A salamander loses its leg. But instead of remaining mutilated forever, the limb simply grows back. Perfectly formed, with all the bones in the right place. And the most amazing thing is that the new leg always fits the animal's body size exactly. Regardless of whether it is a young or an adult axolotl. How does this work? Researchers from Dresden have now developed a mathematical model that solves this puzzle.
The scientists from the Cluster of Excellence Physics of Life (PoL) and the Center for Regenerative Therapies Dresden (CRTD) at TU Dresden published their results in the renowned journal PNAS. They focused on two important messenger substances. These so-called morphogens are called Sonic Hedgehog and Fibroblast Growth Factor 8, which the researchers call SHH and FGF8 for short. These two molecules are produced at opposite ends of the regrowing limb.
Importance beyond the axolotl
The model only explains the first phase of regeneration. But this phase is crucial. It determines how the new limb is built and how many bone elements are formed. The Dresden researchers suspect that their model describes a general principle. It could explain how size control works during development and regeneration in different animal species.
The findings apply not only to salamanders, but possibly also to other species that can regrow limbs. In the long term, such basic findings could also become relevant for regenerative medicine in humans.
