Effect of vehicle or SA repeated treatment (2 mg/kg, i.p.) on spinal microglial cells in mice receiving saline or formalin into the hind-paws. Iba-1 immunoreactivity (Iba-1-ir) is shown in the ipsilateral dorsal horn 3 (B and D) and 7 (C and E) days after saline or formalin (A). “F” and ‘G” represent examples of resting and activated microglia cell morphology, respectively. Quantitative analysis of percentage of activated microglial cells on the total cell number in L4-L6 spinal cord sections is shown in “H”. Data are expressed as mean ± S.E.M of 3 mice per group. * and · indicate statistically significant differences vs veh/saline. † indicates statistically significant differences vs veh/form 3 day after formalin and ° indicates statistically significant differences vs veh/form 7 days after formalin (P <0.05, one-way ANOVA, Tukey post hoc).