was incorporated in final optimal concentration of 10-3 %, while no effects were observed at the remaining doses studied. Conclusions: The genotoxic effects of TM were not different from TAFB1 and TFB1. These mycotoxins could act on different phases of cellular cycle. The TOEO did not show a clear dose-response relation in this genotoxicity test. References: 1.      Voss, K. A., et al. 1990. Mycopathologia 112:81-92. 2.      Shephard, G.S.; et al. 1990. Journal of Liquid Chromatography 13:2077-2087. 3.      Kisaki, T. S., et al.1991. Journal of Immunology 147: 1659-1663.