Electroacupuncture Preconditioning Attenuates Myocardial Ischemia-Reperfusion Injury by Inhibiting Microglial Engulfment of Dendritic Spines in the Fastigial Nucleus

A major side effect of reperfusion therapy following myocardial infarction is myocardial ischemia-reperfusion injury (MIRI). Electroacupuncture preconditioning (EA-pre) has a long history in the treatment of cardiovascular diseases. Here, we demonstrate how EA-pre attenuates MIRI by affecting the phagocytosis of neuronal dendritic spines of microglia of the fastigial nucleus (FNmicroglia). From optical-fiber-based Ca2+ signal recordings in GABAergic neurons of the FN (FNGABA), we observed that EA-pre for 7 days increased activity in FNGABA and then improved myocardial injury by inhibiting abnormal activities of glutaminergic neurons of the FN (FNGlu ) during MIRI. Interestingly, we observed changes in the quantity and shape of FN microglia in mice treated with EA-pre, and a decrease in the phagocytosis of FNGABA neuronal dendritic spines by microglia. Furthermore, the effects of improving MIRI were reversed when EA-pre mice were chemically activated by intra-FN lipopolysaccharide injection, followed by a reduction in FNGABA activity. Overall, our results provide new insight indicating that EA-pre negatively regulates microglial engulfment capacity, thus promoting the improvement of cardiac sympathetic nervous injury and disorders during MIRI.