Repairs To The Spinal Cord Injury By Transplantation Of NGF And VEGF

Objective:To investigate the feasibility and efficacy of transplantation of nerve growth factor (NGF) and vascular endothelial growth factor(VEGF) in repairs of spinal cord injury, and to observe the synergistic effect between them.Methods:1. Establish model of spinal cord injury. We chose adult SD rats weighing 180-220g. Beat T9-T10 of spinal cord with energy of 250gmm, cause spinal cord trauma, to establish model of spinal cord contusion. Subdural catheter was placed in L3-L4 of spinal cord of the models, the external extension of catheter was fixed and controllable blocked, to prepare for the injection. The models of spinal cord injury was divided into 3 groups [normal saline (NS) group (group A),NGF group (group B), NGF plus VEGF group (group C)], each group had 10 rats, and 30 rats in all. NS, NGF, NGF plus VEGF were injected into the subdural cathete of corresponding group through syringes separately.2. Observation. Basso,Beattie,and Bresnnhan locomoter scale (BBB) was carried out at different times (one time each week for 1 to 8 weeks) to all the models after the injection. All models were killed after 8 weeks,complete spinal cord biopsy specimens were taken for histological examination, including hematoxylin and eosin (HE) staining and immunohistochemistry staining, to evaluate the repair of spinal cord of each group.Results:1. The BBB score:No significant difference was observed at the first 2 weeks. From the 3rd week, the BBB score of group B and C were higher than group A (P<0.05) From the 4th week, the BBB score of group C was higher than group A and B (P<0.01)2. Histological examination:HE staining showed that the morphology of the injured part and adjacent segments of spinal cord in group A were not obvious, the spinal cord was tear-shaped broken. The same part in group B and C had relatively complete organizational structure and some continuity, some relatively intact neurons and vascular endothelial cells can be seen in a few parts, and group C is better than group B. Immunohistochemistry staining showed that the combined of NGF and VEGF in group C can promote axon regeneration and reduce neuronal apoptosis, and group C obviously promote the growth of endothelial cells. By counting the number of apoptotic neurons and microvessels in white matter within each high power field, and comparison of average, the result of the number of apoptotic neurons was A>B>C, group A had a similar number of microvessels in white matter to group B, but they were both obviously fewer than group C.Conclusion:1. Simple application of NGF can improve the limb movements of rats after acute spinal cord injury, and reduce neuronal apoptosis, but the duration and specific is limited, and is not very obvious.2. The combination of NGF and VEGF have better repairs in spinal cord injury, they can obviously improve the limb movements of rats after acute spinal cord injury, reduce neuronal apoptosis, and promote the growth of endothelial cells of vessels in white matter, and they have a significant synergistic effect.