Microcystin-RR induces apoptosis in fish lymphocytes by generating reactive oxygen species and causing mitochondrial damage.

Microcystin-RR (MCRR), a very widespread toxic microcystin in China, has previously been proved to induce sensitive apoptosis in Carassius auratus lymphocytes in vitro. This study focused on the role of intracellular Ca(2+), mitochondrial membrane potential, reactive oxygen species, and intracellular ATP in the mechanism of MCRR-induced apoptotic toxicity to fish lymphocytes. Compared with controls, administration of MCRR (10 nmol L(-1)) caused a massive calcium influx resulting in elevation of reactive oxygen species (ROS), rapid disruption of mitochondrial membrane potential (DeltaPsim), and depletion of ATP. This study provided a possible mechanism for the cytotoxicity of microcystins to fish lymphocytes.