Serum metabolic profile involving protective effect of "Neiguan"(PC6)-electroacupuncture preconditioning in rats with myocardial ischemia reperfusion injury

Abstract

To observe the effect of "Neiguan" (PC6)-electroacupuncture (EA) preconditioning on serum metabolites in myocardial ischemia-reperfusion injury (MIRI) rats, so as to reveal its mechanism underlying improvement of ischemic myocardium from metabonomics. A total of 48 male SD rats were randomly divided into control, model, EA "Neiguan"(PC6) and EA "Hegu"(LI4) groups (n＝12 rats/ group). Rats of the control group were just banded on animal boards for 30 min, once daily for 7 days. The MIRI model was established by occlusion of the left anterior descending branch of the left coronary artery for 40 min, followed by reperfusion for 1 h, and rats of the model group were also banded as those in the control group. Before modeling, EA (10 Hz/50 Hz, 1 mA) was applied to bilateral "Neiguan"(PC6) and "Hegu"(LI4) for 30 min, once daily for 7 successive days. After the treatment, serum samples were collected to be analyzed by proton nuclear magnetic resonance (1H NMR) spectroscopy. The orthogonal partial least squares discriminate analysis (PLS-DA) was employed to distinguish the serum differential metabolic profile of rats in different groups and identify potential biomarkers. After modeling, the ECG of model group and electroacupuncture groups showed T wave towering, and there was no obvious ST segment between R wave and T wave. The T wave decreased more than 0.2 mV after reperfusion, and there was no obvious ST segment. Compared with the control group, MIRI induced significant changes of metabolites in the serum including increase of acetoacetate acid, lectic acid, creatine, glycerol and glucose, and decrease of alanine, glutamine, glycerophosphoryl choline and phosphorylcholine. In comparison with the model group, PC6-EA preconditioning induced significant changes, including an increase of glucose, and a decrease of leucine，isoleucine, valine，3-hydroxybutyric acid，lactate，acetate，acetone，acetoacetate acid，pyruvic acid，glutamine，creatine and glycerol. There is no significant difference in metabolic patterns between "Hegu" group and model group. Metabolic pathway enrichment analysis indicated that the protective effect of PC6-EA pretreatment was realized mainly by regulating pathways of glycolysis, gluconeogenesis, citric acid metabolism, pyruvate metabolism, ketone body metabolism, etc. PC6-EA pretreatment has a role in regulating gluconeogenesis, pyruvate metabolism, amino metabolism, ketone body metabolism and energy metabolism in rats with MIRI, which maybe contribute to its protective effect on ischemic myocardium, but the specific metabolic pathways and mechanisms need being studied further.