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

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

[Effect of Electroacupuncture at "Neiguan"(PC 6) on Serum and Myocardial Metabolites in Rats with Myocardial Ischemia Reperfusion Injury Based on Nuclear Magnetic Resonance Spectroscopy].

OBJECTIVE: We have repeatedly demonstrated that electroacupuncture (EA) of "Neiguan"(PC 6) can improve myocardial ischemia in rats. The present study was designed to investigate the metabolomic profile of peripheral blood se-rum and myocardium involving EA-induced improvement of myocardial ischemia-reperfusion injury (MIRI) in rats by using nuclear magnetic resonance spectroscopy. METHODS: Thirty male SD rats were equally randomized into blank control, model and EA groups. Rats of the control group were only banded for 20 min, once a day for 7 days. The MIRI model was established by occlusion of the anterior descending branch of the left coronary artery for 40 min, followed by reperfusion for 60 min, and rats of the model group were banded as those in the control group. EA (10 Hz/50 Hz, 1 mA) was applied to bilateral PC 6 for 20 min, once daily for 7 days. The blood samples and left ventricular myocardial tissues were collected for assaying the profiles of differential metabolites using 1H nuclear magnetic resonance (1H NMR) spectroscopy and multivariate statistical analysis such as the principal components analysis (PCA), partial least squares-discriminant analysis (PLS-DA) and orthogonal PLS-DA (O-PLS-DA) with SIMCA-P software 12.0. RESULTS: A total of 19 differential metabolites (17 down-regulated, 2 up-regulated) in the serum and 14 differential metabolites (13 down-regulated and 1 up-regulated) in the ischemic left myocardium were identified after MIRI. Of the 19 serum differential metabolites, amino acids (leucine, isoleucine, valine,alanine, lysine, glycine, glutamine), 3-hydroxy butyric acid (3-HB), lactic acid, acetate, N-acetyl glycoprotein (NAc), acetone, acetoacetate, succinate, polyunsaturated fatty acids (PUFA), creatine, glycerophosphocholine (GPC) were down-regulated; while low density lipoprotein (LDL), LDL/very low density lipoprotein(LDL/VLDL)and glucose obviously up-regulated. Of the 14 myocardial differential metabolites, amino acids (alanine, lysine, glutamate, glutamine, aspartate, taurine, glycine, threonine), GPC, creatine, lactic acid, adenosine monophosphate (AMP), nicotinamide adenine dinucleotide (NAD＋) were significantly decreased, and glucose was up-regulated. Following EA treatment, most of the decreased serum differential metabolites except acetone, acetoacetate and PUFA, and the increased serum LDL, LDL/VLDL and glucose recovered, basically close to the control level; and the decreased myocardial creatine, GPC and NAD＋ were also apparently up-regulated and the increased myocardial glucose was down-regulated. But, myocardial threonine and AMP still presented a decreasing state. Although the pattern of myocardial differential metabolites of the EA group had a trend to be close to the control group, the significant difference still existed, while the metabolic pattern of serum metabolites in the EA group was close to that of the control group. CONCLUSION: EA stimulation of PC 6 can regulate serum or/and myocardial metabolites as amino acids, carbohydrates, lipids, etc. in MIRI rats, of which both serum and myocardial creatine, GPC and glucose may be jointly confer a favorable potential for EA-induced improvement of MIRI.