Figure 2

Ablation of COX-2 protects TH+ Neurons in SNpc from MPTP. A: In COX-2-/- (KO) mice, dopaminergic neurons are protected from MPTP neurotoxicity. Representative TH immunocytochemistry shows a marked loss of TH-positive neurons in SNpc of COX-2 +/+ (WT) mice compared to both COX-2 -/- (KO) and COX-2 +/- (HT) mice after MPTP treatment. B: MPTP treatment leads to a significant loss in number of TH+ neurons. TH-positive cells in the SNpc were bilaterally counted under 40 × objective. Nissl stain shows similar trends (C&D). E: COX-2 deficiency reduced the MPTP-induced loss of striatal TH immunoreactivity. F: MPTP-treated WT mice had significantly reduced TH immunoreactivity compared to the saline WT (*p < 0.05). Among the MPTP-treated mice, the COX-2-deficient mice had at least 30% higher TH immunoreactivity than the WT mice. Data are means ± SEM for six to eight mice per group, *p < 0.05, **p < 0.01 and ***p < 0.001 compared to saline+vehicle group; #p < 0.05 and ##p < 0.01 compared to MPTP+vehicle group, by ANOVA with subsequent Bonferroni for multiple comparisons. Scale bar, 100 μm.