Synergistic Effects Of RAAV2-IGF-1Gene Therapy And Rehabilitative Training On Recovery After Spinal Cord Injury

Objective：Acase of spinal cord injury （SCI） is defined as the occurrence of anacute traumatic lesion of neural elements in the spinal canal,resulting in temporary orpermanent sensory and motor deficit.It’s meaningful to repair spinal cord injury andhelp patients return normal life.Thus,we explored the synergistic effects of rAAV2-IGF-1gene therapy and rehabilitative training on recovery in spinal cord injury rats.Evaluated the locomotion ability,number of large motor neurons in ventral gray matter,insulin like growth factor1（IGF-1） expression in different time point of each groupthrough locomotion evaluation, histology H&E-stained and immunohistochemistryresearch.Compared the recovery effect of gene therapy, rehabilitative training and theirsynergistic application.Methods：90male SD rats were used to establish spinal cord injury model and thenrandomly divided into five group depend on treating method they received as shamgroup,control group,rAAV2-IGF-1group,training group and rAAV2-IGF-1/traininggroup.rAAV2-IGF-1group received3ul of rAAV2viruses injection at the24th hourafter injury.Training group received swimming training after7days since injury,andrAAV2-IGF!/training group received both the two treating.Histology H&E-stained,IGF-1immunohistochemistry,large motor neurons count,BBB locomotor scale, inclined-plane test were used to evaluate the recovery condition. Experiment results wereanalysed by the SPSS statistics software package（17.0）.Result：（1）rAAV2mediated green fluorescent protein（GFP） were highlyexpressed both in neuron cell and glial cell,while the control group didn’t express GFP.（2） IGF-1immunohistochemistry： Endogenous IGF-1was up-regulated afterinjury,then declined into normal level after42days. IGF-1stable expressed in other group and the order depend on high to low principle was rAAV2-IGF/traininggroup,rAAV2-IGF-1group,training group.The difference was significant betweengroups（p<0.01）.（3）Numbers of large motor neurons in ventral gray matter：Exceed60%of neuron cells were available in rAAV2-IGF-1/training group and rAAV2-IGF-1group,there was no significant difference between two groups.There were exceed40%available neuron cells in training group while it’s remains20%in control group.Thedifference was very significant（p<0.01）.（4）Hindlimb BBB locomotor scale：Thescore of rAAV2-IGF-1/training group was very significant higher than other3group（p<0.01）.Training group was higher versus rAAV2-IGF-1group while rAAV2-IGF-1group was higher compared with control group.（5）inclined-plane test：The order wasrAAV2-IGF-1/training group,training group,rAAV2-IGF-1group,control group dependon high to low principle.The difference was significant.Conclusions：（1）The adeno-associated viral was an ideal vector for gene therapyin spinal cord injury. Because it has high affinity with spinal cell tissue and mediatedstable and long-term expression of exogenous gene（.2）Synergistic application of IGF-1gene therapy and rehabilitative training protect large motor neuron cell from apotosisand accelerate motor function recovery.The result was better than single cureing of genetherapy or rehabilitative training.