Abstract:

BACKGROUND: How to accelerate injury repair and regeneration following peripheral nerve injury is the research focus. Gene therapy may be the possible treatment for this problem. 
OBJECTIVE: To observe the expression of the brain-derived neurotrophic factor (BDNF) gene after microinjected adenovirus-mediated gene transfer of BDNF (AxCA-BDNF) to the sciatic nerve for peripheral nerve regeneration.
METHODS: Based on silicone tube graft as a support to bridge adult rat sciatic nerve gaps, Wistar rat were microinjected recombinant adenovirus vector of BDNF (AxCA-BDNF), BDNF and simple injection of virus buffer to the sciatic nerve respectively. With the methods of in situ hybridization and immunocytochemistry, the BDNF gene expression was certified, the number of the new nerve fibers and motoneurons in anterior horn of the spinal cord were calculated, and the myelin sheath thickness of the new nerve fibers was measured at 3, 7, 14 days and 1, 2, 4 months after operation.
RESULTS AND CONCLUSION: Compared with the BDNF and control group, the expression of the BDNF gene in the proximal end, distal end and spinal cord (L3-6) of injured sciatic nerve were obviously higher than that of the BDNF and control groups    (P < 0.01). The result of retrograde axonal transport of HRP tracer indicated the survival neurons, regenerated nerve fibers, thickness of myelin sheath, as well as the re-formation of nerve connection of the AxCA-BDNF group were superior to the control group(P < 0.01). The results demonstrated that exogenous BDNF gene and its express proteins were uptaken to the spinal cord motoneurons through retrograde axonal transport. Gene therapy for sciatic nerve injury of adult rats by adenovirus-mediated gene transfer of brain-derived neurotrophic factor in vivo not only promotes nerve regeneration but also protects the neurons in the spinal cord.