Axonal regeneration promotion by chondroitinase ABC after spinal cord injury in rats

[Objective]To investigate the effect of chondroitinase ABC(ChABC) after spinal cord injury(SCI) in adult rats,and to evaluate the significance of treatment. [Methods]Forty adult Wistar rats were divided into two groups: the control group(group A),the chondroitinase ABC group(group B).The thoracic T10 spinal cord injury model was made by impactor model II manual.After SCI,group B animals received ChABC treatment,while group A animals only received blank saline.The locomotor functions(BBB score) and the neuroelectrophysiological changes(SEPMEP) of the rats were evaluated.Twelve 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 image analyzing software.All the statistics were performed by SPSS 13.0 software.[Results]At 4 weeks after SCI,group B had obvious higher BBB scores than control group(P0.05),indicating better locomotor recovery.In electromyographic examination(SEPMEP),similar results were got.Group B animals gained better recovery than those in group A(P0.05).In histological observation,HE stain showed more and bigger cavities in control group than other groups,and even more glia scars.In BDA tracing slides,the corticospinal tract axons could hardly cross the injury sites in control group,while some axons could cross the injury sites in ChABC group.The anti-NF-200 stain areas were different between the two groups,with statistical significance(P0.05).[Conclusion]Chondroitinase ABC can degrade the chondroitin sulfate proteoglycans which inhibit axon regeneration in glia scar,and can inprove the inhibitory environment of injury site,thus promoting axon regeneration and functional recovery.