Abstract
The restoration of nerve dysfunction after traumatic brain injury (TBI) faces huge challenges due to the limited self-regenerative abilities of nerve tissues. In situ inductive recovery can be achieved utilizing biological scaffolds combined with endogenous human umbilical cord mesenchymal stem cells (HUCMSCs)-derived exosomes (MExos). In this study, brain-derived neurotrophic factor-stimulated HUCMSCs-derived exosomes (BMExos) were composited with collagen/chitosan by 3D printing technology. 3D-printed collagen/chitosan/BMExos (3D-CC-BMExos) scaffolds have excellent mechanical properties and biocompatibility. Subsequently, in vivo experiments showed that 3D-CC-BMExos therapy could improve the recovery of neuromotor function and cognitive function in a TBI model in rats. Consistent with the behavioural recovery, the results of histomorphological tests showed that 3D-CC-BMExos therapy could facilitate the remodelling of neural networks, such as improving the regeneration of nerve fibres, synaptic connections and myelin sheaths, in lesions after TBI.