Objective   To observe the peripheral nerve regeneration of injured sciatic nerve after adenovirus-mediated gene transfer of brain-derived neurotrophic factor (BDNF) in adult rats.    Methods   Totally 90 Wistar rats were inflicted to sciatic nerve injury by cutting off a nervous fragment of 10 mm. and then divided into 3 group. A silicone tube containing AxCA-BDNF solution

BDNF solution

or AxCA buffer was grafted as a support to bridge adult rat sciatic nerve gap for the 3 groups correspondingly

Another 5 rat

s with no any injury served as normal control. In 3

7

14 d and 1 month after injury

the rats were sacrificed and their lumbar vertebra (L

3

to L

6

) were resected for frozen section. The number of new nerve fibers and motoneurons in anterior horn of the spinal cord was observed with transmission electron microscopy (TEM)

histomorphometry and image analysis

and the myelin sheath thickness of the new nerve fibers was measured. The sciatic nerve function recovery was evaluated with sciatic function index (SFI) and the electrophysiological parameters

including the nerve conduction velocity (NCV) and compound muscle action potential (CMVP) amplitude.    Results   There were more survival neurons

new nerve fibers and thicker myelin sheath in AxCA-BDNF group and BDNF group than in the control group (P0.01). Retrograde axonal transport of HRP tracer indicated that the injured sciatic nerve reconnected with neurons in spinal cord were better in AxCABDNF group and BDNF group than in the control group(P0.01). So were the SFI

NCV and CMVP amplitude (P0.01) in the 2 BDNF groups.    Conclusion   Adenovirus-mediated gene transfer of BDNF in vivo not only promotes nerve regeneration but also protects the neurons in the spinal cord for sciatic nerve injury in adult rats.