The naturally occurring food mycotoxin Fumonisin B1 impairs myelin formation in aggregating brain cell culture

The effects of subchronical applications of the mycotoxin Fumonisin B1 (FB1 ) were analyzed in vitro, using aggregating cell cultures of fetal rat tele ncephalon as a model. As cells in the aggregates developed from an immature state to a highly differentiated state, with synapse and compact myelin fo rmation, it was possible to study the effects of FB1 at different developme ntal stages. The results showed that FB 1 did not cause cell loss and if ha d no effects on neurons. However it decreased strongly the total content of myelin basic protein, the main constituent of the myelin sheath, during th e myelination period (DIV 18-28). The loss of myelin was not accompanied by a loss of oligodendrocytes, the myelinating cells. However FB 1 had effect s on the maturation of oligodendrocytes, as revealed by a decrease in the e xpression of galactocerebroside, and on the compaction of myelin, as shown by a reduction of the expression of the myelin/oligodendrocyte glycoprotein MOG. The content of the cytoskeletal component glial fibrillary acidic pro tein (GFAP) was decreased in differentiated astrocytes, exclusively while n eurons were not affected by 40 mu M of FB1 applied continously for 10 days. In summary, FB1 selectively affected glial cells. In particular, FB1 delay ed oligodendrocyte development and impaired myelin formation and deposition . (C) 1999 Intox Press, Inc.