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(1 H 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.