Scientists have regrown amputated frog legs. That’s how they did it.
Scientists from Tufts University and Harvard University’s Wyss Institute have regrown amputated limbs. In a study published in Science Advances, researchers showed how they used a chemical cocktail to induce limb growth in frogs.
Currently, limb regrowth is limited to “salamanders and superheroes,” the team said in a release. Like humans, whose bodies cover major injuries with scar tissue, adult frogs are unable to regenerate limbs naturally.
For the study, the scientists started by applying a five-ingredient chemical cocktail laced with a silk protein gel to the stump of the African clawed frog and covered it with a silicone dome, which they call a BioDome, to seal it. They removed the dome after 24 hours – and then waited 18 months for the limb to grow back.
David Kaplan, Stern Family Professor of Engineering at Tufts and co-author of the study, said that “Using the BioDome cap for the first 24 hours helps mimic an amniotic-like environment, which, along with the right medication, allows the rebuilding process without.” Continue impairment from scar tissue.”
The five chemicals each had very specific functions, including inhibiting collagen production (which leads to scarring), reducing inflammation, and stimulating nerve, blood vessel, and muscle growth. The cocktail should prevent the frog’s immune system from closing the stump.
“It’s exciting to see that the drugs we selected helped create an almost complete link,” said Nirosha Murugan, a research fellow at the Allen Discovery Center in Tufts and first author of the paper.
The regrowth of an almost fully functional leg in many of the treated frogs was a hopeful result for the scientists. The new limbs had bones, nerves, and several “toes” growing from the ends of the limbs – although the toes had no bones. The frogs could feel when the limb was brushed with a stiff fiber and could use it to swim through the water.
“The fact that it only took a brief exposure to the drugs to kickstart a months-long regenerative process suggests that frogs, and perhaps other animals, have dormant regenerative abilities that can be mobilized,” Murugan said .
“Next we will test how this treatment might be applied to mammals,” said corresponding author Michael Levin, director of the Allen Discovery Center in Tufts.
The research team hopes the study “has brought us one step closer to the goal of regenerative medicine.” They plan to test the treatment in mammals next.