Effect of PPAR-γ and PPAR-δ antagonist on the palmitoylethanolamide-induced decrease of myeloperoxidase activity. Myeloperoxidase (MPO) activity was significantly increased in spinal cord injury (SCI) wildtype (WT) mice in comparison with respective control. Treatment with palmitoylethanolamide (PEA, 1 and 6 hours after injury) significantly reduced the neutrophil influx. The genetic absence of the peroxisome proliferator-activated receptor (PPAR)-α receptor significantly increased the activity of this peroxidase and blocked the effect of PEA. Pretreatment with GSK0660 (1 mg/kg) or GW9662 (1 mg/kg) neutralized the effect of PEA. Data are mean ± standard error of the mean of 10 mice for each group. *P <0.05 vs. WT sham; **P <0.01 vs. WT sham; #P <0.05 vs. SCI WT group.