Abstract: Objective To repair the traumatic brain injury in adult rats by inducing neural synapses formation with neurotrophin- 3 (NT-3) chitosan scaffolds. Methods 60 adult male Wistar rats were equally divided into lesion group, blank chitosan scaffolds group and
NT-3 chitosan scaffolds group. The neural regeneration in the lesion area were observed through immunochemistry 3 days, 7 days, 14 days,28 days, 60 days after operation. Regenerated neural synapses involved the neural circuitry reconstruction in the lesion area were observed through neural tracing and immune electron microscopy 30 days and 60 days after operation. Results The nestin+, β-tubulin-Ⅲ+, microtubule associated protein 2 (MAP2)+ neural cells in hippocampal lesion area were significantly more in the NT-3 chitosan scaffolds group than in the other groups (P<0.01). Newborn neurons that express 5-bromouracil deoxyriboside (BrdU) and MAP2 were observed and formed synaptic connections in hippocampal damage zone in the NT-3 chitosan scaffolds group. Regenerated neural synapses involved the neural circuitry reconstruction in the lesion area. Conclusion NT-3 chitosan scaffolds activate the neural progenitor cells to proliferate and differentiate to mature neurons, which form neural synapses to involve the neural circuitry reconstruction.

Key words: traumatic brain injury, neurotrophin-3 chitosan scaffolds, neural progenitor cells, proliferation, differentiation, synapses, neural network