Protective effect and regulating effect on FXR/SHP gene of electroacupuncture preconditioning on myocardial ischemia-reperfusion injury in rats

Abstract

To explore the protective mechanism of electroacupuncture preconditioning on myocardial ischemia-reperfusion injury in rats. A total of 88 SPF-grade Wistar male rats were randomized into a normal group, a sham-operation group, a model group and an electroacupuncture (EA) group, 22 rats in each one. The rats in the normal group received normal diet and no intervention was given for 7 d. The rats in the sham-operation and the model group were bound for 20 min, once a day for 7 d. In the EA group, EA, continuous wave, 2 Hz and 1 mA, was applied at "Neiguan" (PC 6), "Zusanli" (ST 36) and "Guanyuan" (CV 4) for 20 min, once a day for 7 d. In the 8th day, the blood was collected by abdominal aortic method 60 min after intraperitoneal injection of 10% urethane anesthesia by 10 mL/kg in the normal group, and then the tissue of heart was collected. In the model group and the EA group, ligating the left anterior descending coronary artery (LAD) was adopted for 20 min and reperfusion was applied for 40 min, then the samples were collected. The rats in the sham-operation group recevied open-chest operation and no other intervention, the samples were collected in 60 min. Nitro Blue Tetrazolium Chloride monohydrate (NBT) stain was used to detected myocardial infarct size and weight, ELISA was used to measured myocardial injury markers and inflammatory factors (LDH、CK、cTnI), and the fluorescent quantitative PCR method was used to determine the expressions of FXR and SHP gene. ①There was no significant difference between the normal group and the sham-operation group in myocardial infarct size and weight (P>0.05) .Compared with the normal group, myocardial infarct size and weight were higher in the model group (P<0.01). Compared with the model group, myocardial infarct size and weight were lower in the EA group (P<0.01). ②There was no significant difference between the normal group and the sham-operation group in serum contents of LDH、CK、cTnI (P>0.05). Compared with the normal group, the serum contents of LDH、CK、cTnI were higher in the model group (P<0.05). Compared with the model group, the serum contents of LDH、CK、cTnI were lower in the EA group (P<0.05). ③The expressions of FXR and SHP gene in the model group were higher than those in the normal group (P<0.05). The expressions of FXR and SHP gene in the EA group were lower than those in the model group (P<0.05). Electroacupuncture preconditioning could significantly improve cardiac function of rats with myocardial ischemia-reperfusion, reduce infarct size and inflammatory factors, and down-regulate the expressions of FXR and SHP gene. The protective effect may generate based on regulation of FXR/SHP apoptosis signal pathway.