Biomaterials in axonal regeneration and repair after spinal cord injury

Abstract

Central nervous system (CNS) is composed of brain and spinal cord, where the brain integrating higher level functions and the spinal cord acting as communication pathway amidst the brain and the periphery. Injury to the spinal
cord disrupt ascending and descending pathways, transmitting information from the periphery to the brain and from the brain to the periphery respectively, below the site of injury. Spinal cord injuries (SCI) can be complete and incomplete. Complete spinal injury causes permanent damage to the spinal cord which
eliminates the ability of spinal cord to deliver signals below or above the level of injury, and ultimately leads to paraplegia or tetraplegia . Incomplete injury refers partial damage to spinal cord, which implies some sensation is still present below the site of injury (Barbeau and Rossignol, 1987). Presently, limited options are available for SCI treatment. H o w e v e r , s c i e n t i s t s a r e o p t i m i s t i c i n
investigating new treatment therapies to increase the quality of life of patients with SCI. The injured spinal cord creates an inhibitory e n v i r o n m e n t w h i c h h a m p e r s a x o n a l regeneration. After injury a cavity of fluid is formed which is encircled by glial scar, glycosaminoglycans, reactive astrocytes and other inhibitory factors. All these inhibitory factors hamper neurons from infiltrating from the site of injury, lead to loss of axonal connection. To overcome from the barrier created by inhibitory molecules, neural tissue engineering has recently gained ample attention. Biomaterial scaffolds made up of either natural or synthetic polymers could impede scar tissue formation to some extent. These scaffolds when
coated with neurotropic growth factors could work effectively in promoting axonal sprouts and reconnections with neurons at the caudal end of the injury.