Lost parts of the body grow in some animals. Claw frogs (Xenopus Laevis) are not one of them. At least not in nature. In a laboratory experiment, however, new functional, almost complete limbs developed among the frogs. The animals were able to feel and move their hind legs, as researchers reported in the specialist magazine "Science Advances".
For their experiment, the team administered adult clawed frogs a cocktail of five drugs, MDT for short, using a portable silicone mini-bioreactor. Each drug served a different purpose: one inhibited inflammation, another inhibited collagen production, which would lead to scarring, and the rest caused nerve fibers, blood vessels, and muscles to grow. For 24 hours, the device pumped the active ingredient mix into the respective stump. Within 18 months, a functioning leg was restored.
"The regenerated tissue, consisting of skin, bones, vessels and nerves, exceeded the complexity and sensorimotor skills of the untreated animals and the control animals," writes the team. The data would show that regeneration processes can even be targeted in vertebrates.
In order for limbs to grow back, according to their hypothesis, two components are needed that act at a very early stage of the process: first, a closed environment that allows the wound cells to control the biochemical environment after injury, and second, a series of signals that purposefully trigger the growth process.
Teams have been working on the regeneration of limbs in mammals for years. The researchers hope that their experiments will help develop similar therapies for people in the future who have lost an arm or leg, for example, as a result of a diabetes or an accident.
In fact, organisms such as Xenopus laevis are important models for testing recovery. Their limited ability to regenerate in adulthood reflects that of humans. However, the extent to which the current findings can be transferred to the human body requires further, long-term investigations. "The complex process of limb regeneration is not yet fully understood," the group writes.
