Among the pro-inflammatory molecules measured in the current study, COX-2 showed distinct responses to the PPARα agonists. Wy-14643 and fenofibrate attenuated the LPS-induced elevation of COX-2 at 6 hours after LPS but both drugs rather augmented the elevation at 3 days. Collino et al. (2006) reported irresponsiveness of COX-2 to Wy-14643 (6 mg/kg intra-venous injection at 30 minutes before ischemia) in the rat hippocampus after forebrain ischemia/reperfusion. Since the cellular type that was responsible for COX-2 elevation might be different at 6 hours and 3 days, more detailed cell-type specific analyses are required for understanding the unique response of COX-2 to the PPARα agonists.
