Prevention of oxaliplatin‐induced mechanical allodynia and neurodegeneration by neurotropin in the rat model

Oxaliplatin is a key drug for colorectal cancer, but it causes acute peripheral neuropathy (triggered by cold) and chronic neuropathy (sensory and motor neuropathy) in patients. Neurotropin, a non‐protein extract from the inflamed rabbit skin inoculated with vaccinia virus, has been used to treat various chronic pains. In the present study, we investigated the effect of neurotropin on the oxaliplatin‐induced neuropathy in rats. Repeated administration of oxaliplatin caused cold hyperalgesia from Day 5 to Day 29 and mechanical allodynia from Day 15 to Day 47. Repeated administration of neurotropin relieved the oxaliplatin‐induced mechanical allodynia but not cold hyperalgesia, and inhibited the oxaliplatin‐induced axonal degeneration in rat sciatic nerve. Neurotropin also inhibited the oxaliplatin‐induced neurite degeneration in cultured pheochromocytoma 12 (PC12) and rat dorsal root ganglion (DRG) cells. On the other hand, neurotropin did not affect the oxaliplatin‐induced cell injury in rat DRG cells. These results suggest that repeated administration of neurotropin relieves the oxaliplatin‐induced mechanical allodynia by inhibiting the axonal degeneration and it is useful for the treatment of oxaliplatin‐induced neuropathy clinically.