Regeneration of nervous system is complex and complicated process that involves neuron survival after injury as well as elongation of neurites and their guidance to final targets. Dorsal root ganglion (DRG) sensory neuron axon growth is highly impeded when they encounter neuronal growth cone-collapsing factor semaphorin3A (Sema3A) in both regeneration of adult nervous system and development of nervous system in embryonic stages. On the other hand, precise guidance of axon is mediated by many factors and increasing evidence shows that DRG axon development in both pathological and physiological conditions can be stimulated by nerve growth factor (NGF). The aim of this study was to evaluate the potential of increased NGF concentration to abolish Sema3A induced inhibitory responses in regenerating fifteen days old mouse embryo (e15) DRG axons in vitro. [...].