Effects of aflatoxin M1 and aflatoxin M2 on J774A.1 murinemacrophage cell line

Aflatoxins (AF), contaminants of food and feed, are genotoxic, cancerogenic and immunotoxic; AFB1 represents the most potent hepatocancerogen for both humans and animals. AFM1 and AFM2, hydroxylated metabolites of AFB1 and AFB2 respectively, are excreted with milk. Despite several studies have been carried out about the immune effects of AFB1, only few studies have been performed about the effects of AFM1 on immune functions; no work is available regarding the immunotoxicity of AFM2. The aim of the current study is to evaluate the immunotoxic effects of both AFM1 and AFM2, alone and in combination, on macrophagic functions. Materials and methods: J774A.1 macrophages were cultured under standard conditions and exposed to serial dilutions of AFM1 and AFM2 (0.05–32M), alone and in combination, for 24, 48 and 72 h. At first, we evaluated cell viability through MTT assay. Moreover, we also evaluated the activation of macrophagic functions measuring the amount of nitric oxide (NO) produced in cells exposed to AFM1 and AFM2 (0.05–32M) and stimulated with LPS (1g/ml) for 24 h. Data were statistically examined. Results and discussion: Both AFM1 and AFM2, alone or in combination, do not reduce significantly cell viability in J774A.1 macrophages. Nevertheless, both AFM1 and AFM2 reduced (P < 0.01) the NO production in J774A.1 macrophages stimulated with LPS (1g/ml) at the highest concentration. In conclusion, our results highlighted that AFM1 and AFM2 are immunomodulating mycotoxins and their action exerts through a reduction of NO production in macrophages stimulated with LPS without modify cellular viability. Further investigations will be necessary in order to better clarify the biological activity of AFM1 and AFM2 on macrophagic cells and other cellular models.