Objective To investigate the effects of electroacupuncture（ EA） on myocardial hypertrophy in spontaneously hypertensive rats（ SHRs）. Methods A total of 12 male 12-week-old Wistar Kyoto rats（ WKY） were selected as normal control group

and 24 SHRs were randomized into model and EA group

with 12 in each group. EA was applied on bilateral"Taichong"（ LR3） and"Baihui"（ DU20） of SHRs in EA group

direct inserting 1

2 mm

without any reinforcing-reducing methods. "Baihui"（ DU20） and right side "Taichong"（ LR3） were respectively connected to the positive and negative poles of the HAN’s electro-acupuncture instrument

and the needle was retained for 20 minutes. EA was performed once a day for 30 days. The normal control group and the model group were placed in the same fixture as the EA group for 20 min each day. Systolic blood pressure was measured one day before the start of acupuncture and on the 6 th

12 th

18 th

24 th

and 30 th day of the acupuncture. Echocardiographic was used to detect the left ventricular hypertrophy and function including left ventricular posterior wall thickness（ LVP-WT）

interventricular septum thickness（ IVST）

left ventricular end-diastolic diameter（ LVEDD）

and left ventricular ejection fraction（ LVEF）

and left ventricular mass index（ LVMI）. The myocardial morphology was observed by HE staining

and phosphatidylinositol kinase（ PI3 K）

protein kinase B（ Akt）

mammalian rapamycin target of rapamycin（ m TOR）

homologous phosphatase tensin（ PTEN）

atrial natriuretic peptide（ ANP） protein and mRNA expression in myocardial tissue of each group were detected by RT-PCR and Western blot. Results Compared with the normal control group

LVMI

LVP-WT and IVST in the model group were significantly increased

LVEDD and LVEF significantly decreased（ P

<

0. 01）. Compared with the model group

LVMI

LVP-WT

and IVST of EA group were significantly decreased

LVEDD and LVEF significantly increased（ P

<

0. 05 or P

<

0. 01）. Compared with the normal control group

the myocardial cells in the model group were relatively disordered

the cross-sectional area of the cells was significantly enlarged

the cell spacing was widened

and the nucleus was enlarged and deeply stained.Compared with the model group

the number of nuclei in the unit visual field of EA group increased

the cross-sectional area of the cardiomyocytes was relatively small

and the cell spacing was relatively narrow. Compared with the normal control group

the expression of PI3 K

Akt

m TOR protein and mRNA in the myocardial tissue of the model group was significantly decreased

and the expression of PTEN protein and mRNA was increased（ P

<

0. 05 or P

<

0. 01）. Compared with the model group

the expression of PI3 K

Akt

m TOR protein and mRNA in the EA group was significantly increased

and the expression of PTEN protein and mRNA was decreased（ P

<

0. 05 or P

<

0. 01）.Conclusion EA at "Baihui"（ DU20） and "Taichong"（ LR3） could effectively improve cardiac hypertrophy of SHR

and activation of PI3 K/Akt pathway by EA may be one of its mechanisms.