Figure 6. Proposed mechanism. Bupivacaine may cause oxidative DNA damage to neurons. The damaged DNA activates the largely unknown repair mechanism. Herein, our study showed that both PARP-1 and XPD closely participate in the oxidative DNA damage of neurons caused by bupivacaine. Interestingly, we also found that there is an interaction between the two key repair enzymes instead of completing DNA repair alone. Further, our data suggest that PARP-1 may repair oxidative DNA damage through XPD-mediated interactions.