(CN) — Scientists have successfully use a multidrug treatment to regrow the limbs of frogs, providing a pathway to further research into regenerative techniques.
The new findings were published in the journal Science Advances on Wednesday, and detail the research on how the scientists were able to trigger the regrowth of limbs in frogs, who are unable to normally regrow limbs on their own.
Using 115 adult female African clawed frogs, Nirosha Murugan and colleagues at Tufts University anesthetized the animals before amputating one of their legs. Next, some frogs were left to heal on their own, some were fitted with a device, and some were given the device with a drug treatment.
These wearable devices were made from a silk hydrogel called BioDome and could provide a total of five pro-regenerative compounds to the frog’s wound. The devices were removed from the frogs after 24 hours and the animals were monitored and assessed over the following 18 months.
The scientists found that the frogs who received the treatment showed increases in bone growth, soft tissue pattering, and neuromuscular repair. This repairing caused the frogs to regrow their amputated legs and functionally allowed them to move around in the same way an uninjured frog could.
Frogs mirror the limited regenerative capabilities of humans, and much of the previous research into limb regeneration used animals like the axolotl, salamanders which have high natural regrowth abilities.
“Our collective data suggest that early targeted interventions may shift the burden of regeneration to the limb itself, sidestepping reliance on longer-term therapeutic strategies like the use of stem cells, serialized treatments, and other means of persistent micromanagement of restorative growth and patterning,” the research paper states.
While the progress of the frogs was measured over the course of a year and half, the study found that the animals showed positive effects as early as two weeks after their amputations.
In many cases, even the frogs who received the devices without regenerative compounds showed positive effects, even if those results were less pronounced. The research suggests that perhaps simply the silk-based hydrogel’s interaction was enough to signal to the stump to get a response.
Co-author Michael Levin of Tufts University said researchers are now doing testing in mammals, using the same drug treatment and a few others.
“I want to be clear that we are not ready for human trials yet. However, yes, this would be very impactful based not only on all the people with limb loss who call me all the time, but as a more general solution to other kinds of injury, cancer, aging, degenerative disease, and birth defects,” Levin said.
He explained that the key is triggering specific cells to do what they did during early developmental stages, when the body developed all its intricate mechanisms.
“What's common to all of this is the question of how we can tell a collection of cells to do what they did in embryogenesis and rebuild a desired complex organ - something which is too complex for us to micromanage, but which the cells already know how to do if we can trigger it. If we can learn to do this, it would solve most problems in medicine (except for infectious disease) - not just limb loss,” Levin said.
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