Behavioral and pharmacological characteristics of bortezomib-induced peripheral neuropathy in rats

Bortezomib, an effective anticancer drug for multiple myeloma, often causes peripheral neuropathy which is mainly characterized by numbness and painful paresthesia. Nevertheless, there is no effective strategy to escape or treat bortezomib-induced peripheral neuropathy (BIPN), because we have understood few mechanism of this side effect. In this study, we evaluated behavioral and pathological characteristics of BIPN, and investigated pharmacological efficacy of various analgesic drugs and adjuvants on mechanical allodynia induced by bortezomib treatment in rats. The repeated administration of bortezomib induced mechanical and cold allodynia. There was axonal degeneration of sciatic nerve behind these neuropathic symptoms. Furthermore, the exposure to bortezomib shortened neurite length in PC12 cells. Finally, the result of evaluation of anti-allodynic potency, oral administration of tramadol (10 mg/kg), pregabalin (3 mg/kg), duloxetine (30 mg/kg) or mexiletine (100 mg/kg), but not amitriptyline or diclofenac, transiently relieved the mechanical allodynia induced by bortezomib. These results suggest that axonal degeneration of the sciatic nerve is involved in BIPN and that some analgesic drugs and adjuvants are effective in the relief of painful neuropathy.