PKD1 and Parkinson disease: Compared with the CTRL group, the TH level was downregulated in the SN of PD rats, whereas EGCG increased the TH level; moreover, EGCG did not decrease the TH level in the SN of PD rats when CID755673 was used to inhibit the PKD1 expression and Ad-PARP-1 was used to activate the Parthanatos (Figure 3).