Pleiotrophin over-expression rescues TH-immunoreactive cell bodies in the substantia nigra pars compacta (SNpc). (A) Values (mean ± SEM) are the percentage of TH-immunoreactive (TH-ir) neurons remaining in the substantia nigra injected with AdPTN or Adβgal compared to the contralateral substantia nigra (100%). Sham/Adβgal: 68 ± 5% (n = 9), Sham/AdPTN: 72 ± 3% (n = 9), 6-OHDA/Adβgal: 50 ± 4% (n = 10), 6-OHDA/AdPTN: 64 ± 3% (n = 11). (B) Photomicrographs show TH immunohistochemistry in a coronal section (-5.3 mm from bregma) from a representative animal of each experimental group, at low (left) and high (right) magnification. Note the higher number of remaining cell bodies in the 6-OHDA rat treated with AdPTN (high magnification image). Consistent with the view that PTN over-expression rescued TH-immunoreactive neurons, post hoc analysis revealed a significant effect of PTN over-expression in 6-OHDA-lesioned animals (*p< 0.05, Student Neuman Keuls). Although it is not indicated in the figure for simplicity, the post hoc comparison between Sham/Adβgal and 6-OHDA/Adβgal is also significant at p < 0.05 level. Scale bars: 500 μm (low magnification images) and 50 μm (high magnification images).