Toxic mechanisms induced by fumonisin b1 mycotoxin on human intestinal cell line

The gastrointestinal tract is the main target of exposure to mycotoxin fumonisin B1 (FB1), common natural contaminant in food. Previous studies reported that proliferating cells are more sensitive than confluent cells to the toxic effect of FB1. This study aims to investigate, by dose- and time-dependent experiments on human colon proliferating intestinal cell line (HT-29), the modifications induced by FB1 at concentrations ranging from 0.25 to 69 μM. The choice of highest FB1 concentration considered the low toxicity previously reported on intestinal cell lines, whereas the lowest one corresponded to the lower FBs levels permitted by European Commission Regulation. Different functional parameters were tested such as cell proliferation, oxidative status, immunomodulatory effect and changes in membrane microviscosity. In addition FB1-FITC localization in this cell line was assessed by using confocal laser scanning microscopy. Lipid peroxidation induction was the main and early (12 h) effect induced by FB1 at concentrations ranging from 0.5 to 69 μM, followed by inhibition of cell proliferation (up to 8.6 μM), the immunomodulatory effect (up to 17.2 μM), by assessing IL-8 secretion, and increase in membrane microviscosity (up to 34.5 μM). The toxic effects observed in different functional parameters were not dose-dependent and could be the consequence of the FB1 intracytoplasmatic localization as confirmed by confocal microscopy results. The different timescales and concentrations active of different functional parameters could suggest different cellular targets of FB1.