Representative photomicrographs of COX-2 immunostaining (A to I, SN) in the rat brain after LPS injection. Weak COX-2 positive staining was detectable in the brain sections of control brain (A). LPS injection increased the expression of inducible cyclooxygenase, as indicated by COX-2+ staining, in SN (B, D and G, red) and striatum (J) of P6 rat brain. Celecoxib treatment attenuated the LPS-increased COX-2+ staining in the above areas (C and J). F is a merged image of D and E. Double-labeling (yellow) showed that many COX-2 positive cells (F) were GFAP + cells (astrocytes) (E, green). I is a merged image of G and H. Double-labeling (yellow) also showed that some COX-2 positive cells (I) were TH + cells (dopaminergic neuron) (H, green). The scale bar in A represents 50 μm for A to I. Quantitation of the percentage area of image that contained COX-2+ staining in the SN and striatum was performed as described in Methods. The results are expressed as the mean ± SEM of six animals in each group, and analyzed by one-way ANOVA. *P <0.05 represents a significant difference for the LPS + Vehicle group as compared with the Saline + Vehicle group. #
P <0.05 represents a significant difference for the LPS + Celecoxib group as compared with the LPS + Vehicle group.