The Effect Of NGF Gene Modified Schwann Cells To Nerve Repair After Chronic Injury

Objective To study on the treatment of nerve roots after chronic nerve compression (CNC) injury by transplantation of NGF gene modified SCs.Methods SCs were cultured with one enzyme digestion method, which were transfected with NGF gene by adenovirus.30 adult female SD rats were used in these studies, which were undergone operation to CNC injury on right lumbar nerve roots. Then, they were divided randomly into 4 groups 2 weeks postsurgery:1 Normal saline (NS) group,2 Pure SCs group,3 Ad-NGF group,4 SCs+NGF group. Nerve root tissues were harvested 2 weeks postsurgery of treatment. Western blot were used to detect the proNGF volume in nerve root tissue lysis; Immunohistochemistry (IHC) DAB staining were used to detect nerve regeneration, proNGF gene expression; Double-labeling fluorescent IHC was used to count the number of (3-Tubulin III (a marker for neuron) positive cells and activating transcription factor 3 (ATF3, a marker for injured neuron) positive cells, meanwhile the ratio of injured neurons to survived neurons was calculated.Results Western bolt showed the proNGF volume in nerve root tissue lysis of SCs+NGF group was increased dramatically (P<0.01). IHC DAB staining showed exogenous SCs survived and formed new myelin sheath, proNGF gene expressed in exogenous SCs and endogenous SCs; Double-labeling fluorescent IHC showed SCs+NGF group vs any group, the density of survived neurons in dorsal root ganglion (DRG) was increased significantly (P<0.01), meanwhile the percentage of injured neurons (ATF3 positive cells) in survived neurons (β-Tubulin III positive cells) was decreased dramatically (P<0.01).Conclusion NGF gene Modified SCs could promote the repair of nerve roots with CNC injury, increase and protect the survived DRG neurons. We conclude that this study provides a new method for the treatment on nerve roots with CNC injury.