TH and Parkinson disease: Histological analysis showed that CsA treatment did not affect the survival of nigral dopamine neurons (P = 0.82) (Fig. 4b-c), but as we found in the AAV rat model of PD (Fig. 3e), analysis of striatal tissue showed a reduction in human α-synuclein levels (P < 0.01) and an increased expression of TH (P < 0.05) (Fig. 4e).