Figure 3
Increase in pKr-2 expression disrupts the nigrostriatal DA system in adult rat brains.
(a) One week post-injection of pKr-2 into the SN, degeneration of nigrostriatal DA projections in the rat brain was apparent in coronal sections from the SN and STR immunostained with anti-TH. Many more small-sized, non-neuronal cells stained with cresyl violet (marked with blue arrowheads in the high-magnification image of the SN), were observed in the SN of animals treated with pKr-2 compared with intact controls. Scale bars, 500 μm and 20 μm for the SN and 1000 μm for the STR. (b) A histogram showing results for the quantification of DA neurons in the SN. *p = 0.002 vs. contralateral control side (n = 5, each group). (c) The OD of TH-ip fibers in the STR. **p = 0.026 vs. contralateral control side (n = 5, each group). (d) The amount of dopamine in rat striatal tissues was measured by ELISA and the levels were quantitatively expressed as a percentage of the value for the contralateral control for each sample. #p < 0.001 vs. contralateral/PBS controls (n = 4, each group). (e) HPLC analysis of dopamine and its metabolites, DOPAC and HVA in the STR of rat brains shows that pKr-2 treatment significantly reduced striatal dopamine levels compared with PBS controls (p = 0.018; n = 4, each group). By contrast, the levels of striatal HVA were significantly increased by pKr-2 treatment compared with PBS controls (p = 0.029) and the levels of striatal DOPAC also showed a similar pattern in pKr-2-treated rats, even though this was not significantly different compared with PBS controls (p = 0.087).
