To observe the effects of electroacupuncture（EA）preconditioning on cardiac function，myocardial injury related indexes and autophagy level in rats with myocardial ischemia-reperfusion injury（MIRI），and to explore the possible mechanism of electroacupuncture preconditioning in improving MIRI.

Sixty male SD rats were randomly divided into five groups：sham operation group，model group，EA group，EA+saline group and EA+agonist group，with 12 rats in each group. The I/R model was established by ligation of left anterior descending coronary artery for 30 min and reperfusion for 4 h in rats. The EA group，EA+saline group and EA+agonist group were treated with EA intervention at Neiguan（PC6）for 20 min，once a day for successive4 days. In EA+agonist group，nigericin（1 mg/kg），an agonist of NLRP3 receptor，was injected intraperitoneally 30 min before each EA. In EA+saline group，saline was injected into abdominal cavity 30 min before each EA，and the dose was the same as that in agonist group. The echocardiography was used to observe left ventricular ejection fraction（LVEF）and left ventricular fractional shortening（LVFS）of rats 4 hours after modeling to evaluate cardiac function. Serum levels of IL-6 were de-tected by ELISA. HE staining was used to observe the myocardial tissue morphology of rats. The mRNA and protein expressions of NLRP3，Beclin 1，TRIF，Caspase-1，LC3 and IL-18 were detected by RT-qPCR and Western blot.

Compared with those of the sham operation group，the values of LVEF and LVFSin the model group were significantly decreased（P<0.05），and the myocardial fibers were disordered，with vague structure and large inflammatory infiltration. The level of IL-6 and the contents of NLRP3，TRIF，Beclin 1，LC3 mRNA and protein in the myocardial tissue were all increased（P<0.05）. Compared with those of the model group，the myocardial fiber breakage was reduced and a small amount of inflammatory cells infiltrated. In the EA group，the values of LVEF and LVFSwere significantly increased（P<0.05），the level of IL-6 and the expressions of NLRP3 mRNA and protein in myocardial tissue were all decreased（P<0.05），while the contents of TRIF，Beclin 1 and LC3 mRNA and protein were all increased（P<0.05）. Compared with those of the EA group，the levels of IL-6 and the contents of NLRP3，TRIF，Beclin 1，LC3 mRNA and protein and the values of LVEF and LVFSin the EA+saline group had no obvious changes（P>0.05）. In the EA+agonist group，the myocardial structure of rats was abnormal，with obvious tissue fibrosis and inflammatory infiltration，and the values of LVEF and LVFSin rats were obviously decreased（P<0.05）. The level of IL-6 and the expressions of NLRP3 mRNA and protein in myocardial tissue decreased（P<0.05），while the contents of TRIF，Beclin 1 and LC3 mRNA and protein increased（P<0.05）.

EA preconditioning can alleviate myocardial injury in I/R rats by regulating autophagy level，and its mechanism may be related to activating NLRP3/TRIF/Beclin 1 signal pathway.