Animals vary in their ability to replace body parts lost to injury, a phenomenon known as restorative regeneration. Uncovering conserved signaling steps required for regeneration may aid regenerative medicine. Reactive oxygen species (ROS) are necessary for proper regeneration in species across a wide range of taxa, but it is unknown whether ROS are essential for annelid regeneration. As annelids are a widely used and excellent model for regeneration, we sought to determine whether ROS play a role in the regeneration of the highly regenerative annelid, Lumbriculus variegatus. Using a ROS-sensitive fluorescent probe we observed ROS accumulation at the wound site within 15 min after amputation
this ROS burst lessened by 6 h post-amputation. Chemical inhibition of this ROS burst delayed regeneration, an impairment that was partially rescued with exogenous ROS. Our results suggest that similar to other animals, annelid regeneration depends upon ROS signaling, implying a phylogenetically ancient requirement for ROS in regeneration.