The effects of mycotoxins, fumonisin B1 and aflatoxin B1, on primary swine alveolar macrophages.

Abstract

Mycotoxins were fungal metabolites that were widely present in feed and food; some of them were known to associate with human and animal disease. In the present study, the effects of fumonisin B1 (FmB1) and aflatoxin B1 (AFB1) on swine alveolar macrophages (AM) were examined by exposing primary cultures of swine AM to various concentrations of mycotoxins. Incubation of AM with 5 microg/ml of FmB1 for 72 h led to a reduction in the number of viable cells to 65% of the control levels. In the presence of 1.5 microg/ml of AFB1, the viability of AM falls to less than 41% of controls after 24 h exposure. FmB1, but not AFB1, induced the apoptosis of swine AM with evidence of DNA laddering and nuclear fragmentation. However, both FmB1 and AFB1 exposure induced the expression of apoptosis-related heat shock protein 72 (HSP 72) in AM. Swine AM treated with 50 ng/ml of FmB1 and 100 ng/ml of AFB1 for 24 h led to a reduction in phagocytic ability to approximately 55 and 36% of the control levels, respectively. Incubation of AM with FmB1 (2 and 10 microg/ml) for 24 h dramatically decreased the mRNA levels of interleukin-1beta (IL-1beta) and tumor necrosis factor-alpha (TNF-alpha). However, AFB1 treatment did not affect the expression of IL-1beta and TNF-alpha mRNA. The results suggest that both FmB1 and AFB1 are immunotoxic to swine AM but that they exert their toxic effects via different biochemical mechanisms.