Effect of fumonisin B1 mycotoxin on membrane fluidity of human and rabbit erythrocytes

Abstract

The authors examined the membrane damaging effect of fumonisin B₁ (FB₁). Fist, Hb-free ghosts of erythrocytes were isolated from healthy rabbits, incubated with purified FB₁ (10, 50 and 100 μM) for 1 and 4 hours, labelled with DPH (1,6-diphenyl-1,3,5-hexatriene), for determining the fluorescent anisotropy. Secondly, intact human red blood cells were incubated with purified FB₁ (50 μM and 1 mM) for 7 and 24 hours, and extracellular (EC) K-ion concentration as a sensitive indicator of membrane damage was determined. Finally, rabbits were treated with 5 mg FB₁/day/animal for 10 days. Ghost cells isolated from the treated animals were labelled with DPH, and the fluorescent anisotropy was determined. Increasing concentration of FB₁ (10−50−100 μM) did not cause change in the fluorescent anisotropy of the ghosts isolated from healthy rabbits. After incubation of the intact human erythrocytes with 50 μM FB₁ for 7 hrs, the EC Na+ and K+ concentrations were 147.5−149.2 mmol/L and 0.04−1.64 mmol/L, respectively. No significant difference attributable to the toxin was detected. Incubation with the same concentration of FB₁ for 24 hrs resulted in a slight increase in the EC Na+ level (182.4−190.6 mmol/L), while the K+ level remained unchanged. Ghosts of the rabbits treated with FB₁ showed similar anisotropy to those of untreated animals. It could be concluded that FB₁ in the applied concentrations did not cause changes in the different physical-chemical parameters examined in human and rabbit erythrocytes’ membranes.