| Objective : The experiment also showed that the transplantation of microencapsulated xeno-Schwann cells could improve the function of spinal cord injury in rats, but whether the transplantation of microencapsulated xeno-Schwann cells will effect the expression of NF-κB is still not clear. In this study, we will investigate the effect of transplantation of microencapsulated xeno-Schwann cells on nuclear factor kappaB(NF-κB ) and IκBαactivity after spinal cord injury (SCI) in rats.Methods:Experiments were performed in 120 adult Sprague-Dawley (SD) rats and 10 adult rabbits of either sex, weighing 2000-2500 g and 220-250 g, respectively. Then all of the rats were randomly divided into four groups: Group A (transplantation of microencapsulated sciatic nerve tissue/cells, n=36), Group B (transplantation of tissue/cells suspension, n=36), Group C (single injury control,n=36), Group D (sham control, n=12). After dividing, BBB score was enforced on right hindlimb of rats. Bilateral sciatic nerves pretreated from rabbits were dissected under sterile conditions and made into nerve tissue/cells suspension. Following centrifugation at a low speed, the tissue/cells were mixed with 1.5% sodium alginate solution, which was then extruded into 20mmol/L barium chloride solution by using a droplet generation device, forming microencapsulated sciatic nerve tissue/cells suspension. Group A, B and C were performed a right hemisection injury of spinal cord at T10 level, where were transplanted with the gelatin sponge sticking 10μl microencapsulated nerve tissue/cells suspension, the gelatin sponge sticking 10μl tissue/cells suspension and the gelatin sponge, respectively. Group D was only removed the vertebrae, not injured the spinal cord of and implanted. At 6h,12h,24h,3d,7d,14d after SCI, six rats of each group (two rats in Group D) were anesthetized and perfused transcardially with 4% paraformaldehyde (PH7.4), following BBB score on right hindlimb. The tissue of 1cm spinal cord below the lesion site and corresponding segment of sham group were taken out. After the tissues got were performed the paraffin sections, which were dealed with Nissl staining and anti-NF-κB and anti-IκBαimmun- ohistochemistry.Results:locomotor function of rat posterior limbs on each group gradually got differently recovery after operation, but all experimental groups did not get normal level, in 3days there was not significantly difference between each group, at the seventh day locomotor function recover of rat posterior limbs on A group and B group was better than the other groups, BBB evaluation were higher, there was significant difference compared with the other groups(p<0.05), and recover of A group was better than B group(p<0.05). After SCI the number of the neurons reduced and the Nissl substance lost or dissolved. On the 14th day the number of the Nissl stained neurons rose remarkably and their volume increased. These changes were seen most evidently in Group A(P<0.05).The NF-κB mainly expresses in cytoplasm and cytoblast of neurons and so on.. After SCI the expression of NF-κB increases,reaches the peak level at 24hours,graudlly starts to lower after 3days,and basically lowers to normal at 7days.The expression of NF-κB in microcapsule group were statistically different from those in single slowed pulse group and cellule group (P < 0.05).And the IκBαmainly expresses in cytoplasm of neurons and gliocyte. After SCI the expression of IκBαwere decreased and reached the lowest leve1 at 24 h.The expression of IκBαraised at 3d after injury and returned to normal level at 7 days The expression of IκBαin microcapsule group were statistically different from those in single slowed pulse group and cellule group (P < 0.05).Conclusions:The transplantation of microencapsulated rabbit sciatic nerve could inhibit expression of NF-κB and inhibit the phosphorylation of IκBαafter spinal cord injury in rat,which play a useful role to reduce acute inflammation mediated by NF-κB. And the nuclear factor-κB (NF-κB) is a newly discovered main factor which may be involved in the regulation of secondary injury in acute spinal cord injury. The xenotransplantation of microencapsulated sciatic nerve tissue/cells can reduce secondary injury caused by the primary spinal cord injury, so as to promote functional recovery of spinal cord injury.
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