Quantification of nigral tyrosine hydroxylase-positive neurons following MPTP and intravenous immunoglobulin treatment. Stereological counts of (A) tyrosine hydroxylase (TH)-positive dopaminergic (DAergic) neurons and (B) total DAergic neurons of the substantia nigra pars compacta (SNpc) confirming that exposure to MPTP led to a significant nigral neurodegeneration. (C) Ratio of TH-positive versus total SNpc neurons in the SNpc (n = 12 to 15 animals per group). (D) to (G) Low power photomicrograph representative of the state of the nigral DAergic system following MPTP and intravenous immunoglobulin (IVIg) treatments. Scale bar: 150 μm. (D) Vehicle-control, (E) vehicle-IVIg, (F) MPTP-control, (G) MPTP-IVIg. Statistical analysis: one-way analysis of variance (ANOVA) followed by Tukey’s multiple comparison test, *P <0.05 control-MPTP versus control-vehicle, #
P <0.05 IVIg-MPTP versus IVIg-vehicle. IVIg treatment (E), (G) resulted in a diminution in the number of TH-positive neurons compared with vehicle-treated animals (D), (F), according to two-way ANOVA analyses (∞
P <0.05; ∞∞
P <0.01 IVIg vs. control). Percentage of control values is indicated for significant variation (vehicle-control or vehicle-IVIg, respectively).