Anti-allodynic effects of minocycline in a mouse neuropathic pain model

Abstract

Neuropathic pain presents significant clinical problems. It has recently been reported that minocycline inhibited the activation of microglia, which plays an important role in neuropathic pain. We studied the effects of intraperitoneal (i.p.) administration of minocycline which has inhibitory effect on microglia to develop allodynia. Mechanical allodynia was induced by partial sciatic nerve ligation (PSNL) in mice and evaluated using a von Frey filament. Minocycline was administered daily before and after PSNL (pre-emptive and repeated administration), or only after PSNL. Expressions of microglia and astrocytes in the spinal cord were examined by immunohistological and western blotting analyses. Pre-emptive and repeated administration of minocycline prevented PSNL-induced development of allodynia. In addition, treatment with minocycline after PSNL partially attenuated allodynia. Immunohistological and western blotting analyses showed that microglial proliferation in the ipsilateral side was inhibited by pre-emptive and repeated administration of minocycline. The behavioral and histochemical results suggest that minocycline is a potentially effective therapeutic strategy for management of neuropathic pain.