Planarian, an emerging animal model for toxicology studies

Since a few decades, a new invertebrate animal model has emerged in toxicology studies: the planarian. This non-parasitic flatworm, from phylum Platyhelminthes, has an amazing regenerative capacity and has been described as "immortal under the edge of the knife" in 1814 by Dalyell. This formidable capacity is due to the abundance of stem cells called neoblasts, allowing for a tiny fragment equivalent to 1/279th of the size of the planarian to generate a whole animal. The planarian has also a human-like nervous system with several neurotransmitters and has been used to evaluate developmental perturbations and neurotoxicity. This review summarizes the main planarian toxicology studies and highlights the potential of this original animal model for research.