ABSTRACT
BACKGROUND: Recently, most studies have combined tissue engineering materials with stem cells or factors to improve the microenvironment of animal models of spinal cord injury to increase the duration of action, improve the recovery effect and prognosis. OBJECTIVE: To investigate the effect of sonic hedgehog-polydopamine-fibrin scaffold on the repair of spinal cord injury in rats. METHODS: Fibrin glue was made using a vacuum freeze-dryer. The prepared fibrin glue was immersed in a dopamine hydrochloride solution for 24 hours for cross-linking. Then the cross-linked scaffold was placed in a factor solution for adsorption and cross-linking for 24 hours. Sonic hedgehog-polydopamine-fibrin scaffolds were prepared. Sixty female SD rat models of spinal cord injury were established and then divided into four groups: In the group A, no material was implanted. In the groups B, C and D, fibrin scaffolds, polydopamine-fibrin scaffolds, and sonic hedgehog-polydopamine-fibrin scaffolds were implanted respectively. The Basso, Beattie and Bresnahan (BBB) locomotor scale score of lower limb locomotor function was evaluated within 12 weeks after surgery. At 12 weeks post-surgery, the tissue at the site of spinal cord injury was collected for histological observation (hematoxylin-eosin and immunohistochemical staining) and western blot assay. This study was approved by the Animal Ethics Committee of Jiangsu University, China. RESULTS AND CONCLUSION: (1) From 2 weeks after surgery, the lower limb locomotor function of rats in each group began to recovery. At 5-12 weeks after surgery, the BBB score of group D was significantly higher than that of the other three groups (P < 0.05). Rats in group D had the best recovery of locomotor function of the lower limb. (2) Hematoxylin-eosin staining revealed newly generated nerve fibers in the groups C and D, and that the number of density of new nerve fibers in group C was lower than that in group D. (3) Immunohistochemical staining showed that a large amount of linearly arranged new nerve fibers were observed in the completely transected site of rat spinal cord. In group D, myelin basic protein-, growth related protein- and neurofilament protein-positive rates were significantly higher (P < 0.05), and glial fibrillary acidic protein-positive rate was significantly lower, compared with the other three groups. (4) Western blot assay revealed that in group D, the protein expression of myelin basic protein, growth related protein and neurofilament protein was significantly higher (P < 0.05), and the protein expression of glial fibrillary acidic protein was significantly lower (P < 0.05), compared with the other three groups. (5) These results suggest that sonic hedgehog-polydopamine-fibrin has a good sustained-release performance, which can greatly promote the repair of spinal cord injury in rats.