SNL induces persistent neuropathic pain and glial activation in the spinal cord. SNL-induced rapid and persistent mechanical allodynia (a) and heat hyperalgesia (b). Data are expressed as mean ± SEM (n = 5 for each group). ***P < 0.001, two-way repeated measures ANOVA. c, d Representative images of GFAP and IBA-1 immunofluorescence in the L5 spinal cord from sham and SNL mice. GFAP and IBA-1 immunoreactive were very low in sham-treated mice, but significantly increased in the ipsilateral superficial dorsal horn at 10 days after SNL.