Preconditioning With Electrical Stimulation Promotes Flap Survival by Improving Blood Supply Via ROS/Nrf2/HO1 Pathway

We have previously demonstrated that preconditioning flap donor with electrical stimulation (ES) could increase the survival area of pedicled perforator flaps in a rat model. However, the detailed molecular mechanisms remain unclear. In this study, we first verified the effects of ES through in vivo and in vitro experiments. Then we explored the underlying mechanisms in vitro. The results indicated that preconditioning with ES could not only increase the flap survival area but mitigate human umbilical vein endothelial cells (HUVECs) dysfunction. Furthermore, low level reactive oxygen spices (ROS) were produced in HUVECs after ES, serving assignaling molecule to activate the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HOl) pathway. Then ROS scavenger was used to attenuate thegeneration of ROS, resulting that activation of the Nrf2/HOl pathway was inhibited. These results suggest that ROS/Nrf2/HO1 pathway may play pivotal roles in the ES pretreatment induced flap survival. Overall design: To validate this hypothesis, we utilized the modified McFarlane random flap model in rats and the human umbilical veinendothelial cells (HUVECs)oxygen-glucose deprivation (OGD) model, the study primarily measured the survival area of flaps on postoperative day 7 and assessed cell proliferation activity, both in vivo and in vitro, to confirm the protective effect of electrical stimulation preconditioning against ischemia. Subsequently,Subsequently, the ROS scavenger N-acetyl-L-cysteine (NAC) was introduced to explore potential mechanistic pathways.