Bioactive hydrogels loaded with BMSC-EXOs and GDNF for synergistically spinal cord injury repairing

Spinal cord injury (SCI) is a common lethal injury to the central nervous system (CNS), which severely affects the quality of life of SCI patients. Attempts to enhance the treatment of SCI typically tend to develop functional bioactive hydrogel scaffolds with drug encapsulation. In this work, we proposed novel RGD-functionalized bioactive hydrogel loaded with bone marrow stromal cells-derived exosomes (BMSC-EXOs) and glial cell line-derived neurotrophic factor (GDNF) to synergistically promote SCI repair. The functional hydrogel consisted of methacrylic anhydride-grafted sodium alginate and acrylated RGD, and then combined with BMSC-EXOs and GDNF by photocrosslinking to form a composite bioactive hydrogel. The hydrogel showed good drug-release properties and biocompatibility. When the bioactive hydrogel was implanted into the SCI area of the SD rats, it effectively modulated the adverse inflammatory response in the SCI area. Furthermore, the bioactive hydrogel promoted the regeneration of spinal cord neurons and axons, leading to the improvement in motor function recovery. These results indicate that the bioactive hydrogel loaded with BMSC-EXOs and GDNF has great potential as a therapeutic approach for the repair of spinal cord injuries.