Subchronic microcystin-LR exposure increased hepatic apoptosis and induced compensatory mechanisms in mice.

Acute lethal cytotoxicity of microcystin-LR (MC-LR), a toxin produced by fresh-water cyanobacteria, has been attributed to protein phosphatases type 1 and type 2A (PP1/PP2A) inhibition and reactive oxygen species (ROS) generation. However, the effects and molecular mechanisms of prolonged, sublethal MC-LR exposure are less known. We studied mice intraperitonealy injected with saline or 25 μg MC-LR/kg for 28 days (every 2 days).