OBJECTIVE: Painful neuroma can develop after axonal injury and is often resistant to surgical interventions. In this experiment we investigated whether axonal transport of a neuron-specific toxin (OX7-saporin) led to selective loss of neurons in DRG and ventral horn of Spinal Cord. MAREIALS AND METHODS: Forty Sprague-Dawley rats were randomly assigned to 5 groups: Group A1 (A1), fluoro-gold (FG) was used to label left posterior tibial nerve while fluoro-ruby (FR) was used to label left common peroneal nerve. Group A2 (A2), a reverse labeling method of A1 was used. Group B (GB), the same as A1 plus OX7-saporin injection. Group C (GC), the same as A2 plus OX7-saporin injection. Group D (GD), the same as A2 plus Dulbecco's PBS injection instead of OX7-saporin. At three or six weeks post injection, the rats were sacrificed by transcardially perfusion. The DRG and spinal cord were harvested and 60µm serial sections using sliding freezing microtome were performed and mounted. Fluorescent labeling of neurons in DRG and spinal cord was observed with a fluorescence microscope using appropriate filters. RESULTS: The results showed that there was a significant reduction of FG (GB) or FR (GC) labeled neurons both in DRG and spinal cord of OX7-saporin treated rats. Surprisingly, the fluorescence labeled neurons were almost completely destroyed by OX7-saporin in spinal cord. While non-targeted neurons in DRG and spinal cord were kept intact. CONCLUSION: Those results indicated that OX7-saporin could effectively be transported to the dorsal root ganglia and spinal cord by injection into a selected peripheral nerve, in where it could selectively ablate the targeted parent neurons. The suicide transport of neuron-specific toxins offers a potential molecular neurosurgical approach for the treatment of painful neuroma.