TOKYO (Reuters) – Japanese researchers have shown that one type of sea slug can decapitate itself and regenerate its bodies, a discovery that could have ramifications for regenerative medicine.
The mechanism is believed to be an extreme method for the body to rid itself of parasites, researchers Sayaka Mitoh and Yoichi Yusa wrote in a study published in Current Biology this week. Green slugs have algae cells on their skin, so they can feed on light like a plant until they develop a new body, which takes about 20 days.
Mitoh, a doctoral researcher at Nara Women’s University, noticed one day that a sea slug, known as a sacoglossan, had spontaneously detached its head from its body.
“I was shocked and thought he was going to die, but he kept moving and eating quite energetically,” Mitoh said. “I watched over him for a while and he regenerated his heart and body.”
That prompted a study showing that five of the 15 lab-raised slugs and one from the wild split their bodies from a particular point on the neck during their lives. One did it twice. Each time, the heart of the animal was left behind in the body, which continued to live for some time, but did not grow back a head.
“One of the amazing things about stem cells is that they can be used to regenerate a heart and a body from the edge of the animal’s head,” Mitoh said. “With further study, we may be able to apply these findings to regenerative medicine, but that is still a distant hope at this stage.”
Other animals have been known to intentionally separate and regrow body parts, a mechanism known as autotomy, but this extreme form was previously unknown, the researchers said.
Initially they thought that it could be a method to escape from predators, but now they believe that it is done to get rid of parasites that inhibit reproduction.
Reporting by Rikako Murayama and Rocky Swift in Tokyo; Edited by Karishma Singh