Nivalenol (NIV) is a potent toxic trichothecene mycotoxin produced by Fusarium nivale, and our previous study clarified first that NIV induces apoptosis in lymphoid organs of mice in a dose-dependent manner. In this study, the development of apoptosis and changes in the expression of apoptosis-related genes (fas, c-fos, c-jun, p53, bcl-2 and c-myc) mRNAs were examined in the thymus of mice for up to 12 hours after inoculation (HAI) of NIV (15 mg/kg b.w.) to elucidate the relationship between the molecular genetic regulatory mechanisms and NIV-induced lymphocyte apoptosis. The number of apoptotic lymphocytes evaluated by TUNEL method clearly increased from 3 HAI and peaked at 9 HAL The DNA ladder formation by agarose gel electrophoresis was clearly observed at 6 and 9 HAL The expression of c-fos and c-jun mRNAs clearly elevated from 0.5 HAI and peaked at 1 HAL The expression of fas, p53, bcl-2 and c-myc mRNAs showed no significant changes. These results indicate that c-fos and c-jun may play an important role in NIV- induced lymphocyte apoptosis.
