The ability to regenerate lost body parts is a remarkable trait found in various animals, such as lizards, starfish, and octopuses. Among these, axolotls, a unique salamander species native to Mexico, stand out for their extraordinary regenerative capabilities, allowing them to regrow everything from limbs to parts of their brain and spinal cord. Meanwhile, mammals have largely lost this skill throughout evolution, with regeneration remaining functional in only a limited number of species, such as rabbits and goats.
Wei Wang, a researcher at the National Institute of Biological Sciences in Beijing, is part of a team investigating why certain animals have lost their regenerative abilities and whether it is possible to restore them by reactivating specific genes or pathways. Recently, the team identified one such inactive gene, successfully activating it to restore a degree of regenerative capacity in previously non-regenerating mice.
Examining Regeneration in Mammals
The research team’s approach involved a comparative analysis of the wound healing processes in both regenerating and non-regenerating mammalian species. For their study, they selected rabbits as representatives of regenerating mammals and mice as representatives of non-regenerating species. The ear pinna was chosen as the reference organ due to its simplicity and the diversity of cell types it contains. “We wanted a structure that was relatively simple to observe,” Wang stated.
The experiment involved creating holes in the ear pinnae of both rabbits and mice to monitor the healing process. Initially, both species exhibited similar responses to the injuries. A blastema—a cluster of various cells—developed at the site of the wounds within the first few days post-injury. “Both rabbits and mice will heal the wounds after a few days,” Wang noted. However, significant differences emerged between the 10th and 15th days after the injury. In rabbits, the size of the ear holes began to decrease as new tissue formed above the blastema. In contrast, the healing process in mice came to a complete standstill, resulting in a persistent hole in their ears.
