Background: Bone marrow mesenchymal stem cells (MSCs) are one of the potential tools for treatment of the spinal cord injury; however, the survival and differentiation of MSCs in an injured spinal cord still need to be improved. In the present study, we investigated whether Governor Vessel electro-acupuncture (EA) could efficiently promote bone marrow mesenchymal stem cells (MSCs) survival and differentiation, axonal regeneration and finally, functional recovery in the transected spinal cord.

A self-healing hydrogel enriched with properties from a double-dynamic network (DDN) that has been prepared via two dynamic linkages (imine and borate ester) by using a single polymeric cross-linker. The four-component Ugi reaction was used for easily synthesizing multifunctional poly­(ethylene glycol) (MF-PEG) with a benzaldehyde group and phenylboronic acid group at each end of the chain. This MF-PEG simultaneously cross-linked with poly­(vinyl alcohol) through the borate ester and glycol chitosan via an imine to generate a self-healing hydrogel with a unique DDN structure in seconds under mild conditions (pH ≈ 7, 25 °C). The prepared hydrogel showed enhanced strength and mucoadhesive abilities because of the complimentary interpenetrating dynamic networks. The DDN hydrogel showed satisfying biocompatibility and was further used in an in vivo mouse model. The hydrogel was injected to successfully deliver an antitumor drug and achieved a superior performance compared to traditional delivery methods. To the best of our knowledge, this is the first report of using the Ugi reaction to prepare a DDN self-healing hydrogel. We hereby propose a general strategy for the facile preparation of self-healing materials with improved properties. The strategy also opens a new avenue for synthesizing multifunctional/reinforced materials with the combination of dynamic chemistry and multicomponent reactions.

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Study design: An animal model of transected spinal cord injury (SCI) was used to test the hypothesis that cografted neural stem cells (NSCs) and NT-3-SCs promote morphologic and functional recoveries of injured spinal cord. Objective: To explore whether cotransplant of NSCs and NT-3-SCs could promote the injured spinal cord repair. Setting: Zhongshan Medical College, Sun Yat-sen University, PR China. Methods: Female Sprague-Dawley (SD) rats weighing on 200-220 g were used to prepare SCI models. The spinal cord was transected between T 9 and T 10 , then NSCs, SCs þ NSCs, LacZSCs þ NSCs, or NT-3-SCs þ NSCs were grafted into the transected site. Results: (1) Part of NSCs could differentiate to neuron-like cells in the transected site and the percentage of differentiation was NT-3-SCs þ NSCs group4SCs þ NSCs group4NSCs group. (2) In the grafted groups, there were 5-HT, CGRP, and SP positive nerve fibres within the transected site. Some fluorogold (FG)-labeled cells were found in the spinal cord rostral to the transected site, the red nuclei and the inner pyramidal layer of sensorimotor cortex. (3) The cells grafted could enhance the injured neurons survival in inner pyramidal layer of sensorimotor cortex, red nuclei of midbrain, and Clark's nuclei of spinal cord's L1 segment, could decrease the latency and increase the amplitude of cortical somatosensory evoked potential (CSEP) and cortical motor evoked potential (CMEP), and could promote partly structural and functional recovery of the SCI rats.Conclusion: These results demonstrate that cografted NT-3-SCs and NSCs is a potential therapy for SCI.