Reactive oxygen species contribute to simulated ischemia/reperfusion-induced autophagic cell death in human umbilical vein endothelial cells.

BACKGROUND

Autophagy is important for cells to degrade protein aggregates and organelles. Our preliminary study suggests that ischemia/reperfusion in rabbit hearts promoted autophagic myocardial injury, resulting in no-reflow phenomenon. In this study, we sought to further understand the mechanism and outcome of the upregulation of autophagy in ischemia/reperfusion.

MATERIAL AND METHODS

We employed a simulated ischemia/reperfusion (sI/R) model in human umbilical vein endothelial cells (HUVECs) in vitro, in the presence or absence of antioxidants.

RESULTS

Our study confirms that sI/R induces autophagy in HUVECs as measured by increased expression of Beclin 1 and microtubule-associated protein 1 light chain 3 (LC3), electron microscopic analysis, and special biofluorescent staining with monodansylcadaverine. This sI/R-induced autophagy was also accompanied by increased levels of p65 protein expression and cell death. In addition, we detected the accumulation of reactive oxygen species (ROS) after sI/R. Moreover, with the application of ROS scavengers that block the release of ROS, we were able to demonstrate that inhibition of autophagy increases cell survival.

CONCLUSIONS

The study suggests that ROS accumulation is involved in the sI/R-induced autophagic cell death in HUVECs.