The Experimental Study Of The Combined Therapy Of Chondroitinase And Schwann Cell Transplantation After Spinal Cord Injury In Rats

Objective:To investigate the effect of the combination of chondroitinase and Schwann cells (SCs) transplantation after spinal cord injury (SCI) in adult rats, and to evaluate the significance of the combined treatment.Methods:Obtain Schwann cells (SCs) from the predegenerative sciatic nerve of rats, then culture and purify and proliferate the SCs in vitro.80 adult Wistar rats were divided into four groups:the control group (group A), the Schwann cells transplantation group (SCs group, or group B), the chondroitinase ABC group (ChABC group, or group C) and the SCs transplantation plus chondroitinase ABC group (Combination group, or group D). The thoracic T10 spinal cord injury model was made by dorsal impact method, of all theses four groups. After SCI, group B animals received SCs transplantation in injury sites, group C animals received ChABC treatment, and group D animals received both. While group A animals only received blank saline and medium. The locomotor functions of the rats were evaluated according to the BBB score scale.12 weeks after SCI, biotinylated dextran amine (BDA) was injected into the cerebral cortex to trace the corticospinal tracts (CST). Then two weeks after the tracing, the animals were killed and the spinal cord frozen sections were made. The tissue sections were processed with Cy3 fluorescence stain, HE stain and anti NF-200 immuohistological stain. The section images were analyzed by Image-pro Plus 5.0 image analyzing software. All the statistics were performed by SPSS 13.0 software.Results:Predegeneration of the peripharel nerve helped Schwann cells grow well in culture in vitro. From 4 weeks after SCI, group B, C and D animals had obvious higher BBB scores than control group (P<0.05), indicating better locomotor recovery, and group D was the highest. In histological observation, HE stain showed more and bigger cavity in control group slides than other groups, and even more glia scar. In BDA tracing slides, the corticospinal tract axons could hardly the injury sites in control group, while some axons could cross the injury sites in combined therapy group. The anti-NF-200 stain IOD were different in four groups, had statistical significance (P<0.05), and the density of the combined group stain was the highest. Conclusion:Predeneneration is a good choice for SCs culture and proliferation. SCs can secret several kinds of neurotrophic factors and extracellular matrix, they can promote axon regeneration and extension. Chondroitinase ABC can degrade the CSPGs, which inhibit axon regeneration in glia scar, so it can modify the inhibitory environment of injury site, and promote axon regeneration and functional recovery. Combined therapy with SCs transplantation and ChABC has a synergistic effect, and can get better recovery than any single method. Because of the complexity of SCI pathology, combined therapy will probably become the tendency in the treatment of spinal cord injury.