Changes in the Serum Metabolome of Acute Myocardial Ischemia Rat Pretreatment with Electroacupuncture

Myocardial infarction (MI), the most common symptom is chest pain, occurs when blood flow decreases or stops to a part of the heart, causing damage to the heart muscle. Electroacupuncture pretreatment (EP) is a recent observation which has been shown to induce ischemic tolerance like the ischemia preconditioning, suggesting that EP may be a promising preventive strategy for individual susceptibility to MI. This study investigated mechanisms that underlie the effect of EP on MI through the use of gas chromatography-mass spectrometry (GC-MS)-based metabolic profiling. Male Sprague-Dawley rats were randomly divided to receive or not receive three days of EP at PC6 (Neiguan). Then on the fourth day, each group was further divided to undergo mock surgery or MI, induced by ligation of the left anterior descending coronary artery. After 24  h, the blood samples and hearts were collected for the follow-up research. The results showed that treatment by EP significantly reduced the levels of CK-MB, cTnT, AST, and MDH in serum and decreased myocardial infarction area. According to GC-MS-based serum metabolic profiling and analysis, a total of 636 characteristic peaks were identified, including 158 known and 478 unknown metabolites. MI caused comprehensive metabolic changes in glycolysis-related metabolites, malate-aspartate shuttle (MAS) metabolites, and purine metabolites with anti-oxidant functions, while EP reversed more than half of the differential metabolic changes, mainly affecting amino acid and energy metabolism, especially the glutamate metabolism and MAS. In a word, our findings suggest that EP exerts its cardioprotective effect on MI by regulating amino acid and energy metabolisms. Meanwhile, GC-MS-based metabolomics provided a powerful way to characterize the metabolic features of MI, with and without EP, and thereby improved our understanding of the effect and mechanisms of EP.