A frog underwent 24 hours of intensive care and grew a fully functional limb, including even fingers, in 18 months.< /strong>
In a new study, scientists helped a frog regrow an amputated leg with a cocktail of drugs. The results of the experiment are already being called a breakthrough in regenerative medicine.
The experiment was carried out on the African clawed frog, which is naturally unable to regenerate limbs. She was placed on a 24-hour course of intensive drug therapy, after which, within 18 months, the frog grew a fully functional limb. The researchers hope that in the future, the results of their work can be applied to humans to trigger similar unused regeneration abilities of the body.
«The drugs we chose helped restore the limb. The fact that only a short exposure to the drug was needed to start the many months of regeneration process points to an important aspect. Frogs, and possibly other animals, may have dormant regenerative abilities that can be activated,» says Tufts University study co-author Nirosha Murugan.
Science already knows creatures that can fully regenerate some limbs, including salamanders, starfish, crabs and lizards. Flatworms can be cut into two parts, each of which will recreate a whole organism.
Humans also have some regenerative abilities, for example, a human liver can regenerate even after being split in half. It is also known that fingertips can regrow in children. But so far, no mammal has been able to re-grow a large and complex limb. Tissue scarring protects people from blood loss and infection, but also prevents re-growth.
As part of the experiment, the scientists amputated a frog's leg and covered the wound with a silicone cap containing a cocktail of five drugs. Each of the drugs had its own purpose, which included anti-inflammatory action and collagen production to slow down tissue scarring. The drugs also stimulated the growth of new nerve fibers, blood vessels, and muscles.
The experiment was repeated on dozens of frogs, and in many, a sharp resumption of tissue growth was observed. Some test subjects grew a new, almost fully functional limb, including bone tissue and even fingers.
It is noted that the new limbs moved perfectly, responded to touch, and were also used by frogs for movement.
In the first few days of treatment, the frogs activated molecular pathways that are normally involved in embryonic limb formation. The researchers speculate that humans, too, may have retained the information needed to create different body parts.
«Immersing the wound in a liquid medium under a silicone cap, with the right drug cocktail, may provide the necessary initial signals to start regenerative process,» says Michael Levin, professor of biology and director of the Allen Discovery Center at Tufts University.