Reduction of nigral dopaminergic neurons in both ApoER2 and VLDLr mutant mice at P25.

<p>TH staining of mDA neurons of wildtype (a, e) and single ApoER2 (c) and VLDLr (g) mutant mice defined by dotted black line. (b, d, f, h) Higher magnification images for the areas defined by dotted black lines in (a, c, e, g) reveal a slight reduction of TH-positive neurons of SNc in ApoER2^−/− (d) and a pronounced reduction in VLDLr^−/− (h) as compared to corresponding wildtype littermate controls (b, f). Scale bars = 200 µm. Stereological estimates of the total numbers of TH-positive neurons in SNc in ApoER2 animals (I), SNc, VTA and total numbers of mDA neurons (j, k and l respectively) in VLDLr animals, reveal about 15% and 40% reduction in ApoER2^−/− (i) and VLDLr^−/− (j) respectively, as compared to the wildtype animals, and significant increase of VTA neuron number in VLDLr^−/− (k). There was no significant reduction in the total numbers of mDA neurons between VLDLr^+/+ and VLDLr^−/− (l). Three animals were used for each genotype for cell counting. Results were given as means ± SEM. P-values derived from unpaired t test are ***p<0.0007 in i; ***p<0.0003 in j; ***p<0.0001 in k.