Objective To observe the effect of electroacupuncture(EA) preconditioning on cell apoptosis and the content of mitochondrial reactive oxygen species(ROS) in rats with myocardial ischemia/reperfusion injury(MIRI)

so as to explore their mechanisms underlying improvement of MIRI. Methods Eighty male Wistar rats were randomly divided into control

sham

ischemia reperfusion(IR) and EA groups

with 20 rats in each group. Rats of the control

sham and IR groups were just banded on the boards for 30 min

once daily for 7 days. Before modeling

EA(2 Hz

1 mA) was applied to "Neiguan"(PC6)

"Zusanli"(ST36)

"Guanyuan"(CV4) for 20 min

once daily for 7 successive days in the EA group. The MIRI model was established by occlusion of the left anterior descending branch of the left coronary artery for 20 min

followed by reperfusion for 30 min. Ventricular arrhythmia(VA) score was used to evaluate arrhythmia. Enzyme-linked immunosorbent assay(ELISA) was used to detect the level of CK-MB. DHE staining was used to detect the content of reactive oxygen species(ROS). The gene expression levels of cytochrome C(Cyt-C)

Caspase-9 and Caspase-3 were detected by real-time fluorescent quantitative PCR. Results Compared with the sham group

VA score

serum CK-MB content

ROS content in heart tissue and Cyt-C

Caspase-9 and Caspase-3 gene expression were significantly up-regulated in the MIRI group(all P<0.01). Following the intervention

the increased VA score

serum CK-MB content

ROS content in heart tissue

Cyt-C

Caspase-9 and Caspase-3 gene expression were all reversed in the EA group compared with the MIRI group(all P<0.01). Conclusion The protective effect of EA preconditioning on MIRI may be based on the regulation of ROS mediated-apoptosis pathway.