Objective To gain stable genetic modification of neural stem cells ( NSC ) that constitutively secrete brain-derived neurotropic factor ( BDNF ) and to explore the biological role on the survival and neurite outgrowth of cultured dorsal root ganglion ( DRG ) neurons.目的建立稳定表达脑源性神经营养因子(BDNF)基因的神经干细胞并观察其对于体外培养的脊髓背根神经节(DRG)细胞存活及突起生长的影响。