Chronic minocycline treatment attenuates the spinal nerve ligation-induced increase in OX-42 immunoreactivity (ir) in the lumbar spinal cord. Vehicle (A, B, C, sterile water) or minocycline (D, E, F, 30 mg/kg, ip) was injected daily for 14 days and spinal cords dissected and processed for immunohistochemical detection of OX-42ir at the level of L4 (A-a" and D-d"), L5 (B-b" and E-e") and L6 (C-c" and F-f"). High magnification images of the dorsal area used for OX-42ir signal quantification are also shown. Histograms (G-I) showing effects of minocycline or vehicle in L4-L6 spinal cord OX-42ir (white bars: ipsilateral side; black bars: contralateral side) are shown at the bottom. Data are expressed as mean ± SEM (n = 12 sections from 4 rats per group). Data were analysed using Kruskal Wallis non-parametric test followed by Dunn's multiple comparison posthoc analysis, * P < 0.05, ** P < 0.01, *** P < 0.001 vs ipsilateral-veh, # P < 0.05, ## P < 0.01 vs contralateral-vehicle. Scale bars: F = 1 mm (applies to A-F); f' = 100 μm (applies to a'-f' and a"-f").