Scientists managed to regrow a frog's lost leg: details of the breakthrough

A team of scientists from the United States has restored a frog's lost leg using a combination of five drugs. Next, they plan to test this regeneration technique on mammals.

According to a study published in Science, the experiment was conducted on African clawed frogs. The "cocktail" of drugs was placed in silicone molds that were attached to the wounds (to see the photo, scroll down to the end of the news).

It took 18 months for the frogs to recover their limbs. According to the researchers, they grew "almost fully functional" limbs, including boneless fingers, which they used to swim.

The work was carried out by experts from Tufts University in Medford, Massachusetts, and the Wyss Institute of Harvard University in Boston, Massachusetts.

"It is gratifying to see that the drugs we chose helped to restore the limb almost completely," said one of the study's authors Nirosha Murugan, a researcher at the Allen Center for Discovery at Tufts University.

"The fact that only a short-term exposure to the drug is required to trigger the months-long regeneration process suggests that frogs and possibly other animals may have dormant regenerative abilities that can be activated," she added.

The scientists said that each drug in the "cocktail" performed different tasks, including reducing inflammation, inhibiting collagen production, which could lead to scarring, and stimulating the growth of nerve fibers, blood vessels, and muscles.

The new limbs gained the natural bone structure of the limb, a richer set of internal tissues (including neurons) and several "fingers" that grew from the end of the paw, although they were bone-free.

"The regrown limb moved and responded to stimuli such as touch, and the frogs could use it to swim in the water, moving as they normally would," the researchers noted.

Note that many creatures have the ability to fully regenerate at least some of their limbs. Among them are salamanders, starfish, crabs and lizards, and flatworms.

Humans are able to close wounds by growing new tissue, and our liver has the ability to regenerate to full size after a 50 percent loss. But limbs are a permanent loss for humans.

Now the team wants to grow frogs limbs that are even more functionally perfect - with normal fingers, webbing, and all skeletal and muscle features - before moving on to mammals.

The American scientists hope that their method can bring medicine one step closer to the goal of human limb regeneration.