Subchronic mycotoxicoses in rats. Modulation of the Sa:So ratio imbalance induced by FB1, due to the coexistence of AFB1 in the diet.

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

Córdoba, Argentina

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

Sixth framework programme MYCO-BLOBE

Objetive: To study the effects of aflatoxin B1 (AFB1), in the fumonisin B1 (FB1)-induced imbalance of the sphinganine:sphingosine (Sa:So) ratio, in rats fed with a mixture of both toxins. Methods: Male Wistar rats (n=6 per group) were used. The AFB1 was Sigma (USA). The FB1 was produced by Fusarium verticillioides MRC826 in maize. Separation and quantification of FB1 were done as previously described (1, 2). Rats were fed during 90 days with the following experimental diets: mycotoxins-free (Control), with 100 ppm of FB1 (EDFB1), and with the mixture of AFB1 (40 ppb)+FB1 (100 ppm)(EDM). At the 90th day, rats were housed in metabolic cages for 24 hours to obtain urine samples. Then blood, liver and kidney samples were collected. Urine, sera and tissues were cleaned up through silica gel columns prior to the Sa and So quantifications by HPLC (3). Results: Higher amounts of Sa and So, as well as the inversion of the Sa/So ratio, were detected in all samples from rats fed the EDFB1 or the EDM. These imbalances were mostly caused by increases in the Sa levels, while So concentrations were significantly higher only in livers coming from rats fed the EDFB1. By comparison of the results obtained in both intoxicated groups, the higher inversions of the Sa/So ratio were observed in all samples from rats fed the EDM, however this tendency was significant only in kidneys from rats that consumed the EDFB1. Conclusions: In kidneys from rats fed the EDM, the AFB1 could modify, by means of an unknown mechanism, the ability of renal cells to redirect part of the Sa accumulated into alternative metabolic pathways. Increases in Sa and So levels could be an early event involved in the neoplastic transformation of cells exposed to FB1 individually, or in presence of AFB1. 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. Shephard, G. S., et al. 1998. J Chromatogr B Biomed Sci Appl 710:219-22.