Figure 4.
Striatal glial cell line-derived neurotrophic factor (GDNF) expression after doxycycline induction. (a) Quantification of GDNF tissue levels was performed 6 weeks after injection of 8.0 × 109 or 2.0 × 1010 vg of recombinant adeno-associated virus (rAAV)2/1-V16-hGDNF in the right striatum. Rats were continuously fed with Dox supplemented diet containing 0.025, 0.075, 0.2, or 1 g Dox/kg or with unsupplemented food. Results are expressed as mean of GDNF concentration in striatal protein extracts; n = 6 rats/Dox dose for low dose of vector and n = 8 for high dose of vector (#P < 0.05; ##P < 0.001; ###P < 0.001 versus the enhanced green fluorescent protein group). (b) Spatial distribution of the GDNF transgene product. GDNF immunostaining was performed 9 weeks following injection of 8.0 × 109 vg of rAAV2/1-V16-hGDNF in the right striatum. Rats were continuously fed with Dox-supplemented diet containing 0.025, 0.075, 0.2, or 1 gr of Dox/ kg or with unsupplemeted food. The figure illustrates an example of GDNF immunoreactivity in striatum of a rat treated with 0.2 g Dox /kg of diet. Scale bar: 2 mm. (c) The GDNF labeling was quantified by multiplying the mean of grayscale by the stained area on four slices at the level of injection. n = 4 rats/Dox dose. ***P < 0.001 versus the no Dox group).