Abstract
Despite significant improvements in the comprehension of neuro-regeneration, restoring nerve injury in humans continues to pose a substantial therapeutic difficulty. In the peripheral nervous system (PNS), the nerve regeneration process after injury relies on Schwann cells. These cells play a crucial role in regulating and releasing different extracellular matrix proteins, including laminin and fibronectin, which are essential for facilitating nerve regeneration. However, during regeneration, the nerve is required to regenerate for a long distance and, subsequently, loses its capacity to facilitate regeneration during this progression. Meanwhile, it has been noted that nerve regeneration has limited capabilities in the central nervous system (CNS) compared to in the PNS. The CNS contains factors that impede the regeneration of axons following injury to the axons. The presence of glial scar formation results from this unfavourable condition, where glial cells accumulate at the injury site, generating a physical and chemical barrier that hinders the regeneration of neurons. In contrast to humans, several species, such as axolotls, polychaetes, and planarians, possess the ability to regenerate their neural systems following amputation. This ability is based on the vast amount of pluripotent stem cells that have the remarkable capacity to differentiate and develop into any cell within their body. Although humans also possess these cells, their numbers are extremely limited. Examining the molecular pathways exhibited by these organisms has the potential to offer a foundational understanding of the human regeneration process. This review provides a concise overview of the molecular pathways involved in axolotl, polychaete, and planarian neuro-regeneration. It has the potential to offer a new perspective on therapeutic approaches for neuro-regeneration in humans.