The influence of microcystin-LR on fish phagocytic cells

The in vitro influence of microcystin-LR (MC-LR) on rainbow trout phagocytic cell functions was studied. The cells isolated from the fish blood were exposed on MC-LR at the concentrations of 1, 5, 10, 20 mu g/mL. The viability of the cells after 2, 4 and 24 hour incubation with MC-LR was studied as well as phagocytic cell ability measured as zymozan particle phagocytosis and metabolic activity measured as respiratory burst activity. The toxin caused time- and dose-dependent viability decrease, the strongest after cell exposure on 10 and 20 mu g/mL and observed only after 24 hours incubation when 1 mu g/mL was applied. The phagocytic ability was elevated in the presence of MC-LR at the dose of 5 mu g/mL. MC-LR had also modulatory influence on respiratory burst activity. While the two lower doses caused the stimulation of the parameter, the two higher ones diminished superoxide anion production in the triggered cells. The results show the potency of the toxin to influence the fish phagocytic cell functions.