Objective To observe the effect of electroacupuncture(EA)on ischemic electrocardiogram(ECG)

histopathological changes and serum metabolite profile in chronic myocardial ischemia(CMI)rats

so as to reveal its mechanisms underlying protecting ischemic myocardium.Methods A total of 45 male Wistar rats were randomly divided into normal control

CMI model and EA groups

with 15 rats being in each group.The rats in the control group received subcutaneous injection of 0.9%normal saline(5 mg·mg

(-1)

·d(-1)·d

(-1)

for 7 days)

and those in the model and EA groups received subcutaneous injection of isopropylarterenol hydrochloride(5 mg·mg(-1)

for 7 days)

and those in the model and EA groups received subcutaneous injection of isopropylarterenol hydrochloride(5 mg·mg

(-1)

·d(-1)·d

(-1)

for 7 days)to establish CMI model.EA(2 Hz/100 Hz

1 mA)was applied to bilateral"Zusanli"(ST 36)

"Guanyuan"(CV 4)and"Neiguan"(PC 6)for 10 min

once daily for 21 days.The ECG-ST segment of the standard limb lead II was used for evaluating the severity of myocardial ischemia

and the histopathological changes of myocardium were observed under microscope after H.E.staining.The profile of serum metabolites was analyzed by nuclear magnetic resonance mass spectrometry combined with principal component analysis(PCA)and partial least squares discriminant analysis(PLS-DA)in 21 rats(n=7 in each group).Results After modeling

the amplitude of ECG-ST was significantly increased in comparison with the normal control group(P

<

0.01)

suggesting a successful establishment of CMI model.H.E.stain showed an apparent injury of the myocardial tissue as interstitial edema

vasodilatation and hemorrhage

infiltration of inflammatory cells

unclear veins

and increased intercellular space

etc.with irregularly arranged myocardial cells being dissolved

ruptured and necrotic

and with obvious edema

blurred shape

uneven staining

karyopyknosis

and glass-like lesions.After EA intervention

the amplitude of ECG-ST in the EA group was evidently lower than that of the model group(P

<

0.01)

and the severity of the myocardial injury was relatively milder relevant to the model group

suggesting an alleviation of the injured myocardium.In the PLS-DA score plot

the normal control group and the EA group outline were close to each other

and Glucose

Lactate

Creatine

Acetate

3-Hydroybutyrate might be the potential metabolic differential biomarkers(VIP

>

1).The PLS-DA analysis revealed deviations in 51 differential biomarkers in serum

among which

Glucose

Lactate

Creatine

Acetate and 3-Hydroybutyrate may contribute to the effect of EA in improving CMI.Conclusion EA stimulation of acupoints can ameliorate ischemic myocardial injury in CMI rats

which may be related to its effect in regulating serum sugar

lipid metabolism and energy metabolism.