Acrolein Scavenger Hydralazine Prevents Streptozotocin‐Induced Painful Diabetic Neuropathy and Spinal Neuroinflammation in Rats

ABSTRACT Diabetes‐induced neuropathic pain (DNP) substantially influences people's life qualities. Hyperglycemia‐induced excess free radicals have been considered as the most critical mechanisms underlying DNP. As an unsaturated aldehyde and a reactive product of lipid peroxidation, acrolein plays critical roles in diabetic nephropathy and inflammatory pain. We sought to determine whether acrolein is involved in DNP in this study. Diabetes was induced by a single intraperitoneal (i.p.) injection of 60 mg/kg streptozotocin (STZ). An acrolein scavenger hydralazine (5 mg/kg) was administered through a daily injection for 4 weeks, starting immediately within 30 min after STZ injection. Western blot showed that hydralazine could effectively inhibit STZ‐induced upregulation of acrolein in the spinal dorsal horn on day 7–28 after STZ injection. Behavioral tests showed that STZ injection induced significant mechanical allodynia and thermal hyperalgesia, which could be alleviated by hydralazine. Immunofluorescent histochemistry and Western blot showed that STZ induced significant microglial activation. ELISA data indicated upregulation of inflammatory cytokines IL‐1β and TNF‐α expression in the spinal dorsal horn. Furthermore, hydralazine effectively attenuated microglial activation and expression of inflammatory mediators. Our data indicate that acrolein might be involved in the development of neuroinflammation and behavioral consequences of DNP. Anat Rec, 2017. © 2017 Wiley Periodicals, Inc. Anat Rec, 300:1858–1864, 2017. © 2017 Wiley Periodicals, Inc.