After an injury to the spinal cord, patients often remain paralyzed because damaged nerve tracts do not regrow due to the formation of scar tissue. Scientists from the Max Planck Institute for the Science of Light in Erlangen, together with colleagues from Dresden and Athens, have now been able to identify important cells and molecules in the scar, using zebrafishes as a model organism.
source https://phys.org/news/2021-01-axon-regeneration-zebrafish-spinal-cord.html