Construction Of Modified Chitosan-heparin Mimic Peptide Self-healing Hydrogel Combined With VEGF To Promote The Repair Of Spinal Cord Injury

Spinal cord injury(SCI)can easily lead to paralysis of the lower body of the patient,which brings great harm to the patients,their families and the society.Therefore,it is of practical significance to study the repair of spinal cord injury.In the acute phase after spinal cord injury,the blood-spinal cord barrier(BSCB)is destroyed,causing injury ischemia,excessive inflammation,and cell death.In the chronic phase,glial scars and cysts appear,forming an inhibitory microenvironment that hinders axon regeneration and passing through the injury center,making it difficult to repair spinal cord injury.Therefore,preventing the occurrence of secondary injury after spinal cord injury in time and improving the injury microenvironment are the key to the treatment of spinal cord injury.In this thesis,modified chitosan-heparin mimic peptide self-healing hydrogel(CH-HMP)scaffold combined with vascular endothelial growth factor(VEGF)was constructed and implanted into a gap of rat thoracic spinal cord.The results showed that CH-HMP hydrogel exhibited excellent injectable and self-healing properties,which makes it administrated through a minimal invasive manner with an integrated structure and biomechanical property over the long-term duration,and could regulate the release of VEGF.The implantation into a gap of completely transection injury at the T9 level of spinal cord with self-healing hydrogel can bridge the rostral and caudal ends of the lesion area.In the early stage of injury,the self-healing hydrogel can regulate inflammation and vascular regeneration,and act as a focal point for axon regeneration,guiding the regenerated axon across the injury center.In the chronic phase,it can reduce the formation of glial scars and cysts,create a good microenvironment for axon regeneration and myelination.In conclusion,CH-HMP/VEGF self-healing hydrogel can promote nerve regeneration in the treatment of SCI,accompanied by partial recovery of motor and sensory functions.