Electroacupuncture pretreatment regulates mitophagy in ULK1 knockout mice subjected to cerebral ischemia-reperfusion injury

BACKGROUND: Electroacupuncture (EA) pretreatment can alleviate cerebral ischemia/reperfusion (I/R) injury and mitochondrial impairment. However, the potential protective mechanism associated with mitophagy has not been well elucidated. The aim of this study was to investigate the effect of EA on FUN14 domain-containing protein 1 (FUNDC1) and mitophagy in unc-51 like kinase 1 (ULK1) knockout mice after cerebral I/R injury. METHODS: EA pretreatment was conducted at GV20 and GV26 before ischemia for 30 min over 5 consecutive days in ULK1 knockout mice that underwent modeling of cerebral I/R injury. Neurological function of the mice was assessed using Longa neurological deficit scoring. The area of cerebral infarction was measured by 2,3,5-triphenyltetrazolium (TTC) staining. Mitochondrial structural alterations were observed under transmission electron microscopy, while the mitochondria were stained using MitoTracker Green and the lysosomes were stained with Lyso Tracker Red. Changes in mitochondrial membrane potential were detected by JC-1 staining, and alterations in autophagy-related protein or gene expression were examined using Western blot analysis, qRT-PCR and immunohistochemistry. RESULTS: EA-pretreated mice exhibited significantly decreased neurological deficit scores, cerebral infarct volumes and edema compared with the untreated I/R group of mice. EA pretreatment also reversed I/R-induced mitochondrial structural abnormalities and loss of mitochondrial membrane potential. Furthermore, EA pretreatment upregulated p-mTORC1 compared with no treatment. Protein and mRNA expression of ULK1, FUNDC1 and mTORC1 did not significantly differ between the groups. CONCLUSION: EA pretreatment at GV20 and GV26 alleviated cerebral I/R injury and mitochondrial impairment in ULK1 knockout mice. Knockout of ULK1 did not completely eliminate the regulatory effect of EA.