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 serum 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 1 H nuclear magnetic resonance(1 H 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.