Effects of drugs administration on spinal nerve ligation (SNL) -induced astrocytic activation. A representative spinal section showed that SNL induced a marked astrocytic activation in ipsilateral than that of contralateral spinal dorsal horn (A). B and C show the magnified images of the ipsilateral and contralateral spinal dorsal horn of SNL rats respectively. Compared with Sham-Saline rats (D), SNL induced a marked astrocytic activation (F, J). Intrathecal ketamine (100 μg/kg) didn't affect influence astrocytic activation obviously at both 1 d and 3 d after application (G, K). However, intrathecal LAA (50 nmol) attenuated SNL-induced astrocytic activation at 1 d after administration compared with that of SNL-Saline group (H). Astrocytic activation was further suppressed by coadministration (100 μg/kg of ketamine and 50 nmol of LAA) than that of LAA (50 nmol) injected alone (I). Astrocytic activation was returned obvious 3 d after LAA injection (L). However, drugs coadministration significantly inhibited astrocytic activation compared to that of LAA alone (M). E, Scheme presenting an overview over the detected region. N, Statistics of above results. Scalebar = 800 μm in A, 20 μm in B-C and 200 μm in D, F-M. * or # indicates statistically significant difference with P < 0.05 between groups. KTM: ketamine, LAA: L-α-aminoadipate.