Direct MRI-guided stereotaxic viral mediated gene transfer of alpha-synuclein in the Göttingen minipig CNS.

The aim was to establish a non-primate large animal PD model by lentiviral vector mediated mutant alpha-synuclein overexpression in the substantia nigra. Lentivirus encoding A53T alpha-synuclein (6 x 2.5 μl) was stereotaxically injected into the substantia nigra of six adult female Göttingen minipigs. Contralateral control injections encoding enhanced green fluorescent protein (EGFP) were performed. Gait-analysis was performed pre- and postoperatively. PCR of the transgenes and immunohistochemical staining against alpha-synuclein, EGFP, GFAP and TH was performed after 20 weeks. Gait analysis revealed a significant increase in step length and height, and a decrease in the double stand phase. PCR verified the mesencephalic presence of transgenes. IHC analysis showed alpha-synuclein expression in nigral neurons, around the injection tract and in related nigrostriatal projections. The alpha-synuclein positive neurons appeared swollen and vacuolated, in contrast to the EGFP-injected control side. To transduct all nigrostriatal cells with few microinjections, wider dissemination of the transgene must be achieved.