Fig 1: (A) Representative images of GFAP immunofluorescence, a marker of reactive gliosis, in the ipsilateral and contralateral dorsal horn of the spinal cord. Images are from rats that received intra-articular injection of saline or MIA, and treatment with vehicle or the CB2 receptor agonist JWH133 (1 mg/kg, days 1–28) (scale bar = 5 µm). (B) Quantification of ipsilateral GFAP immunofluorescence expressed as a % of the immunofluorescence for the contralateral spinal cord for the three treatment groups (n = 6–7 sections per rat, n = 4 rats per treatment). Systemic administration of JWH-133 significantly attenuated increases in GFAP immunofluorescence, compared to the effects of vehicle, statistical analysis was conducted via a one-Way ANOVA with a Bonferroni post-hoc test,*p<0.05. (C) Example gel zymography of MMP-9 and MMP-2 activity in the spinal cord from the various treatment conditions, as well as positive controls for purified MMP 2 and MMP 9. (D) Quantification of MMP-9 and pro and active MMP-2 activity in the ipsilateral spinal cord in MIA-treated rats and saline-treated rats. Systemic administration of JWH-133 significantly attenuated increases in MMP-9, MMP-2 and active MMP-2 activity in the spinal cord in MIA-treated rats, compared to the effects of vehicle. Data are expressed as mean densitometry ± SEM (n = 4 rats per group), statistical analysis one-way ANOVA and Bonferroni post-hoc test,**p<0.01, ***p<0.001 vs. saline/Vehicle; #p<0.05, ###p<0.001 vs. MIA/Vehicle.