The AFB1-FB1 mixture enhances the hepatotoxic effects induced by the individual mycotoxins in rat hepatocytes

MARY, VS; OTAIZA GONZÁLEZ, SN; THEUMER, MG; RUBINSTEIN, HR

Córdoba

Congreso; IV Congreso Internacional Ciencia y Tecnología de los alimentos; 2012

MinCyT Córdoba

Mycotoxins are fungal secondary metabolites. Among the most important are Aflatoxin B1 (AFB1) and fumonisin B1 (FB1), which are produced by fungi Aspergillus and Fusarium, respectively. Both mycotoxins are hepatotoxic and carcinogenic in humans and animals. The natural co-contamination with AFB1 and FB1 especially in corn and rice has been reported as a worldwide problem and associated with a high incidence of human hepatocellular carcinoma. Although the toxicological parameters of both toxins acting alone have been well studied, at present, little is known about the interaction of AFB1 and FB1 regarding their toxic and carcinogenic properties and the interactive effects of both-toxins mixtures. This work therefore aims to study the effects on cell cycle and genotoxic potential of an AFB1-FB1 mixture in rat hepatocytes, and to determine the contribution of oxidative stress in the induction of these effects. The study of cell cycle was performed using propidium iodide staining and the subsequent analysis by flow cytometry, and the evaluation of the genotoxic potential of mycotoxins was performed by the micronucleus technique for optical microscopy in the BRL-3A rat liver cell line that was exposed to 20 μM AFB1, 30 μM FB1 and AFB1-FB1 mixture (MIX= 20 μM AFB1 + 30 μM FB1) for 48 h. The results of these experiments showed that all mycotoxins treatments increased and decreased the percentages of cells in the G0-G1 and S phases, respectively, being the MIX which produced the greatest effect. Besides, the MIX was the only treatment that increased the percentage of cells in SubG0 phase. Furthermore, the frequency of micronucleus was significantly raised by AFB1 and MIX, being the latter treatment which produced the largest increase. Moreover, the use of antioxidants prevented the alterations in cell cycle induced by all mycotoxins treatments, and partially reduced the frequency of micronucleus induced by AFB1 and MIX. It is likely to genotoxic ability of these treatments also due to the formation of mutagenic metabolite of AFB1. The results of this study demonstrate that AFB1 and FB1, individual and combined, arrested the cell cycle, and the mixture caused apoptosis in BRL-3A cells. Since apoptosis can play a critical role in the development of cancer, the ability of the MIX to induce apoptosis appears to be related to their toxicological effects. In addition, these results also show that AFB1, alone or in combination with FB1, produced genotoxicity, and evince the involvement of oxidative stress in the induction of these toxic effects by treatment with mycotoxins. Besides, the mixture produces major changes than the toxins individually, indicating a probable interaction between AFB1 and FB1. These results suggest that consumption of food contaminated with AFB1 and FB1 may favor to hepatic damage, and increase the risk of liver cancer, greater extent than the intake of the individual toxins.